1 files changed, 99 insertions, 75 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index b481341c936..8276dc6794c 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -55,6 +55,7 @@
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
 #include <asm/mce.h>
+#include <asm/rcu.h>
 
 #include <asm/mach_traps.h>
 
@@ -107,30 +108,45 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
         dec_preempt_count();
 }
 
-static void __kprobes
-do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
-        long error_code, siginfo_t *info)
+static int __kprobes
+do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
+                  struct pt_regs *regs, long error_code)
 {
-        struct task_struct *tsk = current;
-
 #ifdef CONFIG_X86_32
         if (regs->flags & X86_VM_MASK) {
                 /*
-                 * traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
+                 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
                  * On nmi (interrupt 2), do_trap should not be called.
                  */
-                if (trapnr < X86_TRAP_UD)
-                        goto vm86_trap;
-                goto trap_signal;
+                if (trapnr < X86_TRAP_UD) {
+                        if (!handle_vm86_trap((struct kernel_vm86_regs *) regs,
+                                                error_code, trapnr))
+                                return 0;
+                }
+                return -1;
         }
 #endif
+        if (!user_mode(regs)) {
+                if (!fixup_exception(regs)) {
+                        tsk->thread.error_code = error_code;
+                        tsk->thread.trap_nr = trapnr;
+                        die(str, regs, error_code);
+                }
+                return 0;
+        }
 
-        if (!user_mode(regs))
-                goto kernel_trap;
+        return -1;
+}
 
-#ifdef CONFIG_X86_32
-trap_signal:
-#endif
+static void __kprobes
+do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
+        long error_code, siginfo_t *info)
+{
+        struct task_struct *tsk = current;
+
+
+        if (!do_trap_no_signal(tsk, trapnr, str, regs, error_code))
+                return;
         /*
          * We want error_code and trap_nr set for userspace faults and
          * kernelspace faults which result in die(), but not
@@ -158,33 +174,20 @@ trap_signal:
                 force_sig_info(signr, info, tsk);
         else
                 force_sig(signr, tsk);
-        return;
-
-kernel_trap:
-        if (!fixup_exception(regs)) {
-                tsk->thread.error_code = error_code;
-                tsk->thread.trap_nr = trapnr;
-                die(str, regs, error_code);
-        }
-        return;
-
-#ifdef CONFIG_X86_32
-vm86_trap:
-        if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
-                                                error_code, trapnr))
-                goto trap_signal;
-        return;
-#endif
 }
 
 #define DO_ERROR(trapnr, signr, str, name)                              \
 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)     \
 {                                                                       \
-        if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
-                                                        == NOTIFY_STOP) \
+        exception_enter(regs);                                          \
+        if (notify_die(DIE_TRAP, str, regs, error_code,                 \
+                        trapnr, signr) == NOTIFY_STOP) {                \
+                exception_exit(regs);                                   \
                 return;                                                 \
+        }                                                               \
         conditional_sti(regs);                                          \
         do_trap(trapnr, signr, str, regs, error_code, NULL);            \
+        exception_exit(regs);                                           \
 }
 
 #define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)         \
@@ -195,11 +198,15 @@ dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	\
         info.si_errno = 0;                                              \
         info.si_code = sicode;                                          \
         info.si_addr = (void __user *)siaddr;                           \
-        if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr)  \
-                                                        == NOTIFY_STOP) \
+        exception_enter(regs);                                          \
+        if (notify_die(DIE_TRAP, str, regs, error_code,                 \
+                        trapnr, signr) == NOTIFY_STOP) {                \
+                exception_exit(regs);                                   \
                 return;                                                 \
+        }                                                               \
         conditional_sti(regs);                                          \
         do_trap(trapnr, signr, str, regs, error_code, &info);           \
+        exception_exit(regs);                                           \
 }
 
 DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
@@ -222,12 +229,14 @@ 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);
         if (notify_die(DIE_TRAP, "stack segment", regs, error_code,
-                        X86_TRAP_SS, SIGBUS) == NOTIFY_STOP)
-                return;
-        preempt_conditional_sti(regs);
-        do_trap(X86_TRAP_SS, SIGBUS, "stack segment", regs, error_code, NULL);
-        preempt_conditional_cli(regs);
+                       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);
 }
 
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
@@ -235,6 +244,7 @@ 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);
         /* Return not checked because double check cannot be ignored */
         notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 
@@ -255,16 +265,29 @@ do_general_protection(struct pt_regs *regs, long error_code)
 {
         struct task_struct *tsk;
 
+        exception_enter(regs);
         conditional_sti(regs);
 
 #ifdef CONFIG_X86_32
-        if (regs->flags & X86_VM_MASK)
-                goto gp_in_vm86;
+        if (regs->flags & X86_VM_MASK) {
+                local_irq_enable();
+                handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
+                goto exit;
+        }
 #endif
 
         tsk = current;
-        if (!user_mode(regs))
-                goto gp_in_kernel;
+        if (!user_mode(regs)) {
+                if (fixup_exception(regs))
+                        goto exit;
+
+                tsk->thread.error_code = error_code;
+                tsk->thread.trap_nr = X86_TRAP_GP;
+                if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
+                               X86_TRAP_GP, SIGSEGV) != NOTIFY_STOP)
+                        die("general protection fault", regs, error_code);
+                goto exit;
+        }
 
         tsk->thread.error_code = error_code;
         tsk->thread.trap_nr = X86_TRAP_GP;
@@ -279,25 +302,8 @@ do_general_protection(struct pt_regs *regs, long error_code)
         }
 
         force_sig(SIGSEGV, tsk);
-        return;
-
-#ifdef CONFIG_X86_32
-gp_in_vm86:
-        local_irq_enable();
-        handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
-        return;
-#endif
-
-gp_in_kernel:
-        if (fixup_exception(regs))
-                return;
-
-        tsk->thread.error_code = error_code;
-        tsk->thread.trap_nr = X86_TRAP_GP;
-        if (notify_die(DIE_GPF, "general protection fault", regs, error_code,
-                        X86_TRAP_GP, SIGSEGV) == NOTIFY_STOP)
-                return;
-        die("general protection fault", regs, error_code);
+exit:
+        exception_exit(regs);
 }
 
 /* May run on IST stack. */
@@ -312,15 +318,16 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co
             ftrace_int3_handler(regs))
                 return;
 #endif
+        exception_enter(regs);
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
         if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
                                 SIGTRAP) == NOTIFY_STOP)
-                return;
+                goto exit;
 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 
         if (notify_die(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
                         SIGTRAP) == NOTIFY_STOP)
-                return;
+                goto exit;
 
         /*
          * Let others (NMI) know that the debug stack is in use
@@ -331,6 +338,8 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co
         do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);
         preempt_conditional_cli(regs);
         debug_stack_usage_dec();
+exit:
+        exception_exit(regs);
 }
 
 #ifdef CONFIG_X86_64
@@ -391,6 +400,8 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
         unsigned long dr6;
         int si_code;
 
+        exception_enter(regs);
+
         get_debugreg(dr6, 6);
 
         /* Filter out all the reserved bits which are preset to 1 */
@@ -406,7 +417,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 
         /* Catch kmemcheck conditions first of all! */
         if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
-                return;
+                goto exit;
 
         /* DR6 may or may not be cleared by the CPU */
         set_debugreg(0, 6);
@@ -421,7 +432,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 
         if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
                                                         SIGTRAP) == NOTIFY_STOP)
-                return;
+                goto exit;
 
         /*
          * Let others (NMI) know that the debug stack is in use
@@ -437,7 +448,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
                                         X86_TRAP_DB);
                 preempt_conditional_cli(regs);
                 debug_stack_usage_dec();
-                return;
+                goto exit;
         }
 
         /*
@@ -458,7 +469,8 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
         preempt_conditional_cli(regs);
         debug_stack_usage_dec();
 
-        return;
+exit:
+        exception_exit(regs);
 }
 
 /*
@@ -555,14 +567,17 @@ dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 #ifdef CONFIG_X86_32
         ignore_fpu_irq = 1;
 #endif
-
+        exception_enter(regs);
         math_error(regs, error_code, X86_TRAP_MF);
+        exception_exit(regs);
 }
 
 dotraplinkage void
 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 {
+        exception_enter(regs);
         math_error(regs, error_code, X86_TRAP_XF);
+        exception_exit(regs);
 }
 
 dotraplinkage void
@@ -613,11 +628,12 @@ void math_state_restore(void)
         }
 
         __thread_fpu_begin(tsk);
+
         /*
          * Paranoid restore. send a SIGSEGV if we fail to restore the state.
          */
         if (unlikely(restore_fpu_checking(tsk))) {
-                __thread_fpu_end(tsk);
+                drop_init_fpu(tsk);
                 force_sig(SIGSEGV, tsk);
                 return;
         }
@@ -629,6 +645,9 @@ EXPORT_SYMBOL_GPL(math_state_restore);
 dotraplinkage void __kprobes
 do_device_not_available(struct pt_regs *regs, long error_code)
 {
+        exception_enter(regs);
+        BUG_ON(use_eager_fpu());
+
 #ifdef CONFIG_MATH_EMULATION
         if (read_cr0() & X86_CR0_EM) {
                 struct math_emu_info info = { };
@@ -637,6 +656,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 
                 info.regs = regs;
                 math_emulate(&info);
+                exception_exit(regs);
                 return;
         }
 #endif
@@ -644,12 +664,15 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 #ifdef CONFIG_X86_32
         conditional_sti(regs);
 #endif
+        exception_exit(regs);
 }
 
 #ifdef CONFIG_X86_32
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 {
         siginfo_t info;
+
+        exception_enter(regs);
         local_irq_enable();
 
         info.si_signo = SIGILL;
@@ -657,10 +680,11 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
         info.si_code = ILL_BADSTK;
         info.si_addr = NULL;
         if (notify_die(DIE_TRAP, "iret exception", regs, error_code,
-                        X86_TRAP_IRET, SIGILL) == NOTIFY_STOP)
-                return;
-        do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
-                &info);
+                        X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {
+                do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,
+                        &info);
+        }
+        exception_exit(regs);
 }
 #endif