1 files changed, 241 insertions, 155 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 05b31d92f69..0d0e922fafc 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -9,6 +9,10 @@
 /*
  * Handle hardware traps and faults.
  */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/context_tracking.h>
 #include <linux/interrupt.h>
 #include <linux/kallsyms.h>
 #include <linux/spinlock.h>
@@ -19,6 +23,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/ptrace.h>
+#include <linux/uprobes.h>
 #include <linux/string.h>
 #include <linux/delay.h>
 #include <linux/errno.h>
@@ -52,29 +57,27 @@
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
 #include <asm/mce.h>
-
+#include <asm/fixmap.h>
 #include <asm/mach_traps.h>
+#include <asm/alternative.h>
 
 #ifdef CONFIG_X86_64
 #include <asm/x86_init.h>
 #include <asm/pgalloc.h>
 #include <asm/proto.h>
+
+/* No need to be aligned, but done to keep all IDTs defined the same way. */
+gate_desc debug_idt_table[NR_VECTORS] __page_aligned_bss;
 #else
 #include <asm/processor-flags.h>
 #include <asm/setup.h>
 
 asmlinkage int system_call(void);
-
-/* Do we ignore FPU interrupts ? */
-char ignore_fpu_irq;
-
-/*
- * The IDT has to be page-aligned to simplify the Pentium
- * F0 0F bug workaround.
- */
-gate_desc idt_table[NR_VECTORS] __page_aligned_data = { { { { 0, 0 } } }, };
 #endif
 
+/* Must be page-aligned because the real IDT is used in a fixmap. */
+gate_desc idt_table[NR_VECTORS] __page_aligned_bss;
+
 DECLARE_BITMAP(used_vectors, NR_VECTORS);
 EXPORT_SYMBOL_GPL(used_vectors);
 
@@ -86,7 +89,7 @@ static inline void conditional_sti(struct pt_regs *regs)
 
 static inline void preempt_conditional_sti(struct pt_regs *regs)
 {
-	inc_preempt_count();
+	preempt_count_inc();
 	if (regs->flags & X86_EFLAGS_IF)
 		local_irq_enable();
 }
@@ -101,33 +104,79 @@ static inline void preempt_conditional_cli(struct pt_regs *regs)
 {
 	if (regs->flags & X86_EFLAGS_IF)
 		local_irq_disable();
-	dec_preempt_count();
+	preempt_count_dec();
 }
 
-static void __kprobes
-do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,
-	long error_code, siginfo_t *info)
+static nokprobe_inline int
+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 siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr,
+				siginfo_t *info)
+{
+	unsigned long siaddr;
+	int sicode;
+
+	switch (trapnr) {
+	default:
+		return SEND_SIG_PRIV;
+
+	case X86_TRAP_DE:
+		sicode = FPE_INTDIV;
+		siaddr = uprobe_get_trap_addr(regs);
+		break;
+	case X86_TRAP_UD:
+		sicode = ILL_ILLOPN;
+		siaddr = uprobe_get_trap_addr(regs);
+		break;
+	case X86_TRAP_AC:
+		sicode = BUS_ADRALN;
+		siaddr = 0;
+		break;
+	}
+
+	info->si_signo = signr;
+	info->si_errno = 0;
+	info->si_code = sicode;
+	info->si_addr = (void __user *)siaddr;
+	return info;
+}
+
+static void
+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
@@ -143,89 +192,66 @@ trap_signal:
 #ifdef CONFIG_X86_64
 	if (show_unhandled_signals && unhandled_signal(tsk, signr) &&
 	    printk_ratelimit()) {
-		printk(KERN_INFO
-		       "%s[%d] trap %s ip:%lx sp:%lx error:%lx",
-		       tsk->comm, tsk->pid, str,
-		       regs->ip, regs->sp, error_code);
+		pr_info("%s[%d] trap %s ip:%lx sp:%lx error:%lx",
+			tsk->comm, tsk->pid, str,
+			regs->ip, regs->sp, error_code);
 		print_vma_addr(" in ", regs->ip);
-		printk("\n");
+		pr_cont("\n");
 	}
 #endif
 
-	if (info)
-		force_sig_info(signr, info, tsk);
-	else
-		force_sig(signr, tsk);
-	return;
+	force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);
+}
+NOKPROBE_SYMBOL(do_trap);
 
-kernel_trap:
-	if (!fixup_exception(regs)) {
-		tsk->thread.error_code = error_code;
-		tsk->thread.trap_nr = trapnr;
-		die(str, regs, error_code);
+static void do_error_trap(struct pt_regs *regs, long error_code, char *str,
+			  unsigned long trapnr, int signr)
+{
+	enum ctx_state prev_state = exception_enter();
+	siginfo_t info;
+
+	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=
+			NOTIFY_STOP) {
+		conditional_sti(regs);
+		do_trap(trapnr, signr, str, regs, error_code,
+			fill_trap_info(regs, signr, trapnr, &info));
 	}
-	return;
 
-#ifdef CONFIG_X86_32
-vm86_trap:
-	if (handle_vm86_trap((struct kernel_vm86_regs *) regs,
-						error_code, trapnr))
-		goto trap_signal;
-	return;
-#endif
+	exception_exit(prev_state);
 }
 
 #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)	\
-		return;							\
-	conditional_sti(regs);						\
-	do_trap(trapnr, signr, str, regs, error_code, NULL);		\
+	do_error_trap(regs, error_code, str, trapnr, signr);		\
 }
 
-#define DO_ERROR_INFO(trapnr, signr, str, name, sicode, siaddr)		\
-dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	\
-{									\
-	siginfo_t info;							\
-	info.si_signo = signr;						\
-	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)	\
-		return;							\
-	conditional_sti(regs);						\
-	do_trap(trapnr, signr, str, regs, error_code, &info);		\
-}
-
-DO_ERROR_INFO(X86_TRAP_DE, SIGFPE, "divide error", divide_error, FPE_INTDIV,
-		regs->ip)
-DO_ERROR(X86_TRAP_OF, SIGSEGV, "overflow", overflow)
-DO_ERROR(X86_TRAP_BR, SIGSEGV, "bounds", bounds)
-DO_ERROR_INFO(X86_TRAP_UD, SIGILL, "invalid opcode", invalid_op, ILL_ILLOPN,
-		regs->ip)
-DO_ERROR(X86_TRAP_OLD_MF, SIGFPE, "coprocessor segment overrun",
-		coprocessor_segment_overrun)
-DO_ERROR(X86_TRAP_TS, SIGSEGV, "invalid TSS", invalid_TSS)
-DO_ERROR(X86_TRAP_NP, SIGBUS, "segment not present", segment_not_present)
+DO_ERROR(X86_TRAP_DE,     SIGFPE,  "divide error",		divide_error)
+DO_ERROR(X86_TRAP_OF,     SIGSEGV, "overflow",			overflow)
+DO_ERROR(X86_TRAP_BR,     SIGSEGV, "bounds",			bounds)
+DO_ERROR(X86_TRAP_UD,     SIGILL,  "invalid opcode",		invalid_op)
+DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,  "coprocessor segment overrun",coprocessor_segment_overrun)
+DO_ERROR(X86_TRAP_TS,     SIGSEGV, "invalid TSS",		invalid_TSS)
+DO_ERROR(X86_TRAP_NP,     SIGBUS,  "segment not present",	segment_not_present)
 #ifdef CONFIG_X86_32
-DO_ERROR(X86_TRAP_SS, SIGBUS, "stack segment", stack_segment)
+DO_ERROR(X86_TRAP_SS,     SIGBUS,  "stack segment",		stack_segment)
 #endif
-DO_ERROR_INFO(X86_TRAP_AC, SIGBUS, "alignment check", alignment_check,
-		BUS_ADRALN, 0)
+DO_ERROR(X86_TRAP_AC,     SIGBUS,  "alignment check",		alignment_check)
 
 #ifdef CONFIG_X86_64
 /* Runs on IST stack */
 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code)
 {
+	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)
-		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(prev_state);
 }
 
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
@@ -233,12 +259,16 @@ 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();
 	/* Return not checked because double check cannot be ignored */
 	notify_die(DIE_TRAP, str, regs, error_code, X86_TRAP_DF, SIGSEGV);
 
 	tsk->thread.error_code = error_code;
 	tsk->thread.trap_nr = X86_TRAP_DF;
 
+#ifdef CONFIG_DOUBLEFAULT
+	df_debug(regs, error_code);
+#endif
 	/*
 	 * This is always a kernel trap and never fixable (and thus must
 	 * never return).
@@ -248,60 +278,59 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code)
 }
 #endif
 
-dotraplinkage void __kprobes
+dotraplinkage void
 do_general_protection(struct pt_regs *regs, long error_code)
 {
 	struct task_struct *tsk;
+	enum ctx_state prev_state;
 
+	prev_state = exception_enter();
 	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;
 
 	if (show_unhandled_signals && unhandled_signal(tsk, SIGSEGV) &&
 			printk_ratelimit()) {
-		printk(KERN_INFO
-			"%s[%d] general protection ip:%lx sp:%lx error:%lx",
+		pr_info("%s[%d] general protection ip:%lx sp:%lx error:%lx",
 			tsk->comm, task_pid_nr(tsk),
 			regs->ip, regs->sp, error_code);
 		print_vma_addr(" in ", regs->ip);
-		printk("\n");
+		pr_cont("\n");
 	}
 
-	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);
+	force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
+exit:
+	exception_exit(prev_state);
 }
+NOKPROBE_SYMBOL(do_general_protection);
 
 /* May run on IST stack. */
-dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
+dotraplinkage void 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.
@@ -311,15 +340,24 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co
 	    ftrace_int3_handler(regs))
 		return;
 #endif
+	if (poke_int3_handler(regs))
+		return;
+
+	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)
-		return;
+		goto exit;
 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 
+#ifdef CONFIG_KPROBES
+	if (kprobe_int3_handler(regs))
+		goto exit;
+#endif
+
 	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
@@ -330,7 +368,10 @@ 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(prev_state);
 }
+NOKPROBE_SYMBOL(do_int3);
 
 #ifdef CONFIG_X86_64
 /*
@@ -338,7 +379,7 @@ dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_co
  * for scheduling or signal handling. The actual stack switch is done in
  * entry.S
  */
-asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
+asmlinkage __visible struct pt_regs *sync_regs(struct pt_regs *eregs)
 {
 	struct pt_regs *regs = eregs;
 	/* Did already sync */
@@ -357,6 +398,7 @@ asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
 		*regs = *eregs;
 	return regs;
 }
+NOKPROBE_SYMBOL(sync_regs);
 #endif
 
 /*
@@ -383,13 +425,16 @@ asmlinkage __kprobes struct pt_regs *sync_regs(struct pt_regs *eregs)
  *
  * May run on IST stack.
  */
-dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
+dotraplinkage void 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;
 
+	prev_state = exception_enter();
+
 	get_debugreg(dr6, 6);
 
 	/* Filter out all the reserved bits which are preset to 1 */
@@ -405,7 +450,7 @@ 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);
@@ -418,9 +463,14 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 	/* Store the virtualized DR6 value */
 	tsk->thread.debugreg6 = dr6;
 
-	if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
+#ifdef CONFIG_KPROBES
+	if (kprobe_debug_handler(regs))
+		goto exit;
+#endif
+
+	if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
 							SIGTRAP) == NOTIFY_STOP)
-		return;
+		goto exit;
 
 	/*
 	 * Let others (NMI) know that the debug stack is in use
@@ -436,7 +486,7 @@ 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;
 	}
 
 	/*
@@ -457,15 +507,17 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
 	preempt_conditional_cli(regs);
 	debug_stack_usage_dec();
 
-	return;
+exit:
+	exception_exit(prev_state);
 }
+NOKPROBE_SYMBOL(do_debug);
 
 /*
  * Note that we play around with the 'TS' bit in an attempt to get
  * the correct behaviour even in the presence of the asynchronous
  * IRQ13 behaviour
  */
-void math_error(struct pt_regs *regs, int error_code, int trapnr)
+static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 {
 	struct task_struct *task = current;
 	siginfo_t info;
@@ -495,7 +547,7 @@ void math_error(struct pt_regs *regs, int error_code, int trapnr)
 	task->thread.error_code = error_code;
 	info.si_signo = SIGFPE;
 	info.si_errno = 0;
-	info.si_addr = (void __user *)regs->ip;
+	info.si_addr = (void __user *)uprobe_get_trap_addr(regs);
 	if (trapnr == X86_TRAP_MF) {
 		unsigned short cwd, swd;
 		/*
@@ -551,17 +603,21 @@ void math_error(struct pt_regs *regs, int error_code, int trapnr)
 
 dotraplinkage void do_coprocessor_error(struct pt_regs *regs, long error_code)
 {
-#ifdef CONFIG_X86_32
-	ignore_fpu_irq = 1;
-#endif
+	enum ctx_state prev_state;
 
+	prev_state = exception_enter();
 	math_error(regs, error_code, X86_TRAP_MF);
+	exception_exit(prev_state);
 }
 
 dotraplinkage void
 do_simd_coprocessor_error(struct pt_regs *regs, long error_code)
 {
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
 	math_error(regs, error_code, X86_TRAP_XF);
+	exception_exit(prev_state);
 }
 
 dotraplinkage void
@@ -570,15 +626,15 @@ do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 	conditional_sti(regs);
 #if 0
 	/* No need to warn about this any longer. */
-	printk(KERN_INFO "Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
+	pr_info("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
 #endif
 }
 
-asmlinkage void __attribute__((weak)) smp_thermal_interrupt(void)
+asmlinkage __visible void __attribute__((weak)) smp_thermal_interrupt(void)
 {
 }
 
-asmlinkage void __attribute__((weak)) smp_threshold_interrupt(void)
+asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void)
 {
 }
 
@@ -612,22 +668,28 @@ 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);
-		force_sig(SIGSEGV, tsk);
+		drop_init_fpu(tsk);
+		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 		return;
 	}
 
-	tsk->fpu_counter++;
+	tsk->thread.fpu_counter++;
 }
 EXPORT_SYMBOL_GPL(math_state_restore);
 
-dotraplinkage void __kprobes
+dotraplinkage void
 do_device_not_available(struct pt_regs *regs, long error_code)
 {
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
+	BUG_ON(use_eager_fpu());
+
 #ifdef CONFIG_MATH_EMULATION
 	if (read_cr0() & X86_CR0_EM) {
 		struct math_emu_info info = { };
@@ -636,6 +698,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 
 		info.regs = regs;
 		math_emulate(&info);
+		exception_exit(prev_state);
 		return;
 	}
 #endif
@@ -643,12 +706,17 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 #ifdef CONFIG_X86_32
 	conditional_sti(regs);
 #endif
+	exception_exit(prev_state);
 }
+NOKPROBE_SYMBOL(do_device_not_available);
 
 #ifdef CONFIG_X86_32
 dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 {
 	siginfo_t info;
+	enum ctx_state prev_state;
+
+	prev_state = exception_enter();
 	local_irq_enable();
 
 	info.si_signo = SIGILL;
@@ -656,10 +724,11 @@ 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(prev_state);
 }
 #endif
 
@@ -669,10 +738,19 @@ void __init early_trap_init(void)
 	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);
-	set_intr_gate(X86_TRAP_PF, &page_fault);
+#ifdef CONFIG_X86_32
+	set_intr_gate(X86_TRAP_PF, page_fault);
+#endif
 	load_idt(&idt_descr);
 }
 
+void __init early_trap_pf_init(void)
+{
+#ifdef CONFIG_X86_64
+	set_intr_gate(X86_TRAP_PF, page_fault);
+#endif
+}
+
 void __init trap_init(void)
 {
 	int i;
@@ -685,30 +763,30 @@ void __init trap_init(void)
 	early_iounmap(p, 4);
 #endif
 
-	set_intr_gate(X86_TRAP_DE, &divide_error);
+	set_intr_gate(X86_TRAP_DE, divide_error);
 	set_intr_gate_ist(X86_TRAP_NMI, &nmi, NMI_STACK);
 	/* int4 can be called from all */
 	set_system_intr_gate(X86_TRAP_OF, &overflow);
-	set_intr_gate(X86_TRAP_BR, &bounds);
-	set_intr_gate(X86_TRAP_UD, &invalid_op);
-	set_intr_gate(X86_TRAP_NM, &device_not_available);
+	set_intr_gate(X86_TRAP_BR, bounds);
+	set_intr_gate(X86_TRAP_UD, invalid_op);
+	set_intr_gate(X86_TRAP_NM, device_not_available);
 #ifdef CONFIG_X86_32
 	set_task_gate(X86_TRAP_DF, GDT_ENTRY_DOUBLEFAULT_TSS);
 #else
 	set_intr_gate_ist(X86_TRAP_DF, &double_fault, DOUBLEFAULT_STACK);
 #endif
-	set_intr_gate(X86_TRAP_OLD_MF, &coprocessor_segment_overrun);
-	set_intr_gate(X86_TRAP_TS, &invalid_TSS);
-	set_intr_gate(X86_TRAP_NP, &segment_not_present);
+	set_intr_gate(X86_TRAP_OLD_MF, coprocessor_segment_overrun);
+	set_intr_gate(X86_TRAP_TS, invalid_TSS);
+	set_intr_gate(X86_TRAP_NP, segment_not_present);
 	set_intr_gate_ist(X86_TRAP_SS, &stack_segment, STACKFAULT_STACK);
-	set_intr_gate(X86_TRAP_GP, &general_protection);
-	set_intr_gate(X86_TRAP_SPURIOUS, &spurious_interrupt_bug);
-	set_intr_gate(X86_TRAP_MF, &coprocessor_error);
-	set_intr_gate(X86_TRAP_AC, &alignment_check);
+	set_intr_gate(X86_TRAP_GP, general_protection);
+	set_intr_gate(X86_TRAP_SPURIOUS, spurious_interrupt_bug);
+	set_intr_gate(X86_TRAP_MF, coprocessor_error);
+	set_intr_gate(X86_TRAP_AC, alignment_check);
 #ifdef CONFIG_X86_MCE
 	set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK);
 #endif
-	set_intr_gate(X86_TRAP_XF, &simd_coprocessor_error);
+	set_intr_gate(X86_TRAP_XF, simd_coprocessor_error);
 
 	/* Reserve all the builtin and the syscall vector: */
 	for (i = 0; i < FIRST_EXTERNAL_VECTOR; i++)
@@ -725,6 +803,14 @@ void __init trap_init(void)
 #endif
 
 	/*
+	 * Set the IDT descriptor to a fixed read-only location, so that the
+	 * "sidt" instruction will not leak the location of the kernel, and
+	 * to defend the IDT against arbitrary memory write vulnerabilities.
+	 * It will be reloaded in cpu_init() */
+	__set_fixmap(FIX_RO_IDT, __pa_symbol(idt_table), PAGE_KERNEL_RO);
+	idt_descr.address = fix_to_virt(FIX_RO_IDT);
+
+	/*
 	 * Should be a barrier for any external CPU state:
 	 */
 	cpu_init();
@@ -732,7 +818,7 @@ void __init trap_init(void)
 	x86_init.irqs.trap_init();
 
 #ifdef CONFIG_X86_64
-	memcpy(&nmi_idt_table, &idt_table, IDT_ENTRIES * 16);
+	memcpy(&debug_idt_table, &idt_table, IDT_ENTRIES * 16);
 	set_nmi_gate(X86_TRAP_DB, &debug);
 	set_nmi_gate(X86_TRAP_BP, &int3);
 #endif