[PATCH v3 07/13] arm64, execmem: extend execmem_params for generated code allocations

From: Mike Rapoport
Date: Mon Sep 18 2023 - 03:32:25 EST


From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx>

The memory allocations for kprobes and BPF on arm64 can be placed
anywhere in vmalloc address space and currently this is implemented with
overrides of alloc_insn_page() and bpf_jit_alloc_exec() in arm64.

Define EXECMEM_KPROBES and EXECMEM_BPF ranges in arm64::execmem_params and
drop overrides of alloc_insn_page() and bpf_jit_alloc_exec().

Signed-off-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
---
arch/arm64/kernel/module.c | 13 +++++++++++++
arch/arm64/kernel/probes/kprobes.c | 7 -------
arch/arm64/net/bpf_jit_comp.c | 11 -----------
3 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
index cd6320de1c54..d27db168d2a2 100644
--- a/arch/arm64/kernel/module.c
+++ b/arch/arm64/kernel/module.c
@@ -116,6 +116,16 @@ static struct execmem_params execmem_params __ro_after_init = {
.flags = EXECMEM_KASAN_SHADOW,
.alignment = MODULE_ALIGN,
},
+ [EXECMEM_KPROBES] = {
+ .start = VMALLOC_START,
+ .end = VMALLOC_END,
+ .alignment = 1,
+ },
+ [EXECMEM_BPF] = {
+ .start = VMALLOC_START,
+ .end = VMALLOC_END,
+ .alignment = 1,
+ },
},
};

@@ -140,6 +150,9 @@ struct execmem_params __init *execmem_arch_params(void)
r->end = module_plt_base + SZ_2G;
}

+ execmem_params.ranges[EXECMEM_KPROBES].pgprot = PAGE_KERNEL_ROX;
+ execmem_params.ranges[EXECMEM_BPF].pgprot = PAGE_KERNEL;
+
return &execmem_params;
}

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 70b91a8c6bb3..6fccedd02b2a 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -129,13 +129,6 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)
return 0;
}

-void *alloc_insn_page(void)
-{
- return __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START, VMALLOC_END,
- GFP_KERNEL, PAGE_KERNEL_ROX, VM_FLUSH_RESET_PERMS,
- NUMA_NO_NODE, __builtin_return_address(0));
-}
-
/* arm kprobe: install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 150d1c6543f7..3a7590f828d1 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -1687,17 +1687,6 @@ u64 bpf_jit_alloc_exec_limit(void)
return VMALLOC_END - VMALLOC_START;
}

-void *bpf_jit_alloc_exec(unsigned long size)
-{
- /* Memory is intended to be executable, reset the pointer tag. */
- return kasan_reset_tag(vmalloc(size));
-}
-
-void bpf_jit_free_exec(void *addr)
-{
- return vfree(addr);
-}
-
/* Indicate the JIT backend supports mixing bpf2bpf and tailcalls. */
bool bpf_jit_supports_subprog_tailcalls(void)
{
--
2.39.2