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Commit 9e0e3c51 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

x86/speculation, objtool: Annotate indirect calls/jumps for objtool 



Annotate the indirect calls/jumps in the CALL_NOSPEC/JUMP_NOSPEC
alternatives.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 87358710

arch/x86/include/asm/nospec-branch.h

+23 −4
Original line number Diff line number Diff line
@@ -67,6 +67,18 @@ 
	.popsection

.endm



/*

 * This should be used immediately before an indirect jump/call. It tells

 * objtool the subsequent indirect jump/call is vouched safe for retpoline

 * builds.

 */

.macro ANNOTATE_RETPOLINE_SAFE

	.Lannotate_\@:

	.pushsection .discard.retpoline_safe

	_ASM_PTR .Lannotate_\@

	.popsection

.endm



/*

 * These are the bare retpoline primitives for indirect jmp and call.

 * Do not use these directly; they only exist to make the ALTERNATIVE
@@ -103,9 +115,9 @@ 
.macro JMP_NOSPEC reg:req

#ifdef CONFIG_RETPOLINE

	ANNOTATE_NOSPEC_ALTERNATIVE

	ALTERNATIVE_2 __stringify(jmp *\reg),				\

	ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg),	\

		__stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE,	\

		__stringify(lfence; jmp *\reg), X86_FEATURE_RETPOLINE_AMD

		__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; jmp *\reg), X86_FEATURE_RETPOLINE_AMD

#else

	jmp	*\reg

#endif
@@ -114,9 +126,9 @@ 
.macro CALL_NOSPEC reg:req

#ifdef CONFIG_RETPOLINE

	ANNOTATE_NOSPEC_ALTERNATIVE

	ALTERNATIVE_2 __stringify(call *\reg),				\

	ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg),	\

		__stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\

		__stringify(lfence; call *\reg), X86_FEATURE_RETPOLINE_AMD

		__stringify(lfence; ANNOTATE_RETPOLINE_SAFE; call *\reg), X86_FEATURE_RETPOLINE_AMD

#else

	call	*\reg

#endif
@@ -144,6 +156,12 @@ 
	".long 999b - .\n\t"					\

	".popsection\n\t"



#define ANNOTATE_RETPOLINE_SAFE					\

	"999:\n\t"						\

	".pushsection .discard.retpoline_safe\n\t"		\

	_ASM_PTR " 999b\n\t"					\

	".popsection\n\t"



#if defined(CONFIG_X86_64) && defined(RETPOLINE)



/*
@@ -153,6 +171,7 @@ 
# define CALL_NOSPEC						\

	ANNOTATE_NOSPEC_ALTERNATIVE				\

	ALTERNATIVE(						\

	ANNOTATE_RETPOLINE_SAFE					\

	"call *%[thunk_target]\n",				\

	"call __x86_indirect_thunk_%V[thunk_target]\n",		\

	X86_FEATURE_RETPOLINE)