The jump destination and relocation offset used previously are only
reliable on x86_64 architecture. We abstract these computations by calling
arch-dependent implementations.
Signed-off-by: Raphael Gault <[email protected]>
---
tools/objtool/arch.h | 6 ++++++
tools/objtool/arch/x86/decode.c | 11 +++++++++++
tools/objtool/check.c | 15 ++++++++++-----
3 files changed, 27 insertions(+), 5 deletions(-)
diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index ced3765c4f44..a9a50a25ca66 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -66,6 +66,8 @@ struct stack_op {
struct op_src src;
};
+struct instruction;
+
void arch_initial_func_cfi_state(struct cfi_state *state);
int arch_decode_instruction(struct elf *elf, struct section *sec,
@@ -75,4 +77,8 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
bool arch_callee_saved_reg(unsigned char reg);
+unsigned long arch_jump_destination(struct instruction *insn);
+
+unsigned long arch_dest_rela_offset(int addend);
+
#endif /* _ARCH_H */
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 0567c47a91b1..fa33b3465722 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -11,6 +11,7 @@
#include "lib/inat.c"
#include "lib/insn.c"
+#include "../../check.h"
#include "../../elf.h"
#include "../../arch.h"
#include "../../warn.h"
@@ -66,6 +67,11 @@ bool arch_callee_saved_reg(unsigned char reg)
}
}
+unsigned long arch_dest_rela_offset(int addend)
+{
+ return addend + 4;
+}
+
int arch_decode_instruction(struct elf *elf, struct section *sec,
unsigned long offset, unsigned int maxlen,
unsigned int *len, enum insn_type *type,
@@ -497,3 +503,8 @@ void arch_initial_func_cfi_state(struct cfi_state *state)
state->regs[16].base = CFI_CFA;
state->regs[16].offset = -8;
}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+ return insn->offset + insn->len + insn->immediate;
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 176f2f084060..479fab46b656 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -563,7 +563,7 @@ static int add_jump_destinations(struct objtool_file *file)
insn->len);
if (!rela) {
dest_sec = insn->sec;
- dest_off = insn->offset + insn->len + insn->immediate;
+ dest_off = arch_jump_destination(insn);
} else if (rela->sym->type == STT_SECTION) {
dest_sec = rela->sym->sec;
dest_off = rela->addend + 4;
@@ -659,7 +659,7 @@ static int add_call_destinations(struct objtool_file *file)
rela = find_rela_by_dest_range(insn->sec, insn->offset,
insn->len);
if (!rela) {
- dest_off = insn->offset + insn->len + insn->immediate;
+ dest_off = arch_jump_destination(insn);
insn->call_dest = find_symbol_by_offset(insn->sec,
dest_off);
@@ -672,14 +672,19 @@ static int add_call_destinations(struct objtool_file *file)
}
} else if (rela->sym->type == STT_SECTION) {
+ /*
+ * the original x86_64 code adds 4 to the rela->addend
+ * which is not needed on arm64 architecture.
+ */
+ dest_off = arch_dest_rela_offset(rela->addend);
insn->call_dest = find_symbol_by_offset(rela->sym->sec,
- rela->addend+4);
+ dest_off);
if (!insn->call_dest ||
insn->call_dest->type != STT_FUNC) {
- WARN_FUNC("can't find call dest symbol at %s+0x%x",
+ WARN_FUNC("can't find call dest symbol at %s+0x%lx",
insn->sec, insn->offset,
rela->sym->sec->name,
- rela->addend + 4);
+ dest_off);
return -1;
}
} else
--
2.17.1
Hi Raphaël,
On 16/08/19 13:23, Raphael Gault wrote:
> The jump destination and relocation offset used previously are only
> reliable on x86_64 architecture. We abstract these computations by calling
> arch-dependent implementations.
>
> Signed-off-by: Raphael Gault <[email protected]>
> ---
> tools/objtool/arch.h | 6 ++++++
> tools/objtool/arch/x86/decode.c | 11 +++++++++++
> tools/objtool/check.c | 15 ++++++++++-----
> 3 files changed, 27 insertions(+), 5 deletions(-)
>
> diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
> index ced3765c4f44..a9a50a25ca66 100644
> --- a/tools/objtool/arch.h
> +++ b/tools/objtool/arch.h
> @@ -66,6 +66,8 @@ struct stack_op {
> struct op_src src;
> };
>
> +struct instruction;
> +
> void arch_initial_func_cfi_state(struct cfi_state *state);
>
> int arch_decode_instruction(struct elf *elf, struct section *sec,
> @@ -75,4 +77,8 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
>
> bool arch_callee_saved_reg(unsigned char reg);
>
> +unsigned long arch_jump_destination(struct instruction *insn);
> +
> +unsigned long arch_dest_rela_offset(int addend);
> +
> #endif /* _ARCH_H */
> diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
> index 0567c47a91b1..fa33b3465722 100644
> --- a/tools/objtool/arch/x86/decode.c
> +++ b/tools/objtool/arch/x86/decode.c
> @@ -11,6 +11,7 @@
> #include "lib/inat.c"
> #include "lib/insn.c"
>
> +#include "../../check.h"
> #include "../../elf.h"
> #include "../../arch.h"
> #include "../../warn.h"
> @@ -66,6 +67,11 @@ bool arch_callee_saved_reg(unsigned char reg)
> }
> }
>
> +unsigned long arch_dest_rela_offset(int addend)
> +{
> + return addend + 4;
> +}
> +
> int arch_decode_instruction(struct elf *elf, struct section *sec,
> unsigned long offset, unsigned int maxlen,
> unsigned int *len, enum insn_type *type,
> @@ -497,3 +503,8 @@ void arch_initial_func_cfi_state(struct cfi_state *state)
> state->regs[16].base = CFI_CFA;
> state->regs[16].offset = -8;
> }
> +
> +unsigned long arch_jump_destination(struct instruction *insn)
> +{
> + return insn->offset + insn->len + insn->immediate;
> +}
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 176f2f084060..479fab46b656 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -563,7 +563,7 @@ static int add_jump_destinations(struct objtool_file *file)
> insn->len);
> if (!rela) {
> dest_sec = insn->sec;
> - dest_off = insn->offset + insn->len + insn->immediate;
> + dest_off = arch_jump_destination(insn);
> } else if (rela->sym->type == STT_SECTION) {
> dest_sec = rela->sym->sec;
> dest_off = rela->addend + 4;
> @@ -659,7 +659,7 @@ static int add_call_destinations(struct objtool_file *file)
> rela = find_rela_by_dest_range(insn->sec, insn->offset,
> insn->len);
> if (!rela) {
> - dest_off = insn->offset + insn->len + insn->immediate;
> + dest_off = arch_jump_destination(insn);
> insn->call_dest = find_symbol_by_offset(insn->sec,
> dest_off);
>
> @@ -672,14 +672,19 @@ static int add_call_destinations(struct objtool_file *file)
> }
>
> } else if (rela->sym->type == STT_SECTION) {
> + /*
> + * the original x86_64 code adds 4 to the rela->addend
> + * which is not needed on arm64 architecture.
> + */
I'm not sure this is worth mentioning in generic code. You might include
it in the commit message to justify the change.
> + dest_off = arch_dest_rela_offset(rela->addend);
> insn->call_dest = find_symbol_by_offset(rela->sym->sec,
> - rela->addend+4);
> + dest_off);
> if (!insn->call_dest ||
> insn->call_dest->type != STT_FUNC) {
> - WARN_FUNC("can't find call dest symbol at %s+0x%x",
> + WARN_FUNC("can't find call dest symbol at %s+0x%lx",
> insn->sec, insn->offset,
> rela->sym->sec->name,
> - rela->addend + 4);
> + dest_off);
> return -1;
> }
> } else
>
Otherwise, the change looks good to me.
Thanks,
--
Julien Thierry
On Fri, Aug 16, 2019 at 01:23:46PM +0100, Raphael Gault wrote:
> @@ -672,14 +672,19 @@ static int add_call_destinations(struct objtool_file *file)
> }
>
> } else if (rela->sym->type == STT_SECTION) {
> + /*
> + * the original x86_64 code adds 4 to the rela->addend
> + * which is not needed on arm64 architecture.
> + */
> + dest_off = arch_dest_rela_offset(rela->addend);
I agree with Julien that this comment isn't needed. The "arch_" prefix
already implies there are arch-specific differences.
Also, this patch should replace all the other "addend + 4" usages:
$ git grep "addend + 4" tools/objtool
tools/objtool/arch/x86/decode.c: return addend + 4;
tools/objtool/check.c: dest_off = rela->addend + 4;
tools/objtool/check.c: dest_off = rela->sym->sym.st_value + rela->addend + 4;
--
Josh