[PATCH -tip v5 03/12] kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler()

From: Masami Hiramatsu
Date: Fri Mar 26 2021 - 08:30:06 EST

Remove trampoline_address from kretprobe_trampoline_handler().
Instead of passing the address, kretprobe_trampoline_handler()
can use new kretprobe_trampoline_addr().

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
Changes in v3:
- Remove wrong kretprobe_trampoline declaration from
arch/x86/include/asm/kprobes.h.
Changes in v2:
- Remove arch_deref_entry_point() from comment.
---
arch/arc/kernel/kprobes.c | 2 +-
arch/arm/probes/kprobes/core.c | 3 +--
arch/arm64/kernel/probes/kprobes.c | 3 +--
arch/csky/kernel/probes/kprobes.c | 2 +-
arch/ia64/kernel/kprobes.c | 5 ++---
arch/mips/kernel/kprobes.c | 3 +--
arch/parisc/kernel/kprobes.c | 4 ++--
arch/powerpc/kernel/kprobes.c | 2 +-
arch/riscv/kernel/probes/kprobes.c | 2 +-
arch/s390/kernel/kprobes.c | 2 +-
arch/sh/kernel/kprobes.c | 2 +-
arch/sparc/kernel/kprobes.c | 2 +-
arch/x86/include/asm/kprobes.h | 1 -
arch/x86/kernel/kprobes/core.c | 2 +-
include/linux/kprobes.h | 18 +++++++++++++-----
kernel/kprobes.c | 3 +--
16 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c
index cabef45f11df..3ae01bb5820c 100644
--- a/arch/arc/kernel/kprobes.c
+++ b/arch/arc/kernel/kprobes.c
@@ -397,7 +397,7 @@ 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 a9653117ca0d..1782b41df095 100644
--- a/arch/arm/probes/kprobes/core.c
+++ b/arch/arm/probes/kprobes/core.c
@@ -413,8 +413,7 @@ 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 66aac2881ba8..fce681fdfce6 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -412,8 +412,7 @@ 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 589f090f48b9..cc589bc11904 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -404,7 +404,7 @@ 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 eaf3c734719b..0204953a06cf 100644
--- 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 54dfba8fa77c..001a2f07ef44 100644
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -489,8 +489,7 @@ 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 6d21a515eea5..4a35ac6e2ca2 100644
--- 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 eb0460949e1b..dfd532c43525 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -399,7 +399,7 @@ 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 7e2c78e2ca6b..25fce713a060 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -375,7 +375,7 @@ 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 aae24dc75df6..b149e9169709 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -351,7 +351,7 @@ 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 756100b01e84..48356e81836a 100644
--- 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 217c21a6986a..fa30f9dadff8 100644
--- a/arch/sparc/kernel/kprobes.c
+++ b/arch/sparc/kernel/kprobes.c
@@ -468,7 +468,7 @@ 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 bd7f5886a789..71ea2eab43d5 100644
--- 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 a061a8c8089a..444a7b6b396e 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1070,7 +1070,7 @@ __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 d65c041b5c22..65dadd4238a2 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -205,15 +205,23 @@ 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_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;
/*
@@ -222,7 +230,7 @@ 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 2913de07f4a3..75c0a58c19c2 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1859,7 +1859,6 @@ 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;
@@ -1874,7 +1873,7 @@ 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