linux-kernel - [PATCH 3/9] objtool: Per arch retpoline naming

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Message-ID: <20210312171653.527760836@infradead.org>
Date:   Fri, 12 Mar 2021 18:16:16 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     x86@...nel.org, jpoimboe@...hat.com, jgross@...e.com,
        mbenes@...e.cz
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org
Subject: [PATCH 3/9] objtool: 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@...radead.org>
---
 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(-)

--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -690,3 +690,8 @@ 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
@@ -850,6 +850,11 @@ 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.
  */
@@ -872,7 +877,7 @@ 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.
@@ -1026,7 +1031,7 @@ 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 accodingly.
--- a/tools/objtool/include/objtool/arch.h
+++ b/tools/objtool/include/objtool/arch.h
@@ -85,4 +85,6 @@ 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 */