Messages in this thread Patch in this message | | | Date | Tue, 05 May 2020 15:49:27 +0200 | From | Thomas Gleixner <> | Subject | [patch V4 part 4 01/24] x86/int3: Ensure that poke_int3_handler() is not traced |
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From: Thomas Gleixner <tglx@linutronix.de>
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 <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> --- 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_SIZE 4 -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];
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