[PATCH 1/4] arm64: percpu: Always inline helpers used by noinstr code

[Jisheng Zhang]

The non-instrumentable entry and stack unwinding paths use the per-CPU
offset and read helpers. Plain inline does not guarantee inlining, so
these helpers can be emitted out of line without inheriting the
caller's instrumentation restrictions.

In a GCC build with CONFIG_CC_OPTIMIZE_FOR_SIZE=y,
__kern_my_cpu_offset() was emitted in .text and called from
.noinstr.text.

Mark the per-CPU offset and read helpers __always_inline to keep their
instructions within their callers.

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxx>
Assisted-by: LLM
---
 arch/arm64/include/asm/percpu.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/percpu.h b/arch/arm64/include/asm/percpu.h
index 3cc316091d66..7c344de5052d 100644
--- a/arch/arm64/include/asm/percpu.h
+++ b/arch/arm64/include/asm/percpu.h
@@ -23,7 +23,7 @@ static inline void set_my_cpu_offset(unsigned long off)
 			:: "r" (off) : "memory");
 }
 
-static inline unsigned long __hyp_my_cpu_offset(void)
+static __always_inline unsigned long __hyp_my_cpu_offset(void)
 {
 	/*
 	 * Non-VHE hyp code runs with preemption disabled. No need to hazard
@@ -37,7 +37,7 @@ static inline unsigned long __hyp_my_cpu_offset(void)
 		    "mrs " dst ", tpidr_el2",				\
 		       ARM64_HAS_VIRT_HOST_EXTN)
 
-static inline unsigned long __kern_my_cpu_offset(void)
+static __always_inline unsigned long __kern_my_cpu_offset(void)
 {
 	unsigned long off;
 
@@ -129,7 +129,7 @@ static inline unsigned long __kern_my_cpu_offset(void)
 #endif
 
 #define PERCPU_RW_OPS(w, sfx, sz)						\
-static inline unsigned long __percpu_read_##sz(void __percpu *pcp)		\
+static __always_inline unsigned long __percpu_read_##sz(void __percpu *pcp)		\
 {										\
 	u16 *gprs = &current_thread_info()->pcpu_gprs;				\
 	unsigned long off;							\
-- 
2.55.0