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>

1 files changed, 30 insertions, 4 deletions

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;
                         }