x86: add IRQ context simulation in module mce-inject

mce-inject provides a mechanism to simulate errors so that test
scripts can check for correct operation of the kernel without
requiring any specialized hardware to create rare events.

The existing code can simulate events in normal process context
and also in NMI context - but not in IRQ context. This patch
fills that gap.

Link: https://lkml.org/lkml/2011/12/7/537
Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

2 files changed, 35 insertions, 8 deletions

diff --git a/arch/x86/include/asm/mce.h b/arch/x86/include/asm/mce.h
index 0e8ae57d3656..98165835dc68 100644
--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -50,10 +50,11 @@
 #define MCJ_CTX_MASK            3
 #define MCJ_CTX(flags)          ((flags) & MCJ_CTX_MASK)
 #define MCJ_CTX_RANDOM          0    /* inject context: random */
-#define MCJ_CTX_PROCESS         1    /* inject context: process */
-#define MCJ_CTX_IRQ             2    /* inject context: IRQ */
-#define MCJ_NMI_BROADCAST       4    /* do NMI broadcasting */
-#define MCJ_EXCEPTION           8    /* raise as exception */
+#define MCJ_CTX_PROCESS         0x1  /* inject context: process */
+#define MCJ_CTX_IRQ             0x2  /* inject context: IRQ */
+#define MCJ_NMI_BROADCAST       0x4  /* do NMI broadcasting */
+#define MCJ_EXCEPTION           0x8  /* raise as exception */
+#define MCJ_IRQ_BRAODCAST       0x10 /* do IRQ broadcasting */
 
 /* Fields are zero when not available */
 struct mce {
diff --git a/arch/x86/kernel/cpu/mcheck/mce-inject.c b/arch/x86/kernel/cpu/mcheck/mce-inject.c
index 319882ef848d..fc4beb393577 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-inject.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-inject.c
@@ -17,6 +17,7 @@
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/fs.h>
+#include <linux/preempt.h>
 #include <linux/smp.h>
 #include <linux/notifier.h>
 #include <linux/kdebug.h>
@@ -92,6 +93,18 @@ static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
         return NMI_HANDLED;
 }
 
+static void mce_irq_ipi(void *info)
+{
+        int cpu = smp_processor_id();
+        struct mce *m = &__get_cpu_var(injectm);
+
+        if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
+                        m->inject_flags & MCJ_EXCEPTION) {
+                cpumask_clear_cpu(cpu, mce_inject_cpumask);
+                raise_exception(m, NULL);
+        }
+}
+
 /* Inject mce on current CPU */
 static int raise_local(void)
 {
@@ -139,9 +152,10 @@ static void raise_mce(struct mce *m)
                 return;
 
 #ifdef CONFIG_X86_LOCAL_APIC
-        if (m->inject_flags & MCJ_NMI_BROADCAST) {
+        if (m->inject_flags & (MCJ_IRQ_BRAODCAST | MCJ_NMI_BROADCAST)) {
                 unsigned long start;
                 int cpu;
+
                 get_online_cpus();
                 cpumask_copy(mce_inject_cpumask, cpu_online_mask);
                 cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
@@ -151,13 +165,25 @@ static void raise_mce(struct mce *m)
                             MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
                                 cpumask_clear_cpu(cpu, mce_inject_cpumask);
                 }
-                if (!cpumask_empty(mce_inject_cpumask))
-                        apic->send_IPI_mask(mce_inject_cpumask, NMI_VECTOR);
+                if (!cpumask_empty(mce_inject_cpumask)) {
+                        if (m->inject_flags & MCJ_IRQ_BRAODCAST) {
+                                /*
+                                 * don't wait because mce_irq_ipi is necessary
+                                 * to be sync with following raise_local
+                                 */
+                                preempt_disable();
+                                smp_call_function_many(mce_inject_cpumask,
+                                        mce_irq_ipi, NULL, 0);
+                                preempt_enable();
+                        } else if (m->inject_flags & MCJ_NMI_BROADCAST)
+                                apic->send_IPI_mask(mce_inject_cpumask,
+                                                NMI_VECTOR);
+                }
                 start = jiffies;
                 while (!cpumask_empty(mce_inject_cpumask)) {
                         if (!time_before(jiffies, start + 2*HZ)) {
                                 printk(KERN_ERR
-                                "Timeout waiting for mce inject NMI %lx\n",
+                                "Timeout waiting for mce inject %lx\n",
                                         *cpumask_bits(mce_inject_cpumask));
                                 break;
                         }