1 files changed, 49 insertions, 78 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 5204332f475d..49a401b1d4d7 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -76,7 +76,7 @@ char ignore_fpu_irq;
  * F0 0F bug workaround.. We have a special link segment
  * for this.
  */
-gate_desc idt_table[256]
+gate_desc idt_table[NR_VECTORS]
 	__attribute__((__section__(".data.idt"))) = { { { { 0, 0 } } }, };
 #endif
 
@@ -532,77 +532,56 @@ 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;
-	unsigned long condition;
+	unsigned long dr6;
 	int si_code;
 
-	get_debugreg(condition, 6);
+	get_debugreg(dr6, 6);
 
 	/* Catch kmemcheck conditions first of all! */
-	if (condition & DR_STEP && kmemcheck_trap(regs))
+	if ((dr6 & DR_STEP) && kmemcheck_trap(regs))
 		return;
 
+	/* DR6 may or may not be cleared by the CPU */
+	set_debugreg(0, 6);
 	/*
 	 * The processor cleared BTF, so don't mark that we need it set.
 	 */
 	clear_tsk_thread_flag(tsk, TIF_DEBUGCTLMSR);
 	tsk->thread.debugctlmsr = 0;
 
-	if (notify_die(DIE_DEBUG, "debug", regs, condition, error_code,
-						SIGTRAP) == NOTIFY_STOP)
+	/* Store the virtualized DR6 value */
+	tsk->thread.debugreg6 = dr6;
+
+	if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
+							SIGTRAP) == NOTIFY_STOP)
 		return;
 
 	/* It's safe to allow irq's after DR6 has been saved */
 	preempt_conditional_sti(regs);
 
-	/* Mask out spurious debug traps due to lazy DR7 setting */
-	if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3)) {
-		if (!tsk->thread.debugreg7)
-			goto clear_dr7;
+	if (regs->flags & X86_VM_MASK) {
+		handle_vm86_trap((struct kernel_vm86_regs *) regs,
+				error_code, 1);
+		return;
 	}
 
-#ifdef CONFIG_X86_32
-	if (regs->flags & X86_VM_MASK)
-		goto debug_vm86;
-#endif
-
-	/* Save debug status register where ptrace can see it */
-	tsk->thread.debugreg6 = condition;
-
 	/*
-	 * Single-stepping through TF: make sure we ignore any events in
-	 * kernel space (but re-enable TF when returning to user mode).
+	 * Single-stepping through system calls: ignore any exceptions in
+	 * kernel space, but re-enable TF when returning to user mode.
+	 *
+	 * We already checked v86 mode above, so we can check for kernel mode
+	 * by just checking the CPL of CS.
 	 */
-	if (condition & DR_STEP) {
-		if (!user_mode(regs))
-			goto clear_TF_reenable;
+	if ((dr6 & DR_STEP) && !user_mode(regs)) {
+		tsk->thread.debugreg6 &= ~DR_STEP;
+		set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
+		regs->flags &= ~X86_EFLAGS_TF;
 	}
-
-	si_code = get_si_code(condition);
-	/* Ok, finally something we can handle */
-	send_sigtrap(tsk, regs, error_code, si_code);
-
-	/*
-	 * Disable additional traps. They'll be re-enabled when
-	 * the signal is delivered.
-	 */
-clear_dr7:
-	set_debugreg(0, 7);
+	si_code = get_si_code(tsk->thread.debugreg6);
+	if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS))
+		send_sigtrap(tsk, regs, error_code, si_code);
 	preempt_conditional_cli(regs);
-	return;
 
-#ifdef CONFIG_X86_32
-debug_vm86:
-	/* reenable preemption: handle_vm86_trap() might sleep */
-	dec_preempt_count();
-	handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
-	conditional_cli(regs);
-	return;
-#endif
-
-clear_TF_reenable:
-	set_tsk_thread_flag(tsk, TIF_SINGLESTEP);
-	regs->flags &= ~X86_EFLAGS_TF;
-	preempt_conditional_cli(regs);
 	return;
 }
 
@@ -786,33 +765,34 @@ do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 #endif
 }
 
-#ifdef CONFIG_X86_32
-unsigned long patch_espfix_desc(unsigned long uesp, unsigned long kesp)
+asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
 {
-	struct desc_struct *gdt = get_cpu_gdt_table(smp_processor_id());
-	unsigned long base = (kesp - uesp) & -THREAD_SIZE;
-	unsigned long new_kesp = kesp - base;
-	unsigned long lim_pages = (new_kesp | (THREAD_SIZE - 1)) >> PAGE_SHIFT;
-	__u64 desc = *(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS];
-
-	/* Set up base for espfix segment */
-	desc &= 0x00f0ff0000000000ULL;
-	desc |=	((((__u64)base) << 16) & 0x000000ffffff0000ULL) |
-		((((__u64)base) << 32) & 0xff00000000000000ULL) |
-		((((__u64)lim_pages) << 32) & 0x000f000000000000ULL) |
-		(lim_pages & 0xffff);
-	*(__u64 *)&gdt[GDT_ENTRY_ESPFIX_SS] = desc;
-
-	return new_kesp;
 }
-#endif
 
-asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
+asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
 {
 }
 
-asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
+/*
+ * __math_state_restore assumes that cr0.TS is already clear and the
+ * fpu state is all ready for use.  Used during context switch.
+ */
+void __math_state_restore(void)
 {
+	struct thread_info *thread = current_thread_info();
+	struct task_struct *tsk = thread->task;
+
+	/*
+	 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
+	 */
+	if (unlikely(restore_fpu_checking(tsk))) {
+		stts();
+		force_sig(SIGSEGV, tsk);
+		return;
+	}
+
+	thread->status |= TS_USEDFPU;	/* So we fnsave on switch_to() */
+	tsk->fpu_counter++;
 }
 
 /*
@@ -846,17 +826,8 @@ asmlinkage void math_state_restore(void)
 	}
 
 	clts();				/* Allow maths ops (or we recurse) */
-	/*
-	 * Paranoid restore. send a SIGSEGV if we fail to restore the state.
-	 */
-	if (unlikely(restore_fpu_checking(tsk))) {
-		stts();
-		force_sig(SIGSEGV, tsk);
-		return;
-	}
 
-	thread->status |= TS_USEDFPU;	/* So we fnsave on switch_to() */
-	tsk->fpu_counter++;
+	__math_state_restore();
 }
 EXPORT_SYMBOL_GPL(math_state_restore);