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

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

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: David Woodhouse <dwmw@amazon.co.uk>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2018-01-17 22:34:34 +01:00 committed by Ingo Molnar
parent 87358710c1
commit 9e0e3c5130
1 changed files with 23 additions and 4 deletions
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27
arch/x86/include/asm/nospec-branch.h
View File

@ -67,6 +67,18 @@
.popsection .popsection
.endm .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. * These are the bare retpoline primitives for indirect jmp and call.
* Do not use these directly; they only exist to make the ALTERNATIVE * Do not use these directly; they only exist to make the ALTERNATIVE
@ -103,9 +115,9 @@
.macro JMP_NOSPEC reg:req .macro JMP_NOSPEC reg:req
#ifdef CONFIG_RETPOLINE #ifdef CONFIG_RETPOLINE
ANNOTATE_NOSPEC_ALTERNATIVE ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE_2 __stringify(jmp *\reg), \ ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; jmp *\reg), \
__stringify(RETPOLINE_JMP \reg), X86_FEATURE_RETPOLINE, \ __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 #else
jmp *\reg jmp *\reg
#endif #endif
@ -114,9 +126,9 @@
.macro CALL_NOSPEC reg:req .macro CALL_NOSPEC reg:req
#ifdef CONFIG_RETPOLINE #ifdef CONFIG_RETPOLINE
ANNOTATE_NOSPEC_ALTERNATIVE ANNOTATE_NOSPEC_ALTERNATIVE
ALTERNATIVE_2 __stringify(call *\reg), \ ALTERNATIVE_2 __stringify(ANNOTATE_RETPOLINE_SAFE; call *\reg), \
__stringify(RETPOLINE_CALL \reg), X86_FEATURE_RETPOLINE,\ __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 #else
call *\reg call *\reg
#endif #endif
@ -144,6 +156,12 @@
".long 999b - .\n\t" \ ".long 999b - .\n\t" \
".popsection\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) #if defined(CONFIG_X86_64) && defined(RETPOLINE)
/* /*
@ -153,6 +171,7 @@
# define CALL_NOSPEC \ # define CALL_NOSPEC \
ANNOTATE_NOSPEC_ALTERNATIVE \ ANNOTATE_NOSPEC_ALTERNATIVE \
ALTERNATIVE( \ ALTERNATIVE( \
ANNOTATE_RETPOLINE_SAFE \
"call *%[thunk_target]\n", \ "call *%[thunk_target]\n", \
"call __x86_indirect_thunk_%V[thunk_target]\n", \ "call __x86_indirect_thunk_%V[thunk_target]\n", \
X86_FEATURE_RETPOLINE) X86_FEATURE_RETPOLINE)