Messages in this thread Patch in this message |  | | From | Sasha Levin <> | | Subject | [PATCH AUTOSEL 6.13 23/34] x86/bugs: Use SBPB in write_ibpb() if applicable | | Date | Mon, 14 Apr 2025 09:27:17 -0400 |
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From: Josh Poimboeuf <jpoimboe@kernel.org>
[ Upstream commit fc9fd3f98423367c79e0bd85a9515df26dc1b3cc ]
write_ibpb() does IBPB, which (among other things) flushes branch type predictions on AMD. If the CPU has SRSO_NO, or if the SRSO mitigation has been disabled, branch type flushing isn't needed, in which case the lighter-weight SBPB can be used.
The 'x86_pred_cmd' variable already keeps track of whether IBPB or SBPB should be used. Use that instead of hardcoding IBPB.
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/17c5dcd14b29199b75199d67ff7758de9d9a4928.1744148254.git.jpoimboe@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org> --- arch/x86/entry/entry.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/entry/entry.S b/arch/x86/entry/entry.S index b7ea3e8e9eccd..58e3124ee2b42 100644 --- a/arch/x86/entry/entry.S +++ b/arch/x86/entry/entry.S @@ -18,7 +18,7 @@ SYM_FUNC_START(entry_ibpb) movl $MSR_IA32_PRED_CMD, %ecx - movl $PRED_CMD_IBPB, %eax + movl _ASM_RIP(x86_pred_cmd), %eax xorl %edx, %edx wrmsr -- 2.39.5
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