diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index e8bb0d61ecdc..cd6d9a5a42f6 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -254,16 +254,18 @@ EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason); dotraplinkage void __kprobes do_async_page_fault(struct pt_regs *regs, unsigned long error_code) { + enum ctx_state prev_state; + switch (kvm_read_and_reset_pf_reason()) { default: do_page_fault(regs, error_code); break; case KVM_PV_REASON_PAGE_NOT_PRESENT: /* page is swapped out by the host. */ - exception_enter(regs); + prev_state = exception_enter(); exit_idle(); kvm_async_pf_task_wait((u32)read_cr2()); - exception_exit(regs); + exception_exit(prev_state); break; case KVM_PV_REASON_PAGE_READY: rcu_irq_enter(); diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index ecc4ccbdd0cf..ff6d2271cbe2 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -175,34 +175,38 @@ do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, #define DO_ERROR(trapnr, signr, str, name) \ dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ { \ - exception_enter(regs); \ + enum ctx_state prev_state; \ + \ + prev_state = exception_enter(); \ if (notify_die(DIE_TRAP, str, regs, error_code, \ trapnr, signr) == NOTIFY_STOP) { \ - exception_exit(regs); \ + exception_exit(prev_state); \ return; \ } \ conditional_sti(regs); \ do_trap(trapnr, signr, str, regs, error_code, NULL); \ - exception_exit(regs); \ + exception_exit(prev_state); \ } #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr) \ dotraplinkage void do_##name(struct pt_regs *regs, long error_code) \ { \ siginfo_t info; \ + enum ctx_state prev_state; \ + \ info.si_signo = signr; \ info.si_errno = 0; \ info.si_code = sicode; \ info.si_addr = (void __user *)siaddr; \ - exception_enter(regs); \ + prev_state = exception_enter(); \ if (notify_die(DIE_TRAP, str, regs, error_code, \ trapnr, signr) == NOTIFY_STOP) { \ - exception_exit(regs); \ + exception_exit(prev_state); \ return; \ } \ conditional_sti(regs); \ do_trap(trapnr, signr, str, regs, error_code, &info); \ - exception_exit(regs); \ + exception_exit(prev_state); \ } DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV, @@ -225,14 +229,16 @@ DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check, /* Runs on IST stack */ dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code) { - exception_enter(regs); + enum ctx_state prev_state; + + prev_state = exception_enter(); if (notify_die(DIE_TRAP, "stack segment", regs, error_code, X86_TRAP_SS, SIGBUS) != NOTIFY_STOP) { preempt_conditional_sti(regs); do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL); preempt_conditional_cli(regs); } - exception_exit(regs); + exception_exit(prev_state); } dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) @@ -240,7 +246,7 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code) static const char str[] = "double fault"; struct task_struct *tsk = current; - exception_enter(regs); + exception_enter(); /* Return not checked because double check cannot be ignored */ notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV); @@ -260,8 +266,9 @@ dotraplinkage void __kprobes do_general_protection(struct pt_regs *regs, long error_code) { struct task_struct *tsk; + enum ctx_state prev_state; - exception_enter(regs); + prev_state = exception_enter(); conditional_sti(regs); #ifdef CONFIG_X86_32 @@ -299,12 +306,14 @@ do_general_protection(struct pt_regs *regs, long error_code) force_sig(SIGSEGV, tsk); exit: - exception_exit(regs); + exception_exit(prev_state); } /* May run on IST stack. */ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code) { + enum ctx_state prev_state; + #ifdef CONFIG_DYNAMIC_FTRACE /* * ftrace must be first, everything else may cause a recursive crash. @@ -314,7 +323,7 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co ftrace_int3_handler(regs)) return; #endif - exception_enter(regs); + prev_state = exception_enter(); #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP, SIGTRAP) == NOTIFY_STOP) @@ -335,7 +344,7 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co preempt_conditional_cli(regs); debug_stack_usage_dec(); exit: - exception_exit(regs); + exception_exit(prev_state); } #ifdef CONFIG_X86_64 @@ -392,11 +401,12 @@ asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs) dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) { struct task_struct *tsk = current; + enum ctx_state prev_state; int user_icebp = 0; unsigned long dr6; int si_code; - exception_enter(regs); + prev_state = exception_enter(); get_debugreg(dr6, 6); @@ -466,7 +476,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code) debug_stack_usage_dec(); exit: - exception_exit(regs); + exception_exit(prev_state); } /* @@ -560,17 +570,21 @@ void math_error(struct pt_regs *regs, int error_code, int trapnr) dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code) { - exception_enter(regs); + enum ctx_state prev_state; + + prev_state = exception_enter(); math_error(regs, error_code, X86_TRAP_MF); - exception_exit(regs); + exception_exit(prev_state); } dotraplinkage void do_simd_coprocessor_error(struct pt_regs *regs, long error_code) { - exception_enter(regs); + enum ctx_state prev_state; + + prev_state = exception_enter(); math_error(regs, error_code, X86_TRAP_XF); - exception_exit(regs); + exception_exit(prev_state); } dotraplinkage void @@ -638,7 +652,9 @@ EXPORT_SYMBOL_GPL(math_state_restore); dotraplinkage void __kprobes do_device_not_available(struct pt_regs *regs, long error_code) { - exception_enter(regs); + enum ctx_state prev_state; + + prev_state = exception_enter(); BUG_ON(use_eager_fpu()); #ifdef CONFIG_MATH_EMULATION @@ -649,7 +665,7 @@ do_device_not_available(struct pt_regs *regs, long error_code) info.regs = regs; math_emulate(&info); - exception_exit(regs); + exception_exit(prev_state); return; } #endif @@ -657,15 +673,16 @@ do_device_not_available(struct pt_regs *regs, long error_code) #ifdef CONFIG_X86_32 conditional_sti(regs); #endif - exception_exit(regs); + exception_exit(prev_state); } #ifdef CONFIG_X86_32 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) { siginfo_t info; + enum ctx_state prev_state; - exception_enter(regs); + prev_state = exception_enter(); local_irq_enable(); info.si_signo = SIGILL; @@ -677,7 +694,7 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code, &info); } - exception_exit(regs); + exception_exit(prev_state); } #endif diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index f946e6ce3315..fa8c02de0d25 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1222,7 +1222,9 @@ good_area: dotraplinkage void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) { - exception_enter(regs); + enum ctx_state prev_state; + + prev_state = exception_enter(); __do_page_fault(regs, error_code); - exception_exit(regs); + exception_exit(prev_state); } diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 5a69273e93e6..365f4a61bf04 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -5,7 +5,6 @@ #include #include -#ifdef CONFIG_CONTEXT_TRACKING struct context_tracking { /* * When active is false, probes are unset in order @@ -14,12 +13,13 @@ struct context_tracking { * may be further optimized using static keys. */ bool active; - enum { + enum ctx_state { IN_KERNEL = 0, IN_USER, } state; }; +#ifdef CONFIG_CONTEXT_TRACKING DECLARE_PER_CPU(struct context_tracking, context_tracking); static inline bool context_tracking_in_user(void) @@ -35,14 +35,19 @@ static inline bool context_tracking_active(void) extern void user_enter(void); extern void user_exit(void); -static inline void exception_enter(struct pt_regs *regs) +static inline enum ctx_state exception_enter(void) { + enum ctx_state prev_ctx; + + prev_ctx = this_cpu_read(context_tracking.state); user_exit(); + + return prev_ctx; } -static inline void exception_exit(struct pt_regs *regs) +static inline void exception_exit(enum ctx_state prev_ctx) { - if (user_mode(regs)) + if (prev_ctx == IN_USER) user_enter(); } @@ -52,8 +57,8 @@ extern void context_tracking_task_switch(struct task_struct *prev, static inline bool context_tracking_in_user(void) { return false; } static inline void user_enter(void) { } static inline void user_exit(void) { } -static inline void exception_enter(struct pt_regs *regs) { } -static inline void exception_exit(struct pt_regs *regs) { } +static inline enum ctx_state exception_enter(void) { return 0; } +static inline void exception_exit(enum ctx_state prev_ctx) { } static inline void context_tracking_task_switch(struct task_struct *prev, struct task_struct *next) { } #endif /* !CONFIG_CONTEXT_TRACKING */