[tip: x86/core] objtool: Handle per arch retpoline naming

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     3b652980a250c1ed9e0c361750f029781831cdc3
Gitweb:        https://git.kernel.org/tip/3b652980a250c1ed9e0c361750f029781831cdc3
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Fri, 26 Mar 2021 16:12:04 +01:00
Committer:     Borislav Petkov <bp@xxxxxxx>
CommitterDate: Thu, 01 Apr 2021 11:36:52 +02:00

objtool: Handle per arch retpoline naming

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

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
Link: https://lkml.kernel.org/r/20210326151259.630296706@xxxxxxxxxxxxx
---
 tools/objtool/arch/x86/decode.c      |  5 +++++
 tools/objtool/check.c                |  9 +++++++--
 tools/objtool/include/objtool/arch.h |  2 ++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 8380d0b..e5fa3a5 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -645,3 +645,8 @@ int arch_decode_hint_reg(struct instruction *insn, u8 sp_reg)
 
 	return 0;
 }
+
+bool arch_is_retpoline(struct symbol *sym)
+{
+	return !strncmp(sym->name, "__x86_indirect_", 15);
+}
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 519af4b..6fbc001 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -850,6 +850,11 @@ static int add_ignore_alternatives(struct objtool_file *file)
 	return 0;
 }
 
+__weak bool arch_is_retpoline(struct symbol *sym)
+{
+	return false;
+}
+
 /*
  * Find the destination instructions for all jumps.
  */
@@ -872,7 +877,7 @@ static int add_jump_destinations(struct objtool_file *file)
 		} 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.
@@ -1026,7 +1031,7 @@ static int add_call_destinations(struct objtool_file *file)
 				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.
diff --git a/tools/objtool/include/objtool/arch.h b/tools/objtool/include/objtool/arch.h
index 6ff0685..bb30993 100644
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/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 */