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x86/bugs: Rename entry_ibpb() to write_ibpb()

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There's nothing entry-specific about entry_ibpb().  In preparation for
calling it from elsewhere, rename it to write_ibpb().

Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/1e54ace131e79b760de3fe828264e26d0896e3ac.1744148254.git.jpoimboe@kernel.org
This commit is contained in:
Josh Poimboeuf 2025-04-08 14:47:30 -07:00 committed by Ingo Molnar
parent 996457176b
commit 13235d6d50
3 changed files with 10 additions and 9 deletions
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7
arch/x86/entry/entry.S
View File

@ -17,7 +17,8 @@
.pushsection .noinstr.text, "ax"
SYM_FUNC_START(entry_ibpb)
/* Clobbers AX, CX, DX */
SYM_FUNC_START(write_ibpb)
ANNOTATE_NOENDBR
movl $MSR_IA32_PRED_CMD, %ecx
movl $PRED_CMD_IBPB, %eax
@ -27,9 +28,9 @@ SYM_FUNC_START(entry_ibpb)
/* Make sure IBPB clears return stack preductions too. */
FILL_RETURN_BUFFER %rax, RSB_CLEAR_LOOPS, X86_BUG_IBPB_NO_RET
RET
SYM_FUNC_END(entry_ibpb)
SYM_FUNC_END(write_ibpb)
/* For KVM */
EXPORT_SYMBOL_GPL(entry_ibpb);
EXPORT_SYMBOL_GPL(write_ibpb);
.popsection

6
arch/x86/include/asm/nospec-branch.h
View File

@ -269,7 +269,7 @@
* typically has NO_MELTDOWN).
*
* While retbleed_untrain_ret() doesn't clobber anything but requires stack,
* entry_ibpb() will clobber AX, CX, DX.
* write_ibpb() will clobber AX, CX, DX.
*
* As such, this must be placed after every *SWITCH_TO_KERNEL_CR3 at a point
* where we have a stack but before any RET instruction.
@ -279,7 +279,7 @@
VALIDATE_UNRET_END
CALL_UNTRAIN_RET
ALTERNATIVE_2 "", \
"call entry_ibpb", \ibpb_feature, \
"call write_ibpb", \ibpb_feature, \
__stringify(\call_depth_insns), X86_FEATURE_CALL_DEPTH
#endif
.endm
@ -368,7 +368,7 @@ extern void srso_return_thunk(void);
extern void srso_alias_return_thunk(void);
extern void entry_untrain_ret(void);
extern void entry_ibpb(void);
extern void write_ibpb(void);
#ifdef CONFIG_X86_64
extern void clear_bhb_loop(void);

6
arch/x86/kernel/cpu/bugs.c
View File

@ -1142,7 +1142,7 @@ static void __init retbleed_select_mitigation(void)
setup_clear_cpu_cap(X86_FEATURE_RETHUNK);
/*
* There is no need for RSB filling: entry_ibpb() ensures
* There is no need for RSB filling: write_ibpb() ensures
* all predictions, including the RSB, are invalidated,
* regardless of IBPB implementation.
*/
@ -2676,7 +2676,7 @@ static void __init srso_select_mitigation(void)
setup_clear_cpu_cap(X86_FEATURE_RETHUNK);
/*
* There is no need for RSB filling: entry_ibpb() ensures
* There is no need for RSB filling: write_ibpb() ensures
* all predictions, including the RSB, are invalidated,
* regardless of IBPB implementation.
*/
@ -2701,7 +2701,7 @@ static void __init srso_select_mitigation(void)
srso_mitigation = SRSO_MITIGATION_IBPB_ON_VMEXIT;
/*
* There is no need for RSB filling: entry_ibpb() ensures
* There is no need for RSB filling: write_ibpb() ensures
* all predictions, including the RSB, are invalidated,
* regardless of IBPB implementation.
*/