diff options
| -rw-r--r-- | arch/x86/Kconfig.debug | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/smp.h | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi_selftest.c | 179 | ||||
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 1 |
5 files changed, 199 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 4caec1261f1..97da3c17b42 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -287,4 +287,16 @@ config DEBUG_STRICT_USER_COPY_CHECKS If unsure, or if you run an older (pre 4.4) gcc, say N. +config DEBUG_NMI_SELFTEST + bool "NMI Selftest" + depends on DEBUG_KERNEL + ---help--- + Enabling this option turns on a quick NMI selftest to verify + that the NMI behaves correctly. + + This might help diagnose strange hangs that rely on NMI to + function properly. + + If unsure, say N. + endmenu diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h index 73b11bc0ae6..0434c400287 100644 --- a/arch/x86/include/asm/smp.h +++ b/arch/x86/include/asm/smp.h @@ -225,5 +225,11 @@ extern int hard_smp_processor_id(void); #endif /* CONFIG_X86_LOCAL_APIC */ +#ifdef CONFIG_DEBUG_NMI_SELFTEST +extern void nmi_selftest(void); +#else +#define nmi_selftest() do { } while (0) +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_X86_SMP_H */ diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 8baca3c4871..02b2f05b371 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -80,6 +80,7 @@ obj-$(CONFIG_APB_TIMER) += apb_timer.o obj-$(CONFIG_AMD_NB) += amd_nb.o obj-$(CONFIG_DEBUG_RODATA_TEST) += test_rodata.o obj-$(CONFIG_DEBUG_NX_TEST) += test_nx.o +obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o obj-$(CONFIG_KVM_GUEST) += kvm.o obj-$(CONFIG_KVM_CLOCK) += kvmclock.o diff --git a/arch/x86/kernel/nmi_selftest.c b/arch/x86/kernel/nmi_selftest.c new file mode 100644 index 00000000000..572adb62225 --- /dev/null +++ b/arch/x86/kernel/nmi_selftest.c @@ -0,0 +1,179 @@ +/* + * arch/x86/kernel/nmi-selftest.c + * + * Testsuite for NMI: IPIs + * + * Started by Don Zickus: + * (using lib/locking-selftest.c as a guide) + * + * Copyright (C) 2011 Red Hat, Inc., Don Zickus <dzickus@redhat.com> + */ + +#include <linux/smp.h> +#include <linux/cpumask.h> +#include <linux/delay.h> + +#include <asm/apic.h> +#include <asm/nmi.h> + +#define SUCCESS 0 +#define FAILURE 1 +#define TIMEOUT 2 + +static int nmi_fail; + +/* check to see if NMI IPIs work on this machine */ +static DECLARE_BITMAP(nmi_ipi_mask, NR_CPUS) __read_mostly; + +static int testcase_total; +static int testcase_successes; +static int expected_testcase_failures; +static int unexpected_testcase_failures; +static int unexpected_testcase_unknowns; + +static int nmi_unk_cb(unsigned int val, struct pt_regs *regs) +{ + unexpected_testcase_unknowns++; + return NMI_HANDLED; +} + +static void init_nmi_testsuite(void) +{ + /* trap all the unknown NMIs we may generate */ + register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk"); +} + +static void cleanup_nmi_testsuite(void) +{ + unregister_nmi_handler(NMI_UNKNOWN, "nmi_selftest_unk"); +} + +static int test_nmi_ipi_callback(unsigned int val, struct pt_regs *regs) +{ + int cpu = raw_smp_processor_id(); + + if (cpumask_test_and_clear_cpu(cpu, to_cpumask(nmi_ipi_mask))) + return NMI_HANDLED; + + return NMI_DONE; +} + +static void test_nmi_ipi(struct cpumask *mask) +{ + unsigned long timeout; + + if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback, + NMI_FLAG_FIRST, "nmi_selftest")) { + nmi_fail = FAILURE; + return; + } + + /* sync above data before sending NMI */ + wmb(); + + apic->send_IPI_mask(mask, NMI_VECTOR); + + /* Don't wait longer than a second */ + timeout = USEC_PER_SEC; + while (!cpumask_empty(mask) && timeout--) + udelay(1); + + /* What happens if we timeout, do we still unregister?? */ + unregister_nmi_handler(NMI_LOCAL, "nmi_selftest"); + + if (!timeout) + nmi_fail = TIMEOUT; + return; +} + +static void remote_ipi(void) +{ + cpumask_copy(to_cpumask(nmi_ipi_mask), cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask)); + test_nmi_ipi(to_cpumask(nmi_ipi_mask)); +} + +static void local_ipi(void) +{ + cpumask_clear(to_cpumask(nmi_ipi_mask)); + cpumask_set_cpu(smp_processor_id(), to_cpumask(nmi_ipi_mask)); + test_nmi_ipi(to_cpumask(nmi_ipi_mask)); +} + +static void reset_nmi(void) +{ + nmi_fail = 0; +} + +static void dotest(void (*testcase_fn)(void), int expected) +{ + testcase_fn(); + /* + * Filter out expected failures: + */ + if (nmi_fail != expected) { + unexpected_testcase_failures++; + + if (nmi_fail == FAILURE) + printk("FAILED |"); + else if (nmi_fail == TIMEOUT) + printk("TIMEOUT|"); + else + printk("ERROR |"); + dump_stack(); + } else { + testcase_successes++; + printk(" ok |"); + } + testcase_total++; + + reset_nmi(); +} + +static inline void print_testname(const char *testname) +{ + printk("%12s:", testname); +} + +void nmi_selftest(void) +{ + init_nmi_testsuite(); + + /* + * Run the testsuite: + */ + printk("----------------\n"); + printk("| NMI testsuite:\n"); + printk("--------------------\n"); + + print_testname("remote IPI"); + dotest(remote_ipi, SUCCESS); + printk("\n"); + print_testname("local IPI"); + dotest(local_ipi, SUCCESS); + printk("\n"); + + cleanup_nmi_testsuite(); + + if (unexpected_testcase_failures) { + printk("--------------------\n"); + printk("BUG: %3d unexpected failures (out of %3d) - debugging disabled! |\n", + unexpected_testcase_failures, testcase_total); + printk("-----------------------------------------------------------------\n"); + } else if (expected_testcase_failures && testcase_successes) { + printk("--------------------\n"); + printk("%3d out of %3d testcases failed, as expected. |\n", + expected_testcase_failures, testcase_total); + printk("----------------------------------------------------\n"); + } else if (expected_testcase_failures && !testcase_successes) { + printk("--------------------\n"); + printk("All %3d testcases failed, as expected. |\n", + expected_testcase_failures); + printk("----------------------------------------\n"); + } else { + printk("--------------------\n"); + printk("Good, all %3d testcases passed! |\n", + testcase_successes); + printk("---------------------------------\n"); + } +} diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 9f548cb4a95..19277817eff 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1142,6 +1142,7 @@ void __init native_smp_cpus_done(unsigned int max_cpus) { pr_debug("Boot done.\n"); + nmi_selftest(); impress_friends(); #ifdef CONFIG_X86_IO_APIC setup_ioapic_dest(); |