Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[sfrench/cifs-2.6.git] / arch / x86 / kernel / traps.c

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index edf66c066da9b504dbdc3c9c1f31a71ff8137efb..f4fa991406cd78463299631466298e46cf2ffcea 100644 (file)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -112,7 +112,7 @@ enum ctx_state ist_enter(struct pt_regs *regs)
 {
        enum ctx_state prev_state;
 
-       if (user_mode_vm(regs)) {
+       if (user_mode(regs)) {
                /* Other than that, we're just an exception. */
                prev_state = exception_enter();
        } else {
@@ -146,7 +146,7 @@ void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
        /* Must be before exception_exit. */
        preempt_count_sub(HARDIRQ_OFFSET);
 
-       if (user_mode_vm(regs))
+       if (user_mode(regs))
                return exception_exit(prev_state);
        else
                rcu_nmi_exit();
@@ -158,7 +158,7 @@ void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
  *
  * IST exception handlers normally cannot schedule.  As a special
  * exception, if the exception interrupted userspace code (i.e.
- * user_mode_vm(regs) would return true) and the exception was not
+ * user_mode(regs) would return true) and the exception was not
  * a double fault, it can be safe to schedule.  ist_begin_non_atomic()
  * begins a non-atomic section within an ist_enter()/ist_exit() region.
  * Callers are responsible for enabling interrupts themselves inside
@@ -167,15 +167,15 @@ void ist_exit(struct pt_regs *regs, enum ctx_state prev_state)
  */
 void ist_begin_non_atomic(struct pt_regs *regs)
 {
-       BUG_ON(!user_mode_vm(regs));
+       BUG_ON(!user_mode(regs));
 
        /*
         * Sanity check: we need to be on the normal thread stack.  This
         * will catch asm bugs and any attempt to use ist_preempt_enable
         * from double_fault.
         */
-       BUG_ON(((current_stack_pointer() ^ this_cpu_read_stable(kernel_stack))
-               & ~(THREAD_SIZE - 1)) != 0);
+       BUG_ON((unsigned long)(current_top_of_stack() -
+                              current_stack_pointer()) >= THREAD_SIZE);
 
        preempt_count_sub(HARDIRQ_OFFSET);
 }
@@ -194,8 +194,7 @@ static nokprobe_inline int
 do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
                  struct pt_regs *regs, long error_code)
 {
-#ifdef CONFIG_X86_32
-       if (regs->flags & X86_VM_MASK) {
+       if (v8086_mode(regs)) {
                /*
                 * Traps 0, 1, 3, 4, and 5 should be forwarded to vm86.
                 * On nmi (interrupt 2), do_trap should not be called.
@@ -207,7 +206,7 @@ do_trap_no_signal(struct task_struct *tsk, int trapnr, char *str,
                }
                return -1;
        }
-#endif
+
        if (!user_mode(regs)) {
                if (!fixup_exception(regs)) {
                        tsk->thread.error_code = error_code;
@@ -384,7 +383,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
                goto exit;
        conditional_sti(regs);
 
-       if (!user_mode_vm(regs))
+       if (!user_mode(regs))
                die("bounds", regs, error_code);
 
        if (!cpu_feature_enabled(X86_FEATURE_MPX)) {
@@ -462,13 +461,11 @@ do_general_protection(struct pt_regs *regs, long error_code)
        prev_state = exception_enter();
        conditional_sti(regs);
 
-#ifdef CONFIG_X86_32
-       if (regs->flags & X86_VM_MASK) {
+       if (v8086_mode(regs)) {
                local_irq_enable();
                handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
                goto exit;
        }
-#endif
 
        tsk = current;
        if (!user_mode(regs)) {
@@ -587,7 +584,7 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s)
        /* Copy the remainder of the stack from the current stack. */
        memmove(new_stack, s, offsetof(struct bad_iret_stack, regs.ip));
 
-       BUG_ON(!user_mode_vm(&new_stack->regs));
+       BUG_ON(!user_mode(&new_stack->regs));
        return new_stack;
 }
 NOKPROBE_SYMBOL(fixup_bad_iret);
@@ -637,7 +634,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
         * then it's very likely the result of an icebp/int01 trap.
         * User wants a sigtrap for that.
         */
-       if (!dr6 && user_mode_vm(regs))
+       if (!dr6 && user_mode(regs))
                user_icebp = 1;
 
        /* Catch kmemcheck conditions first of all! */
@@ -673,7 +670,7 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code)
        /* It's safe to allow irq's after DR6 has been saved */
        preempt_conditional_sti(regs);
 
-       if (regs->flags & X86_VM_MASK) {
+       if (v8086_mode(regs)) {
                handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code,
                                        X86_TRAP_DB);
                preempt_conditional_cli(regs);
@@ -721,7 +718,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
                return;
        conditional_sti(regs);
 
-       if (!user_mode_vm(regs))
+       if (!user_mode(regs))
        {
                if (!fixup_exception(regs)) {
                        task->thread.error_code = error_code;
@@ -925,9 +922,21 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 /* Set of traps needed for early debugging. */
 void __init early_trap_init(void)
 {
-       set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
+       /*
+        * Don't use IST to set DEBUG_STACK as it doesn't work until TSS
+        * is ready in cpu_init() <-- trap_init(). Before trap_init(),
+        * CPU runs at ring 0 so it is impossible to hit an invalid
+        * stack.  Using the original stack works well enough at this
+        * early stage. DEBUG_STACK will be equipped after cpu_init() in
+        * trap_init().
+        *
+        * We don't need to set trace_idt_table like set_intr_gate(),
+        * since we don't have trace_debug and it will be reset to
+        * 'debug' in trap_init() by set_intr_gate_ist().
+        */
+       set_intr_gate_notrace(X86_TRAP_DB, debug);
        /* int3 can be called from all */
-       set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
+       set_system_intr_gate(X86_TRAP_BP, &int3);
 #ifdef CONFIG_X86_32
        set_intr_gate(X86_TRAP_PF, page_fault);
 #endif
@@ -1005,6 +1014,15 @@ void __init trap_init(void)
         */
        cpu_init();
 
+       /*
+        * X86_TRAP_DB and X86_TRAP_BP have been set
+        * in early_trap_init(). However, ITS works only after
+        * cpu_init() loads TSS. See comments in early_trap_init().
+        */
+       set_intr_gate_ist(X86_TRAP_DB, &debug, DEBUG_STACK);
+       /* int3 can be called from all */
+       set_system_intr_gate_ist(X86_TRAP_BP, &int3, DEBUG_STACK);
+
        x86_init.irqs.trap_init();
 
 #ifdef CONFIG_X86_64