kprobes: treewide: Make it harder to refer kretprobe_trampoline directly

Since now there is kretprobe_trampoline_addr() for referring the
address of kretprobe trampoline code, we don't need to access
kretprobe_trampoline directly.

Make it harder to refer by renaming it to __kretprobe_trampoline().

Link: https://lkml.kernel.org/r/163163045446.489837.14510577516938803097.stgit@devnote2

Suggested-by: Ingo Molnar <[e-mail]>
Signed-off-by: Masami Hiramatsu <[e-mail]>
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>

arch/arc/include/asm/kprobes.h

···
 };
 
 int kprobe_fault_handler(struct pt_regs *regs, unsigned long cause);
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 void trap_is_kprobe(unsigned long address, struct pt_regs *regs);
 #else
 #define trap_is_kprobe(address, regs)

arch/arc/kernel/kprobes.c

···
 
 static void __used kretprobe_trampoline_holder(void)
 {
-	__asm__ __volatile__(".global kretprobe_trampoline\n"
-			     "kretprobe_trampoline:\n" "nop\n");
+	__asm__ __volatile__(".global __kretprobe_trampoline\n"
+			     "__kretprobe_trampoline:\n"
+			     "nop\n");
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
···
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->blink = (unsigned long)&kretprobe_trampoline;
+	regs->blink = (unsigned long)&__kretprobe_trampoline;
 }
 
 static int __kprobes trampoline_probe_handler(struct kprobe *p,
···
 }
 
 static struct kprobe trampoline_p = {
-	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *) &__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 
···
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 {
-	if (p->addr == (kprobe_opcode_t *) &kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *) &__kretprobe_trampoline)
 		return 1;
 
 	return 0;

arch/arm/probes/kprobes/core.c

···
  * for kretprobe handlers which should normally be interested in r0 only
  * anyway.
  */
-void __naked __kprobes kretprobe_trampoline(void)
+void __naked __kprobes __kretprobe_trampoline(void)
 {
 	__asm__ __volatile__ (
 		"stmdb	sp!, {r0 - r11}		\n\t"
···
 		: : : "memory");
 }
 
-/* Called from kretprobe_trampoline */
+/* Called from __kretprobe_trampoline */
 static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
 {
 	return (void *)kretprobe_trampoline_handler(regs, (void *)regs->ARM_fp);
···
 	ri->fp = (void *)regs->ARM_fp;
 
 	/* Replace the return addr with trampoline addr. */
-	regs->ARM_lr = (unsigned long)&kretprobe_trampoline;
+	regs->ARM_lr = (unsigned long)&__kretprobe_trampoline;
 }
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)

arch/arm64/include/asm/kprobes.h

···
 int kprobe_fault_handler(struct pt_regs *regs, unsigned int fsr);
 int kprobe_exceptions_notify(struct notifier_block *self,
 			     unsigned long val, void *data);
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 void __kprobes *trampoline_probe_handler(struct pt_regs *regs);
 
 #endif /* CONFIG_KPROBES */

arch/arm64/kernel/probes/kprobes.c

···
 	ri->fp = (void *)kernel_stack_pointer(regs);
 
 	/* replace return addr (x30) with trampoline */
-	regs->regs[30] = (long)&kretprobe_trampoline;
+	regs->regs[30] = (long)&__kretprobe_trampoline;
 }
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)

arch/arm64/kernel/probes/kprobes_trampoline.S

···
 	ldp x28, x29, [sp, #S_X28]
 	.endm
 
-SYM_CODE_START(kretprobe_trampoline)
+SYM_CODE_START(__kretprobe_trampoline)
 	sub sp, sp, #PT_REGS_SIZE
 
 	save_all_base_regs
···
 	add sp, sp, #PT_REGS_SIZE
 	ret
 
-SYM_CODE_END(kretprobe_trampoline)
+SYM_CODE_END(__kretprobe_trampoline)

arch/csky/include/asm/kprobes.h

···
 int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);
 int kprobe_breakpoint_handler(struct pt_regs *regs);
 int kprobe_single_step_handler(struct pt_regs *regs);
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 void __kprobes *trampoline_probe_handler(struct pt_regs *regs);
 
 #endif /* CONFIG_KPROBES */

arch/csky/kernel/probes/kprobes.c

···
 {
 	ri->ret_addr = (kprobe_opcode_t *)regs->lr;
 	ri->fp = NULL;
-	regs->lr = (unsigned long) &kretprobe_trampoline;
+	regs->lr = (unsigned long) &__kretprobe_trampoline;
 }
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)

arch/csky/kernel/probes/kprobes_trampoline.S

···
 
 #include <abi/entry.h>
 
-ENTRY(kretprobe_trampoline)
+ENTRY(__kretprobe_trampoline)
 	SAVE_REGS_FTRACE
 
 	mov	a0, sp /* pt_regs */
···
 
 	RESTORE_REGS_FTRACE
 	rts
-ENDPROC(kretprobe_trampoline)
+ENDPROC(__kretprobe_trampoline)

arch/ia64/kernel/kprobes.c

···
 	__this_cpu_write(current_kprobe, p);
 }
 
-void kretprobe_trampoline(void)
+void __kretprobe_trampoline(void)
 {
 }
 
···
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->b0 = (unsigned long)dereference_function_descriptor(kretprobe_trampoline);
+	regs->b0 = (unsigned long)dereference_function_descriptor(__kretprobe_trampoline);
 }
 
 /* Check the instruction in the slot is break */
···
 int __init arch_init_kprobes(void)
 {
 	trampoline_p.addr =
-		dereference_function_descriptor(kretprobe_trampoline);
+		dereference_function_descriptor(__kretprobe_trampoline);
 	return register_kprobe(&trampoline_p);
 }
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 {
 	if (p->addr ==
-		dereference_function_descriptor(kretprobe_trampoline))
+		dereference_function_descriptor(__kretprobe_trampoline))
 		return 1;
 
 	return 0;

arch/mips/kernel/kprobes.c

···
 		/* Keep the assembler from reordering and placing JR here. */
 		".set noreorder\n\t"
 		"nop\n\t"
-		".global kretprobe_trampoline\n"
-		"kretprobe_trampoline:\n\t"
+		".global __kretprobe_trampoline\n"
+		"__kretprobe_trampoline:\n\t"
 		"nop\n\t"
 		".set pop"
 		: : : "memory");
 }
 
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 				      struct pt_regs *regs)
···
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->regs[31] = (unsigned long)kretprobe_trampoline;
+	regs->regs[31] = (unsigned long)__kretprobe_trampoline;
 }
 
 /*
···
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 {
-	if (p->addr == (kprobe_opcode_t *)kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *)__kretprobe_trampoline)
 		return 1;
 
 	return 0;
 }
 
 static struct kprobe trampoline_p = {
-	.addr = (kprobe_opcode_t *)kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *)__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 

arch/parisc/kernel/kprobes.c

···
 	return 1;
 }
 
-void kretprobe_trampoline(void)
+void __kretprobe_trampoline(void)
 {
 	asm volatile("nop");
 	asm volatile("nop");
···
 int __init arch_init_kprobes(void)
 {
 	trampoline_p.addr = (kprobe_opcode_t *)
-		dereference_function_descriptor(kretprobe_trampoline);
+		dereference_function_descriptor(__kretprobe_trampoline);
 	return register_kprobe(&trampoline_p);
 }

arch/powerpc/include/asm/kprobes.h

···
 #define flush_insn_slot(p)	do { } while (0)
 #define kretprobe_blacklist_size 0
 
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 extern void arch_remove_kprobe(struct kprobe *p);
 
 /* Architecture specific copy of original instruction */

arch/powerpc/kernel/kprobes.c

···
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->link = (unsigned long)kretprobe_trampoline;
+	regs->link = (unsigned long)__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 
···
  * 	- When the probed function returns, this probe
  * 		causes the handlers to fire
  */
-asm(".global kretprobe_trampoline\n"
-	".type kretprobe_trampoline, @function\n"
-	"kretprobe_trampoline:\n"
+asm(".global __kretprobe_trampoline\n"
+	".type __kretprobe_trampoline, @function\n"
+	"__kretprobe_trampoline:\n"
 	"nop\n"
 	"blr\n"
-	".size kretprobe_trampoline, .-kretprobe_trampoline\n");
+	".size __kretprobe_trampoline, .-__kretprobe_trampoline\n");
 
 /*
  * Called when the probe at kretprobe trampoline is hit
···
 	 * as it is used to determine the return address from the trap.
 	 * For (2), since nip is not honoured with optprobes, we instead setup
 	 * the link register properly so that the subsequent 'blr' in
-	 * kretprobe_trampoline jumps back to the right instruction.
+	 * __kretprobe_trampoline jumps back to the right instruction.
 	 *
 	 * For nip, we should set the address to the previous instruction since
 	 * we end up emulating it in kprobe_handler(), which increments the nip
···
 NOKPROBE_SYMBOL(kprobe_fault_handler);
 
 static struct kprobe trampoline_p = {
-	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *) &__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 
···
 
 int arch_trampoline_kprobe(struct kprobe *p)
 {
-	if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *)&__kretprobe_trampoline)
 		return 1;
 
 	return 0;

arch/powerpc/kernel/optprobes.c

···
 	 * has a 'nop' instruction, which can be emulated.
 	 * So further checks can be skipped.
 	 */
-	if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *)&__kretprobe_trampoline)
 		return addr + sizeof(kprobe_opcode_t);
 
 	/*

arch/powerpc/kernel/stacktrace.c

···
 		 * Mark stacktraces with kretprobed functions on them
 		 * as unreliable.
 		 */
-		if (ip == (unsigned long)kretprobe_trampoline)
+		if (ip == (unsigned long)__kretprobe_trampoline)
 			return -EINVAL;
 #endif
 

arch/riscv/include/asm/kprobes.h

···
 int kprobe_fault_handler(struct pt_regs *regs, unsigned int trapnr);
 bool kprobe_breakpoint_handler(struct pt_regs *regs);
 bool kprobe_single_step_handler(struct pt_regs *regs);
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 void __kprobes *trampoline_probe_handler(struct pt_regs *regs);
 
 #endif /* CONFIG_KPROBES */

arch/riscv/kernel/probes/kprobes.c

···
 {
 	ri->ret_addr = (kprobe_opcode_t *)regs->ra;
 	ri->fp = NULL;
-	regs->ra = (unsigned long) &kretprobe_trampoline;
+	regs->ra = (unsigned long) &__kretprobe_trampoline;
 }
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)

arch/riscv/kernel/probes/kprobes_trampoline.S

···
 	REG_L x31, PT_T6(sp)
 	.endm
 
-ENTRY(kretprobe_trampoline)
+ENTRY(__kretprobe_trampoline)
 	addi sp, sp, -(PT_SIZE_ON_STACK)
 	save_all_base_regs
 
···
 	addi sp, sp, PT_SIZE_ON_STACK
 
 	ret
-ENDPROC(kretprobe_trampoline)
+ENDPROC(__kretprobe_trampoline)

arch/s390/include/asm/kprobes.h

···
 };
 
 void arch_remove_kprobe(struct kprobe *p);
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 
 int kprobe_fault_handler(struct pt_regs *regs, int trapnr);
 int kprobe_exceptions_notify(struct notifier_block *self,

arch/s390/kernel/kprobes.c

···
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
+	regs->gprs[14] = (unsigned long) &__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 
···
  */
 static void __used kretprobe_trampoline_holder(void)
 {
-	asm volatile(".global kretprobe_trampoline\n"
-		     "kretprobe_trampoline: bcr 0,0\n");
+	asm volatile(".global __kretprobe_trampoline\n"
+		     "__kretprobe_trampoline: bcr 0,0\n");
 }
 
 /*
···
 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
 
 static struct kprobe trampoline = {
-	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *) &__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 
···
 
 int arch_trampoline_kprobe(struct kprobe *p)
 {
-	return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline;
+	return p->addr == (kprobe_opcode_t *) &__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_trampoline_kprobe);

arch/s390/kernel/stacktrace.c

···
 		 * Mark stacktraces with kretprobed functions on them
 		 * as unreliable.
 		 */
-		if (state.ip == (unsigned long)kretprobe_trampoline)
+		if (state.ip == (unsigned long)__kretprobe_trampoline)
 			return -EINVAL;
 #endif
 

arch/sh/include/asm/kprobes.h

···
 struct kprobe;
 
 void arch_remove_kprobe(struct kprobe *);
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 
 /* Architecture specific copy of original instruction*/
 struct arch_specific_insn {

arch/sh/kernel/kprobes.c

···
 	ri->fp = NULL;
 
 	/* Replace the return addr with trampoline addr */
-	regs->pr = (unsigned long)kretprobe_trampoline;
+	regs->pr = (unsigned long)__kretprobe_trampoline;
 }
 
 static int __kprobes kprobe_handler(struct pt_regs *regs)
···
  */
 static void __used kretprobe_trampoline_holder(void)
 {
-	asm volatile (".globl kretprobe_trampoline\n"
-		      "kretprobe_trampoline:\n\t"
+	asm volatile (".globl __kretprobe_trampoline\n"
+		      "__kretprobe_trampoline:\n\t"
 		      "nop\n");
 }
 
 /*
- * Called when we hit the probe point at kretprobe_trampoline
+ * Called when we hit the probe point at __kretprobe_trampoline
  */
 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
···
 }
 
 static struct kprobe trampoline_p = {
-	.addr = (kprobe_opcode_t *)&kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *)&__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 

arch/sparc/include/asm/kprobes.h

···
 	flushi(&(p)->ainsn.insn[1]);	\
 } while (0)
 
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 
 /* Architecture specific copy of original instruction*/
 struct arch_specific_insn {

arch/sparc/kernel/kprobes.c

···
 
 	/* Replace the return addr with trampoline addr */
 	regs->u_regs[UREG_RETPC] =
-		((unsigned long)kretprobe_trampoline) - 8;
+		((unsigned long)__kretprobe_trampoline) - 8;
 }
 
 /*
···
 
 static void __used kretprobe_trampoline_holder(void)
 {
-	asm volatile(".global kretprobe_trampoline\n"
-		     "kretprobe_trampoline:\n"
+	asm volatile(".global __kretprobe_trampoline\n"
+		     "__kretprobe_trampoline:\n"
 		     "\tnop\n"
 		     "\tnop\n");
 }
 static struct kprobe trampoline_p = {
-	.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
+	.addr = (kprobe_opcode_t *) &__kretprobe_trampoline,
 	.pre_handler = trampoline_probe_handler
 };
 
···
 
 int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 {
-	if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
+	if (p->addr == (kprobe_opcode_t *)&__kretprobe_trampoline)
 		return 1;
 
 	return 0;

arch/x86/kernel/kprobes/core.c

···
 	ri->fp = sara;
 
 	/* Replace the return addr with trampoline addr */
-	*sara = (unsigned long) &kretprobe_trampoline;
+	*sara = (unsigned long) &__kretprobe_trampoline;
 }
 NOKPROBE_SYMBOL(arch_prepare_kretprobe);
 
···
  */
 asm(
 	".text\n"
-	".global kretprobe_trampoline\n"
-	".type kretprobe_trampoline, @function\n"
-	"kretprobe_trampoline:\n"
+	".global __kretprobe_trampoline\n"
+	".type __kretprobe_trampoline, @function\n"
+	"__kretprobe_trampoline:\n"
 	/* We don't bother saving the ss register */
 #ifdef CONFIG_X86_64
 	"	pushq %rsp\n"
···
 	"	popfl\n"
 #endif
 	"	ret\n"
-	".size kretprobe_trampoline, .-kretprobe_trampoline\n"
+	".size __kretprobe_trampoline, .-__kretprobe_trampoline\n"
 );
-NOKPROBE_SYMBOL(kretprobe_trampoline);
-STACK_FRAME_NON_STANDARD(kretprobe_trampoline);
+NOKPROBE_SYMBOL(__kretprobe_trampoline);
+STACK_FRAME_NON_STANDARD(__kretprobe_trampoline);
 
 
 /*
- * Called from kretprobe_trampoline
+ * Called from __kretprobe_trampoline
  */
 __used __visible void *trampoline_handler(struct pt_regs *regs)
 {
···
 #ifdef CONFIG_X86_32
 	regs->gs = 0;
 #endif
-	regs->ip = (unsigned long)&kretprobe_trampoline;
+	regs->ip = (unsigned long)&__kretprobe_trampoline;
 	regs->orig_ax = ~0UL;
 
 	return (void *)kretprobe_trampoline_handler(regs, &regs->sp);

include/linux/kprobes.h

···
 				   struct pt_regs *regs);
 extern int arch_trampoline_kprobe(struct kprobe *p);
 
-void kretprobe_trampoline(void);
+void __kretprobe_trampoline(void);
 /*
  * Since some architecture uses structured function pointer,
  * use dereference_function_descriptor() to get real function address.
  */
 static nokprobe_inline void *kretprobe_trampoline_addr(void)
 {
-	return dereference_kernel_function_descriptor(kretprobe_trampoline);
+	return dereference_kernel_function_descriptor(__kretprobe_trampoline);
 }
 
 /* If the trampoline handler called from a kprobe, use this version */

kernel/trace/trace_output.c

···
 #ifdef CONFIG_KRETPROBES
 static inline const char *kretprobed(const char *name)
 {
-	static const char tramp_name[] = "kretprobe_trampoline";
+	static const char tramp_name[] = "__kretprobe_trampoline";
 	int size = sizeof(tramp_name);
 
 	if (strncmp(tramp_name, name, size) == 0)