kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler()

The __kretprobe_trampoline_handler() callback, called from low level
arch kprobes methods, has the 'trampoline_address' parameter, which is
entirely superfluous as it basically just replicates:

  dereference_kernel_function_descriptor(kretprobe_trampoline)

In fact we had bugs in arch code where it wasn't replicated correctly.

So remove this superfluous parameter and use kretprobe_trampoline_addr()
instead.

Link: https://lkml.kernel.org/r/163163044546.489837.13505751885476015002.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c
index 5f0415f..3cee75c 100644 (file)
--- a/arch/arc/kernel/kprobes.c
+++ b/arch/arc/kernel/kprobes.c
@@ -381,7 +381,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 static int __kprobes trampoline_probe_handler(struct kprobe *p,
                                              struct pt_regs *regs)
 {
-       regs->ret = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       regs->ret = __kretprobe_trampoline_handler(regs, NULL);
 
        /* By returning a non zero value, we are telling the kprobe handler
         * that we don't want the post_handler to run

diff --git a/arch/arm/probes/kprobes/core.c b/arch/arm/probes/kprobes/core.c
index a59e38d..08098ed 100644 (file)
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -392,8 +392,7 @@ void __naked __kprobes kretprobe_trampoline(void)
 /* Called from kretprobe_trampoline */
 static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
 {
-       return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
-                                                   (void *)regs->ARM_fp);
+       return (void *)kretprobe_trampoline_handler(regs, (void *)regs->ARM_fp);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,

diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index ce429cb..f627a12 100644 (file)
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -401,8 +401,7 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-       return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline,
-                                       (void *)kernel_stack_pointer(regs));
+       return (void *)kretprobe_trampoline_handler(regs, (void *)kernel_stack_pointer(regs));
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 632407b..784c5ab 100644 (file)
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -386,7 +386,7 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-       return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       return (void *)kretprobe_trampoline_handler(regs, NULL);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 0f8573b..44c84c2 100644 (file)
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -392,14 +392,13 @@ static void __kprobes set_current_kprobe(struct kprobe *p,
        __this_cpu_write(current_kprobe, p);
 }
 
-static void kretprobe_trampoline(void)
+void kretprobe_trampoline(void)
 {
 }
 
 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-       regs->cr_iip = __kretprobe_trampoline_handler(regs,
-               dereference_function_descriptor(kretprobe_trampoline), NULL);
+       regs->cr_iip = __kretprobe_trampoline_handler(regs, NULL);
        /*
         * By returning a non-zero value, we are telling
         * kprobe_handler() that we don't want the post_handler

diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c
index b0934a0..b33bd24 100644 (file)
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -485,8 +485,7 @@ void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
 static int __kprobes trampoline_probe_handler(struct kprobe *p,
                                                struct pt_regs *regs)
 {
-       instruction_pointer(regs) = __kretprobe_trampoline_handler(regs,
-                                               kretprobe_trampoline, NULL);
+       instruction_pointer(regs) = __kretprobe_trampoline_handler(regs, NULL);
        /*
         * By returning a non-zero value, we are telling
         * kprobe_handler() that we don't want the post_handler

diff --git a/arch/parisc/kernel/kprobes.c b/arch/parisc/kernel/kprobes.c
index 6d21a51..4a35ac6 100644 (file)
--- a/arch/parisc/kernel/kprobes.c
+++ b/arch/parisc/kernel/kprobes.c
@@ -175,7 +175,7 @@ int __kprobes parisc_kprobe_ss_handler(struct pt_regs *regs)
        return 1;
 }
 
-static inline void kretprobe_trampoline(void)
+void kretprobe_trampoline(void)
 {
        asm volatile("nop");
        asm volatile("nop");
@@ -193,7 +193,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
 {
        unsigned long orig_ret_address;
 
-       orig_ret_address = __kretprobe_trampoline_handler(regs, trampoline_p.addr, NULL);
+       orig_ret_address = __kretprobe_trampoline_handler(regs, NULL);
        instruction_pointer_set(regs, orig_ret_address);
 
        return 1;

diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index d422e29..43c7714 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -417,7 +417,7 @@ static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
        unsigned long orig_ret_address;
 
-       orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       orig_ret_address = __kretprobe_trampoline_handler(regs, NULL);
        /*
         * We get here through one of two paths:
         * 1. by taking a trap -> kprobe_handler() -> here

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index cab6f87..62d477c 100644 (file)
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -347,7 +347,7 @@ int __init arch_populate_kprobe_blacklist(void)
 
 void __kprobes __used *trampoline_probe_handler(struct pt_regs *regs)
 {
-       return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       return (void *)kretprobe_trampoline_handler(regs, NULL);
 }
 
 void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,

diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 952d44b..5fa86e5 100644 (file)
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -343,7 +343,7 @@ static void __used kretprobe_trampoline_holder(void)
  */
 static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-       regs->psw.addr = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       regs->psw.addr = __kretprobe_trampoline_handler(regs, NULL);
        /*
         * By returning a non-zero value, we are telling
         * kprobe_handler() that we don't want the post_handler

diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
index 1c7f358..8e76a35 100644 (file)
--- a/arch/sh/kernel/kprobes.c
+++ b/arch/sh/kernel/kprobes.c
@@ -303,7 +303,7 @@ static void __used kretprobe_trampoline_holder(void)
  */
 int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 {
-       regs->pc = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       regs->pc = __kretprobe_trampoline_handler(regs, NULL);
 
        return 1;
 }

diff --git a/arch/sparc/kernel/kprobes.c b/arch/sparc/kernel/kprobes.c
index 4c05a4e..4015342 100644 (file)
--- a/arch/sparc/kernel/kprobes.c
+++ b/arch/sparc/kernel/kprobes.c
@@ -451,7 +451,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p,
 {
        unsigned long orig_ret_address = 0;
 
-       orig_ret_address = __kretprobe_trampoline_handler(regs, &kretprobe_trampoline, NULL);
+       orig_ret_address = __kretprobe_trampoline_handler(regs, NULL);
        regs->tpc = orig_ret_address;
        regs->tnpc = orig_ret_address + 4;
 

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index bd7f588..71ea2ea 100644 (file)
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -49,7 +49,6 @@ extern __visible kprobe_opcode_t optprobe_template_end[];
 extern const int kretprobe_blacklist_size;
 
 void arch_remove_kprobe(struct kprobe *p);
-asmlinkage void kretprobe_trampoline(void);
 
 extern void arch_kprobe_override_function(struct pt_regs *regs);
 

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index b6e046e..0c59ef5 100644 (file)
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1064,7 +1064,7 @@ __used __visible void *trampoline_handler(struct pt_regs *regs)
        regs->ip = (unsigned long)&kretprobe_trampoline;
        regs->orig_ax = ~0UL;
 
-       return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, &regs->sp);
+       return (void *)kretprobe_trampoline_handler(regs, &regs->sp);
 }
 NOKPROBE_SYMBOL(trampoline_handler);
 

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 2ed61fc..96f5df9 100644 (file)
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -188,15 +188,23 @@ extern void arch_prepare_kretprobe(struct kretprobe_instance *ri,
                                   struct pt_regs *regs);
 extern int arch_trampoline_kprobe(struct kprobe *p);
 
+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);
+}
+
 /* If the trampoline handler called from a kprobe, use this version */
 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
-                               void *trampoline_address,
-                               void *frame_pointer);
+                                            void *frame_pointer);
 
 static nokprobe_inline
 unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
-                               void *trampoline_address,
-                               void *frame_pointer)
+                                          void *frame_pointer)
 {
        unsigned long ret;
        /*
@@ -205,7 +213,7 @@ unsigned long kretprobe_trampoline_handler(struct pt_regs *regs,
         * be running at this point.
         */
        kprobe_busy_begin();
-       ret = __kretprobe_trampoline_handler(regs, trampoline_address, frame_pointer);
+       ret = __kretprobe_trampoline_handler(regs, frame_pointer);
        kprobe_busy_end();
 
        return ret;

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 550042d..6ed7551 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1864,7 +1864,6 @@ static struct notifier_block kprobe_exceptions_nb = {
 #ifdef CONFIG_KRETPROBES
 
 unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
-                                            void *trampoline_address,
                                             void *frame_pointer)
 {
        kprobe_opcode_t *correct_ret_addr = NULL;
@@ -1879,7 +1878,7 @@ unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
 
                BUG_ON(ri->fp != frame_pointer);
 
-               if (ri->ret_addr != trampoline_address) {
+               if (ri->ret_addr != kretprobe_trampoline_addr()) {
                        correct_ret_addr = ri->ret_addr;
                        /*
                         * This is the real return address. Any other