[PATCH 5.10 024/148] objtool: Handle per arch retpoline naming

Greg Kroah-Hartman
2022-07-23T09:59:22Z

From: Peter Zijlstra <peterz@infradead.org>

commit 530b4ddd9dd92b263081f5c7786d39a8129c8b2d upstream.

The __x86_indirect_ naming is obviously not generic. Shorten to allow
matching some additional magic names later.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lkml.kernel.org/r/20210326151259.630296706@infradead.org
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/objtool/arch.h | 2 ++
tools/objtool/arch/x86/decode.c | 5 +++++
tools/objtool/check.c | 9 +++++++--
3 files changed, 14 insertions(+), 2 deletions(-)

--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -86,4 +86,6 @@ const char *arch_nop_insn(int len);

int arch_decode_hint_reg(struct instruction *insn, u8 sp_reg);

+bool arch_is_retpoline(struct symbol *sym);
+
#endif /* _ARCH_H */
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -620,3 +620,8 @@ int arch_decode_hint_reg(struct instruct

return 0;
}
+
+bool arch_is_retpoline(struct symbol *sym)
+{
+ return !strncmp(sym->name, "__x86_indirect_", 15);
+}
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -778,6 +778,11 @@ static int add_ignore_alternatives(struc
return 0;
}

+__weak bool arch_is_retpoline(struct symbol *sym)
+{
+ return false;
+}
+
/*
* Find the destination instructions for all jumps.
*/
@@ -800,7 +805,7 @@ static int add_jump_destinations(struct
} else if (reloc->sym->type == STT_SECTION) {
dest_sec = reloc->sym->sec;
dest_off = arch_dest_reloc_offset(reloc->addend);
- } else if (!strncmp(reloc->sym->name, "__x86_indirect_thunk_", 21)) {
+ } else if (arch_is_retpoline(reloc->sym)) {
/*
* Retpoline jumps are really dynamic jumps in
* disguise, so convert them accordingly.
@@ -954,7 +959,7 @@ static int add_call_destinations(struct
return -1;
}

- } else if (!strncmp(reloc->sym->name, "__x86_indirect_thunk_", 21)) {
+ } else if (arch_is_retpoline(reloc->sym)) {
/*
* Retpoline calls are really dynamic calls in
* disguise, so convert them accordingly.