[PATCH -tip v3 07/23] kprobes/x86: Use NOKPROBE_SYMBOL instead of__kprobes

From: Masami Hiramatsu
Date: Tue Nov 19 2013 - 23:25:45 EST

Use NOKPROBE_SYMBOL macro for protecting functions
from kprobes instead of __kprobes annotation in x86
kprobes code.
This applies __always_inline annotation for some cases,
because NOKPROBE_SYMBOL() will inhibit inlining by
referring the symbol address.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/kprobes/core.c | 77 ++++++++++++++++++++++++--------------
arch/x86/kernel/kprobes/ftrace.c | 15 ++++---
arch/x86/kernel/kprobes/opt.c | 8 ++--
3 files changed, 63 insertions(+), 37 deletions(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index c2f7b1f..54ada0b 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -112,7 +112,8 @@ struct kretprobe_blackpoint kretprobe_blacklist[] = {

const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);

-static void __kprobes __synthesize_relative_insn(void *from, void *to, u8 op)
+static __always_inline
+void __synthesize_relative_insn(void *from, void *to, u8 op)
{
struct __arch_relative_insn {
u8 op;
@@ -125,21 +126,23 @@ static void __kprobes __synthesize_relative_insn(void *from, void *to, u8 op)
}

/* Insert a jump instruction at address 'from', which jumps to address 'to'.*/
-void __kprobes synthesize_reljump(void *from, void *to)
+void synthesize_reljump(void *from, void *to)
{
__synthesize_relative_insn(from, to, RELATIVEJUMP_OPCODE);
}
+NOKPROBE_SYMBOL(synthesize_reljump);

/* Insert a call instruction at address 'from', which calls address 'to'.*/
-void __kprobes synthesize_relcall(void *from, void *to)
+void synthesize_relcall(void *from, void *to)
{
__synthesize_relative_insn(from, to, RELATIVECALL_OPCODE);
}
+NOKPROBE_SYMBOL(synthesize_relcall);

/*
* Skip the prefixes of the instruction.
*/
-static kprobe_opcode_t *__kprobes skip_prefixes(kprobe_opcode_t *insn)
+static kprobe_opcode_t *skip_prefixes(kprobe_opcode_t *insn)
{
insn_attr_t attr;

@@ -154,6 +157,7 @@ static kprobe_opcode_t *__kprobes skip_prefixes(kprobe_opcode_t *insn)
#endif
return insn;
}
+NOKPROBE_SYMBOL(skip_prefixes);

/*
* Returns non-zero if opcode is boostable.
@@ -425,7 +429,8 @@ void arch_remove_kprobe(struct kprobe *p)
}
}

-static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
+static __always_inline
+void save_previous_kprobe(struct kprobe_ctlblk *kcb)
{
kcb->prev_kprobe.kp = kprobe_running();
kcb->prev_kprobe.status = kcb->kprobe_status;
@@ -433,7 +438,8 @@ static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
}

-static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
+static __always_inline
+void restore_previous_kprobe(struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
kcb->kprobe_status = kcb->prev_kprobe.status;
@@ -441,8 +447,9 @@ static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
}

-static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
+static __always_inline
+void set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
{
__this_cpu_write(current_kprobe, p);
kcb->kprobe_saved_flags = kcb->kprobe_old_flags
@@ -451,7 +458,7 @@ static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
kcb->kprobe_saved_flags &= ~X86_EFLAGS_IF;
}

-static void __kprobes clear_btf(void)
+static __always_inline void clear_btf(void)
{
if (test_thread_flag(TIF_BLOCKSTEP)) {
unsigned long debugctl = get_debugctlmsr();
@@ -461,7 +468,7 @@ static void __kprobes clear_btf(void)
}
}

-static void __kprobes restore_btf(void)
+static __always_inline void restore_btf(void)
{
if (test_thread_flag(TIF_BLOCKSTEP)) {
unsigned long debugctl = get_debugctlmsr();
@@ -471,8 +478,7 @@ static void __kprobes restore_btf(void)
}
}

-void __kprobes
-arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
+void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long *sara = stack_addr(regs);

@@ -481,9 +487,10 @@ arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
/* Replace the return addr with trampoline addr */
*sara = (unsigned long) &kretprobe_trampoline;
}
+NOKPROBE_SYMBOL(arch_prepare_kretprobe);

-static void __kprobes
-setup_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb, int reenter)
+static void setup_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb, int reenter)
{
if (setup_detour_execution(p, regs, reenter))
return;
@@ -519,14 +526,15 @@ setup_singlestep(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *k
else
regs->ip = (unsigned long)p->ainsn.insn;
}
+NOKPROBE_SYMBOL(setup_singlestep);

/*
* We have reentered the kprobe_handler(), since another probe was hit while
* within the handler. We save the original kprobes variables and just single
* step on the instruction of the new probe without calling any user handlers.
*/
-static int __kprobes
-reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb)
+static int reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
{
switch (kcb->kprobe_status) {
case KPROBE_HIT_SSDONE:
@@ -553,12 +561,13 @@ reenter_kprobe(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb

return 1;
}
+NOKPROBE_SYMBOL(reenter_kprobe);

/*
* Interrupts are disabled on entry as trap3 is an interrupt gate and they
* remain disabled throughout this function.
*/
-static int __kprobes kprobe_handler(struct pt_regs *regs)
+static int kprobe_handler(struct pt_regs *regs)
{
kprobe_opcode_t *addr;
struct kprobe *p;
@@ -621,12 +630,13 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
preempt_enable_no_resched();
return 0;
}
+NOKPROBE_SYMBOL(kprobe_handler);

/*
* When a retprobed function returns, this code saves registers and
* calls trampoline_handler() runs, which calls the kretprobe's handler.
*/
-static void __used __kprobes kretprobe_trampoline_holder(void)
+static void __used kretprobe_trampoline_holder(void)
{
asm volatile (
".global kretprobe_trampoline\n"
@@ -657,11 +667,13 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
#endif
" ret\n");
}
+NOKPROBE_SYMBOL(kretprobe_trampoline_holder);
+NOKPROBE_SYMBOL(kretprobe_trampoline);

/*
* Called from kretprobe_trampoline
*/
-__visible __used __kprobes void *trampoline_handler(struct pt_regs *regs)
+__visible __used void *trampoline_handler(struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
@@ -747,6 +759,7 @@ __visible __used __kprobes void *trampoline_handler(struct pt_regs *regs)
}
return (void *)orig_ret_address;
}
+NOKPROBE_SYMBOL(trampoline_handler);

/*
* Called after single-stepping. p->addr is the address of the
@@ -775,8 +788,8 @@ __visible __used __kprobes void *trampoline_handler(struct pt_regs *regs)
* jump instruction after the copied instruction, that jumps to the next
* instruction after the probepoint.
*/
-static void __kprobes
-resume_execution(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb)
+static void resume_execution(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
{
unsigned long *tos = stack_addr(regs);
unsigned long copy_ip = (unsigned long)p->ainsn.insn;
@@ -851,12 +864,13 @@ resume_execution(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *k
no_change:
restore_btf();
}
+NOKPROBE_SYMBOL(resume_execution);

/*
* Interrupts are disabled on entry as trap1 is an interrupt gate and they
* remain disabled throughout this function.
*/
-static int __kprobes post_kprobe_handler(struct pt_regs *regs)
+static int post_kprobe_handler(struct pt_regs *regs)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -891,8 +905,9 @@ out:

return 1;
}
+NOKPROBE_SYMBOL(post_kprobe_handler);

-int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
+int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
{
struct kprobe *cur = kprobe_running();
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
@@ -951,12 +966,13 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
}
return 0;
}
+NOKPROBE_SYMBOL(kprobe_fault_handler);

/*
* Wrapper routine for handling exceptions.
*/
-int __kprobes
-kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *data)
+int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
+ void *data)
{
struct die_args *args = data;
int ret = NOTIFY_DONE;
@@ -994,8 +1010,9 @@ kprobe_exceptions_notify(struct notifier_block *self, unsigned long val, void *d
}
return ret;
}
+NOKPROBE_SYMBOL(kprobe_exceptions_notify);

-int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
struct jprobe *jp = container_of(p, struct jprobe, kp);
unsigned long addr;
@@ -1019,8 +1036,9 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
regs->ip = (unsigned long)(jp->entry);
return 1;
}
+NOKPROBE_SYMBOL(setjmp_pre_handler);

-void __kprobes jprobe_return(void)
+void jprobe_return(void)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();

@@ -1036,8 +1054,10 @@ void __kprobes jprobe_return(void)
" nop \n"::"b"
(kcb->jprobe_saved_sp):"memory");
}
+NOKPROBE_SYMBOL(jprobe_return);
+NOKPROBE_SYMBOL(jprobe_return_end);

-int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
+int longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
u8 *addr = (u8 *) (regs->ip - 1);
@@ -1065,6 +1085,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
}
return 0;
}
+NOKPROBE_SYMBOL(longjmp_break_handler);

bool arch_within_kprobe_blacklist(unsigned long addr)
{
diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index dcaa131..068ea83a 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -25,8 +25,9 @@

#include "common.h"

-static int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
+static __always_inline
+int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
{
/*
* Emulate singlestep (and also recover regs->ip)
@@ -41,18 +42,19 @@ static int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
return 1;
}

-int __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
- struct kprobe_ctlblk *kcb)
+int skip_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
{
if (kprobe_ftrace(p))
return __skip_singlestep(p, regs, kcb);
else
return 0;
}
+NOKPROBE_SYMBOL(skip_singlestep);

/* Ftrace callback handler for kprobes */
-void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
- struct ftrace_ops *ops, struct pt_regs *regs)
+void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *ops, struct pt_regs *regs)
{
struct kprobe *p;
struct kprobe_ctlblk *kcb;
@@ -84,6 +86,7 @@ void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
end:
local_irq_restore(flags);
}
+NOKPROBE_SYMBOL(kprobe_ftrace_handler);

int arch_prepare_kprobe_ftrace(struct kprobe *p)
{
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index fba7fb0..f304773 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -138,7 +138,8 @@ asm (
#define INT3_SIZE sizeof(kprobe_opcode_t)

/* Optimized kprobe call back function: called from optinsn */
-static void __kprobes optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
+static void
+optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs)
{
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
unsigned long flags;
@@ -168,6 +169,7 @@ static void __kprobes optimized_callback(struct optimized_kprobe *op, struct pt_
}
local_irq_restore(flags);
}
+NOKPROBE_SYMBOL(optimized_callback);

static int copy_optimized_instructions(u8 *dest, u8 *src)
{
@@ -424,8 +426,7 @@ extern void arch_unoptimize_kprobes(struct list_head *oplist,
}
}

-int __kprobes
-setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
+int setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
{
struct optimized_kprobe *op;

@@ -441,3 +442,4 @@ setup_detour_execution(struct kprobe *p, struct pt_regs *regs, int reenter)
}
return 0;
}
+NOKPROBE_SYMBOL(setup_detour_execution);


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