Re: [PATCH v2] arm: eBPF JIT compiler

From: Shubham Bansal
Date: Tue Jun 06 2017 - 15:48:17 EST

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Hi Russell, Alexei, David, Daniel, kees,

Any update on this patch moving forward?
Best,
Shubham Bansal

On Wed, May 31, 2017 at 12:49 AM, Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> Forwarding this to net-dev and eBPF folks, who weren't on CC...
>
> -Kees
>
> On Thu, May 25, 2017 at 4:13 PM, Shubham Bansal
> <illusionist.neo@xxxxxxxxx> wrote:
>> The JIT compiler emits ARM 32 bit instructions. Currently, It supports
>> eBPF only. Classic BPF is supported because of the conversion by BPF
>> core.
>>
>> This patch is essentially changing the current implementation of JIT
>> compiler of Berkeley Packet Filter from classic to internal with almost
>> all instructions from eBPF ISA supported except the following
>> BPF_ALU64 | BPF_DIV | BPF_K
>> BPF_ALU64 | BPF_DIV | BPF_X
>> BPF_ALU64 | BPF_MOD | BPF_K
>> BPF_ALU64 | BPF_MOD | BPF_X
>> BPF_STX | BPF_XADD | BPF_W
>> BPF_STX | BPF_XADD | BPF_DW
>> BPF_JMP | BPF_CALL
>>
>> Implementation is using scratch space to emulate 64 bit eBPF ISA on 32 bit
>> ARM because of deficiency of general purpose registers on ARM. Currently,
>> only LITTLE ENDIAN machines are supported in this eBPF JIT Compiler.
>>
>> Tested on ARMv7 with QEMU by me (Shubham Bansal).
>> Tested on ARMv5 by Andrew Lunn (andrew@xxxxxxx).
>> Expected to work on ARMv6 as well, as its a part ARMv7 and part ARMv5.
>> Although, a proper testing is not done for ARMv6.
>>
>> Both of these testing are done with and without CONFIG_FRAME_POINTER
>> separately for LITTLE ENDIAN machine.
>>
>> For testing:
>>
>> 1. JIT is enabled with
>> echo 1 > /proc/sys/net/core/bpf_jit_enable
>> 2. Constant Blinding can be enabled along with JIT using
>> echo 1 > /proc/sys/net/core/bpf_jit_enable
>> echo 2 > /proc/sys/net/core/bpf_jit_harden
>>
>> See Documentation/networking/filter.txt for more information.
>>
>> Result : test_bpf: Summary: 314 PASSED, 0 FAILED, [278/306 JIT'ed]
>>
>> Signed-off-by: Shubham Bansal <illusionist.neo@xxxxxxxxx>
>> ---
>> Documentation/networking/filter.txt | 4 +-
>> arch/arm/Kconfig | 2 +-
>> arch/arm/net/bpf_jit_32.c | 2404 ++++++++++++++++++++++++-----------
>> arch/arm/net/bpf_jit_32.h | 108 +-
>> 4 files changed, 1713 insertions(+), 805 deletions(-)
>>
>> diff --git a/Documentation/networking/filter.txt b/Documentation/networking/filter.txt
>> index b69b205..01165ac 100644
>> --- a/Documentation/networking/filter.txt
>> +++ b/Documentation/networking/filter.txt
>> @@ -596,8 +596,8 @@ skb pointer). All constraints and restrictions from bpf_check_classic() apply
>> before a conversion to the new layout is being done behind the scenes!
>>
>> Currently, the classic BPF format is being used for JITing on most 32-bit
>> -architectures, whereas x86-64, aarch64, s390x, powerpc64, sparc64 perform JIT
>> -compilation from eBPF instruction set.
>> +architectures, whereas x86-64, aarch64, arm, s390x, powerpc64, sparc64 perform
>> +JIT compilation from eBPF instruction set.
>>
>> Some core changes of the new internal format:
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index 8a7ab5e..13ade46 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -47,7 +47,7 @@ config ARM
>> select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
>> select HAVE_ARCH_TRACEHOOK
>> select HAVE_ARM_SMCCC if CPU_V7
>> - select HAVE_CBPF_JIT
>> + select HAVE_EBPF_JIT
>> select HAVE_CC_STACKPROTECTOR
>> select HAVE_CONTEXT_TRACKING
>> select HAVE_C_RECORDMCOUNT
>> diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
>> index 93d0b6d..c7476e5 100644
>> --- a/arch/arm/net/bpf_jit_32.c
>> +++ b/arch/arm/net/bpf_jit_32.c
>> @@ -1,13 +1,15 @@
>> /*
>> - * Just-In-Time compiler for BPF filters on 32bit ARM
>> + * Just-In-Time compiler for eBPF filters on 32bit ARM
>> *
>> * Copyright (c) 2011 Mircea Gherzan <mgherzan@xxxxxxxxx>
>> + * Copyright (c) 2017 Shubham Bansal <illusionist.neo@xxxxxxxxx>
>> *
>> * This program is free software; you can redistribute it and/or modify it
>> * under the terms of the GNU General Public License as published by the
>> * Free Software Foundation; version 2 of the License.
>> */
>>
>> +#include <linux/bpf.h>
>> #include <linux/bitops.h>
>> #include <linux/compiler.h>
>> #include <linux/errno.h>
>> @@ -23,44 +25,91 @@
>>
>> #include "bpf_jit_32.h"
>>
>> +int bpf_jit_enable __read_mostly;
>> +
>> +#define STACK_OFFSET(k) (k)
>> +#define TMP_REG_1 (MAX_BPF_JIT_REG + 0) /* TEMP Register 1 */
>> +#define TMP_REG_2 (MAX_BPF_JIT_REG + 1) /* TEMP Register 2 */
>> +#define TCALL_CNT (MAX_BPF_JIT_REG + 2) /* Tail Call Count */
>> +
>> +/* Flags used for JIT optimization */
>> +#define SEEN_CALL (1 << 0)
>> +
>> +#define FLAG_IMM_OVERFLOW (1 << 0)
>> +
>> /*
>> - * ABI:
>> + * Map eBPF registers to ARM 32bit registers or stack scratch space.
>> + *
>> + * 1. First argument is passed using the arm 32bit registers and rest of the
>> + * arguments are passed on stack scratch space.
>> + * 2. First callee-saved aregument is mapped to arm 32 bit registers and rest
>> + * arguments are mapped to scratch space on stack.
>> + * 3. We need two 64 bit temp registers to do complex operations on eBPF
>> + * registers.
>> + *
>> + * As the eBPF registers are all 64 bit registers and arm has only 32 bit
>> + * registers, we have to map each eBPF registers with two arm 32 bit regs or
>> + * scratch memory space and we have to build eBPF 64 bit register from those.
>> *
>> - * r0 scratch register
>> - * r4 BPF register A
>> - * r5 BPF register X
>> - * r6 pointer to the skb
>> - * r7 skb->data
>> - * r8 skb_headlen(skb)
>> */
>> +static const u8 bpf2a32[][2] = {
>> + /* return value from in-kernel function, and exit value from eBPF */
>> + [BPF_REG_0] = {ARM_R1, ARM_R0},
>> + /* arguments from eBPF program to in-kernel function */
>> + [BPF_REG_1] = {ARM_R3, ARM_R2},
>> + /* Stored on stack scratch space */
>> + [BPF_REG_2] = {STACK_OFFSET(0), STACK_OFFSET(4)},
>> + [BPF_REG_3] = {STACK_OFFSET(8), STACK_OFFSET(12)},
>> + [BPF_REG_4] = {STACK_OFFSET(16), STACK_OFFSET(20)},
>> + [BPF_REG_5] = {STACK_OFFSET(24), STACK_OFFSET(28)},
>> + /* callee saved registers that in-kernel function will preserve */
>> + [BPF_REG_6] = {ARM_R5, ARM_R4},
>> + /* Stored on stack scratch space */
>> + [BPF_REG_7] = {STACK_OFFSET(32), STACK_OFFSET(36)},
>> + [BPF_REG_8] = {STACK_OFFSET(40), STACK_OFFSET(44)},
>> + [BPF_REG_9] = {STACK_OFFSET(48), STACK_OFFSET(52)},
>> + /* Read only Frame Pointer to access Stack */
>> + [BPF_REG_FP] = {STACK_OFFSET(56), STACK_OFFSET(60)},
>> + /* Temporary Register for internal BPF JIT, can be used
>> + * for constant blindings and others.
>> + */
>> + [TMP_REG_1] = {ARM_R7, ARM_R6},
>> + [TMP_REG_2] = {ARM_R10, ARM_R8},
>> + /* Tail call count. Stored on stack scratch space. */
>> + [TCALL_CNT] = {STACK_OFFSET(64), STACK_OFFSET(68)},
>> + /* temporary register for blinding constants.
>> + * Stored on stack scratch space.
>> + */
>> + [BPF_REG_AX] = {STACK_OFFSET(72), STACK_OFFSET(76)},
>> +};
>>
>> -#define r_scratch ARM_R0
>> -/* r1-r3 are (also) used for the unaligned loads on the non-ARMv7 slowpath */
>> -#define r_off ARM_R1
>> -#define r_A ARM_R4
>> -#define r_X ARM_R5
>> -#define r_skb ARM_R6
>> -#define r_skb_data ARM_R7
>> -#define r_skb_hl ARM_R8
>> -
>> -#define SCRATCH_SP_OFFSET 0
>> -#define SCRATCH_OFF(k) (SCRATCH_SP_OFFSET + 4 * (k))
>> -
>> -#define SEEN_MEM ((1 << BPF_MEMWORDS) - 1)
>> -#define SEEN_MEM_WORD(k) (1 << (k))
>> -#define SEEN_X (1 << BPF_MEMWORDS)
>> -#define SEEN_CALL (1 << (BPF_MEMWORDS + 1))
>> -#define SEEN_SKB (1 << (BPF_MEMWORDS + 2))
>> -#define SEEN_DATA (1 << (BPF_MEMWORDS + 3))
>> +#define dst_lo dst[1]
>> +#define dst_hi dst[0]
>> +#define src_lo src[1]
>> +#define src_hi src[0]
>>
>> -#define FLAG_NEED_X_RESET (1 << 0)
>> -#define FLAG_IMM_OVERFLOW (1 << 1)
>> +/*
>> + * JIT Context:
>> + *
>> + * prog : bpf_prog
>> + * idx : index of current last JITed instruction.
>> + * prologue_bytes : bytes used in prologue.
>> + * epilogue_offset : offset of epilogue starting.
>> + * seen : bit mask used for JIT optimization.
>> + * offsets : array of eBPF instruction offsets in
>> + * JITed code.
>> + * target : final JITed code.
>> + * epilogue_bytes : no of bytes used in epilogue.
>> + * imm_count : no of immediate counts used for global
>> + * variables.
>> + * imms : array of global variable addresses.
>> + */
>>
>> struct jit_ctx {
>> - const struct bpf_prog *skf;
>> - unsigned idx;
>> - unsigned prologue_bytes;
>> - int ret0_fp_idx;
>> + const struct bpf_prog *prog;
>> + unsigned int idx;
>> + unsigned int prologue_bytes;
>> + unsigned int epilogue_offset;
>> u32 seen;
>> u32 flags;
>> u32 *offsets;
>> @@ -72,68 +121,16 @@ struct jit_ctx {
>> #endif
>> };
>>
>> -int bpf_jit_enable __read_mostly;
>> -
>> -static inline int call_neg_helper(struct sk_buff *skb, int offset, void *ret,
>> - unsigned int size)
>> -{
>> - void *ptr = bpf_internal_load_pointer_neg_helper(skb, offset, size);
>> -
>> - if (!ptr)
>> - return -EFAULT;
>> - memcpy(ret, ptr, size);
>> - return 0;
>> -}
>> -
>> -static u64 jit_get_skb_b(struct sk_buff *skb, int offset)
>> -{
>> - u8 ret;
>> - int err;
>> -
>> - if (offset < 0)
>> - err = call_neg_helper(skb, offset, &ret, 1);
>> - else
>> - err = skb_copy_bits(skb, offset, &ret, 1);
>> -
>> - return (u64)err << 32 | ret;
>> -}
>> -
>> -static u64 jit_get_skb_h(struct sk_buff *skb, int offset)
>> -{
>> - u16 ret;
>> - int err;
>> -
>> - if (offset < 0)
>> - err = call_neg_helper(skb, offset, &ret, 2);
>> - else
>> - err = skb_copy_bits(skb, offset, &ret, 2);
>> -
>> - return (u64)err << 32 | ntohs(ret);
>> -}
>> -
>> -static u64 jit_get_skb_w(struct sk_buff *skb, int offset)
>> -{
>> - u32 ret;
>> - int err;
>> -
>> - if (offset < 0)
>> - err = call_neg_helper(skb, offset, &ret, 4);
>> - else
>> - err = skb_copy_bits(skb, offset, &ret, 4);
>> -
>> - return (u64)err << 32 | ntohl(ret);
>> -}
>> -
>> /*
>> * Wrappers which handle both OABI and EABI and assures Thumb2 interworking
>> * (where the assembly routines like __aeabi_uidiv could cause problems).
>> */
>> -static u32 jit_udiv(u32 dividend, u32 divisor)
>> +static u32 jit_udiv32(u32 dividend, u32 divisor)
>> {
>> return dividend / divisor;
>> }
>>
>> -static u32 jit_mod(u32 dividend, u32 divisor)
>> +static u32 jit_mod32(u32 dividend, u32 divisor)
>> {
>> return dividend % divisor;
>> }
>> @@ -157,36 +154,22 @@ static inline void emit(u32 inst, struct jit_ctx *ctx)
>> _emit(ARM_COND_AL, inst, ctx);
>> }
>>
>> -static u16 saved_regs(struct jit_ctx *ctx)
>> +/*
>> + * Checks if immediate value can be converted to imm12(12 bits) value.
>> + */
>> +static int16_t imm8m(u32 x)
>> {
>> - u16 ret = 0;
>> -
>> - if ((ctx->skf->len > 1) ||
>> - (ctx->skf->insns[0].code == (BPF_RET | BPF_A)))
>> - ret |= 1 << r_A;
>> -
>> -#ifdef CONFIG_FRAME_POINTER
>> - ret |= (1 << ARM_FP) | (1 << ARM_IP) | (1 << ARM_LR) | (1 << ARM_PC);
>> -#else
>> - if (ctx->seen & SEEN_CALL)
>> - ret |= 1 << ARM_LR;
>> -#endif
>> - if (ctx->seen & (SEEN_DATA | SEEN_SKB))
>> - ret |= 1 << r_skb;
>> - if (ctx->seen & SEEN_DATA)
>> - ret |= (1 << r_skb_data) | (1 << r_skb_hl);
>> - if (ctx->seen & SEEN_X)
>> - ret |= 1 << r_X;
>> -
>> - return ret;
>> -}
>> + u32 rot;
>>
>> -static inline int mem_words_used(struct jit_ctx *ctx)
>> -{
>> - /* yes, we do waste some stack space IF there are "holes" in the set" */
>> - return fls(ctx->seen & SEEN_MEM);
>> + for (rot = 0; rot < 16; rot++)
>> + if ((x & ~ror32(0xff, 2 * rot)) == 0)
>> + return rol32(x, 2 * rot) | (rot << 8);
>> + return -1;
>> }
>>
>> +/*
>> + * Initializes the JIT space with undefined instructions.
>> + */
>> static void jit_fill_hole(void *area, unsigned int size)
>> {
>> u32 *ptr;
>> @@ -195,88 +178,34 @@ static void jit_fill_hole(void *area, unsigned int size)
>> *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF);
>> }
>>
>> -static void build_prologue(struct jit_ctx *ctx)
>> -{
>> - u16 reg_set = saved_regs(ctx);
>> - u16 off;
>> -
>> -#ifdef CONFIG_FRAME_POINTER
>> - emit(ARM_MOV_R(ARM_IP, ARM_SP), ctx);
>> - emit(ARM_PUSH(reg_set), ctx);
>> - emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx);
>> -#else
>> - if (reg_set)
>> - emit(ARM_PUSH(reg_set), ctx);
>> -#endif
>> +/* Stack must be multiples of 16 Bytes */
>> +#define STACK_ALIGN(sz) (((sz) + 15) & ~15)
>>
>> - if (ctx->seen & (SEEN_DATA | SEEN_SKB))
>> - emit(ARM_MOV_R(r_skb, ARM_R0), ctx);
>> -
>> - if (ctx->seen & SEEN_DATA) {
>> - off = offsetof(struct sk_buff, data);
>> - emit(ARM_LDR_I(r_skb_data, r_skb, off), ctx);
>> - /* headlen = len - data_len */
>> - off = offsetof(struct sk_buff, len);
>> - emit(ARM_LDR_I(r_skb_hl, r_skb, off), ctx);
>> - off = offsetof(struct sk_buff, data_len);
>> - emit(ARM_LDR_I(r_scratch, r_skb, off), ctx);
>> - emit(ARM_SUB_R(r_skb_hl, r_skb_hl, r_scratch), ctx);
>> - }
>> -
>> - if (ctx->flags & FLAG_NEED_X_RESET)
>> - emit(ARM_MOV_I(r_X, 0), ctx);
>> -
>> - /* do not leak kernel data to userspace */
>> - if (bpf_needs_clear_a(&ctx->skf->insns[0]))
>> - emit(ARM_MOV_I(r_A, 0), ctx);
>> -
>> - /* stack space for the BPF_MEM words */
>> - if (ctx->seen & SEEN_MEM)
>> - emit(ARM_SUB_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx);
>> -}
>> -
>> -static void build_epilogue(struct jit_ctx *ctx)
>> -{
>> - u16 reg_set = saved_regs(ctx);
>> -
>> - if (ctx->seen & SEEN_MEM)
>> - emit(ARM_ADD_I(ARM_SP, ARM_SP, mem_words_used(ctx) * 4), ctx);
>> -
>> - reg_set &= ~(1 << ARM_LR);
>> -
>> -#ifdef CONFIG_FRAME_POINTER
>> - /* the first instruction of the prologue was: mov ip, sp */
>> - reg_set &= ~(1 << ARM_IP);
>> - reg_set |= (1 << ARM_SP);
>> - emit(ARM_LDM(ARM_SP, reg_set), ctx);
>> -#else
>> - if (reg_set) {
>> - if (ctx->seen & SEEN_CALL)
>> - reg_set |= 1 << ARM_PC;
>> - emit(ARM_POP(reg_set), ctx);
>> - }
>> +/* Stack space for BPF_REG_2, BPF_REG_3, BPF_REG_4,
>> + * BPF_REG_5, BPF_REG_7, BPF_REG_8, BPF_REG_9,
>> + * BPF_REG_FP and Tail call counts.
>> + */
>> +#define SCRATCH_SIZE 80
>>
>> - if (!(ctx->seen & SEEN_CALL))
>> - emit(ARM_BX(ARM_LR), ctx);
>> -#endif
>> -}
>> +/* total stack size used in JITed code */
>> +#define _STACK_SIZE \
>> + (MAX_BPF_STACK + \
>> + + SCRATCH_SIZE + \
>> + + 4 /* extra for skb_copy_bits buffer */)
>>
>> -static int16_t imm8m(u32 x)
>> -{
>> - u32 rot;
>> +#define STACK_SIZE STACK_ALIGN(_STACK_SIZE)
>>
>> - for (rot = 0; rot < 16; rot++)
>> - if ((x & ~ror32(0xff, 2 * rot)) == 0)
>> - return rol32(x, 2 * rot) | (rot << 8);
>> +/* Get the offset of eBPF REGISTERs stored on scratch space. */
>> +#define STACK_VAR(off) (STACK_SIZE-off-4)
>>
>> - return -1;
>> -}
>> +/* Offset of skb_copy_bits buffer */
>> +#define SKB_BUFFER STACK_VAR(SCRATCH_SIZE)
>>
>> #if __LINUX_ARM_ARCH__ < 7
>>
>> static u16 imm_offset(u32 k, struct jit_ctx *ctx)
>> {
>> - unsigned i = 0, offset;
>> + unsigned int i = 0, offset;
>> u16 imm;
>>
>> /* on the "fake" run we just count them (duplicates included) */
>> @@ -295,7 +224,7 @@ static u16 imm_offset(u32 k, struct jit_ctx *ctx)
>> ctx->imms[i] = k;
>>
>> /* constants go just after the epilogue */
>> - offset = ctx->offsets[ctx->skf->len];
>> + offset = ctx->offsets[ctx->prog->len - 1] * 4;
>> offset += ctx->prologue_bytes;
>> offset += ctx->epilogue_bytes;
>> offset += i * 4;
>> @@ -319,10 +248,22 @@ static u16 imm_offset(u32 k, struct jit_ctx *ctx)
>>
>> #endif /* __LINUX_ARM_ARCH__ */
>>
>> +static inline int bpf2a32_offset(int bpf_to, int bpf_from,
>> + const struct jit_ctx *ctx) {
>> + int to, from;
>> +
>> + if (ctx->target == NULL)
>> + return 0;
>> + to = ctx->offsets[bpf_to];
>> + from = ctx->offsets[bpf_from];
>> +
>> + return to - from - 1;
>> +}
>> +
>> /*
>> * Move an immediate that's not an imm8m to a core register.
>> */
>> -static inline void emit_mov_i_no8m(int rd, u32 val, struct jit_ctx *ctx)
>> +static inline void emit_mov_i_no8m(const u8 rd, u32 val, struct jit_ctx *ctx)
>> {
>> #if __LINUX_ARM_ARCH__ < 7
>> emit(ARM_LDR_I(rd, ARM_PC, imm_offset(val, ctx)), ctx);
>> @@ -333,7 +274,7 @@ static inline void emit_mov_i_no8m(int rd, u32 val, struct jit_ctx *ctx)
>> #endif
>> }
>>
>> -static inline void emit_mov_i(int rd, u32 val, struct jit_ctx *ctx)
>> +static inline void emit_mov_i(const u8 rd, u32 val, struct jit_ctx *ctx)
>> {
>> int imm12 = imm8m(val);
>>
>> @@ -343,676 +284,1553 @@ static inline void emit_mov_i(int rd, u32 val, struct jit_ctx *ctx)
>> emit_mov_i_no8m(rd, val, ctx);
>> }
>>
>> -#if __LINUX_ARM_ARCH__ < 6
>> -
>> -static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
>> +static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx)
>> {
>> - _emit(cond, ARM_LDRB_I(ARM_R3, r_addr, 1), ctx);
>> - _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx);
>> - _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 3), ctx);
>> - _emit(cond, ARM_LSL_I(ARM_R3, ARM_R3, 16), ctx);
>> - _emit(cond, ARM_LDRB_I(ARM_R0, r_addr, 2), ctx);
>> - _emit(cond, ARM_ORR_S(ARM_R3, ARM_R3, ARM_R1, SRTYPE_LSL, 24), ctx);
>> - _emit(cond, ARM_ORR_R(ARM_R3, ARM_R3, ARM_R2), ctx);
>> - _emit(cond, ARM_ORR_S(r_res, ARM_R3, ARM_R0, SRTYPE_LSL, 8), ctx);
>> + ctx->seen |= SEEN_CALL;
>> +#if __LINUX_ARM_ARCH__ < 5
>> + emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx);
>> +
>> + if (elf_hwcap & HWCAP_THUMB)
>> + emit(ARM_BX(tgt_reg), ctx);
>> + else
>> + emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx);
>> +#else
>> + emit(ARM_BLX_R(tgt_reg), ctx);
>> +#endif
>> }
>>
>> -static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
>> +static inline int epilogue_offset(const struct jit_ctx *ctx)
>> {
>> - _emit(cond, ARM_LDRB_I(ARM_R1, r_addr, 0), ctx);
>> - _emit(cond, ARM_LDRB_I(ARM_R2, r_addr, 1), ctx);
>> - _emit(cond, ARM_ORR_S(r_res, ARM_R2, ARM_R1, SRTYPE_LSL, 8), ctx);
>> + int to, from;
>> + /* No need for 1st dummy run */
>> + if (ctx->target == NULL)
>> + return 0;
>> + to = ctx->epilogue_offset;
>> + from = ctx->idx;
>> +
>> + return to - from - 2;
>> }
>>
>> -static inline void emit_swap16(u8 r_dst, u8 r_src, struct jit_ctx *ctx)
>> +static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx, u8 op)
>> {
>> - /* r_dst = (r_src << 8) | (r_src >> 8) */
>> - emit(ARM_LSL_I(ARM_R1, r_src, 8), ctx);
>> - emit(ARM_ORR_S(r_dst, ARM_R1, r_src, SRTYPE_LSR, 8), ctx);
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + s32 jmp_offset;
>> +
>> + /* checks if divisor is zero or not. If it is, then
>> + * exit directly.
>> + */
>> + emit(ARM_CMP_I(rn, 0), ctx);
>> + _emit(ARM_COND_EQ, ARM_MOV_I(ARM_R0, 0), ctx);
>> + jmp_offset = epilogue_offset(ctx);
>> + _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
>> +#if __LINUX_ARM_ARCH__ == 7
>> + if (elf_hwcap & HWCAP_IDIVA) {
>> + if (op == BPF_DIV)
>> + emit(ARM_UDIV(rd, rm, rn), ctx);
>> + else {
>> + emit(ARM_UDIV(ARM_IP, rm, rn), ctx);
>> + emit(ARM_MLS(rd, rn, ARM_IP, rm), ctx);
>> + }
>> + return;
>> + }
>> +#endif
>>
>> /*
>> - * we need to mask out the bits set in r_dst[23:16] due to
>> - * the first shift instruction.
>> - *
>> - * note that 0x8ff is the encoded immediate 0x00ff0000.
>> + * For BPF_ALU | BPF_DIV | BPF_K instructions
>> + * As ARM_R1 and ARM_R0 contains 1st argument of bpf
>> + * function, we need to save it on caller side to save
>> + * it from getting destroyed within callee.
>> + * After the return from the callee, we restore ARM_R0
>> + * ARM_R1.
>> */
>> - emit(ARM_BIC_I(r_dst, r_dst, 0x8ff), ctx);
>> -}
>> + if (rn != ARM_R1) {
>> + emit(ARM_MOV_R(tmp[0], ARM_R1), ctx);
>> + emit(ARM_MOV_R(ARM_R1, rn), ctx);
>> + }
>> + if (rm != ARM_R0) {
>> + emit(ARM_MOV_R(tmp[1], ARM_R0), ctx);
>> + emit(ARM_MOV_R(ARM_R0, rm), ctx);
>> + }
>>
>> -#else /* ARMv6+ */
>> + /* Call appropriate function */
>> + ctx->seen |= SEEN_CALL;
>> + emit_mov_i(ARM_IP, op == BPF_DIV ?
>> + (u32)jit_udiv32 : (u32)jit_mod32, ctx);
>> + emit_blx_r(ARM_IP, ctx);
>>
>> -static void emit_load_be32(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
>> -{
>> - _emit(cond, ARM_LDR_I(r_res, r_addr, 0), ctx);
>> -#ifdef __LITTLE_ENDIAN
>> - _emit(cond, ARM_REV(r_res, r_res), ctx);
>> -#endif
>> + /* Save return value */
>> + if (rd != ARM_R0)
>> + emit(ARM_MOV_R(rd, ARM_R0), ctx);
>> +
>> + /* Restore ARM_R0 and ARM_R1 */
>> + if (rn != ARM_R1)
>> + emit(ARM_MOV_R(ARM_R1, tmp[0]), ctx);
>> + if (rm != ARM_R0)
>> + emit(ARM_MOV_R(ARM_R0, tmp[1]), ctx);
>> }
>>
>> -static void emit_load_be16(u8 cond, u8 r_res, u8 r_addr, struct jit_ctx *ctx)
>> +/* Checks whether BPF register is on scratch stack space or not. */
>> +static inline bool is_on_stack(u8 bpf_reg)
>> {
>> - _emit(cond, ARM_LDRH_I(r_res, r_addr, 0), ctx);
>> -#ifdef __LITTLE_ENDIAN
>> - _emit(cond, ARM_REV16(r_res, r_res), ctx);
>> -#endif
>> + static u8 stack_regs[] = {BPF_REG_AX, BPF_REG_3, BPF_REG_4, BPF_REG_5,
>> + BPF_REG_7, BPF_REG_8, BPF_REG_9, TCALL_CNT,
>> + BPF_REG_2, BPF_REG_FP};
>> + int i, reg_len = sizeof(stack_regs);
>> +
>> + for (i = 0 ; i < reg_len ; i++) {
>> + if (bpf_reg == stack_regs[i])
>> + return true;
>> + }
>> + return false;
>> }
>>
>> -static inline void emit_swap16(u8 r_dst __maybe_unused,
>> - u8 r_src __maybe_unused,
>> - struct jit_ctx *ctx __maybe_unused)
>> +static inline void emit_a32_mov_i(const u8 dst, const u32 val,
>> + bool dstk, struct jit_ctx *ctx)
>> {
>> -#ifdef __LITTLE_ENDIAN
>> - emit(ARM_REV16(r_dst, r_src), ctx);
>> -#endif
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> +
>> + if (dstk) {
>> + emit_mov_i(tmp[1], val, ctx);
>> + emit(ARM_STR_I(tmp[1], ARM_SP, STACK_VAR(dst)), ctx);
>> + } else {
>> + emit_mov_i(dst, val, ctx);
>> + }
>> }
>>
>> -#endif /* __LINUX_ARM_ARCH__ < 6 */
>> +/* Sign extended move */
>> +static inline void emit_a32_mov_i64(const bool is64, const u8 dst[],
>> + const u32 val, bool dstk,
>> + struct jit_ctx *ctx) {
>> + u32 hi = 0;
>>
>> + if (is64 && (val & (1<<31)))
>> + hi = (u32)~0;
>> + emit_a32_mov_i(dst_lo, val, dstk, ctx);
>> + emit_a32_mov_i(dst_hi, hi, dstk, ctx);
>> +}
>>
>> -/* Compute the immediate value for a PC-relative branch. */
>> -static inline u32 b_imm(unsigned tgt, struct jit_ctx *ctx)
>> -{
>> - u32 imm;
>> +static inline void emit_a32_add_r(const u8 dst, const u8 src,
>> + const bool is64, const bool hi,
>> + struct jit_ctx *ctx) {
>> + /* 64 bit :
>> + * adds dst_lo, dst_lo, src_lo
>> + * adc dst_hi, dst_hi, src_hi
>> + * 32 bit :
>> + * add dst_lo, dst_lo, src_lo
>> + */
>> + if (!hi && is64)
>> + emit(ARM_ADDS_R(dst, dst, src), ctx);
>> + else if (hi && is64)
>> + emit(ARM_ADC_R(dst, dst, src), ctx);
>> + else
>> + emit(ARM_ADD_R(dst, dst, src), ctx);
>> +}
>>
>> - if (ctx->target == NULL)
>> - return 0;
>> - /*
>> - * BPF allows only forward jumps and the offset of the target is
>> - * still the one computed during the first pass.
>> +static inline void emit_a32_sub_r(const u8 dst, const u8 src,
>> + const bool is64, const bool hi,
>> + struct jit_ctx *ctx) {
>> + /* 64 bit :
>> + * subs dst_lo, dst_lo, src_lo
>> + * sbc dst_hi, dst_hi, src_hi
>> + * 32 bit :
>> + * sub dst_lo, dst_lo, src_lo
>> */
>> - imm = ctx->offsets[tgt] + ctx->prologue_bytes - (ctx->idx * 4 + 8);
>> + if (!hi && is64)
>> + emit(ARM_SUBS_R(dst, dst, src), ctx);
>> + else if (hi && is64)
>> + emit(ARM_SBC_R(dst, dst, src), ctx);
>> + else
>> + emit(ARM_SUB_R(dst, dst, src), ctx);
>> +}
>>
>> - return imm >> 2;
>> +static inline void emit_alu_r(const u8 dst, const u8 src, const bool is64,
>> + const bool hi, const u8 op, struct jit_ctx *ctx){
>> + switch (BPF_OP(op)) {
>> + /* dst = dst + src */
>> + case BPF_ADD:
>> + emit_a32_add_r(dst, src, is64, hi, ctx);
>> + break;
>> + /* dst = dst - src */
>> + case BPF_SUB:
>> + emit_a32_sub_r(dst, src, is64, hi, ctx);
>> + break;
>> + /* dst = dst | src */
>> + case BPF_OR:
>> + emit(ARM_ORR_R(dst, dst, src), ctx);
>> + break;
>> + /* dst = dst & src */
>> + case BPF_AND:
>> + emit(ARM_AND_R(dst, dst, src), ctx);
>> + break;
>> + /* dst = dst ^ src */
>> + case BPF_XOR:
>> + emit(ARM_EOR_R(dst, dst, src), ctx);
>> + break;
>> + /* dst = dst * src */
>> + case BPF_MUL:
>> + emit(ARM_MUL(dst, dst, src), ctx);
>> + break;
>> + /* dst = dst << src */
>> + case BPF_LSH:
>> + emit(ARM_LSL_R(dst, dst, src), ctx);
>> + break;
>> + /* dst = dst >> src */
>> + case BPF_RSH:
>> + emit(ARM_LSR_R(dst, dst, src), ctx);
>> + break;
>> + /* dst = dst >> src (signed)*/
>> + case BPF_ARSH:
>> + emit(ARM_MOV_SR(dst, dst, SRTYPE_ASR, src), ctx);
>> + break;
>> + }
>> }
>>
>> -#define OP_IMM3(op, r1, r2, imm_val, ctx) \
>> - do { \
>> - imm12 = imm8m(imm_val); \
>> - if (imm12 < 0) { \
>> - emit_mov_i_no8m(r_scratch, imm_val, ctx); \
>> - emit(op ## _R((r1), (r2), r_scratch), ctx); \
>> - } else { \
>> - emit(op ## _I((r1), (r2), imm12), ctx); \
>> - } \
>> - } while (0)
>> -
>> -static inline void emit_err_ret(u8 cond, struct jit_ctx *ctx)
>> -{
>> - if (ctx->ret0_fp_idx >= 0) {
>> - _emit(cond, ARM_B(b_imm(ctx->ret0_fp_idx, ctx)), ctx);
>> - /* NOP to keep the size constant between passes */
>> - emit(ARM_MOV_R(ARM_R0, ARM_R0), ctx);
>> +/* ALU operation (32 bit)
>> + * dst = dst (op) src
>> + */
>> +static inline void emit_a32_alu_r(const u8 dst, const u8 src,
>> + bool dstk, bool sstk,
>> + struct jit_ctx *ctx, const bool is64,
>> + const bool hi, const u8 op) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + u8 rn = sstk ? tmp[1] : src;
>> +
>> + if (sstk)
>> + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src)), ctx);
>> +
>> + /* ALU operation */
>> + if (dstk) {
>> + emit(ARM_LDR_I(tmp[0], ARM_SP, STACK_VAR(dst)), ctx);
>> + emit_alu_r(tmp[0], rn, is64, hi, op, ctx);
>> + emit(ARM_STR_I(tmp[0], ARM_SP, STACK_VAR(dst)), ctx);
>> } else {
>> - _emit(cond, ARM_MOV_I(ARM_R0, 0), ctx);
>> - _emit(cond, ARM_B(b_imm(ctx->skf->len, ctx)), ctx);
>> + emit_alu_r(dst, rn, is64, hi, op, ctx);
>> }
>> }
>>
>> -static inline void emit_blx_r(u8 tgt_reg, struct jit_ctx *ctx)
>> -{
>> -#if __LINUX_ARM_ARCH__ < 5
>> - emit(ARM_MOV_R(ARM_LR, ARM_PC), ctx);
>> +/* ALU operation (64 bit) */
>> +static inline void emit_a32_alu_r64(const bool is64, const u8 dst[],
>> + const u8 src[], bool dstk,
>> + bool sstk, struct jit_ctx *ctx,
>> + const u8 op) {
>> + emit_a32_alu_r(dst_lo, src_lo, dstk, sstk, ctx, is64, false, op);
>> + if (is64)
>> + emit_a32_alu_r(dst_hi, src_hi, dstk, sstk, ctx, is64, true, op);
>> + else
>> + emit_a32_mov_i(dst_hi, 0, dstk, ctx);
>> +}
>>
>> - if (elf_hwcap & HWCAP_THUMB)
>> - emit(ARM_BX(tgt_reg), ctx);
>> +/* dst = imm (4 bytes)*/
>> +static inline void emit_a32_mov_r(const u8 dst, const u8 src,
>> + bool dstk, bool sstk,
>> + struct jit_ctx *ctx) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + u8 rt = sstk ? tmp[0] : src;
>> +
>> + if (sstk)
>> + emit(ARM_LDR_I(tmp[0], ARM_SP, STACK_VAR(src)), ctx);
>> + if (dstk)
>> + emit(ARM_STR_I(rt, ARM_SP, STACK_VAR(dst)), ctx);
>> else
>> - emit(ARM_MOV_R(ARM_PC, tgt_reg), ctx);
>> -#else
>> - emit(ARM_BLX_R(tgt_reg), ctx);
>> -#endif
>> + emit(ARM_MOV_R(dst, rt), ctx);
>> }
>>
>> -static inline void emit_udivmod(u8 rd, u8 rm, u8 rn, struct jit_ctx *ctx,
>> - int bpf_op)
>> -{
>> -#if __LINUX_ARM_ARCH__ == 7
>> - if (elf_hwcap & HWCAP_IDIVA) {
>> - if (bpf_op == BPF_DIV)
>> - emit(ARM_UDIV(rd, rm, rn), ctx);
>> - else {
>> - emit(ARM_UDIV(ARM_R3, rm, rn), ctx);
>> - emit(ARM_MLS(rd, rn, ARM_R3, rm), ctx);
>> - }
>> - return;
>> +/* dst = src */
>> +static inline void emit_a32_mov_r64(const bool is64, const u8 dst[],
>> + const u8 src[], bool dstk,
>> + bool sstk, struct jit_ctx *ctx) {
>> + emit_a32_mov_r(dst_lo, src_lo, dstk, sstk, ctx);
>> + if (is64) {
>> + /* complete 8 byte move */
>> + emit_a32_mov_r(dst_hi, src_hi, dstk, sstk, ctx);
>> + } else {
>> + /* Zero out high 4 bytes */
>> + emit_a32_mov_i(dst_hi, 0, dstk, ctx);
>> }
>> -#endif
>> +}
>>
>> - /*
>> - * For BPF_ALU | BPF_DIV | BPF_K instructions, rm is ARM_R4
>> - * (r_A) and rn is ARM_R0 (r_scratch) so load rn first into
>> - * ARM_R1 to avoid accidentally overwriting ARM_R0 with rm
>> - * before using it as a source for ARM_R1.
>> - *
>> - * For BPF_ALU | BPF_DIV | BPF_X rm is ARM_R4 (r_A) and rn is
>> - * ARM_R5 (r_X) so there is no particular register overlap
>> - * issues.
>> - */
>> - if (rn != ARM_R1)
>> - emit(ARM_MOV_R(ARM_R1, rn), ctx);
>> - if (rm != ARM_R0)
>> - emit(ARM_MOV_R(ARM_R0, rm), ctx);
>> +/* Shift operations */
>> +static inline void emit_a32_alu_i(const u8 dst, const u32 val, bool dstk,
>> + struct jit_ctx *ctx, const u8 op) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + u8 rd = dstk ? tmp[0] : dst;
>> +
>> + if (dstk)
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst)), ctx);
>> +
>> + /* Do shift operation */
>> + switch (op) {
>> + case BPF_LSH:
>> + emit(ARM_LSL_I(rd, rd, val), ctx);
>> + break;
>> + case BPF_RSH:
>> + emit(ARM_LSR_I(rd, rd, val), ctx);
>> + break;
>> + case BPF_NEG:
>> + emit(ARM_RSB_I(rd, rd, val), ctx);
>> + break;
>> + }
>> +
>> + if (dstk)
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst)), ctx);
>> +}
>> +
>> +/* dst = ~dst (64 bit) */
>> +static inline void emit_a32_neg64(const u8 dst[], bool dstk,
>> + struct jit_ctx *ctx){
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + u8 rd = dstk ? tmp[1] : dst[1];
>> + u8 rm = dstk ? tmp[0] : dst[0];
>> +
>> + /* Setup Operand */
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do Negate Operation */
>> + emit(ARM_RSBS_I(rd, rd, 0), ctx);
>> + emit(ARM_RSC_I(rm, rm, 0), ctx);
>> +
>> + if (dstk) {
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +}
>>
>> +/* dst = dst << src */
>> +static inline void emit_a32_lsh_r64(const u8 dst[], const u8 src[], bool dstk,
>> + bool sstk, struct jit_ctx *ctx) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> +
>> + /* Setup Operands */
>> + u8 rt = sstk ? tmp2[1] : src_lo;
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> +
>> + if (sstk)
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do LSH operation */
>> + emit(ARM_SUB_I(ARM_IP, rt, 32), ctx);
>> + emit(ARM_RSB_I(tmp2[0], rt, 32), ctx);
>> + /* As we are using ARM_LR */
>> ctx->seen |= SEEN_CALL;
>> - emit_mov_i(ARM_R3, bpf_op == BPF_DIV ? (u32)jit_udiv : (u32)jit_mod,
>> - ctx);
>> - emit_blx_r(ARM_R3, ctx);
>> + emit(ARM_MOV_SR(ARM_LR, rm, SRTYPE_ASL, rt), ctx);
>> + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rd, SRTYPE_ASL, ARM_IP), ctx);
>> + emit(ARM_ORR_SR(ARM_IP, ARM_LR, rd, SRTYPE_LSR, tmp2[0]), ctx);
>> + emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_ASL, rt), ctx);
>> +
>> + if (dstk) {
>> + emit(ARM_STR_I(ARM_LR, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + } else {
>> + emit(ARM_MOV_R(rd, ARM_LR), ctx);
>> + emit(ARM_MOV_R(rm, ARM_IP), ctx);
>> + }
>> +}
>>
>> - if (rd != ARM_R0)
>> - emit(ARM_MOV_R(rd, ARM_R0), ctx);
>> +/* dst = dst >> src (signed)*/
>> +static inline void emit_a32_arsh_r64(const u8 dst[], const u8 src[], bool dstk,
>> + bool sstk, struct jit_ctx *ctx) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + /* Setup Operands */
>> + u8 rt = sstk ? tmp2[1] : src_lo;
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> +
>> + if (sstk)
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do the ARSH operation */
>> + emit(ARM_RSB_I(ARM_IP, rt, 32), ctx);
>> + emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx);
>> + /* As we are using ARM_LR */
>> + ctx->seen |= SEEN_CALL;
>> + emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_LSR, rt), ctx);
>> + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_ASL, ARM_IP), ctx);
>> + _emit(ARM_COND_MI, ARM_B(0), ctx);
>> + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_ASR, tmp2[0]), ctx);
>> + emit(ARM_MOV_SR(ARM_IP, rm, SRTYPE_ASR, rt), ctx);
>> + if (dstk) {
>> + emit(ARM_STR_I(ARM_LR, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + } else {
>> + emit(ARM_MOV_R(rd, ARM_LR), ctx);
>> + emit(ARM_MOV_R(rm, ARM_IP), ctx);
>> + }
>> }
>>
>> -static inline void update_on_xread(struct jit_ctx *ctx)
>> +/* dst = dst >> src */
>> +static inline void emit_a32_lsr_r64(const u8 dst[], const u8 src[], bool dstk,
>> + bool sstk, struct jit_ctx *ctx) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + /* Setup Operands */
>> + u8 rt = sstk ? tmp2[1] : src_lo;
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> +
>> + if (sstk)
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do LSH operation */
>> + emit(ARM_RSB_I(ARM_IP, rt, 32), ctx);
>> + emit(ARM_SUBS_I(tmp2[0], rt, 32), ctx);
>> + /* As we are using ARM_LR */
>> + ctx->seen |= SEEN_CALL;
>> + emit(ARM_MOV_SR(ARM_LR, rd, SRTYPE_LSR, rt), ctx);
>> + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_ASL, ARM_IP), ctx);
>> + emit(ARM_ORR_SR(ARM_LR, ARM_LR, rm, SRTYPE_LSR, tmp2[0]), ctx);
>> + emit(ARM_MOV_SR(ARM_IP, rm, SRTYPE_LSR, rt), ctx);
>> + if (dstk) {
>> + emit(ARM_STR_I(ARM_LR, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + } else {
>> + emit(ARM_MOV_R(rd, ARM_LR), ctx);
>> + emit(ARM_MOV_R(rm, ARM_IP), ctx);
>> + }
>> +}
>> +
>> +/* dst = dst << val */
>> +static inline void emit_a32_lsh_i64(const u8 dst[], bool dstk,
>> + const u32 val, struct jit_ctx *ctx){
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + /* Setup operands */
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> +
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do LSH operation */
>> + if (val < 32) {
>> + emit(ARM_MOV_SI(tmp2[0], rm, SRTYPE_ASL, val), ctx);
>> + emit(ARM_ORR_SI(rm, tmp2[0], rd, SRTYPE_LSR, 32 - val), ctx);
>> + emit(ARM_MOV_SI(rd, rd, SRTYPE_ASL, val), ctx);
>> + } else {
>> + if (val == 32)
>> + emit(ARM_MOV_R(rm, rd), ctx);
>> + else
>> + emit(ARM_MOV_SI(rm, rd, SRTYPE_ASL, val - 32), ctx);
>> + emit(ARM_EOR_R(rd, rd, rd), ctx);
>> + }
>> +
>> + if (dstk) {
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +}
>> +
>> +/* dst = dst >> val */
>> +static inline void emit_a32_lsr_i64(const u8 dst[], bool dstk,
>> + const u32 val, struct jit_ctx *ctx) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + /* Setup operands */
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> +
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do LSR operation */
>> + if (val < 32) {
>> + emit(ARM_MOV_SI(tmp2[1], rd, SRTYPE_LSR, val), ctx);
>> + emit(ARM_ORR_SI(rd, tmp2[1], rm, SRTYPE_ASL, 32 - val), ctx);
>> + emit(ARM_MOV_SI(rm, rm, SRTYPE_LSR, val), ctx);
>> + } else if (val == 32) {
>> + emit(ARM_MOV_R(rd, rm), ctx);
>> + emit(ARM_MOV_I(rm, 0), ctx);
>> + } else {
>> + emit(ARM_MOV_SI(rd, rm, SRTYPE_LSR, val - 32), ctx);
>> + emit(ARM_MOV_I(rm, 0), ctx);
>> + }
>> +
>> + if (dstk) {
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +}
>> +
>> +/* dst = dst >> val (signed) */
>> +static inline void emit_a32_arsh_i64(const u8 dst[], bool dstk,
>> + const u32 val, struct jit_ctx *ctx){
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + /* Setup operands */
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> +
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Do ARSH operation */
>> + if (val < 32) {
>> + emit(ARM_MOV_SI(tmp2[1], rd, SRTYPE_LSR, val), ctx);
>> + emit(ARM_ORR_SI(rd, tmp2[1], rm, SRTYPE_ASL, 32 - val), ctx);
>> + emit(ARM_MOV_SI(rm, rm, SRTYPE_ASR, val), ctx);
>> + } else if (val == 32) {
>> + emit(ARM_MOV_R(rd, rm), ctx);
>> + emit(ARM_MOV_SI(rm, rm, SRTYPE_ASR, 31), ctx);
>> + } else {
>> + emit(ARM_MOV_SI(rd, rm, SRTYPE_ASR, val - 32), ctx);
>> + emit(ARM_MOV_SI(rm, rm, SRTYPE_ASR, 31), ctx);
>> + }
>> +
>> + if (dstk) {
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +}
>> +
>> +static inline void emit_a32_mul_r64(const u8 dst[], const u8 src[], bool dstk,
>> + bool sstk, struct jit_ctx *ctx) {
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + /* Setup operands for multiplication */
>> + u8 rd = dstk ? tmp[1] : dst_lo;
>> + u8 rm = dstk ? tmp[0] : dst_hi;
>> + u8 rt = sstk ? tmp2[1] : src_lo;
>> + u8 rn = sstk ? tmp2[0] : src_hi;
>> +
>> + if (dstk) {
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> + if (sstk) {
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_hi)), ctx);
>> + }
>> +
>> + /* Do Multiplication */
>> + emit(ARM_MUL(ARM_IP, rd, rn), ctx);
>> + emit(ARM_MUL(ARM_LR, rm, rt), ctx);
>> + /* As we are using ARM_LR */
>> + ctx->seen |= SEEN_CALL;
>> + emit(ARM_ADD_R(ARM_LR, ARM_IP, ARM_LR), ctx);
>> +
>> + emit(ARM_UMULL(ARM_IP, rm, rd, rt), ctx);
>> + emit(ARM_ADD_R(rm, ARM_LR, rm), ctx);
>> + if (dstk) {
>> + emit(ARM_STR_I(ARM_IP, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(rm, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + } else {
>> + emit(ARM_MOV_R(rd, ARM_IP), ctx);
>> + }
>> +}
>> +
>> +/* *(size *)(dst + off) = src */
>> +static inline void emit_str_r(const u8 dst, const u8 src, bool dstk,
>> + const s32 off, struct jit_ctx *ctx, const u8 sz){
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + u8 rd = dstk ? tmp[1] : dst;
>> +
>> + if (dstk)
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst)), ctx);
>> + if (off) {
>> + emit_a32_mov_i(tmp[0], off, false, ctx);
>> + emit(ARM_ADD_R(tmp[0], rd, tmp[0]), ctx);
>> + rd = tmp[0];
>> + }
>> + switch (sz) {
>> + case BPF_W:
>> + /* Store a Word */
>> + emit(ARM_STR_I(src, rd, 0), ctx);
>> + break;
>> + case BPF_H:
>> + /* Store a HalfWord */
>> + emit(ARM_STRH_I(src, rd, 0), ctx);
>> + break;
>> + case BPF_B:
>> + /* Store a Byte */
>> + emit(ARM_STRB_I(src, rd, 0), ctx);
>> + break;
>> + }
>> +}
>> +
>> +/* dst = *(size*)(src + off) */
>> +static inline void emit_ldx_r(const u8 dst, const u8 src, bool dstk,
>> + const s32 off, struct jit_ctx *ctx, const u8 sz){
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + u8 rd = dstk ? tmp[1] : dst;
>> + u8 rm = src;
>> +
>> + if (off) {
>> + emit_a32_mov_i(tmp[0], off, false, ctx);
>> + emit(ARM_ADD_R(tmp[0], tmp[0], src), ctx);
>> + rm = tmp[0];
>> + }
>> + switch (sz) {
>> + case BPF_W:
>> + /* Load a Word */
>> + emit(ARM_LDR_I(rd, rm, 0), ctx);
>> + break;
>> + case BPF_H:
>> + /* Load a HalfWord */
>> + emit(ARM_LDRH_I(rd, rm, 0), ctx);
>> + break;
>> + case BPF_B:
>> + /* Load a Byte */
>> + emit(ARM_LDRB_I(rd, rm, 0), ctx);
>> + break;
>> + }
>> + if (dstk)
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst)), ctx);
>> +}
>> +
>> +/* Arithmatic Operation */
>> +static inline void emit_ar_r(const u8 rd, const u8 rt, const u8 rm,
>> + const u8 rn, struct jit_ctx *ctx, u8 op) {
>> + switch (op) {
>> + case BPF_JSET:
>> + ctx->seen |= SEEN_CALL;
>> + emit(ARM_AND_R(ARM_IP, rt, rn), ctx);
>> + emit(ARM_AND_R(ARM_LR, rd, rm), ctx);
>> + emit(ARM_ORRS_R(ARM_IP, ARM_LR, ARM_IP), ctx);
>> + break;
>> + case BPF_JEQ:
>> + case BPF_JNE:
>> + case BPF_JGT:
>> + case BPF_JGE:
>> + emit(ARM_CMP_R(rd, rm), ctx);
>> + _emit(ARM_COND_EQ, ARM_CMP_R(rt, rn), ctx);
>> + break;
>> + case BPF_JSGT:
>> + emit(ARM_CMP_R(rn, rt), ctx);
>> + emit(ARM_SBCS_R(ARM_IP, rm, rd), ctx);
>> + break;
>> + case BPF_JSGE:
>> + emit(ARM_CMP_R(rt, rn), ctx);
>> + emit(ARM_SBCS_R(ARM_IP, rd, rm), ctx);
>> + break;
>> + }
>> +}
>> +
>> +static int out_offset = -1; /* initialized on the first pass of build_body() */
>> +static int emit_bpf_tail_call(struct jit_ctx *ctx)
>> +{
>> +
>> + /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
>> + const u8 *r2 = bpf2a32[BPF_REG_2];
>> + const u8 *r3 = bpf2a32[BPF_REG_3];
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + const u8 *tcc = bpf2a32[TCALL_CNT];
>> + const int idx0 = ctx->idx;
>> +#define cur_offset (ctx->idx - idx0)
>> +#define jmp_offset (out_offset - (cur_offset))
>> + u32 off, lo, hi;
>> +
>> + /* if (index >= array->map.max_entries)
>> + * goto out;
>> + */
>> + off = offsetof(struct bpf_array, map.max_entries);
>> + /* array->map.max_entries */
>> + emit_a32_mov_i(tmp[1], off, false, ctx);
>> + emit(ARM_LDR_I(tmp2[1], ARM_SP, STACK_VAR(r2[1])), ctx);
>> + emit(ARM_LDR_R(tmp[1], tmp2[1], tmp[1]), ctx);
>> + /* index (64 bit) */
>> + emit(ARM_LDR_I(tmp2[1], ARM_SP, STACK_VAR(r3[1])), ctx);
>> + /* index >= array->map.max_entries */
>> + emit(ARM_CMP_R(tmp2[1], tmp[1]), ctx);
>> + _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
>> +
>> + /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
>> + * goto out;
>> + * tail_call_cnt++;
>> + */
>> + lo = (u32)MAX_TAIL_CALL_CNT;
>> + hi = (u32)((u64)MAX_TAIL_CALL_CNT >> 32);
>> + emit(ARM_LDR_I(tmp[1], ARM_SP, STACK_VAR(tcc[1])), ctx);
>> + emit(ARM_LDR_I(tmp[0], ARM_SP, STACK_VAR(tcc[0])), ctx);
>> + emit(ARM_CMP_I(tmp[0], hi), ctx);
>> + _emit(ARM_COND_EQ, ARM_CMP_I(tmp[1], lo), ctx);
>> + _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx);
>> + emit(ARM_ADDS_I(tmp[1], tmp[1], 1), ctx);
>> + emit(ARM_ADC_I(tmp[0], tmp[0], 0), ctx);
>> + emit(ARM_STR_I(tmp[1], ARM_SP, STACK_VAR(tcc[1])), ctx);
>> + emit(ARM_STR_I(tmp[0], ARM_SP, STACK_VAR(tcc[0])), ctx);
>> +
>> + /* prog = array->ptrs[index]
>> + * if (prog == NULL)
>> + * goto out;
>> + */
>> + off = offsetof(struct bpf_array, ptrs);
>> + emit_a32_mov_i(tmp[1], off, false, ctx);
>> + emit(ARM_LDR_I(tmp2[1], ARM_SP, STACK_VAR(r2[1])), ctx);
>> + emit(ARM_LDR_R(tmp[1], tmp2[1], tmp[1]), ctx);
>> + emit(ARM_LDR_I(tmp2[1], ARM_SP, STACK_VAR(r3[1])), ctx);
>> + emit(ARM_MOV_SI(tmp[0], tmp2[1], SRTYPE_ASL, 2), ctx);
>> + emit(ARM_LDR_R(tmp[1], tmp[1], tmp[0]), ctx);
>> + emit(ARM_CMP_I(tmp[1], 0), ctx);
>> + _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
>> +
>> + /* goto *(prog->bpf_func + prologue_size); */
>> + off = offsetof(struct bpf_prog, bpf_func);
>> + emit_a32_mov_i(tmp2[1], off, false, ctx);
>> + emit(ARM_LDR_R(tmp[1], tmp[1], tmp2[1]), ctx);
>> + emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx);
>> + emit(ARM_BX(tmp[1]), ctx);
>> +
>> + /* out: */
>> + if (out_offset == -1)
>> + out_offset = cur_offset;
>> + if (cur_offset != out_offset) {
>> + pr_err_once("tail_call out_offset = %d, expected %d!\n",
>> + cur_offset, out_offset);
>> + return -1;
>> + }
>> + return 0;
>> +#undef cur_offset
>> +#undef jmp_offset
>> +}
>> +
>> +/* 0xabcd => 0xcdab */
>> +static inline void emit_rev16(const u8 rd, const u8 rn, struct jit_ctx *ctx)
>> {
>> - if (!(ctx->seen & SEEN_X))
>> - ctx->flags |= FLAG_NEED_X_RESET;
>> +#if __LINUX_ARM_ARCH__ < 6
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> +
>> + emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx);
>> + emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 8), ctx);
>> + emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx);
>> + emit(ARM_ORR_SI(rd, tmp2[0], tmp2[1], SRTYPE_LSL, 8), ctx);
>> +#else /* ARMv6+ */
>> + emit(ARM_REV16(rd, rn), ctx);
>> +#endif
>> +}
>>
>> - ctx->seen |= SEEN_X;
>> +/* 0xabcdefgh => 0xghefcdab */
>> +static inline void emit_rev32(const u8 rd, const u8 rn, struct jit_ctx *ctx)
>> +{
>> +#if __LINUX_ARM_ARCH__ < 6
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> +
>> + emit(ARM_AND_I(tmp2[1], rn, 0xff), ctx);
>> + emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 24), ctx);
>> + emit(ARM_ORR_SI(ARM_IP, tmp2[0], tmp2[1], SRTYPE_LSL, 24), ctx);
>> +
>> + emit(ARM_MOV_SI(tmp2[1], rn, SRTYPE_LSR, 8), ctx);
>> + emit(ARM_AND_I(tmp2[1], tmp2[1], 0xff), ctx);
>> + emit(ARM_MOV_SI(tmp2[0], rn, SRTYPE_LSR, 16), ctx);
>> + emit(ARM_AND_I(tmp2[0], tmp2[0], 0xff), ctx);
>> + emit(ARM_MOV_SI(tmp2[0], tmp2[0], SRTYPE_LSL, 8), ctx);
>> + emit(ARM_ORR_SI(tmp2[0], tmp2[0], tmp2[1], SRTYPE_LSL, 16), ctx);
>> + emit(ARM_ORR_R(rd, ARM_IP, tmp2[0]), ctx);
>> +
>> +#else /* ARMv6+ */
>> + emit(ARM_REV(rd, rn), ctx);
>> +#endif
>> }
>>
>> -static int build_body(struct jit_ctx *ctx)
>> +static void build_prologue(struct jit_ctx *ctx)
>> {
>> - void *load_func[] = {jit_get_skb_b, jit_get_skb_h, jit_get_skb_w};
>> - const struct bpf_prog *prog = ctx->skf;
>> - const struct sock_filter *inst;
>> - unsigned i, load_order, off, condt;
>> - int imm12;
>> - u32 k;
>> + const u8 r0 = bpf2a32[BPF_REG_0][1];
>> + const u8 r2 = bpf2a32[BPF_REG_1][1];
>> + const u8 r3 = bpf2a32[BPF_REG_1][0];
>> + const u8 r4 = bpf2a32[BPF_REG_6][1];
>> + const u8 r5 = bpf2a32[BPF_REG_6][0];
>> + const u8 r6 = bpf2a32[TMP_REG_1][1];
>> + const u8 r7 = bpf2a32[TMP_REG_1][0];
>> + const u8 r8 = bpf2a32[TMP_REG_2][1];
>> + const u8 r10 = bpf2a32[TMP_REG_2][0];
>> + const u8 fplo = bpf2a32[BPF_REG_FP][1];
>> + const u8 fphi = bpf2a32[BPF_REG_FP][0];
>> + const u8 sp = ARM_SP;
>> + const u8 *tcc = bpf2a32[TCALL_CNT];
>> +
>> + u16 reg_set = 0;
>>
>> - for (i = 0; i < prog->len; i++) {
>> - u16 code;
>> + /*
>> + * eBPF prog stack layout
>> + *
>> + * high
>> + * original ARM_SP => +-----+ eBPF prologue
>> + * |FP/LR|
>> + * current ARM_FP => +-----+
>> + * | ... | callee saved registers
>> + * eBPF fp register => +-----+ <= (BPF_FP)
>> + * | ... | eBPF JIT scratch space
>> + * | | eBPF prog stack
>> + * +-----+
>> + * |RSVD | JIT scratchpad
>> + * current A64_SP => +-----+ <= (BPF_FP - STACK_SIZE)
>> + * | |
>> + * | ... | Function call stack
>> + * | |
>> + * +-----+
>> + * low
>> + */
>>
>> - inst = &(prog->insns[i]);
>> - /* K as an immediate value operand */
>> - k = inst->k;
>> - code = bpf_anc_helper(inst);
>> + /* Save callee saved registers. */
>> + reg_set |= (1<<r4) | (1<<r5) | (1<<r6) | (1<<r7) | (1<<r8) | (1<<r10);
>> +#ifdef CONFIG_FRAME_POINTER
>> + reg_set |= (1<<ARM_FP) | (1<<ARM_IP) | (1<<ARM_LR) | (1<<ARM_PC);
>> + emit(ARM_MOV_R(ARM_IP, sp), ctx);
>> + emit(ARM_PUSH(reg_set), ctx);
>> + emit(ARM_SUB_I(ARM_FP, ARM_IP, 4), ctx);
>> +#else
>> + /* Check if call instruction exists in BPF body */
>> + if (ctx->seen & SEEN_CALL)
>> + reg_set |= (1<<ARM_LR);
>> + emit(ARM_PUSH(reg_set), ctx);
>> +#endif
>> + /* Save frame pointer for later */
>> + emit(ARM_SUB_I(ARM_IP, sp, SCRATCH_SIZE), ctx);
>> +
>> + /* Set up function call stack */
>> + emit(ARM_SUB_I(ARM_SP, ARM_SP, imm8m(STACK_SIZE)), ctx);
>> +
>> + /* Set up BPF prog stack base register */
>> + emit_a32_mov_r(fplo, ARM_IP, true, false, ctx);
>> + emit_a32_mov_i(fphi, 0, true, ctx);
>> +
>> + /* mov r4, 0 */
>> + emit(ARM_MOV_I(r4, 0), ctx);
>> + /* MOV bpf_ctx pointer to BPF_R1 */
>> + emit(ARM_MOV_R(r3, r4), ctx);
>> + emit(ARM_MOV_R(r2, r0), ctx);
>> + /* Initialize Tail Count */
>> + emit(ARM_STR_I(r4, ARM_SP, STACK_VAR(tcc[0])), ctx);
>> + emit(ARM_STR_I(r4, ARM_SP, STACK_VAR(tcc[1])), ctx);
>> + /* end of prologue */
>> +}
>>
>> - /* compute offsets only in the fake pass */
>> - if (ctx->target == NULL)
>> - ctx->offsets[i] = ctx->idx * 4;
>> +static void build_epilogue(struct jit_ctx *ctx)
>> +{
>> + const u8 r4 = bpf2a32[BPF_REG_6][1];
>> + const u8 r5 = bpf2a32[BPF_REG_6][0];
>> + const u8 r6 = bpf2a32[TMP_REG_1][1];
>> + const u8 r7 = bpf2a32[TMP_REG_1][0];
>> + const u8 r8 = bpf2a32[TMP_REG_2][1];
>> + const u8 r10 = bpf2a32[TMP_REG_2][0];
>> + u16 reg_set = 0;
>> +
>> + /* unwind function call stack */
>> + emit(ARM_ADD_I(ARM_SP, ARM_SP, imm8m(STACK_SIZE)), ctx);
>> +
>> + /* restore callee saved registers. */
>> + reg_set |= (1<<r4) | (1<<r5) | (1<<r6) | (1<<r7) | (1<<r8) | (1<<r10);
>> +#ifdef CONFIG_FRAME_POINTER
>> + /* the first instruction of the prologue was: mov ip, sp */
>> + reg_set |= (1<<ARM_FP) | (1<<ARM_SP) | (1<<ARM_PC);
>> + emit(ARM_LDM(ARM_SP, reg_set), ctx);
>> +#else
>> + if (ctx->seen & SEEN_CALL)
>> + reg_set |= (1<<ARM_PC);
>> + /* Restore callee saved registers. */
>> + emit(ARM_POP(reg_set), ctx);
>> + /* Return back to the callee function */
>> + if (!(ctx->seen & SEEN_CALL))
>> + emit(ARM_BX(ARM_LR), ctx);
>> +#endif
>> +}
>>
>> - switch (code) {
>> - case BPF_LD | BPF_IMM:
>> - emit_mov_i(r_A, k, ctx);
>> +/*
>> + * Convert an eBPF instruction to native instruction, i.e
>> + * JITs an eBPF instruction.
>> + * Returns :
>> + * 0 - Successfully JITed an 8-byte eBPF instruction
>> + * >0 - Successfully JITed a 16-byte eBPF instruction
>> + * <0 - Failed to JIT.
>> + */
>> +static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
>> +{
>> + const u8 code = insn->code;
>> + const u8 *dst = bpf2a32[insn->dst_reg];
>> + const u8 *src = bpf2a32[insn->src_reg];
>> + const u8 *tmp = bpf2a32[TMP_REG_1];
>> + const u8 *tmp2 = bpf2a32[TMP_REG_2];
>> + const s16 off = insn->off;
>> + const s32 imm = insn->imm;
>> + const int i = insn - ctx->prog->insnsi;
>> + const bool is64 = BPF_CLASS(code) == BPF_ALU64;
>> + const bool dstk = is_on_stack(insn->dst_reg);
>> + const bool sstk = is_on_stack(insn->src_reg);
>> + u8 rd, rt, rm, rn;
>> + s32 jmp_offset;
>> +
>> +#define check_imm(bits, imm) do { \
>> + if ((((imm) > 0) && ((imm) >> (bits))) || \
>> + (((imm) < 0) && (~(imm) >> (bits)))) { \
>> + pr_info("[%2d] imm=%d(0x%x) out of range\n", \
>> + i, imm, imm); \
>> + return -EINVAL; \
>> + } \
>> +} while (0)
>> +#define check_imm24(imm) check_imm(24, imm)
>> +
>> + switch (code) {
>> + /* ALU operations */
>> +
>> + /* dst = src */
>> + case BPF_ALU | BPF_MOV | BPF_K:
>> + case BPF_ALU | BPF_MOV | BPF_X:
>> + case BPF_ALU64 | BPF_MOV | BPF_K:
>> + case BPF_ALU64 | BPF_MOV | BPF_X:
>> + switch (BPF_SRC(code)) {
>> + case BPF_X:
>> + emit_a32_mov_r64(is64, dst, src, dstk, sstk, ctx);
>> break;
>> - case BPF_LD | BPF_W | BPF_LEN:
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, len) != 4);
>> - emit(ARM_LDR_I(r_A, r_skb,
>> - offsetof(struct sk_buff, len)), ctx);
>> + case BPF_K:
>> + /* Sign-extend immediate value to destination reg */
>> + emit_a32_mov_i64(is64, dst, imm, dstk, ctx);
>> break;
>> - case BPF_LD | BPF_MEM:
>> - /* A = scratch[k] */
>> - ctx->seen |= SEEN_MEM_WORD(k);
>> - emit(ARM_LDR_I(r_A, ARM_SP, SCRATCH_OFF(k)), ctx);
>> + }
>> + break;
>> + /* dst = dst + src/imm */
>> + /* dst = dst - src/imm */
>> + /* dst = dst | src/imm */
>> + /* dst = dst & src/imm */
>> + /* dst = dst ^ src/imm */
>> + /* dst = dst * src/imm */
>> + /* dst = dst << src */
>> + /* dst = dst >> src */
>> + case BPF_ALU | BPF_ADD | BPF_K:
>> + case BPF_ALU | BPF_ADD | BPF_X:
>> + case BPF_ALU | BPF_SUB | BPF_K:
>> + case BPF_ALU | BPF_SUB | BPF_X:
>> + case BPF_ALU | BPF_OR | BPF_K:
>> + case BPF_ALU | BPF_OR | BPF_X:
>> + case BPF_ALU | BPF_AND | BPF_K:
>> + case BPF_ALU | BPF_AND | BPF_X:
>> + case BPF_ALU | BPF_XOR | BPF_K:
>> + case BPF_ALU | BPF_XOR | BPF_X:
>> + case BPF_ALU | BPF_MUL | BPF_K:
>> + case BPF_ALU | BPF_MUL | BPF_X:
>> + case BPF_ALU | BPF_LSH | BPF_X:
>> + case BPF_ALU | BPF_RSH | BPF_X:
>> + case BPF_ALU | BPF_ARSH | BPF_K:
>> + case BPF_ALU | BPF_ARSH | BPF_X:
>> + case BPF_ALU64 | BPF_ADD | BPF_K:
>> + case BPF_ALU64 | BPF_ADD | BPF_X:
>> + case BPF_ALU64 | BPF_SUB | BPF_K:
>> + case BPF_ALU64 | BPF_SUB | BPF_X:
>> + case BPF_ALU64 | BPF_OR | BPF_K:
>> + case BPF_ALU64 | BPF_OR | BPF_X:
>> + case BPF_ALU64 | BPF_AND | BPF_K:
>> + case BPF_ALU64 | BPF_AND | BPF_X:
>> + case BPF_ALU64 | BPF_XOR | BPF_K:
>> + case BPF_ALU64 | BPF_XOR | BPF_X:
>> + switch (BPF_SRC(code)) {
>> + case BPF_X:
>> + emit_a32_alu_r64(is64, dst, src, dstk, sstk,
>> + ctx, BPF_OP(code));
>> break;
>> - case BPF_LD | BPF_W | BPF_ABS:
>> - load_order = 2;
>> - goto load;
>> - case BPF_LD | BPF_H | BPF_ABS:
>> - load_order = 1;
>> - goto load;
>> - case BPF_LD | BPF_B | BPF_ABS:
>> - load_order = 0;
>> -load:
>> - emit_mov_i(r_off, k, ctx);
>> -load_common:
>> - ctx->seen |= SEEN_DATA | SEEN_CALL;
>> -
>> - if (load_order > 0) {
>> - emit(ARM_SUB_I(r_scratch, r_skb_hl,
>> - 1 << load_order), ctx);
>> - emit(ARM_CMP_R(r_scratch, r_off), ctx);
>> - condt = ARM_COND_GE;
>> - } else {
>> - emit(ARM_CMP_R(r_skb_hl, r_off), ctx);
>> - condt = ARM_COND_HI;
>> - }
>> -
>> - /*
>> - * test for negative offset, only if we are
>> - * currently scheduled to take the fast
>> - * path. this will update the flags so that
>> - * the slowpath instruction are ignored if the
>> - * offset is negative.
>> - *
>> - * for loard_order == 0 the HI condition will
>> - * make loads at offset 0 take the slow path too.
>> + case BPF_K:
>> + /* Move immediate value to the temporary register
>> + * and then do the ALU operation on the temporary
>> + * register as this will sign-extend the immediate
>> + * value into temporary reg and then it would be
>> + * safe to do the operation on it.
>> */
>> - _emit(condt, ARM_CMP_I(r_off, 0), ctx);
>> -
>> - _emit(condt, ARM_ADD_R(r_scratch, r_off, r_skb_data),
>> - ctx);
>> -
>> - if (load_order == 0)
>> - _emit(condt, ARM_LDRB_I(r_A, r_scratch, 0),
>> - ctx);
>> - else if (load_order == 1)
>> - emit_load_be16(condt, r_A, r_scratch, ctx);
>> - else if (load_order == 2)
>> - emit_load_be32(condt, r_A, r_scratch, ctx);
>> -
>> - _emit(condt, ARM_B(b_imm(i + 1, ctx)), ctx);
>> -
>> - /* the slowpath */
>> - emit_mov_i(ARM_R3, (u32)load_func[load_order], ctx);
>> - emit(ARM_MOV_R(ARM_R0, r_skb), ctx);
>> - /* the offset is already in R1 */
>> - emit_blx_r(ARM_R3, ctx);
>> - /* check the result of skb_copy_bits */
>> - emit(ARM_CMP_I(ARM_R1, 0), ctx);
>> - emit_err_ret(ARM_COND_NE, ctx);
>> - emit(ARM_MOV_R(r_A, ARM_R0), ctx);
>> + emit_a32_mov_i64(is64, tmp2, imm, false, ctx);
>> + emit_a32_alu_r64(is64, dst, tmp2, dstk, false,
>> + ctx, BPF_OP(code));
>> break;
>> - case BPF_LD | BPF_W | BPF_IND:
>> - load_order = 2;
>> - goto load_ind;
>> - case BPF_LD | BPF_H | BPF_IND:
>> - load_order = 1;
>> - goto load_ind;
>> - case BPF_LD | BPF_B | BPF_IND:
>> - load_order = 0;
>> -load_ind:
>> - update_on_xread(ctx);
>> - OP_IMM3(ARM_ADD, r_off, r_X, k, ctx);
>> - goto load_common;
>> - case BPF_LDX | BPF_IMM:
>> - ctx->seen |= SEEN_X;
>> - emit_mov_i(r_X, k, ctx);
>> + }
>> + break;
>> + /* dst = dst / src(imm) */
>> + /* dst = dst % src(imm) */
>> + case BPF_ALU | BPF_DIV | BPF_K:
>> + case BPF_ALU | BPF_DIV | BPF_X:
>> + case BPF_ALU | BPF_MOD | BPF_K:
>> + case BPF_ALU | BPF_MOD | BPF_X:
>> + rt = src_lo;
>> + rd = dstk ? tmp2[1] : dst_lo;
>> + if (dstk)
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + switch (BPF_SRC(code)) {
>> + case BPF_X:
>> + rt = sstk ? tmp2[0] : rt;
>> + if (sstk)
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(src_lo)),
>> + ctx);
>> break;
>> - case BPF_LDX | BPF_W | BPF_LEN:
>> - ctx->seen |= SEEN_X | SEEN_SKB;
>> - emit(ARM_LDR_I(r_X, r_skb,
>> - offsetof(struct sk_buff, len)), ctx);
>> + case BPF_K:
>> + rt = tmp2[0];
>> + emit_a32_mov_i(rt, imm, false, ctx);
>> break;
>> - case BPF_LDX | BPF_MEM:
>> - ctx->seen |= SEEN_X | SEEN_MEM_WORD(k);
>> - emit(ARM_LDR_I(r_X, ARM_SP, SCRATCH_OFF(k)), ctx);
>> + }
>> + emit_udivmod(rd, rd, rt, ctx, BPF_OP(code));
>> + if (dstk)
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit_a32_mov_i(dst_hi, 0, dstk, ctx);
>> + break;
>> + case BPF_ALU64 | BPF_DIV | BPF_K:
>> + case BPF_ALU64 | BPF_DIV | BPF_X:
>> + case BPF_ALU64 | BPF_MOD | BPF_K:
>> + case BPF_ALU64 | BPF_MOD | BPF_X:
>> + goto notyet;
>> + /* dst = dst >> imm */
>> + /* dst = dst << imm */
>> + case BPF_ALU | BPF_RSH | BPF_K:
>> + case BPF_ALU | BPF_LSH | BPF_K:
>> + if (unlikely(imm > 31))
>> + return -EINVAL;
>> + if (imm)
>> + emit_a32_alu_i(dst_lo, imm, dstk, ctx, BPF_OP(code));
>> + emit_a32_mov_i(dst_hi, 0, dstk, ctx);
>> + break;
>> + /* dst = dst << imm */
>> + case BPF_ALU64 | BPF_LSH | BPF_K:
>> + if (unlikely(imm > 63))
>> + return -EINVAL;
>> + emit_a32_lsh_i64(dst, dstk, imm, ctx);
>> + break;
>> + /* dst = dst >> imm */
>> + case BPF_ALU64 | BPF_RSH | BPF_K:
>> + if (unlikely(imm > 63))
>> + return -EINVAL;
>> + emit_a32_lsr_i64(dst, dstk, imm, ctx);
>> + break;
>> + /* dst = dst << src */
>> + case BPF_ALU64 | BPF_LSH | BPF_X:
>> + emit_a32_lsh_r64(dst, src, dstk, sstk, ctx);
>> + break;
>> + /* dst = dst >> src */
>> + case BPF_ALU64 | BPF_RSH | BPF_X:
>> + emit_a32_lsr_r64(dst, src, dstk, sstk, ctx);
>> + break;
>> + /* dst = dst >> src (signed) */
>> + case BPF_ALU64 | BPF_ARSH | BPF_X:
>> + emit_a32_arsh_r64(dst, src, dstk, sstk, ctx);
>> + break;
>> + /* dst = dst >> imm (signed) */
>> + case BPF_ALU64 | BPF_ARSH | BPF_K:
>> + if (unlikely(imm > 63))
>> + return -EINVAL;
>> + emit_a32_arsh_i64(dst, dstk, imm, ctx);
>> + break;
>> + /* dst = ~dst */
>> + case BPF_ALU | BPF_NEG:
>> + emit_a32_alu_i(dst_lo, 0, dstk, ctx, BPF_OP(code));
>> + emit_a32_mov_i(dst_hi, 0, dstk, ctx);
>> + break;
>> + /* dst = ~dst (64 bit) */
>> + case BPF_ALU64 | BPF_NEG:
>> + emit_a32_neg64(dst, dstk, ctx);
>> + break;
>> + /* dst = dst * src/imm */
>> + case BPF_ALU64 | BPF_MUL | BPF_X:
>> + case BPF_ALU64 | BPF_MUL | BPF_K:
>> + switch (BPF_SRC(code)) {
>> + case BPF_X:
>> + emit_a32_mul_r64(dst, src, dstk, sstk, ctx);
>> break;
>> - case BPF_LDX | BPF_B | BPF_MSH:
>> - /* x = ((*(frame + k)) & 0xf) << 2; */
>> - ctx->seen |= SEEN_X | SEEN_DATA | SEEN_CALL;
>> - /* the interpreter should deal with the negative K */
>> - if ((int)k < 0)
>> - return -1;
>> - /* offset in r1: we might have to take the slow path */
>> - emit_mov_i(r_off, k, ctx);
>> - emit(ARM_CMP_R(r_skb_hl, r_off), ctx);
>> -
>> - /* load in r0: common with the slowpath */
>> - _emit(ARM_COND_HI, ARM_LDRB_R(ARM_R0, r_skb_data,
>> - ARM_R1), ctx);
>> - /*
>> - * emit_mov_i() might generate one or two instructions,
>> - * the same holds for emit_blx_r()
>> + case BPF_K:
>> + /* Move immediate value to the temporary register
>> + * and then do the multiplication on it as this
>> + * will sign-extend the immediate value into temp
>> + * reg then it would be safe to do the operation
>> + * on it.
>> */
>> - _emit(ARM_COND_HI, ARM_B(b_imm(i + 1, ctx) - 2), ctx);
>> -
>> - emit(ARM_MOV_R(ARM_R0, r_skb), ctx);
>> - /* r_off is r1 */
>> - emit_mov_i(ARM_R3, (u32)jit_get_skb_b, ctx);
>> - emit_blx_r(ARM_R3, ctx);
>> - /* check the return value of skb_copy_bits */
>> - emit(ARM_CMP_I(ARM_R1, 0), ctx);
>> - emit_err_ret(ARM_COND_NE, ctx);
>> -
>> - emit(ARM_AND_I(r_X, ARM_R0, 0x00f), ctx);
>> - emit(ARM_LSL_I(r_X, r_X, 2), ctx);
>> - break;
>> - case BPF_ST:
>> - ctx->seen |= SEEN_MEM_WORD(k);
>> - emit(ARM_STR_I(r_A, ARM_SP, SCRATCH_OFF(k)), ctx);
>> - break;
>> - case BPF_STX:
>> - update_on_xread(ctx);
>> - ctx->seen |= SEEN_MEM_WORD(k);
>> - emit(ARM_STR_I(r_X, ARM_SP, SCRATCH_OFF(k)), ctx);
>> - break;
>> - case BPF_ALU | BPF_ADD | BPF_K:
>> - /* A += K */
>> - OP_IMM3(ARM_ADD, r_A, r_A, k, ctx);
>> - break;
>> - case BPF_ALU | BPF_ADD | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_ADD_R(r_A, r_A, r_X), ctx);
>> - break;
>> - case BPF_ALU | BPF_SUB | BPF_K:
>> - /* A -= K */
>> - OP_IMM3(ARM_SUB, r_A, r_A, k, ctx);
>> - break;
>> - case BPF_ALU | BPF_SUB | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_SUB_R(r_A, r_A, r_X), ctx);
>> - break;
>> - case BPF_ALU | BPF_MUL | BPF_K:
>> - /* A *= K */
>> - emit_mov_i(r_scratch, k, ctx);
>> - emit(ARM_MUL(r_A, r_A, r_scratch), ctx);
>> - break;
>> - case BPF_ALU | BPF_MUL | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_MUL(r_A, r_A, r_X), ctx);
>> - break;
>> - case BPF_ALU | BPF_DIV | BPF_K:
>> - if (k == 1)
>> - break;
>> - emit_mov_i(r_scratch, k, ctx);
>> - emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_DIV);
>> - break;
>> - case BPF_ALU | BPF_DIV | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_CMP_I(r_X, 0), ctx);
>> - emit_err_ret(ARM_COND_EQ, ctx);
>> - emit_udivmod(r_A, r_A, r_X, ctx, BPF_DIV);
>> - break;
>> - case BPF_ALU | BPF_MOD | BPF_K:
>> - if (k == 1) {
>> - emit_mov_i(r_A, 0, ctx);
>> - break;
>> - }
>> - emit_mov_i(r_scratch, k, ctx);
>> - emit_udivmod(r_A, r_A, r_scratch, ctx, BPF_MOD);
>> + emit_a32_mov_i64(is64, tmp2, imm, false, ctx);
>> + emit_a32_mul_r64(dst, tmp2, dstk, false, ctx);
>> break;
>> - case BPF_ALU | BPF_MOD | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_CMP_I(r_X, 0), ctx);
>> - emit_err_ret(ARM_COND_EQ, ctx);
>> - emit_udivmod(r_A, r_A, r_X, ctx, BPF_MOD);
>> - break;
>> - case BPF_ALU | BPF_OR | BPF_K:
>> - /* A |= K */
>> - OP_IMM3(ARM_ORR, r_A, r_A, k, ctx);
>> + }
>> + break;
>> + /* dst = htole(dst) */
>> + /* dst = htobe(dst) */
>> + case BPF_ALU | BPF_END | BPF_FROM_LE:
>> + case BPF_ALU | BPF_END | BPF_FROM_BE:
>> + rd = dstk ? tmp[0] : dst_hi;
>> + rt = dstk ? tmp[1] : dst_lo;
>> + if (dstk) {
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> + if (BPF_SRC(code) == BPF_FROM_LE)
>> + goto emit_bswap_uxt;
>> + switch (imm) {
>> + case 16:
>> + emit_rev16(rt, rt, ctx);
>> + goto emit_bswap_uxt;
>> + case 32:
>> + emit_rev32(rt, rt, ctx);
>> + goto emit_bswap_uxt;
>> + case 64:
>> + /* Because of the usage of ARM_LR */
>> + ctx->seen |= SEEN_CALL;
>> + emit_rev32(ARM_LR, rt, ctx);
>> + emit_rev32(rt, rd, ctx);
>> + emit(ARM_MOV_R(rd, ARM_LR), ctx);
>> break;
>> - case BPF_ALU | BPF_OR | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_ORR_R(r_A, r_A, r_X), ctx);
>> + }
>> + goto exit;
>> +emit_bswap_uxt:
>> + switch (imm) {
>> + case 16:
>> + /* zero-extend 16 bits into 64 bits */
>> +#if __LINUX_ARM_ARCH__ < 6
>> + emit_a32_mov_i(tmp2[1], 0xffff, false, ctx);
>> + emit(ARM_AND_R(rt, rt, tmp2[1]), ctx);
>> +#else /* ARMv6+ */
>> + emit(ARM_UXTH(rt, rt), ctx);
>> +#endif
>> + emit(ARM_EOR_R(rd, rd, rd), ctx);
>> break;
>> - case BPF_ALU | BPF_XOR | BPF_K:
>> - /* A ^= K; */
>> - OP_IMM3(ARM_EOR, r_A, r_A, k, ctx);
>> + case 32:
>> + /* zero-extend 32 bits into 64 bits */
>> + emit(ARM_EOR_R(rd, rd, rd), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_ALU_XOR_X:
>> - case BPF_ALU | BPF_XOR | BPF_X:
>> - /* A ^= X */
>> - update_on_xread(ctx);
>> - emit(ARM_EOR_R(r_A, r_A, r_X), ctx);
>> + case 64:
>> + /* nop */
>> break;
>> - case BPF_ALU | BPF_AND | BPF_K:
>> - /* A &= K */
>> - OP_IMM3(ARM_AND, r_A, r_A, k, ctx);
>> + }
>> +exit:
>> + if (dstk) {
>> + emit(ARM_STR_I(rt, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_STR_I(rd, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> + break;
>> + /* dst = imm64 */
>> + case BPF_LD | BPF_IMM | BPF_DW:
>> + {
>> + const struct bpf_insn insn1 = insn[1];
>> + u32 hi, lo = imm;
>> +
>> + if (insn1.code != 0 || insn1.src_reg != 0 ||
>> + insn1.dst_reg != 0 || insn1.off != 0) {
>> + /* Note: verifier in BPF core must catch invalid
>> + * instruction.
>> + */
>> + pr_err_once("Invalid BPF_LD_IMM64 instruction\n");
>> + return -EINVAL;
>> + }
>> + hi = insn1.imm;
>> + emit_a32_mov_i(dst_lo, lo, dstk, ctx);
>> + emit_a32_mov_i(dst_hi, hi, dstk, ctx);
>> +
>> + return 1;
>> + }
>> + /* LDX: dst = *(size *)(src + off) */
>> + case BPF_LDX | BPF_MEM | BPF_W:
>> + case BPF_LDX | BPF_MEM | BPF_H:
>> + case BPF_LDX | BPF_MEM | BPF_B:
>> + case BPF_LDX | BPF_MEM | BPF_DW:
>> + rn = sstk ? tmp2[1] : src_lo;
>> + if (sstk)
>> + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + switch (BPF_SIZE(code)) {
>> + case BPF_W:
>> + /* Load a Word */
>> + case BPF_H:
>> + /* Load a Half-Word */
>> + case BPF_B:
>> + /* Load a Byte */
>> + emit_ldx_r(dst_lo, rn, dstk, off, ctx, BPF_SIZE(code));
>> + emit_a32_mov_i(dst_hi, 0, dstk, ctx);
>> break;
>> - case BPF_ALU | BPF_AND | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_AND_R(r_A, r_A, r_X), ctx);
>> + case BPF_DW:
>> + /* Load a double word */
>> + emit_ldx_r(dst_lo, rn, dstk, off, ctx, BPF_W);
>> + emit_ldx_r(dst_hi, rn, dstk, off+4, ctx, BPF_W);
>> break;
>> - case BPF_ALU | BPF_LSH | BPF_K:
>> - if (unlikely(k > 31))
>> - return -1;
>> - emit(ARM_LSL_I(r_A, r_A, k), ctx);
>> + }
>> + break;
>> + /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */
>> + case BPF_LD | BPF_ABS | BPF_W:
>> + case BPF_LD | BPF_ABS | BPF_H:
>> + case BPF_LD | BPF_ABS | BPF_B:
>> + /* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */
>> + case BPF_LD | BPF_IND | BPF_W:
>> + case BPF_LD | BPF_IND | BPF_H:
>> + case BPF_LD | BPF_IND | BPF_B:
>> + {
>> + const u8 r4 = bpf2a32[BPF_REG_6][1]; /* r4 = ptr to sk_buff */
>> + const u8 r0 = bpf2a32[BPF_REG_0][1]; /*r0: struct sk_buff *skb*/
>> + /* rtn value */
>> + const u8 r1 = bpf2a32[BPF_REG_0][0]; /* r1: int k */
>> + const u8 r2 = bpf2a32[BPF_REG_1][1]; /* r2: unsigned int size */
>> + const u8 r3 = bpf2a32[BPF_REG_1][0]; /* r3: void *buffer */
>> + const u8 r6 = bpf2a32[TMP_REG_1][1]; /* r6: void *(*func)(..) */
>> + int size;
>> +
>> + /* Setting up first argument */
>> + emit(ARM_MOV_R(r0, r4), ctx);
>> +
>> + /* Setting up second argument */
>> + emit_a32_mov_i(r1, imm, false, ctx);
>> + if (BPF_MODE(code) == BPF_IND)
>> + emit_a32_alu_r(r1, src_lo, false, sstk, ctx,
>> + false, false, BPF_ADD);
>> +
>> + /* Setting up third argument */
>> + switch (BPF_SIZE(code)) {
>> + case BPF_W:
>> + size = 4;
>> break;
>> - case BPF_ALU | BPF_LSH | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_LSL_R(r_A, r_A, r_X), ctx);
>> + case BPF_H:
>> + size = 2;
>> break;
>> - case BPF_ALU | BPF_RSH | BPF_K:
>> - if (unlikely(k > 31))
>> - return -1;
>> - if (k)
>> - emit(ARM_LSR_I(r_A, r_A, k), ctx);
>> + case BPF_B:
>> + size = 1;
>> break;
>> - case BPF_ALU | BPF_RSH | BPF_X:
>> - update_on_xread(ctx);
>> - emit(ARM_LSR_R(r_A, r_A, r_X), ctx);
>> + default:
>> + return -EINVAL;
>> + }
>> + emit_a32_mov_i(r2, size, false, ctx);
>> +
>> + /* Setting up fourth argument */
>> + emit(ARM_ADD_I(r3, ARM_SP, imm8m(SKB_BUFFER)), ctx);
>> +
>> + /* Setting up function pointer to call */
>> + emit_a32_mov_i(r6, (unsigned int)bpf_load_pointer, false, ctx);
>> + emit_blx_r(r6, ctx);
>> +
>> + emit(ARM_EOR_R(r1, r1, r1), ctx);
>> + /* Check if return address is NULL or not.
>> + * if NULL then jump to epilogue
>> + * else continue to load the value from retn address
>> + */
>> + emit(ARM_CMP_I(r0, 0), ctx);
>> + jmp_offset = epilogue_offset(ctx);
>> + check_imm24(jmp_offset);
>> + _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
>> +
>> + /* Load value from the address */
>> + switch (BPF_SIZE(code)) {
>> + case BPF_W:
>> + emit(ARM_LDR_I(r0, r0, 0), ctx);
>> + emit_rev32(r0, r0, ctx);
>> break;
>> - case BPF_ALU | BPF_NEG:
>> - /* A = -A */
>> - emit(ARM_RSB_I(r_A, r_A, 0), ctx);
>> + case BPF_H:
>> + emit(ARM_LDRH_I(r0, r0, 0), ctx);
>> + emit_rev16(r0, r0, ctx);
>> break;
>> - case BPF_JMP | BPF_JA:
>> - /* pc += K */
>> - emit(ARM_B(b_imm(i + k + 1, ctx)), ctx);
>> + case BPF_B:
>> + emit(ARM_LDRB_I(r0, r0, 0), ctx);
>> + /* No need to reverse */
>> break;
>> - case BPF_JMP | BPF_JEQ | BPF_K:
>> - /* pc += (A == K) ? pc->jt : pc->jf */
>> - condt = ARM_COND_EQ;
>> - goto cmp_imm;
>> - case BPF_JMP | BPF_JGT | BPF_K:
>> - /* pc += (A > K) ? pc->jt : pc->jf */
>> - condt = ARM_COND_HI;
>> - goto cmp_imm;
>> - case BPF_JMP | BPF_JGE | BPF_K:
>> - /* pc += (A >= K) ? pc->jt : pc->jf */
>> - condt = ARM_COND_HS;
>> -cmp_imm:
>> - imm12 = imm8m(k);
>> - if (imm12 < 0) {
>> - emit_mov_i_no8m(r_scratch, k, ctx);
>> - emit(ARM_CMP_R(r_A, r_scratch), ctx);
>> - } else {
>> - emit(ARM_CMP_I(r_A, imm12), ctx);
>> - }
>> -cond_jump:
>> - if (inst->jt)
>> - _emit(condt, ARM_B(b_imm(i + inst->jt + 1,
>> - ctx)), ctx);
>> - if (inst->jf)
>> - _emit(condt ^ 1, ARM_B(b_imm(i + inst->jf + 1,
>> - ctx)), ctx);
>> + }
>> + break;
>> + }
>> + /* ST: *(size *)(dst + off) = imm */
>> + case BPF_ST | BPF_MEM | BPF_W:
>> + case BPF_ST | BPF_MEM | BPF_H:
>> + case BPF_ST | BPF_MEM | BPF_B:
>> + case BPF_ST | BPF_MEM | BPF_DW:
>> + switch (BPF_SIZE(code)) {
>> + case BPF_DW:
>> + /* Sign-extend immediate value into temp reg */
>> + emit_a32_mov_i64(true, tmp2, imm, false, ctx);
>> + emit_str_r(dst_lo, tmp2[1], dstk, off, ctx, BPF_W);
>> + emit_str_r(dst_lo, tmp2[0], dstk, off+4, ctx, BPF_W);
>> break;
>> - case BPF_JMP | BPF_JEQ | BPF_X:
>> - /* pc += (A == X) ? pc->jt : pc->jf */
>> - condt = ARM_COND_EQ;
>> - goto cmp_x;
>> - case BPF_JMP | BPF_JGT | BPF_X:
>> - /* pc += (A > X) ? pc->jt : pc->jf */
>> - condt = ARM_COND_HI;
>> - goto cmp_x;
>> - case BPF_JMP | BPF_JGE | BPF_X:
>> - /* pc += (A >= X) ? pc->jt : pc->jf */
>> - condt = ARM_COND_CS;
>> -cmp_x:
>> - update_on_xread(ctx);
>> - emit(ARM_CMP_R(r_A, r_X), ctx);
>> - goto cond_jump;
>> - case BPF_JMP | BPF_JSET | BPF_K:
>> - /* pc += (A & K) ? pc->jt : pc->jf */
>> - condt = ARM_COND_NE;
>> - /* not set iff all zeroes iff Z==1 iff EQ */
>> -
>> - imm12 = imm8m(k);
>> - if (imm12 < 0) {
>> - emit_mov_i_no8m(r_scratch, k, ctx);
>> - emit(ARM_TST_R(r_A, r_scratch), ctx);
>> - } else {
>> - emit(ARM_TST_I(r_A, imm12), ctx);
>> - }
>> - goto cond_jump;
>> - case BPF_JMP | BPF_JSET | BPF_X:
>> - /* pc += (A & X) ? pc->jt : pc->jf */
>> - update_on_xread(ctx);
>> - condt = ARM_COND_NE;
>> - emit(ARM_TST_R(r_A, r_X), ctx);
>> - goto cond_jump;
>> - case BPF_RET | BPF_A:
>> - emit(ARM_MOV_R(ARM_R0, r_A), ctx);
>> - goto b_epilogue;
>> - case BPF_RET | BPF_K:
>> - if ((k == 0) && (ctx->ret0_fp_idx < 0))
>> - ctx->ret0_fp_idx = i;
>> - emit_mov_i(ARM_R0, k, ctx);
>> -b_epilogue:
>> - if (i != ctx->skf->len - 1)
>> - emit(ARM_B(b_imm(prog->len, ctx)), ctx);
>> + case BPF_W:
>> + case BPF_H:
>> + case BPF_B:
>> + emit_a32_mov_i(tmp2[1], imm, false, ctx);
>> + emit_str_r(dst_lo, tmp2[1], dstk, off, ctx,
>> + BPF_SIZE(code));
>> break;
>> - case BPF_MISC | BPF_TAX:
>> - /* X = A */
>> - ctx->seen |= SEEN_X;
>> - emit(ARM_MOV_R(r_X, r_A), ctx);
>> + }
>> + break;
>> + /* STX XADD: lock *(u32 *)(dst + off) += src */
>> + case BPF_STX | BPF_XADD | BPF_W:
>> + /* STX XADD: lock *(u64 *)(dst + off) += src */
>> + case BPF_STX | BPF_XADD | BPF_DW:
>> + goto notyet;
>> + /* STX: *(size *)(dst + off) = src */
>> + case BPF_STX | BPF_MEM | BPF_W:
>> + case BPF_STX | BPF_MEM | BPF_H:
>> + case BPF_STX | BPF_MEM | BPF_B:
>> + case BPF_STX | BPF_MEM | BPF_DW:
>> + {
>> + u8 sz = BPF_SIZE(code);
>> +
>> + rn = sstk ? tmp2[1] : src_lo;
>> + rm = sstk ? tmp2[0] : src_hi;
>> + if (!sstk)
>> + goto do_store;
>> + switch (BPF_SIZE(code)) {
>> + case BPF_W:
>> + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + goto empty_hi;
>> + case BPF_H:
>> + emit(ARM_LDRH_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + goto empty_hi;
>> + case BPF_B:
>> + emit(ARM_LDRB_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + goto empty_hi;
>> +empty_hi:
>> + emit(ARM_EOR_R(rm, rm, rm), ctx);
>> + case BPF_DW:
>> + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(src_hi)), ctx);
>> + sz = BPF_W;
>> break;
>> - case BPF_MISC | BPF_TXA:
>> - /* A = X */
>> - update_on_xread(ctx);
>> - emit(ARM_MOV_R(r_A, r_X), ctx);
>> + }
>> +
>> +do_store:
>> + /* Clear higher word except for BPF_DW */
>> + if (BPF_SIZE(code) != BPF_DW)
>> + emit(ARM_EOR_R(rm, rm, rm), ctx);
>> +
>> + /* Store the value */
>> + emit_str_r(dst_lo, rn, dstk, off, ctx, sz);
>> + emit_str_r(dst_lo, rm, dstk, off+4, ctx, BPF_W);
>> + break;
>> + }
>> + /* PC += off if dst == src */
>> + /* PC += off if dst > src */
>> + /* PC += off if dst >= src */
>> + /* PC += off if dst != src */
>> + /* PC += off if dst > src (signed) */
>> + /* PC += off if dst >= src (signed) */
>> + /* PC += off if dst & src */
>> + case BPF_JMP | BPF_JEQ | BPF_X:
>> + case BPF_JMP | BPF_JGT | BPF_X:
>> + case BPF_JMP | BPF_JGE | BPF_X:
>> + case BPF_JMP | BPF_JNE | BPF_X:
>> + case BPF_JMP | BPF_JSGT | BPF_X:
>> + case BPF_JMP | BPF_JSGE | BPF_X:
>> + case BPF_JMP | BPF_JSET | BPF_X:
>> + /* Setup source registers */
>> + rm = sstk ? tmp2[0] : src_hi;
>> + rn = sstk ? tmp2[1] : src_lo;
>> + if (sstk) {
>> + emit(ARM_LDR_I(rn, ARM_SP, STACK_VAR(src_lo)), ctx);
>> + emit(ARM_LDR_I(rm, ARM_SP, STACK_VAR(src_hi)), ctx);
>> + }
>> + goto go_jmp;
>> + /* PC += off if dst == imm */
>> + /* PC += off if dst > imm */
>> + /* PC += off if dst >= imm */
>> + /* PC += off if dst != imm */
>> + /* PC += off if dst > imm (signed) */
>> + /* PC += off if dst >= imm (signed) */
>> + /* PC += off if dst & imm */
>> + case BPF_JMP | BPF_JEQ | BPF_K:
>> + case BPF_JMP | BPF_JGT | BPF_K:
>> + case BPF_JMP | BPF_JGE | BPF_K:
>> + case BPF_JMP | BPF_JNE | BPF_K:
>> + case BPF_JMP | BPF_JSGT | BPF_K:
>> + case BPF_JMP | BPF_JSGE | BPF_K:
>> + case BPF_JMP | BPF_JSET | BPF_K:
>> + if (off == 0)
>> break;
>> - case BPF_ANC | SKF_AD_PROTOCOL:
>> - /* A = ntohs(skb->protocol) */
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
>> - protocol) != 2);
>> - off = offsetof(struct sk_buff, protocol);
>> - emit(ARM_LDRH_I(r_scratch, r_skb, off), ctx);
>> - emit_swap16(r_A, r_scratch, ctx);
>> + rm = tmp2[0];
>> + rn = tmp2[1];
>> + /* Sign-extend immediate value */
>> + emit_a32_mov_i64(true, tmp2, imm, false, ctx);
>> +go_jmp:
>> + /* Setup destination register */
>> + rd = dstk ? tmp[0] : dst_hi;
>> + rt = dstk ? tmp[1] : dst_lo;
>> + if (dstk) {
>> + emit(ARM_LDR_I(rt, ARM_SP, STACK_VAR(dst_lo)), ctx);
>> + emit(ARM_LDR_I(rd, ARM_SP, STACK_VAR(dst_hi)), ctx);
>> + }
>> +
>> + /* Check for the condition */
>> + emit_ar_r(rd, rt, rm, rn, ctx, BPF_OP(code));
>> +
>> + /* Setup JUMP instruction */
>> + jmp_offset = bpf2a32_offset(i+off, i, ctx);
>> + switch (BPF_OP(code)) {
>> + case BPF_JNE:
>> + case BPF_JSET:
>> + _emit(ARM_COND_NE, ARM_B(jmp_offset), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_CPU:
>> - /* r_scratch = current_thread_info() */
>> - OP_IMM3(ARM_BIC, r_scratch, ARM_SP, THREAD_SIZE - 1, ctx);
>> - /* A = current_thread_info()->cpu */
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct thread_info, cpu) != 4);
>> - off = offsetof(struct thread_info, cpu);
>> - emit(ARM_LDR_I(r_A, r_scratch, off), ctx);
>> + case BPF_JEQ:
>> + _emit(ARM_COND_EQ, ARM_B(jmp_offset), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_IFINDEX:
>> - case BPF_ANC | SKF_AD_HATYPE:
>> - /* A = skb->dev->ifindex */
>> - /* A = skb->dev->type */
>> - ctx->seen |= SEEN_SKB;
>> - off = offsetof(struct sk_buff, dev);
>> - emit(ARM_LDR_I(r_scratch, r_skb, off), ctx);
>> -
>> - emit(ARM_CMP_I(r_scratch, 0), ctx);
>> - emit_err_ret(ARM_COND_EQ, ctx);
>> -
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
>> - ifindex) != 4);
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct net_device,
>> - type) != 2);
>> -
>> - if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
>> - off = offsetof(struct net_device, ifindex);
>> - emit(ARM_LDR_I(r_A, r_scratch, off), ctx);
>> - } else {
>> - /*
>> - * offset of field "type" in "struct
>> - * net_device" is above what can be
>> - * used in the ldrh rd, [rn, #imm]
>> - * instruction, so load the offset in
>> - * a register and use ldrh rd, [rn, rm]
>> - */
>> - off = offsetof(struct net_device, type);
>> - emit_mov_i(ARM_R3, off, ctx);
>> - emit(ARM_LDRH_R(r_A, r_scratch, ARM_R3), ctx);
>> - }
>> + case BPF_JGT:
>> + _emit(ARM_COND_HI, ARM_B(jmp_offset), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_MARK:
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, mark) != 4);
>> - off = offsetof(struct sk_buff, mark);
>> - emit(ARM_LDR_I(r_A, r_skb, off), ctx);
>> + case BPF_JGE:
>> + _emit(ARM_COND_CS, ARM_B(jmp_offset), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_RXHASH:
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, hash) != 4);
>> - off = offsetof(struct sk_buff, hash);
>> - emit(ARM_LDR_I(r_A, r_skb, off), ctx);
>> + case BPF_JSGT:
>> + _emit(ARM_COND_LT, ARM_B(jmp_offset), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_VLAN_TAG:
>> - case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff, vlan_tci) != 2);
>> - off = offsetof(struct sk_buff, vlan_tci);
>> - emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
>> - if (code == (BPF_ANC | SKF_AD_VLAN_TAG))
>> - OP_IMM3(ARM_AND, r_A, r_A, ~VLAN_TAG_PRESENT, ctx);
>> - else {
>> - OP_IMM3(ARM_LSR, r_A, r_A, 12, ctx);
>> - OP_IMM3(ARM_AND, r_A, r_A, 0x1, ctx);
>> - }
>> + case BPF_JSGE:
>> + _emit(ARM_COND_GE, ARM_B(jmp_offset), ctx);
>> break;
>> - case BPF_ANC | SKF_AD_PKTTYPE:
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
>> - __pkt_type_offset[0]) != 1);
>> - off = PKT_TYPE_OFFSET();
>> - emit(ARM_LDRB_I(r_A, r_skb, off), ctx);
>> - emit(ARM_AND_I(r_A, r_A, PKT_TYPE_MAX), ctx);
>> -#ifdef __BIG_ENDIAN_BITFIELD
>> - emit(ARM_LSR_I(r_A, r_A, 5), ctx);
>> -#endif
>> + }
>> + break;
>> + /* JMP OFF */
>> + case BPF_JMP | BPF_JA:
>> + {
>> + if (off == 0)
>> break;
>> - case BPF_ANC | SKF_AD_QUEUE:
>> - ctx->seen |= SEEN_SKB;
>> - BUILD_BUG_ON(FIELD_SIZEOF(struct sk_buff,
>> - queue_mapping) != 2);
>> - BUILD_BUG_ON(offsetof(struct sk_buff,
>> - queue_mapping) > 0xff);
>> - off = offsetof(struct sk_buff, queue_mapping);
>> - emit(ARM_LDRH_I(r_A, r_skb, off), ctx);
>> + jmp_offset = bpf2a32_offset(i+off, i, ctx);
>> + check_imm24(jmp_offset);
>> + emit(ARM_B(jmp_offset), ctx);
>> + break;
>> + }
>> + /* tail call */
>> + case BPF_JMP | BPF_CALL | BPF_X:
>> + if (emit_bpf_tail_call(ctx))
>> + return -EFAULT;
>> + break;
>> + /* function call */
>> + case BPF_JMP | BPF_CALL:
>> + goto notyet;
>> + /* function return */
>> + case BPF_JMP | BPF_EXIT:
>> + /* Optimization: when last instruction is EXIT
>> + * simply fallthrough to epilogue.
>> + */
>> + if (i == ctx->prog->len - 1)
>> break;
>> - case BPF_ANC | SKF_AD_PAY_OFFSET:
>> - ctx->seen |= SEEN_SKB | SEEN_CALL;
>> + jmp_offset = epilogue_offset(ctx);
>> + check_imm24(jmp_offset);
>> + emit(ARM_B(jmp_offset), ctx);
>> + break;
>> +notyet:
>> + pr_info_once("*** NOT YET: opcode %02x ***\n", code);
>> + return -EFAULT;
>> + default:
>> + pr_err_once("unknown opcode %02x\n", code);
>> + return -EINVAL;
>> + }
>>
>> - emit(ARM_MOV_R(ARM_R0, r_skb), ctx);
>> - emit_mov_i(ARM_R3, (unsigned int)skb_get_poff, ctx);
>> - emit_blx_r(ARM_R3, ctx);
>> - emit(ARM_MOV_R(r_A, ARM_R0), ctx);
>> - break;
>> - case BPF_LDX | BPF_W | BPF_ABS:
>> - /*
>> - * load a 32bit word from struct seccomp_data.
>> - * seccomp_check_filter() will already have checked
>> - * that k is 32bit aligned and lies within the
>> - * struct seccomp_data.
>> - */
>> - ctx->seen |= SEEN_SKB;
>> - emit(ARM_LDR_I(r_A, r_skb, k), ctx);
>> - break;
>> - default:
>> - return -1;
>> + if (ctx->flags & FLAG_IMM_OVERFLOW)
>> + /*
>> + * this instruction generated an overflow when
>> + * trying to access the literal pool, so
>> + * delegate this filter to the kernel interpreter.
>> + */
>> + return -1;
>> + return 0;
>> +}
>> +
>> +static int build_body(struct jit_ctx *ctx)
>> +{
>> + const struct bpf_prog *prog = ctx->prog;
>> + unsigned int i;
>> +
>> + for (i = 0; i < prog->len; i++) {
>> + const struct bpf_insn *insn = &(prog->insnsi[i]);
>> + int ret;
>> +
>> + ret = build_insn(insn, ctx);
>> +
>> + /* It's used with loading the 64 bit immediate value. */
>> + if (ret > 0) {
>> + i++;
>> + if (ctx->target == NULL)
>> + ctx->offsets[i] = ctx->idx;
>> + continue;
>> }
>>
>> - if (ctx->flags & FLAG_IMM_OVERFLOW)
>> - /*
>> - * this instruction generated an overflow when
>> - * trying to access the literal pool, so
>> - * delegate this filter to the kernel interpreter.
>> - */
>> - return -1;
>> + if (ctx->target == NULL)
>> + ctx->offsets[i] = ctx->idx;
>> +
>> + /* If unsuccesfull, return with error code */
>> + if (ret)
>> + return ret;
>> }
>> + return 0;
>> +}
>>
>> - /* compute offsets only during the first pass */
>> - if (ctx->target == NULL)
>> - ctx->offsets[i] = ctx->idx * 4;
>> +static int validate_code(struct jit_ctx *ctx)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < ctx->idx; i++) {
>> + u32 a32_insn = le32_to_cpu(ctx->target[i]);
>> +
>> + if (a32_insn == ARM_INST_UDF)
>> + return -1;
>> + }
>>
>> return 0;
>> }
>>
>> +void bpf_jit_compile(struct bpf_prog *prog)
>> +{
>> + /* Nothing to do here. We support Internal BPF. */
>> +}
>>
>> -void bpf_jit_compile(struct bpf_prog *fp)
>> +struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
>> {
>> +#ifdef __LITTLE_ENDIAN
>> + struct bpf_prog *tmp, *orig_prog = prog;
>> struct bpf_binary_header *header;
>> + bool tmp_blinded = false;
>> struct jit_ctx ctx;
>> - unsigned tmp_idx;
>> - unsigned alloc_size;
>> - u8 *target_ptr;
>> + unsigned int tmp_idx;
>> + unsigned int image_size;
>> + u8 *image_ptr;
>>
>> + /* If BPF JIT was not enabled then we must fall back to
>> + * the interpreter.
>> + */
>> if (!bpf_jit_enable)
>> - return;
>> + return orig_prog;
>>
>> - memset(&ctx, 0, sizeof(ctx));
>> - ctx.skf = fp;
>> - ctx.ret0_fp_idx = -1;
>> + /* If constant blinding was enabled and we failed during blinding
>> + * then we must fall back to the interpreter. Otherwise, we save
>> + * the new JITed code.
>> + */
>> + tmp = bpf_jit_blind_constants(prog);
>>
>> - ctx.offsets = kzalloc(4 * (ctx.skf->len + 1), GFP_KERNEL);
>> - if (ctx.offsets == NULL)
>> - return;
>> + if (IS_ERR(tmp))
>> + return orig_prog;
>> + if (tmp != prog) {
>> + tmp_blinded = true;
>> + prog = tmp;
>> + }
>> +
>> + memset(&ctx, 0, sizeof(ctx));
>> + ctx.prog = prog;
>>
>> - /* fake pass to fill in the ctx->seen */
>> - if (unlikely(build_body(&ctx)))
>> + /* Not able to allocate memory for offsets[] , then
>> + * we must fall back to the interpreter
>> + */
>> + ctx.offsets = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
>> + if (ctx.offsets == NULL) {
>> + prog = orig_prog;
>> goto out;
>> + }
>> +
>> + /* 1) fake pass to find in the length of the JITed code,
>> + * to compute ctx->offsets and other context variables
>> + * needed to compute final JITed code.
>> + * Also, calculate random starting pointer/start of JITed code
>> + * which is prefixed by random number of fault instructions.
>> + *
>> + * If the first pass fails then there is no chance of it
>> + * being successful in the second pass, so just fall back
>> + * to the interpreter.
>> + */
>> + if (build_body(&ctx)) {
>> + prog = orig_prog;
>> + goto out_off;
>> + }
>>
>> tmp_idx = ctx.idx;
>> build_prologue(&ctx);
>> ctx.prologue_bytes = (ctx.idx - tmp_idx) * 4;
>>
>> + ctx.epilogue_offset = ctx.idx;
>> +
>> #if __LINUX_ARM_ARCH__ < 7
>> tmp_idx = ctx.idx;
>> build_epilogue(&ctx);
>> @@ -1020,64 +1838,96 @@ void bpf_jit_compile(struct bpf_prog *fp)
>>
>> ctx.idx += ctx.imm_count;
>> if (ctx.imm_count) {
>> - ctx.imms = kzalloc(4 * ctx.imm_count, GFP_KERNEL);
>> - if (ctx.imms == NULL)
>> - goto out;
>> + ctx.imms = kcalloc(ctx.imm_count, sizeof(u32), GFP_KERNEL);
>> + if (ctx.imms == NULL) {
>> + prog = orig_prog;
>> + goto out_off;
>> + }
>> }
>> #else
>> - /* there's nothing after the epilogue on ARMv7 */
>> + /* there's nothing about the epilogue on ARMv7 */
>> build_epilogue(&ctx);
>> #endif
>> - alloc_size = 4 * ctx.idx;
>> - header = bpf_jit_binary_alloc(alloc_size, &target_ptr,
>> - 4, jit_fill_hole);
>> - if (header == NULL)
>> - goto out;
>> + /* Now we can get the actual image size of the JITed arm code.
>> + * Currently, we are not considering the THUMB-2 instructions
>> + * for jit, although it can decrease the size of the image.
>> + *
>> + * As each arm instruction is of length 32bit, we are translating
>> + * number of JITed intructions into the size required to store these
>> + * JITed code.
>> + */
>> + image_size = sizeof(u32) * ctx.idx;
>>
>> - ctx.target = (u32 *) target_ptr;
>> + /* Now we know the size of the structure to make */
>> + header = bpf_jit_binary_alloc(image_size, &image_ptr,
>> + sizeof(u32), jit_fill_hole);
>> + /* Not able to allocate memory for the structure then
>> + * we must fall back to the interpretation
>> + */
>> + if (header == NULL) {
>> + prog = orig_prog;
>> + goto out_imms;
>> + }
>> +
>> + /* 2.) Actual pass to generate final JIT code */
>> + ctx.target = (u32 *) image_ptr;
>> ctx.idx = 0;
>>
>> build_prologue(&ctx);
>> +
>> + /* If building the body of the JITed code fails somehow,
>> + * we fall back to the interpretation.
>> + */
>> if (build_body(&ctx) < 0) {
>> -#if __LINUX_ARM_ARCH__ < 7
>> - if (ctx.imm_count)
>> - kfree(ctx.imms);
>> -#endif
>> + image_ptr = NULL;
>> bpf_jit_binary_free(header);
>> - goto out;
>> + prog = orig_prog;
>> + goto out_imms;
>> }
>> build_epilogue(&ctx);
>>
>> + /* 3.) Extra pass to validate JITed Code */
>> + if (validate_code(&ctx)) {
>> + image_ptr = NULL;
>> + bpf_jit_binary_free(header);
>> + prog = orig_prog;
>> + goto out_imms;
>> + }
>> flush_icache_range((u32)header, (u32)(ctx.target + ctx.idx));
>>
>> -#if __LINUX_ARM_ARCH__ < 7
>> - if (ctx.imm_count)
>> - kfree(ctx.imms);
>> -#endif
>> -
>> if (bpf_jit_enable > 1)
>> /* there are 2 passes here */
>> - bpf_jit_dump(fp->len, alloc_size, 2, ctx.target);
>> + bpf_jit_dump(prog->len, image_size, 2, ctx.target);
>>
>> set_memory_ro((unsigned long)header, header->pages);
>> - fp->bpf_func = (void *)ctx.target;
>> - fp->jited = 1;
>> -out:
>> + prog->bpf_func = (void *)ctx.target;
>> + prog->jited = 1;
>> +out_imms:
>> +#if __LINUX_ARM_ARCH__ < 7
>> + if (ctx.imm_count)
>> + kfree(ctx.imms);
>> +#endif
>> +out_off:
>> kfree(ctx.offsets);
>> - return;
>> +out:
>> + if (tmp_blinded)
>> + bpf_jit_prog_release_other(prog, prog == orig_prog ?
>> + tmp : orig_prog);
>> +#endif /* __LITTLE_ENDIAN */
>> + return prog;
>> }
>>
>> -void bpf_jit_free(struct bpf_prog *fp)
>> +void bpf_jit_free(struct bpf_prog *prog)
>> {
>> - unsigned long addr = (unsigned long)fp->bpf_func & PAGE_MASK;
>> + unsigned long addr = (unsigned long)prog->bpf_func & PAGE_MASK;
>> struct bpf_binary_header *header = (void *)addr;
>>
>> - if (!fp->jited)
>> + if (!prog->jited)
>> goto free_filter;
>>
>> set_memory_rw(addr, header->pages);
>> bpf_jit_binary_free(header);
>>
>> free_filter:
>> - bpf_prog_unlock_free(fp);
>> + bpf_prog_unlock_free(prog);
>> }
>> diff --git a/arch/arm/net/bpf_jit_32.h b/arch/arm/net/bpf_jit_32.h
>> index c46fca2..d5cf5f6 100644
>> --- a/arch/arm/net/bpf_jit_32.h
>> +++ b/arch/arm/net/bpf_jit_32.h
>> @@ -11,6 +11,7 @@
>> #ifndef PFILTER_OPCODES_ARM_H
>> #define PFILTER_OPCODES_ARM_H
>>
>> +/* ARM 32bit Registers */
>> #define ARM_R0 0
>> #define ARM_R1 1
>> #define ARM_R2 2
>> @@ -22,38 +23,43 @@
>> #define ARM_R8 8
>> #define ARM_R9 9
>> #define ARM_R10 10
>> -#define ARM_FP 11
>> -#define ARM_IP 12
>> -#define ARM_SP 13
>> -#define ARM_LR 14
>> -#define ARM_PC 15
>> -
>> -#define ARM_COND_EQ 0x0
>> -#define ARM_COND_NE 0x1
>> -#define ARM_COND_CS 0x2
>> +#define ARM_FP 11 /* Frame Pointer */
>> +#define ARM_IP 12 /* Intra-procedure scratch register */
>> +#define ARM_SP 13 /* Stack pointer: as load/store base reg */
>> +#define ARM_LR 14 /* Link Register */
>> +#define ARM_PC 15 /* Program counter */
>> +
>> +#define ARM_COND_EQ 0x0 /* == */
>> +#define ARM_COND_NE 0x1 /* != */
>> +#define ARM_COND_CS 0x2 /* unsigned >= */
>> #define ARM_COND_HS ARM_COND_CS
>> -#define ARM_COND_CC 0x3
>> +#define ARM_COND_CC 0x3 /* unsigned < */
>> #define ARM_COND_LO ARM_COND_CC
>> -#define ARM_COND_MI 0x4
>> -#define ARM_COND_PL 0x5
>> -#define ARM_COND_VS 0x6
>> -#define ARM_COND_VC 0x7
>> -#define ARM_COND_HI 0x8
>> -#define ARM_COND_LS 0x9
>> -#define ARM_COND_GE 0xa
>> -#define ARM_COND_LT 0xb
>> -#define ARM_COND_GT 0xc
>> -#define ARM_COND_LE 0xd
>> -#define ARM_COND_AL 0xe
>> +#define ARM_COND_MI 0x4 /* < 0 */
>> +#define ARM_COND_PL 0x5 /* >= 0 */
>> +#define ARM_COND_VS 0x6 /* Signed Overflow */
>> +#define ARM_COND_VC 0x7 /* No Signed Overflow */
>> +#define ARM_COND_HI 0x8 /* unsigned > */
>> +#define ARM_COND_LS 0x9 /* unsigned <= */
>> +#define ARM_COND_GE 0xa /* Signed >= */
>> +#define ARM_COND_LT 0xb /* Signed < */
>> +#define ARM_COND_GT 0xc /* Signed > */
>> +#define ARM_COND_LE 0xd /* Signed <= */
>> +#define ARM_COND_AL 0xe /* None */
>>
>> /* register shift types */
>> #define SRTYPE_LSL 0
>> #define SRTYPE_LSR 1
>> #define SRTYPE_ASR 2
>> #define SRTYPE_ROR 3
>> +#define SRTYPE_ASL (SRTYPE_LSL)
>>
>> #define ARM_INST_ADD_R 0x00800000
>> +#define ARM_INST_ADDS_R 0x00900000
>> +#define ARM_INST_ADC_R 0x00a00000
>> +#define ARM_INST_ADC_I 0x02a00000
>> #define ARM_INST_ADD_I 0x02800000
>> +#define ARM_INST_ADDS_I 0x02900000
>>
>> #define ARM_INST_AND_R 0x00000000
>> #define ARM_INST_AND_I 0x02000000
>> @@ -76,8 +82,10 @@
>> #define ARM_INST_LDRH_I 0x01d000b0
>> #define ARM_INST_LDRH_R 0x019000b0
>> #define ARM_INST_LDR_I 0x05900000
>> +#define ARM_INST_LDR_R 0x07900000
>>
>> #define ARM_INST_LDM 0x08900000
>> +#define ARM_INST_LDM_IA 0x08b00000
>>
>> #define ARM_INST_LSL_I 0x01a00000
>> #define ARM_INST_LSL_R 0x01a00010
>> @@ -86,6 +94,7 @@
>> #define ARM_INST_LSR_R 0x01a00030
>>
>> #define ARM_INST_MOV_R 0x01a00000
>> +#define ARM_INST_MOVS_R 0x01b00000
>> #define ARM_INST_MOV_I 0x03a00000
>> #define ARM_INST_MOVW 0x03000000
>> #define ARM_INST_MOVT 0x03400000
>> @@ -96,17 +105,28 @@
>> #define ARM_INST_PUSH 0x092d0000
>>
>> #define ARM_INST_ORR_R 0x01800000
>> +#define ARM_INST_ORRS_R 0x01900000
>> #define ARM_INST_ORR_I 0x03800000
>>
>> #define ARM_INST_REV 0x06bf0f30
>> #define ARM_INST_REV16 0x06bf0fb0
>>
>> #define ARM_INST_RSB_I 0x02600000
>> +#define ARM_INST_RSBS_I 0x02700000
>> +#define ARM_INST_RSC_I 0x02e00000
>>
>> #define ARM_INST_SUB_R 0x00400000
>> +#define ARM_INST_SUBS_R 0x00500000
>> +#define ARM_INST_RSB_R 0x00600000
>> #define ARM_INST_SUB_I 0x02400000
>> +#define ARM_INST_SUBS_I 0x02500000
>> +#define ARM_INST_SBC_I 0x02c00000
>> +#define ARM_INST_SBC_R 0x00c00000
>> +#define ARM_INST_SBCS_R 0x00d00000
>>
>> #define ARM_INST_STR_I 0x05800000
>> +#define ARM_INST_STRB_I 0x05c00000
>> +#define ARM_INST_STRH_I 0x01c000b0
>>
>> #define ARM_INST_TST_R 0x01100000
>> #define ARM_INST_TST_I 0x03100000
>> @@ -117,6 +137,8 @@
>>
>> #define ARM_INST_MLS 0x00600090
>>
>> +#define ARM_INST_UXTH 0x06ff0070
>> +
>> /*
>> * Use a suitable undefined instruction to use for ARM/Thumb2 faulting.
>> * We need to be careful not to conflict with those used by other modules
>> @@ -135,9 +157,15 @@
>> #define _AL3_R(op, rd, rn, rm) ((op ## _R) | (rd) << 12 | (rn) << 16 | (rm))
>> /* immediate */
>> #define _AL3_I(op, rd, rn, imm) ((op ## _I) | (rd) << 12 | (rn) << 16 | (imm))
>> +/* register with register-shift */
>> +#define _AL3_SR(inst) (inst | (1 << 4))
>>
>> #define ARM_ADD_R(rd, rn, rm) _AL3_R(ARM_INST_ADD, rd, rn, rm)
>> +#define ARM_ADDS_R(rd, rn, rm) _AL3_R(ARM_INST_ADDS, rd, rn, rm)
>> #define ARM_ADD_I(rd, rn, imm) _AL3_I(ARM_INST_ADD, rd, rn, imm)
>> +#define ARM_ADDS_I(rd, rn, imm) _AL3_I(ARM_INST_ADDS, rd, rn, imm)
>> +#define ARM_ADC_R(rd, rn, rm) _AL3_R(ARM_INST_ADC, rd, rn, rm)
>> +#define ARM_ADC_I(rd, rn, imm) _AL3_I(ARM_INST_ADC, rd, rn, imm)
>>
>> #define ARM_AND_R(rd, rn, rm) _AL3_R(ARM_INST_AND, rd, rn, rm)
>> #define ARM_AND_I(rd, rn, imm) _AL3_I(ARM_INST_AND, rd, rn, imm)
>> @@ -156,7 +184,9 @@
>> #define ARM_EOR_I(rd, rn, imm) _AL3_I(ARM_INST_EOR, rd, rn, imm)
>>
>> #define ARM_LDR_I(rt, rn, off) (ARM_INST_LDR_I | (rt) << 12 | (rn) << 16 \
>> - | (off))
>> + | ((off) & 0xfff))
>> +#define ARM_LDR_R(rt, rn, rm) (ARM_INST_LDR_R | (rt) << 12 | (rn) << 16 \
>> + | (rm))
>> #define ARM_LDRB_I(rt, rn, off) (ARM_INST_LDRB_I | (rt) << 12 | (rn) << 16 \
>> | (off))
>> #define ARM_LDRB_R(rt, rn, rm) (ARM_INST_LDRB_R | (rt) << 12 | (rn) << 16 \
>> @@ -167,15 +197,23 @@
>> | (rm))
>>
>> #define ARM_LDM(rn, regs) (ARM_INST_LDM | (rn) << 16 | (regs))
>> +#define ARM_LDM_IA(rn, regs) (ARM_INST_LDM_IA | (rn) << 16 | (regs))
>>
>> #define ARM_LSL_R(rd, rn, rm) (_AL3_R(ARM_INST_LSL, rd, 0, rn) | (rm) << 8)
>> #define ARM_LSL_I(rd, rn, imm) (_AL3_I(ARM_INST_LSL, rd, 0, rn) | (imm) << 7)
>>
>> #define ARM_LSR_R(rd, rn, rm) (_AL3_R(ARM_INST_LSR, rd, 0, rn) | (rm) << 8)
>> #define ARM_LSR_I(rd, rn, imm) (_AL3_I(ARM_INST_LSR, rd, 0, rn) | (imm) << 7)
>> +#define ARM_ASR_R(rd, rn, rm) (_AL3_R(ARM_INST_ASR, rd, 0, rn) | (rm) << 8)
>> +#define ARM_ASR_I(rd, rn, imm) (_AL3_I(ARM_INST_ASR, rd, 0, rn) | (imm) << 7)
>>
>> #define ARM_MOV_R(rd, rm) _AL3_R(ARM_INST_MOV, rd, 0, rm)
>> +#define ARM_MOVS_R(rd, rm) _AL3_R(ARM_INST_MOVS, rd, 0, rm)
>> #define ARM_MOV_I(rd, imm) _AL3_I(ARM_INST_MOV, rd, 0, imm)
>> +#define ARM_MOV_SR(rd, rm, type, rs) \
>> + (_AL3_SR(ARM_MOV_R(rd, rm)) | (type) << 5 | (rs) << 8)
>> +#define ARM_MOV_SI(rd, rm, type, imm6) \
>> + (ARM_MOV_R(rd, rm) | (type) << 5 | (imm6) << 7)
>>
>> #define ARM_MOVW(rd, imm) \
>> (ARM_INST_MOVW | ((imm) >> 12) << 16 | (rd) << 12 | ((imm) & 0x0fff))
>> @@ -190,19 +228,38 @@
>>
>> #define ARM_ORR_R(rd, rn, rm) _AL3_R(ARM_INST_ORR, rd, rn, rm)
>> #define ARM_ORR_I(rd, rn, imm) _AL3_I(ARM_INST_ORR, rd, rn, imm)
>> -#define ARM_ORR_S(rd, rn, rm, type, rs) \
>> - (ARM_ORR_R(rd, rn, rm) | (type) << 5 | (rs) << 7)
>> +#define ARM_ORR_SR(rd, rn, rm, type, rs) \
>> + (_AL3_SR(ARM_ORR_R(rd, rn, rm)) | (type) << 5 | (rs) << 8)
>> +#define ARM_ORRS_R(rd, rn, rm) _AL3_R(ARM_INST_ORRS, rd, rn, rm)
>> +#define ARM_ORRS_SR(rd, rn, rm, type, rs) \
>> + (_AL3_SR(ARM_ORRS_R(rd, rn, rm)) | (type) << 5 | (rs) << 8)
>> +#define ARM_ORR_SI(rd, rn, rm, type, imm6) \
>> + (ARM_ORR_R(rd, rn, rm) | (type) << 5 | (imm6) << 7)
>> +#define ARM_ORRS_SI(rd, rn, rm, type, imm6) \
>> + (ARM_ORRS_R(rd, rn, rm) | (type) << 5 | (imm6) << 7)
>>
>> #define ARM_REV(rd, rm) (ARM_INST_REV | (rd) << 12 | (rm))
>> #define ARM_REV16(rd, rm) (ARM_INST_REV16 | (rd) << 12 | (rm))
>>
>> #define ARM_RSB_I(rd, rn, imm) _AL3_I(ARM_INST_RSB, rd, rn, imm)
>> +#define ARM_RSBS_I(rd, rn, imm) _AL3_I(ARM_INST_RSBS, rd, rn, imm)
>> +#define ARM_RSC_I(rd, rn, imm) _AL3_I(ARM_INST_RSC, rd, rn, imm)
>>
>> #define ARM_SUB_R(rd, rn, rm) _AL3_R(ARM_INST_SUB, rd, rn, rm)
>> +#define ARM_SUBS_R(rd, rn, rm) _AL3_R(ARM_INST_SUBS, rd, rn, rm)
>> +#define ARM_RSB_R(rd, rn, rm) _AL3_R(ARM_INST_RSB, rd, rn, rm)
>> +#define ARM_SBC_R(rd, rn, rm) _AL3_R(ARM_INST_SBC, rd, rn, rm)
>> +#define ARM_SBCS_R(rd, rn, rm) _AL3_R(ARM_INST_SBCS, rd, rn, rm)
>> #define ARM_SUB_I(rd, rn, imm) _AL3_I(ARM_INST_SUB, rd, rn, imm)
>> +#define ARM_SUBS_I(rd, rn, imm) _AL3_I(ARM_INST_SUBS, rd, rn, imm)
>> +#define ARM_SBC_I(rd, rn, imm) _AL3_I(ARM_INST_SBC, rd, rn, imm)
>>
>> #define ARM_STR_I(rt, rn, off) (ARM_INST_STR_I | (rt) << 12 | (rn) << 16 \
>> - | (off))
>> + | ((off) & 0xfff))
>> +#define ARM_STRH_I(rt, rn, off) (ARM_INST_STRH_I | (rt) << 12 | (rn) << 16 \
>> + | (((off) & 0xf0) << 4) | ((off) & 0xf))
>> +#define ARM_STRB_I(rt, rn, off) (ARM_INST_STRB_I | (rt) << 12 | (rn) << 16 \
>> + | (((off) & 0xf0) << 4) | ((off) & 0xf))
>>
>> #define ARM_TST_R(rn, rm) _AL3_R(ARM_INST_TST, 0, rn, rm)
>> #define ARM_TST_I(rn, imm) _AL3_I(ARM_INST_TST, 0, rn, imm)
>> @@ -214,5 +271,6 @@
>>
>> #define ARM_MLS(rd, rn, rm, ra) (ARM_INST_MLS | (rd) << 16 | (rn) | (rm) << 8 \
>> | (ra) << 12)
>> +#define ARM_UXTH(rd, rm) (ARM_INST_UXTH | (rd) << 12 | (rm))
>>
>> #endif /* PFILTER_OPCODES_ARM_H */
>> --
>> 2.7.4
>>
>
>
>
> --
> Kees Cook
> Pixel Security

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