diff options
| -rw-r--r-- | arch/x86/include/asm/debugreg.h | 22 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 14 |
4 files changed, 40 insertions, 8 deletions
diff --git a/arch/x86/include/asm/debugreg.h b/arch/x86/include/asm/debugreg.h index 078ad0c..b903d5e 100644 --- a/arch/x86/include/asm/debugreg.h +++ b/arch/x86/include/asm/debugreg.h @@ -101,6 +101,28 @@ extern void aout_dump_debugregs(struct user *dump); extern void hw_breakpoint_restore(void); +#ifdef CONFIG_X86_64 +DECLARE_PER_CPU(int, debug_stack_usage); +static inline void debug_stack_usage_inc(void) +{ + __get_cpu_var(debug_stack_usage)++; +} +static inline void debug_stack_usage_dec(void) +{ + __get_cpu_var(debug_stack_usage)--; +} +int is_debug_stack(unsigned long addr); +void debug_stack_set_zero(void); +void debug_stack_reset(void); +#else /* !X86_64 */ +static inline int is_debug_stack(unsigned long addr) { return 0; } +static inline void debug_stack_set_zero(void) { } +static inline void debug_stack_reset(void) { } +static inline void debug_stack_usage_inc(void) { } +static inline void debug_stack_usage_dec(void) { } +#endif /* X86_64 */ + + #endif /* __KERNEL__ */ #endif /* _ASM_X86_DEBUGREG_H */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 4b39d6d..b650435 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -402,9 +402,6 @@ DECLARE_PER_CPU(char *, irq_stack_ptr); DECLARE_PER_CPU(unsigned int, irq_count); extern unsigned long kernel_eflags; extern asmlinkage void ignore_sysret(void); -int is_debug_stack(unsigned long addr); -void debug_stack_set_zero(void); -void debug_stack_reset(void); #else /* X86_64 */ #ifdef CONFIG_CC_STACKPROTECTOR /* @@ -419,9 +416,6 @@ struct stack_canary { }; DECLARE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); #endif -static inline int is_debug_stack(unsigned long addr) { return 0; } -static inline void debug_stack_set_zero(void) { } -static inline void debug_stack_reset(void) { } #endif /* X86_64 */ extern unsigned int xstate_size; diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index caa4045..266e464 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1093,11 +1093,13 @@ unsigned long kernel_eflags; DEFINE_PER_CPU(struct orig_ist, orig_ist); static DEFINE_PER_CPU(unsigned long, debug_stack_addr); +DEFINE_PER_CPU(int, debug_stack_usage); int is_debug_stack(unsigned long addr) { - return addr <= __get_cpu_var(debug_stack_addr) && - addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ); + return __get_cpu_var(debug_stack_usage) || + (addr <= __get_cpu_var(debug_stack_addr) && + addr > (__get_cpu_var(debug_stack_addr) - DEBUG_STKSZ)); } void debug_stack_set_zero(void) diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index a93c5ca..0072b38 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -316,9 +316,15 @@ dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code) return; #endif + /* + * Let others (NMI) know that the debug stack is in use + * as we may switch to the interrupt stack. + */ + debug_stack_usage_inc(); preempt_conditional_sti(regs); do_trap(3, SIGTRAP, "int3", regs, error_code, NULL); preempt_conditional_cli(regs); + debug_stack_usage_dec(); } #ifdef CONFIG_X86_64 @@ -411,6 +417,12 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) SIGTRAP) == NOTIFY_STOP) return; + /* + * Let others (NMI) know that the debug stack is in use + * as we may switch to the interrupt stack. + */ + debug_stack_usage_inc(); + /* It's safe to allow irq's after DR6 has been saved */ preempt_conditional_sti(regs); @@ -418,6 +430,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1); preempt_conditional_cli(regs); + debug_stack_usage_dec(); return; } @@ -437,6 +450,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp) send_sigtrap(tsk, regs, error_code, si_code); preempt_conditional_cli(regs); + debug_stack_usage_dec(); return; } |