From: Thomas Gleixner
In order to ensure poke_int3_handler() is completely self contained -- this
is called while modifying other text, imagine the fun of hitting another
INT3 -- ensure that everything it uses is not traced.
The primary means here is to force inlining; bsearch() is notrace because
all of lib/ is.
Signed-off-by: Thomas Gleixner
Signed-off-by: Peter Zijlstra (Intel)
---
arch/x86/include/asm/ptrace.h|2 +-
arch/x86/include/asm/text-patching.h | 11 +++
arch/x86/kernel/alternative.c| 13 ++---
3 files changed, 14 insertions(+), 12 deletions(-)
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -123,7 +123,7 @@ static inline void regs_set_return_value
* On x86_64, vm86 mode is mercifully nonexistent, and we don't need
* the extra check.
*/
-static inline int user_mode(struct pt_regs *regs)
+static __always_inline int user_mode(struct pt_regs *regs)
{
#ifdef CONFIG_X86_32
return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >=
USER_RPL;
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -64,7 +64,7 @@ extern void text_poke_finish(void);
#define DISP32_SIZE4
-static inline int text_opcode_size(u8 opcode)
+static __always_inline int text_opcode_size(u8 opcode)
{
int size = 0;
@@ -118,12 +118,14 @@ extern __ro_after_init struct mm_struct
extern __ro_after_init unsigned long poking_addr;
#ifndef CONFIG_UML_X86
-static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+static __always_inline
+void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
{
regs->ip = ip;
}
-static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
+static __always_inline
+void int3_emulate_push(struct pt_regs *regs, unsigned long val)
{
/*
* The int3 handler in entry_64.S adds a gap between the
@@ -138,7 +140,8 @@ static inline void int3_emulate_push(str
*(unsigned long *)regs->sp = val;
}
-static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
+static __always_inline
+void int3_emulate_call(struct pt_regs *regs, unsigned long func)
{
int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
int3_emulate_jmp(regs, func);
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -957,7 +957,8 @@ struct bp_patching_desc {
static struct bp_patching_desc *bp_desc;
-static inline struct bp_patching_desc *try_get_desc(struct bp_patching_desc
**descp)
+static __always_inline
+struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp)
{
struct bp_patching_desc *desc = READ_ONCE(*descp); /* rcu_dereference */
@@ -967,18 +968,18 @@ static inline struct bp_patching_desc *t
return desc;
}
-static inline void put_desc(struct bp_patching_desc *desc)
+static __always_inline void put_desc(struct bp_patching_desc *desc)
{
smp_mb__before_atomic();
atomic_dec(&desc->refs);
}
-static inline void *text_poke_addr(struct text_poke_loc *tp)
+static __always_inline void *text_poke_addr(struct text_poke_loc *tp)
{
return _stext + tp->rel_addr;
}
-static int notrace patch_cmp(const void *key, const void *elt)
+static int noinstr patch_cmp(const void *key, const void *elt)
{
struct text_poke_loc *tp = (struct text_poke_loc *) elt;
@@ -988,9 +989,8 @@ static int notrace patch_cmp(const void
return 1;
return 0;
}
-NOKPROBE_SYMBOL(patch_cmp);
-int notrace poke_int3_handler(struct pt_regs *regs)
+int noinstr poke_int3_handler(struct pt_regs *regs)
{
struct bp_patching_desc *desc;
struct text_poke_loc *tp;
@@ -1064,7 +1064,6 @@ int notrace poke_int3_handler(struct pt_
put_desc(desc);
return ret;
}
-NOKPROBE_SYMBOL(poke_int3_handler);
#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc))
static struct text_poke_loc tp_vec[TP_VEC_MAX];
