3.16.57-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Ingo Molnar <mingo@xxxxxxxxxx> commit d72f4e29e6d84b7ec02ae93088aa459ac70e733b upstream. firmware_restrict_branch_speculation_*() recently started using preempt_enable()/disable(), but those are relatively high level primitives and cause build failures on some 32-bit builds. Since we want to keep <asm/nospec-branch.h> low level, convert them to macros to avoid header hell... Cc: David Woodhouse <dwmw@xxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: arjan.van.de.ven@xxxxxxxxx Cc: bp@xxxxxxxxx Cc: dave.hansen@xxxxxxxxx Cc: jmattson@xxxxxxxxxx Cc: karahmed@xxxxxxxxx Cc: kvm@xxxxxxxxxxxxxxx Cc: pbonzini@xxxxxxxxxx Cc: rkrcmar@xxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- arch/x86/include/asm/nospec-branch.h | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -213,20 +213,22 @@ static inline void indirect_branch_predi /* * With retpoline, we must use IBRS to restrict branch prediction * before calling into firmware. + * + * (Implemented as CPP macros due to header hell.) */ -static inline void firmware_restrict_branch_speculation_start(void) -{ - preempt_disable(); - alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS, - X86_FEATURE_USE_IBRS_FW); -} +#define firmware_restrict_branch_speculation_start() \ +do { \ + preempt_disable(); \ + alternative_msr_write(MSR_IA32_SPEC_CTRL, SPEC_CTRL_IBRS, \ + X86_FEATURE_USE_IBRS_FW); \ +} while (0) -static inline void firmware_restrict_branch_speculation_end(void) -{ - alternative_msr_write(MSR_IA32_SPEC_CTRL, 0, - X86_FEATURE_USE_IBRS_FW); - preempt_enable(); -} +#define firmware_restrict_branch_speculation_end() \ +do { \ + alternative_msr_write(MSR_IA32_SPEC_CTRL, 0, \ + X86_FEATURE_USE_IBRS_FW); \ + preempt_enable(); \ +} while (0) #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_NOSPEC_BRANCH_H_ */