[RFC PATCH v3 15/22] objtool: arm64: Add unwind hint support
From: madvenka
Date: Thu Feb 02 2023 - 02:43:30 EST
From: "Madhavan T. Venkataraman" <madvenka@xxxxxxxxxxxxxxxxxxx>
Implement the unwind hint macros for ARM64. Define the unwind hint types
as well.
Process the unwind hints section for dynamic FP validation for ARM64.
Signed-off-by: Madhavan T. Venkataraman <madvenka@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/unwind_hints.h | 104 ++++++++++++++++++++
include/linux/objtool.h | 3 +
tools/arch/arm64/include/asm/unwind_hints.h | 104 ++++++++++++++++++++
tools/include/linux/objtool.h | 3 +
tools/objtool/Build | 2 +-
tools/objtool/arch/arm64/decode.c | 21 ++++
tools/objtool/arch/arm64/orc.c | 4 +
tools/objtool/dcheck.c | 4 +
tools/objtool/include/objtool/endianness.h | 1 +
tools/objtool/sync-check.sh | 1 +
tools/objtool/unwind_hints.c | 24 +++--
11 files changed, 260 insertions(+), 11 deletions(-)
create mode 100644 arch/arm64/include/asm/unwind_hints.h
create mode 100644 tools/arch/arm64/include/asm/unwind_hints.h
diff --git a/arch/arm64/include/asm/unwind_hints.h b/arch/arm64/include/asm/unwind_hints.h
new file mode 100644
index 000000000000..fb1b924d85bc
--- /dev/null
+++ b/arch/arm64/include/asm/unwind_hints.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_ARM64_UNWIND_HINTS_H
+#define _ASM_ARM64_UNWIND_HINTS_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * CFI for an instruction. We have to use s16 instead of s8 for some of these
+ * fields as 8-bit fields are not relocated by some assemblers.
+ */
+struct unwind_hint {
+ u32 ip;
+ s16 sp_offset;
+ s16 sp_reg;
+ s16 type;
+ s16 end;
+};
+
+#endif
+
+#include <linux/objtool.h>
+
+#include "orc_types.h"
+
+#ifdef CONFIG_STACK_VALIDATION
+
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+ "987: \n\t" \
+ ".pushsection .discard.unwind_hints\n\t" \
+ /* struct unwind_hint */ \
+ ".long 987b - .\n\t" \
+ ".short " __stringify(sp_offset) "\n\t" \
+ ".short " __stringify(sp_reg) "\n\t" \
+ ".short " __stringify(type) "\n\t" \
+ ".short " __stringify(end) "\n\t" \
+ ".popsection\n\t"
+
+#else /* __ASSEMBLY__ */
+
+/*
+ * There are points in ASM code where it is useful to unwind through even
+ * though the ASM code itself may be unreliable from an unwind perspective.
+ * E.g., interrupt and exception handlers.
+ *
+ * These macros provide hints to objtool to compute the CFI information at
+ * such instructions.
+ */
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.Lunwind_hint_pc_\@:
+ .pushsection .discard.unwind_hints
+ /* struct unwind_hint */
+ .long .Lunwind_hint_pc_\@ - .
+ .short \sp_offset
+ .short \sp_reg
+ .short \type
+ .short \end
+ .popsection
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#else /* !CONFIG_STACK_VALIDATION */
+
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+ "\n\t"
+#else
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.endm
+#endif
+
+#endif /* CONFIG_STACK_VALIDATION */
+#ifdef __ASSEMBLY__
+
+.macro UNWIND_HINT_FTRACE, offset
+ .set sp_reg, ORC_REG_SP
+ .set sp_offset, \offset
+ .set type, UNWIND_HINT_TYPE_FTRACE
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+.macro UNWIND_HINT_REGS, offset
+ .set sp_reg, ORC_REG_SP
+ .set sp_offset, \offset
+ .set type, UNWIND_HINT_TYPE_REGS
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+.macro UNWIND_HINT_IRQ, offset
+ .set sp_reg, ORC_REG_SP
+ .set sp_offset, \offset
+ .set type, UNWIND_HINT_TYPE_IRQ_STACK
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ARM64_UNWIND_HINTS_H */
diff --git a/include/linux/objtool.h b/include/linux/objtool.h
index 1af295efc12c..dcbd365944f6 100644
--- a/include/linux/objtool.h
+++ b/include/linux/objtool.h
@@ -17,6 +17,8 @@
* Useful for code which doesn't have an ELF function annotation.
*
* UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
+ *
+ * UNWIND_HINT_TYPE_IRQ_STACK: Used to unwind through the IRQ stack.
*/
#define UNWIND_HINT_TYPE_CALL 0
#define UNWIND_HINT_TYPE_REGS 1
@@ -25,6 +27,7 @@
#define UNWIND_HINT_TYPE_ENTRY 4
#define UNWIND_HINT_TYPE_SAVE 5
#define UNWIND_HINT_TYPE_RESTORE 6
+#define UNWIND_HINT_TYPE_IRQ_STACK 7
#ifdef CONFIG_OBJTOOL
diff --git a/tools/arch/arm64/include/asm/unwind_hints.h b/tools/arch/arm64/include/asm/unwind_hints.h
new file mode 100644
index 000000000000..fb1b924d85bc
--- /dev/null
+++ b/tools/arch/arm64/include/asm/unwind_hints.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_ARM64_UNWIND_HINTS_H
+#define _ASM_ARM64_UNWIND_HINTS_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/types.h>
+
+/*
+ * This struct is used by asm and inline asm code to manually annotate the
+ * CFI for an instruction. We have to use s16 instead of s8 for some of these
+ * fields as 8-bit fields are not relocated by some assemblers.
+ */
+struct unwind_hint {
+ u32 ip;
+ s16 sp_offset;
+ s16 sp_reg;
+ s16 type;
+ s16 end;
+};
+
+#endif
+
+#include <linux/objtool.h>
+
+#include "orc_types.h"
+
+#ifdef CONFIG_STACK_VALIDATION
+
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+ "987: \n\t" \
+ ".pushsection .discard.unwind_hints\n\t" \
+ /* struct unwind_hint */ \
+ ".long 987b - .\n\t" \
+ ".short " __stringify(sp_offset) "\n\t" \
+ ".short " __stringify(sp_reg) "\n\t" \
+ ".short " __stringify(type) "\n\t" \
+ ".short " __stringify(end) "\n\t" \
+ ".popsection\n\t"
+
+#else /* __ASSEMBLY__ */
+
+/*
+ * There are points in ASM code where it is useful to unwind through even
+ * though the ASM code itself may be unreliable from an unwind perspective.
+ * E.g., interrupt and exception handlers.
+ *
+ * These macros provide hints to objtool to compute the CFI information at
+ * such instructions.
+ */
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.Lunwind_hint_pc_\@:
+ .pushsection .discard.unwind_hints
+ /* struct unwind_hint */
+ .long .Lunwind_hint_pc_\@ - .
+ .short \sp_offset
+ .short \sp_reg
+ .short \type
+ .short \end
+ .popsection
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#else /* !CONFIG_STACK_VALIDATION */
+
+#ifndef __ASSEMBLY__
+
+#define UNWIND_HINT(sp_reg, sp_offset, type, end) \
+ "\n\t"
+#else
+.macro UNWIND_HINT sp_reg:req sp_offset=0 type:req end=0
+.endm
+#endif
+
+#endif /* CONFIG_STACK_VALIDATION */
+#ifdef __ASSEMBLY__
+
+.macro UNWIND_HINT_FTRACE, offset
+ .set sp_reg, ORC_REG_SP
+ .set sp_offset, \offset
+ .set type, UNWIND_HINT_TYPE_FTRACE
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+.macro UNWIND_HINT_REGS, offset
+ .set sp_reg, ORC_REG_SP
+ .set sp_offset, \offset
+ .set type, UNWIND_HINT_TYPE_REGS
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+.macro UNWIND_HINT_IRQ, offset
+ .set sp_reg, ORC_REG_SP
+ .set sp_offset, \offset
+ .set type, UNWIND_HINT_TYPE_IRQ_STACK
+ UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ARM64_UNWIND_HINTS_H */
diff --git a/tools/include/linux/objtool.h b/tools/include/linux/objtool.h
index 1af295efc12c..dcbd365944f6 100644
--- a/tools/include/linux/objtool.h
+++ b/tools/include/linux/objtool.h
@@ -17,6 +17,8 @@
* Useful for code which doesn't have an ELF function annotation.
*
* UNWIND_HINT_ENTRY: machine entry without stack, SYSCALL/SYSENTER etc.
+ *
+ * UNWIND_HINT_TYPE_IRQ_STACK: Used to unwind through the IRQ stack.
*/
#define UNWIND_HINT_TYPE_CALL 0
#define UNWIND_HINT_TYPE_REGS 1
@@ -25,6 +27,7 @@
#define UNWIND_HINT_TYPE_ENTRY 4
#define UNWIND_HINT_TYPE_SAVE 5
#define UNWIND_HINT_TYPE_RESTORE 6
+#define UNWIND_HINT_TYPE_IRQ_STACK 7
#ifdef CONFIG_OBJTOOL
diff --git a/tools/objtool/Build b/tools/objtool/Build
index fb0846b7d95e..2780e402babb 100644
--- a/tools/objtool/Build
+++ b/tools/objtool/Build
@@ -9,7 +9,7 @@ objtool-y += builtin-check.o
objtool-y += cfi.o
objtool-y += insn.o
objtool-y += decode.o
-objtool-$(STATIC_CHECK) += unwind_hints.o
+objtool-y += unwind_hints.o
objtool-y += elf.o
objtool-y += objtool.o
diff --git a/tools/objtool/arch/arm64/decode.c b/tools/objtool/arch/arm64/decode.c
index f723be80c09a..570069ac68ae 100644
--- a/tools/objtool/arch/arm64/decode.c
+++ b/tools/objtool/arch/arm64/decode.c
@@ -17,6 +17,8 @@
#include <objtool/elf.h>
#include <objtool/warn.h>
+#include <asm/orc_types.h>
+
/* ARM64 instructions are all 4 bytes wide. */
#define INSN_SIZE 4
@@ -47,6 +49,25 @@ unsigned long arch_jump_destination(struct instruction *insn)
return insn->offset + insn->immediate;
}
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+ switch (sp_reg) {
+ case ORC_REG_UNDEFINED:
+ *base = CFI_UNDEFINED;
+ break;
+ case ORC_REG_SP:
+ *base = CFI_SP;
+ break;
+ case ORC_REG_FP:
+ *base = CFI_FP;
+ break;
+ default:
+ return -1;
+ }
+
+ return 0;
+}
+
/* --------------------- instruction decode structs ------------------------ */
struct decode_var {
diff --git a/tools/objtool/arch/arm64/orc.c b/tools/objtool/arch/arm64/orc.c
index cef14114e1ec..5b155585258a 100644
--- a/tools/objtool/arch/arm64/orc.c
+++ b/tools/objtool/arch/arm64/orc.c
@@ -57,6 +57,10 @@ const char *orc_type_name(unsigned int type)
switch (type) {
case UNWIND_HINT_TYPE_CALL:
return "call";
+ case UNWIND_HINT_TYPE_REGS:
+ return "regs";
+ case UNWIND_HINT_TYPE_IRQ_STACK:
+ return "irqstack";
default:
return "?";
}
diff --git a/tools/objtool/dcheck.c b/tools/objtool/dcheck.c
index 57499752c523..567f492b0e3e 100644
--- a/tools/objtool/dcheck.c
+++ b/tools/objtool/dcheck.c
@@ -349,6 +349,10 @@ int check(struct objtool_file *file)
walk_sections(file);
+ ret = read_unwind_hints(file);
+ if (ret)
+ return ret;
+
if (opts.orc)
ret = orc_create(file);
diff --git a/tools/objtool/include/objtool/endianness.h b/tools/objtool/include/objtool/endianness.h
index 10241341eff3..9a53ab421a19 100644
--- a/tools/objtool/include/objtool/endianness.h
+++ b/tools/objtool/include/objtool/endianness.h
@@ -29,6 +29,7 @@
case 8: __ret = __NEED_BSWAP ? bswap_64(val) : (val); break; \
case 4: __ret = __NEED_BSWAP ? bswap_32(val) : (val); break; \
case 2: __ret = __NEED_BSWAP ? bswap_16(val) : (val); break; \
+ case 1: __ret = (val); break; \
default: \
BUILD_BUG(); break; \
} \
diff --git a/tools/objtool/sync-check.sh b/tools/objtool/sync-check.sh
index 0d0656f6ce4a..3742d1e2585c 100755
--- a/tools/objtool/sync-check.sh
+++ b/tools/objtool/sync-check.sh
@@ -31,6 +31,7 @@ fi
if [ "$SRCARCH" = "arm64" ]; then
FILES="$FILES
+arch/arm64/include/asm/unwind_hints.h
arch/arm64/include/asm/orc_types.h
include/linux/orc_entry.h
"
diff --git a/tools/objtool/unwind_hints.c b/tools/objtool/unwind_hints.c
index f2521659bae5..c51013c5d0b3 100644
--- a/tools/objtool/unwind_hints.c
+++ b/tools/objtool/unwind_hints.c
@@ -16,6 +16,7 @@ int read_unwind_hints(struct objtool_file *file)
struct unwind_hint *hint;
struct instruction *insn;
struct reloc *reloc;
+ u8 sp_reg, type;
int i;
sec = find_section_by_name(file->elf, ".discard.unwind_hints");
@@ -38,6 +39,9 @@ int read_unwind_hints(struct objtool_file *file)
for (i = 0; i < sec->sh.sh_size / sizeof(struct unwind_hint); i++) {
hint = (struct unwind_hint *)sec->data->d_buf + i;
+ sp_reg = bswap_if_needed(hint->sp_reg);
+ type = bswap_if_needed(hint->type);
+
reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint));
if (!reloc) {
WARN("can't find reloc for unwind_hints[%d]", i);
@@ -52,18 +56,18 @@ int read_unwind_hints(struct objtool_file *file)
insn->hint = true;
- if (hint->type == UNWIND_HINT_TYPE_SAVE) {
+ if (type == UNWIND_HINT_TYPE_SAVE) {
insn->hint = false;
insn->save = true;
continue;
}
- if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
+ if (type == UNWIND_HINT_TYPE_RESTORE) {
insn->restore = true;
continue;
}
- if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
+ if (type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
if (sym && sym->bind == STB_GLOBAL) {
@@ -76,12 +80,12 @@ int read_unwind_hints(struct objtool_file *file)
}
}
- if (hint->type == UNWIND_HINT_TYPE_ENTRY) {
- hint->type = UNWIND_HINT_TYPE_CALL;
+ if (type == UNWIND_HINT_TYPE_ENTRY) {
+ type = UNWIND_HINT_TYPE_CALL;
insn->entry = 1;
}
- if (hint->type == UNWIND_HINT_TYPE_FUNC) {
+ if (type == UNWIND_HINT_TYPE_FUNC) {
insn->cfi = &func_cfi;
continue;
}
@@ -89,15 +93,15 @@ int read_unwind_hints(struct objtool_file *file)
if (insn->cfi)
cfi = *(insn->cfi);
- if (arch_decode_hint_reg(hint->sp_reg, &cfi.cfa.base)) {
+ if (arch_decode_hint_reg(sp_reg, &cfi.cfa.base)) {
WARN_FUNC("unsupported unwind_hint sp base reg %d",
- insn->sec, insn->offset, hint->sp_reg);
+ insn->sec, insn->offset, sp_reg);
return -1;
}
cfi.cfa.offset = bswap_if_needed(hint->sp_offset);
- cfi.type = hint->type;
- cfi.end = hint->end;
+ cfi.type = type;
+ cfi.end = bswap_if_needed(hint->end);
insn->cfi = cfi_hash_find_or_add(&cfi);
}
--
2.25.1