[tip: sched/core] cpuidle, nospec: Make mds_idle_clear_cpu_buffers() noinstr clean

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the sched/core branch of tip:

Commit-ID:     10fdb38cee36b8dc4775e6fe4ad85e78bafdbd65
Gitweb:        https://git.kernel.org/tip/10fdb38cee36b8dc4775e6fe4ad85e78bafdbd65
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Thu, 12 Jan 2023 20:43:45 +01:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Fri, 13 Jan 2023 11:48:16 +01:00

cpuidle, nospec: Make mds_idle_clear_cpu_buffers() noinstr clean

objtool found that the mds_idle_clear_cpu_buffers() method got
uninlined by the compiler where it called out into instrumentation:

  vmlinux.o: warning: objtool: mwait_idle+0x47: call to mds_idle_clear_cpu_buffers() leaves .noinstr.text section
  vmlinux.o: warning: objtool: acpi_processor_ffh_cstate_enter+0xa2: call to mds_idle_clear_cpu_buffers() leaves .noinstr.text section
  vmlinux.o: warning: objtool: intel_idle+0x91: call to mds_idle_clear_cpu_buffers() leaves .noinstr.text section
  vmlinux.o: warning: objtool: intel_idle_s2idle+0x8c: call to mds_idle_clear_cpu_buffers() leaves .noinstr.text section
  vmlinux.o: warning: objtool: intel_idle_irq+0xaa: call to mds_idle_clear_cpu_buffers() leaves .noinstr.text section

Solve this by marking mds_idle_clear_cpu_buffers() as __always_inline.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
Tested-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Acked-by: Frederic Weisbecker <frederic@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230112195541.233779815@xxxxxxxxxxxxx
---
 arch/x86/include/asm/nospec-branch.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 771b0a2..e04313e 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -564,7 +564,7 @@ static __always_inline void mds_user_clear_cpu_buffers(void)
  *
  * Clear CPU buffers if the corresponding static key is enabled
  */
-static inline void mds_idle_clear_cpu_buffers(void)
+static __always_inline void mds_idle_clear_cpu_buffers(void)
 {
 	if (static_branch_likely(&mds_idle_clear))
 		mds_clear_cpu_buffers();