1 files changed, 71 insertions, 96 deletions

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 60788dee0f8a..b9b67166f9de 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -83,6 +83,13 @@ EXPORT_SYMBOL_GPL(used_vectors);
 
 static int ignore_nmis;
 
+int unknown_nmi_panic;
+/*
+ * Prevent NMI reason port (0x61) being accessed simultaneously, can
+ * only be used in NMI handler.
+ */
+static DEFINE_RAW_SPINLOCK(nmi_reason_lock);
+
 static inline void conditional_sti(struct pt_regs *regs)
 {
         if (regs->flags & X86_EFLAGS_IF)
@@ -300,16 +307,23 @@ gp_in_kernel:
         die("general protection fault", regs, error_code);
 }
 
-static notrace __kprobes void
-mem_parity_error(unsigned char reason, struct pt_regs *regs)
+static int __init setup_unknown_nmi_panic(char *str)
 {
-        printk(KERN_EMERG
-                "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
-                        reason, smp_processor_id());
+        unknown_nmi_panic = 1;
+        return 1;
+}
+__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
 
-        printk(KERN_EMERG
-                "You have some hardware problem, likely on the PCI bus.\n");
+static notrace __kprobes void
+pci_serr_error(unsigned char reason, struct pt_regs *regs)
+{
+        pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n",
+                 reason, smp_processor_id());
 
+        /*
+         * On some machines, PCI SERR line is used to report memory
+         * errors. EDAC makes use of it.
+         */
 #if defined(CONFIG_EDAC)
         if (edac_handler_set()) {
                 edac_atomic_assert_error();
@@ -320,11 +334,11 @@ mem_parity_error(unsigned char reason, struct pt_regs *regs)
         if (panic_on_unrecovered_nmi)
                 panic("NMI: Not continuing");
 
-        printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
+        pr_emerg("Dazed and confused, but trying to continue\n");
 
-        /* Clear and disable the memory parity error line. */
-        reason = (reason & 0xf) | 4;
-        outb(reason, 0x61);
+        /* Clear and disable the PCI SERR error line. */
+        reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_SERR;
+        outb(reason, NMI_REASON_PORT);
 }
 
 static notrace __kprobes void
@@ -332,22 +346,26 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
 {
         unsigned long i;
 
-        printk(KERN_EMERG "NMI: IOCK error (debug interrupt?)\n");
+        pr_emerg(
+        "NMI: IOCK error (debug interrupt?) for reason %02x on CPU %d.\n",
+                 reason, smp_processor_id());
         show_registers(regs);
 
         if (panic_on_io_nmi)
                 panic("NMI IOCK error: Not continuing");
 
         /* Re-enable the IOCK line, wait for a few seconds */
-        reason = (reason & 0xf) | 8;
-        outb(reason, 0x61);
+        reason = (reason & NMI_REASON_CLEAR_MASK) | NMI_REASON_CLEAR_IOCHK;
+        outb(reason, NMI_REASON_PORT);
 
-        i = 2000;
-        while (--i)
-                udelay(1000);
+        i = 20000;
+        while (--i) {
+                touch_nmi_watchdog();
+                udelay(100);
+        }
 
-        reason &= ~8;
-        outb(reason, 0x61);
+        reason &= ~NMI_REASON_CLEAR_IOCHK;
+        outb(reason, NMI_REASON_PORT);
 }
 
 static notrace __kprobes void
@@ -366,69 +384,50 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
                 return;
         }
 #endif
-        printk(KERN_EMERG
-                "Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
-                        reason, smp_processor_id());
+        pr_emerg("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
+                 reason, smp_processor_id());
 
-        printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
-        if (panic_on_unrecovered_nmi)
+        pr_emerg("Do you have a strange power saving mode enabled?\n");
+        if (unknown_nmi_panic || panic_on_unrecovered_nmi)
                 panic("NMI: Not continuing");
 
-        printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
+        pr_emerg("Dazed and confused, but trying to continue\n");
 }
 
 static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
 {
         unsigned char reason = 0;
-        int cpu;
 
-        cpu = smp_processor_id();
-
-        /* Only the BSP gets external NMIs from the system. */
-        if (!cpu)
-                reason = get_nmi_reason();
-
-        if (!(reason & 0xc0)) {
-                if (notify_die(DIE_NMI_IPI, "nmi_ipi", regs, reason, 2, SIGINT)
-                                                                == NOTIFY_STOP)
-                        return;
+        /*
+         * CPU-specific NMI must be processed before non-CPU-specific
+         * NMI, otherwise we may lose it, because the CPU-specific
+         * NMI can not be detected/processed on other CPUs.
+         */
+        if (notify_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP)
+                return;
 
-#ifdef CONFIG_X86_LOCAL_APIC
-                if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
-                                                        == NOTIFY_STOP)
-                        return;
+        /* Non-CPU-specific NMI: NMI sources can be processed on any CPU */
+        raw_spin_lock(&nmi_reason_lock);
+        reason = get_nmi_reason();
 
-#ifndef CONFIG_LOCKUP_DETECTOR
+        if (reason & NMI_REASON_MASK) {
+                if (reason & NMI_REASON_SERR)
+                        pci_serr_error(reason, regs);
+                else if (reason & NMI_REASON_IOCHK)
+                        io_check_error(reason, regs);
+#ifdef CONFIG_X86_32
                 /*
-                 * Ok, so this is none of the documented NMI sources,
-                 * so it must be the NMI watchdog.
+                 * Reassert NMI in case it became active
+                 * meanwhile as it's edge-triggered:
                  */
-                if (nmi_watchdog_tick(regs, reason))
-                        return;
-                if (!do_nmi_callback(regs, cpu))
-#endif /* !CONFIG_LOCKUP_DETECTOR */
-                        unknown_nmi_error(reason, regs);
-#else
-                unknown_nmi_error(reason, regs);
+                reassert_nmi();
 #endif
-
+                raw_spin_unlock(&nmi_reason_lock);
                 return;
         }
-        if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP)
-                return;
+        raw_spin_unlock(&nmi_reason_lock);
 
-        /* AK: following checks seem to be broken on modern chipsets. FIXME */
-        if (reason & 0x80)
-                mem_parity_error(reason, regs);
-        if (reason & 0x40)
-                io_check_error(reason, regs);
-#ifdef CONFIG_X86_32
-        /*
-         * Reassert NMI in case it became active meanwhile
-         * as it's edge-triggered:
-         */
-        reassert_nmi();
-#endif
+        unknown_nmi_error(reason, regs);
 }
 
 dotraplinkage notrace __kprobes void
@@ -446,14 +445,12 @@ do_nmi(struct pt_regs *regs, long error_code)
 
 void stop_nmi(void)
 {
-        acpi_nmi_disable();
         ignore_nmis++;
 }
 
 void restart_nmi(void)
 {
         ignore_nmis--;
-        acpi_nmi_enable();
 }
 
 /* May run on IST stack. */
@@ -575,6 +572,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
         if (regs->flags & X86_VM_MASK) {
                 handle_vm86_trap((struct kernel_vm86_regs *) regs,
                                 error_code, 1);
+                preempt_conditional_cli(regs);
                 return;
         }
 
@@ -776,21 +774,10 @@ asmlinkage void math_state_restore(void)
 }
 EXPORT_SYMBOL_GPL(math_state_restore);
 
-#ifndef CONFIG_MATH_EMULATION
-void math_emulate(struct math_emu_info *info)
-{
-        printk(KERN_EMERG
-                "math-emulation not enabled and no coprocessor found.\n");
-        printk(KERN_EMERG "killing %s.\n", current->comm);
-        force_sig(SIGFPE, current);
-        schedule();
-}
-#endif /* CONFIG_MATH_EMULATION */
-
 dotraplinkage void __kprobes
 do_device_not_available(struct pt_regs *regs, long error_code)
 {
-#ifdef CONFIG_X86_32
+#ifdef CONFIG_MATH_EMULATION
         if (read_cr0() & X86_CR0_EM) {
                 struct math_emu_info info = { };
 
@@ -798,12 +785,12 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 
                 info.regs = regs;
                 math_emulate(&info);
-        } else {
-                math_state_restore(); /* interrupts still off */
-                conditional_sti(regs);
+                return;
         }
-#else
-        math_state_restore();
+#endif
+        math_state_restore(); /* interrupts still off */
+#ifdef CONFIG_X86_32
+        conditional_sti(regs);
 #endif
 }
 
@@ -881,18 +868,6 @@ void __init trap_init(void)
 #endif
 
 #ifdef CONFIG_X86_32
-        if (cpu_has_fxsr) {
-                printk(KERN_INFO "Enabling fast FPU save and restore... ");
-                set_in_cr4(X86_CR4_OSFXSR);
-                printk("done.\n");
-        }
-        if (cpu_has_xmm) {
-                printk(KERN_INFO
-                        "Enabling unmasked SIMD FPU exception support... ");
-                set_in_cr4(X86_CR4_OSXMMEXCPT);
-                printk("done.\n");
-        }
-
         set_system_trap_gate(SYSCALL_VECTOR, &system_call);
         set_bit(SYSCALL_VECTOR, used_vectors);
 #endif