linux-kernel - [PATCH v3 05/16] x86/retpoline: Remove unused replacement symbols

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Date:   Tue, 26 Oct 2021 14:01:37 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     x86@...nel.org, jpoimboe@...hat.com, andrew.cooper3@...rix.com
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        alexei.starovoitov@...il.com, ndesaulniers@...gle.com,
        bpf@...r.kernel.org
Subject: [PATCH v3 05/16] x86/retpoline: Remove unused replacement symbols

Now that objtool no longer creates alternatives, these replacement
symbols are no longer needed, remove them.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/include/asm/asm-prototypes.h |   10 --------
 arch/x86/lib/retpoline.S              |   42 ----------------------------------
 2 files changed, 52 deletions(-)

--- a/arch/x86/include/asm/asm-prototypes.h
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -24,14 +24,4 @@ extern void cmpxchg8b_emu(void);
 	extern asmlinkage void __x86_indirect_thunk_ ## reg (void);
 #include <asm/GEN-for-each-reg.h>
 
-#undef GEN
-#define GEN(reg) \
-	extern asmlinkage void __x86_indirect_alt_call_ ## reg (void);
-#include <asm/GEN-for-each-reg.h>
-
-#undef GEN
-#define GEN(reg) \
-	extern asmlinkage void __x86_indirect_alt_jmp_ ## reg (void);
-#include <asm/GEN-for-each-reg.h>
-
 #endif /* CONFIG_RETPOLINE */
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -41,36 +41,6 @@ SYM_FUNC_END(__x86_indirect_thunk_\reg)
 .endm
 
 /*
- * This generates .altinstr_replacement symbols for use by objtool. They,
- * however, must not actually live in .altinstr_replacement since that will be
- * discarded after init, but module alternatives will also reference these
- * symbols.
- *
- * Their names matches the "__x86_indirect_" prefix to mark them as retpolines.
- */
-.macro ALT_THUNK reg
-
-	.align 1
-
-SYM_FUNC_START_NOALIGN(__x86_indirect_alt_call_\reg)
-	ANNOTATE_RETPOLINE_SAFE
-1:	call	*%\reg
-2:	.skip	5-(2b-1b), 0x90
-SYM_FUNC_END(__x86_indirect_alt_call_\reg)
-
-STACK_FRAME_NON_STANDARD(__x86_indirect_alt_call_\reg)
-
-SYM_FUNC_START_NOALIGN(__x86_indirect_alt_jmp_\reg)
-	ANNOTATE_RETPOLINE_SAFE
-1:	jmp	*%\reg
-2:	.skip	5-(2b-1b), 0x90
-SYM_FUNC_END(__x86_indirect_alt_jmp_\reg)
-
-STACK_FRAME_NON_STANDARD(__x86_indirect_alt_jmp_\reg)
-
-.endm
-
-/*
  * Despite being an assembler file we can't just use .irp here
  * because __KSYM_DEPS__ only uses the C preprocessor and would
  * only see one instance of "__x86_indirect_thunk_\reg" rather
@@ -92,15 +62,3 @@ STACK_FRAME_NON_STANDARD(__x86_indirect_
 #undef GEN
 #define GEN(reg) EXPORT_THUNK(reg)
 #include <asm/GEN-for-each-reg.h>
-
-#undef GEN
-#define GEN(reg) ALT_THUNK reg
-#include <asm/GEN-for-each-reg.h>
-
-#undef GEN
-#define GEN(reg) __EXPORT_THUNK(__x86_indirect_alt_call_ ## reg)
-#include <asm/GEN-for-each-reg.h>
-
-#undef GEN
-#define GEN(reg) __EXPORT_THUNK(__x86_indirect_alt_jmp_ ## reg)
-#include <asm/GEN-for-each-reg.h>