diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/traps.c | 55 |
1 files changed, 27 insertions, 28 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 5566fe50ef98..7febae381b91 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -775,26 +775,44 @@ static __always_inline void debug_exit(unsigned long dr7) * * May run on IST stack. */ -static void noinstr handle_debug(struct pt_regs *regs, unsigned long dr6, - bool user_icebp) +static void handle_debug(struct pt_regs *regs, unsigned long dr6, bool user) { struct task_struct *tsk = current; + bool user_icebp; int si_code; + /* + * The SDM says "The processor clears the BTF flag when it + * generates a debug exception." Clear TIF_BLOCKSTEP to keep + * TIF_BLOCKSTEP in sync with the hardware BTF flag. + */ + clear_thread_flag(TIF_BLOCKSTEP); + + /* + * If DR6 is zero, no point in trying to handle it. The kernel is + * not using INT1. + */ + if (!user && !dr6) + return; + + /* + * If dr6 has no reason to give us about the origin of this trap, + * then it's very likely the result of an icebp/int01 trap. + * User wants a sigtrap for that. + */ + user_icebp = user && !dr6; + /* Store the virtualized DR6 value */ tsk->thread.debugreg6 = dr6; - instrumentation_begin(); #ifdef CONFIG_KPROBES if (kprobe_debug_handler(regs)) { - instrumentation_end(); return; } #endif if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, 0, SIGTRAP) == NOTIFY_STOP) { - instrumentation_end(); return; } @@ -825,7 +843,6 @@ static void noinstr handle_debug(struct pt_regs *regs, unsigned long dr6, out: cond_local_irq_disable(regs); - instrumentation_end(); } static __always_inline void exc_debug_kernel(struct pt_regs *regs, @@ -834,14 +851,6 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, nmi_enter(); instrumentation_begin(); trace_hardirqs_off_finish(); - instrumentation_end(); - - /* - * The SDM says "The processor clears the BTF flag when it - * generates a debug exception." Clear TIF_BLOCKSTEP to keep - * TIF_BLOCKSTEP in sync with the hardware BTF flag. - */ - clear_thread_flag(TIF_BLOCKSTEP); /* * Catch SYSENTER with TF set and clear DR_STEP. If this hit a @@ -850,14 +859,8 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, if ((dr6 & DR_STEP) && is_sysenter_singlestep(regs)) dr6 &= ~DR_STEP; - /* - * If DR6 is zero, no point in trying to handle it. The kernel is - * not using INT1. - */ - if (dr6) - handle_debug(regs, dr6, false); + handle_debug(regs, dr6, false); - instrumentation_begin(); if (regs->flags & X86_EFLAGS_IF) trace_hardirqs_on_prepare(); instrumentation_end(); @@ -868,14 +871,10 @@ static __always_inline void exc_debug_user(struct pt_regs *regs, unsigned long dr6) { idtentry_enter_user(regs); - clear_thread_flag(TIF_BLOCKSTEP); + instrumentation_begin(); - /* - * If dr6 has no reason to give us about the origin of this trap, - * then it's very likely the result of an icebp/int01 trap. - * User wants a sigtrap for that. - */ - handle_debug(regs, dr6, !dr6); + handle_debug(regs, dr6, true); + instrumentation_end(); idtentry_exit_user(regs); } |