x86/ptrace: Always inline trivial accessors

A KASAN build bloats these single load/store helpers such that
it fails to inline them:

  vmlinux.o: error: objtool: irqentry_exit+0x5e8: call to instruction_pointer_set() with UACCESS enabled

Make sure the compiler isn't allowed to do stupid.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20251031105435.GU4068168@noisy.programming.kicks-ass.net

Author: Peter Zijlstra

arch/x86/include/asm/ptrace.h

@@ -187,12 +187,12 @@ convert_ip_to_linear(struct task_struct *child, struct pt_regs *regs);
 extern void send_sigtrap(struct pt_regs *regs, int error_code, int si_code);
 
 
-static inline unsigned long regs_return_value(struct pt_regs *regs)
+static __always_inline unsigned long regs_return_value(struct pt_regs *regs)
 {
 	return regs->ax;
 }
 
-static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
+static __always_inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
 {
 	regs->ax = rc;
 }
@@ -277,34 +277,34 @@ static __always_inline bool ip_within_syscall_gap(struct pt_regs *regs)
 }
 #endif
 
-static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
+static __always_inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
 {
 	return regs->sp;
 }
 
-static inline unsigned long instruction_pointer(struct pt_regs *regs)
+static __always_inline unsigned long instruction_pointer(struct pt_regs *regs)
 {
 	return regs->ip;
 }
 
-static inline void instruction_pointer_set(struct pt_regs *regs,
-		unsigned long val)
+static __always_inline
+void instruction_pointer_set(struct pt_regs *regs, unsigned long val)
 {
 	regs->ip = val;
 }
 
-static inline unsigned long frame_pointer(struct pt_regs *regs)
+static __always_inline unsigned long frame_pointer(struct pt_regs *regs)
 {
 	return regs->bp;
 }
 
-static inline unsigned long user_stack_pointer(struct pt_regs *regs)
+static __always_inline unsigned long user_stack_pointer(struct pt_regs *regs)
 {
 	return regs->sp;
 }
 
-static inline void user_stack_pointer_set(struct pt_regs *regs,
-		unsigned long val)
+static __always_inline
+void user_stack_pointer_set(struct pt_regs *regs, unsigned long val)
 {
 	regs->sp = val;
 }