PANIC_MCE: Introduce a new panic flag for fatal MCE, capture related information
Fatal machine check exceptions (caused due to hardware memory errors) will now result in a 'slim' coredump that captures vital information about the MCE. This patch introduces a new panic flag, and new parameters to *panic functions that can capture more information pertaining to the cause of crash. Enable a new elf-notes section to store additional information about the crash. For MCE, enable a new notes section that captures relevant register status (struct mce) to be later read during coredump analysis. Signed-off-by: K.Prasad <[email protected]> --- arch/arm/kernel/traps.c | 2 +- arch/powerpc/kernel/traps.c | 2 +- arch/sh/kernel/traps_32.c | 2 +- arch/x86/kernel/cpu/mcheck/mce.c | 7 +++---- arch/x86/kernel/dumpstack.c | 2 +- include/linux/elf.h | 5 +++++ include/linux/kernel.h | 9 +++++---- include/linux/kexec.h | 9 ++++++--- kernel/kexec.c | 17 +++++++++++------ kernel/panic.c | 16 ++++++++-------- 10 files changed, 42 insertions(+), 29 deletions(-) Index: linux-2.6.slim_kdump/include/linux/kernel.h =================================================================== --- linux-2.6.slim_kdump.orig/include/linux/kernel.h +++ linux-2.6.slim_kdump/include/linux/kernel.h @@ -178,17 +178,18 @@ static inline void might_fault(void) enum panic_flags { PANIC_NO_KEXEC = (1 << 0), PANIC_NO_BACKTRACE = (1 << 1), + PANIC_MCE = (1 << 2), }; extern struct atomic_notifier_head panic_notifier_list; extern long (*panic_blink)(int state); NORET_TYPE void panic(const char * fmt, ...) __attribute__ ((NORET_AND format (printf, 1, 2))) __cold; -NORET_TYPE void xpanic(enum panic_flags flags, int timeout, - const char *fmt, ...) - __attribute__ ((NORET_AND format (printf, 3, 4))) __cold; +NORET_TYPE void xpanic(enum panic_flags flags, int timeout, void *arch_info, + size_t arch_info_size, const char *fmt, ...) + __attribute__ ((NORET_AND format (printf, 5, 6))) __cold; NORET_TYPE void vpanic(enum panic_flags flags, int timeout, - const char *fmt, + void *arch_info, size_t arch_info_size, const char *fmt, va_list ap) __noreturn __cold; extern void oops_enter(void); extern void oops_exit(void); Index: linux-2.6.slim_kdump/kernel/panic.c =================================================================== --- linux-2.6.slim_kdump.orig/kernel/panic.c +++ linux-2.6.slim_kdump/kernel/panic.c @@ -61,21 +61,21 @@ NORET_TYPE void panic(const char *fmt, . { va_list ap; va_start(ap, fmt); - vpanic(0, 0, fmt, ap); + vpanic(0, 0, NULL, 0, fmt, ap); } EXPORT_SYMBOL(panic); -NORET_TYPE void xpanic(enum panic_flags flags, int timeout, - const char *fmt, ...) +NORET_TYPE void xpanic(enum panic_flags flags, int timeout, void *arch_info, + size_t arch_info_size, const char *fmt, ...) { va_list ap; va_start(ap, fmt); - vpanic(flags, timeout, fmt, ap); + vpanic(flags, timeout, arch_info, arch_info_size, fmt, ap); } EXPORT_SYMBOL(xpanic); -NORET_TYPE void vpanic(enum panic_flags flags, int timeout, - const char * fmt, va_list args) +NORET_TYPE void vpanic(enum panic_flags flags, int timeout, void *arch_info, + size_t arch_info_size, const char * fmt, va_list args) { static char buf[1024]; long i, i_next = 0; @@ -99,7 +99,7 @@ NORET_TYPE void vpanic(enum panic_flags vsnprintf(buf, sizeof(buf), fmt, args); printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); #ifdef CONFIG_DEBUG_BUGVERBOSE - if (!(flags & PANIC_NO_BACKTRACE)) + if (!(flags & (PANIC_NO_BACKTRACE | PANIC_MCE))) dump_stack(); #endif @@ -109,7 +109,7 @@ NORET_TYPE void vpanic(enum panic_flags * Do we want to call this before we try to display a message? */ if (!(flags & PANIC_NO_KEXEC)) - crash_kexec(NULL); + crash_kexec(NULL, arch_info, arch_info_size, flags); kmsg_dump(KMSG_DUMP_PANIC); Index: linux-2.6.slim_kdump/arch/x86/kernel/cpu/mcheck/mce.c =================================================================== --- linux-2.6.slim_kdump.orig/arch/x86/kernel/cpu/mcheck/mce.c +++ linux-2.6.slim_kdump/arch/x86/kernel/cpu/mcheck/mce.c @@ -258,8 +258,7 @@ static void wait_for_panic(void) local_irq_enable(); while (timeout-- > 0) udelay(1); - xpanic(PANIC_NO_KEXEC|PANIC_NO_BACKTRACE, 0, - "Panicing machine check CPU died"); + xpanic(PANIC_MCE, 0, NULL, 0, "Panicing machine check CPU died"); } static void mce_panic(char *msg, struct mce *final, char *exp) @@ -315,8 +314,8 @@ static void mce_panic(char *msg, struct if (exp) pr_emerg(HW_ERR "Machine check: %s\n", exp); if (!fake_panic) { - xpanic(PANIC_NO_KEXEC|PANIC_NO_BACKTRACE, mce_panic_timeout, - msg); + xpanic(PANIC_MCE, mce_panic_timeout, final, + sizeof(struct mce), msg); } else pr_emerg(HW_ERR "Fake kernel panic: %s\n", msg); } Index: linux-2.6.slim_kdump/arch/arm/kernel/traps.c =================================================================== --- linux-2.6.slim_kdump.orig/arch/arm/kernel/traps.c +++ linux-2.6.slim_kdump/arch/arm/kernel/traps.c @@ -274,7 +274,7 @@ void die(const char *str, struct pt_regs ret = __die(str, err, thread, regs); if (regs && kexec_should_crash(thread->task)) - crash_kexec(regs); + crash_kexec(regs, NULL, 0, 0); bust_spinlocks(0); add_taint(TAINT_DIE); Index: linux-2.6.slim_kdump/arch/powerpc/kernel/traps.c =================================================================== --- linux-2.6.slim_kdump.orig/arch/powerpc/kernel/traps.c +++ linux-2.6.slim_kdump/arch/powerpc/kernel/traps.c @@ -161,7 +161,7 @@ int die(const char *str, struct pt_regs if (kexec_should_crash(current) || kexec_sr_activated(smp_processor_id())) - crash_kexec(regs); + crash_kexec(regs, NULL, 0, 0); crash_kexec_secondary(regs); if (in_interrupt()) Index: linux-2.6.slim_kdump/arch/sh/kernel/traps_32.c =================================================================== --- linux-2.6.slim_kdump.orig/arch/sh/kernel/traps_32.c +++ linux-2.6.slim_kdump/arch/sh/kernel/traps_32.c @@ -106,7 +106,7 @@ void die(const char * str, struct pt_reg oops_exit(); if (kexec_should_crash(current)) - crash_kexec(regs); + crash_kexec(regs, NULL, 0, 0); if (in_interrupt()) panic("Fatal exception in interrupt"); Index: linux-2.6.slim_kdump/arch/x86/kernel/dumpstack.c =================================================================== --- linux-2.6.slim_kdump.orig/arch/x86/kernel/dumpstack.c +++ linux-2.6.slim_kdump/arch/x86/kernel/dumpstack.c @@ -241,7 +241,7 @@ EXPORT_SYMBOL_GPL(oops_begin); void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr) { if (regs && kexec_should_crash(current)) - crash_kexec(regs); + crash_kexec(regs, NULL, 0, 0); bust_spinlocks(0); die_owner = -1; Index: linux-2.6.slim_kdump/include/linux/elf.h =================================================================== --- linux-2.6.slim_kdump.orig/include/linux/elf.h +++ linux-2.6.slim_kdump/include/linux/elf.h @@ -381,6 +381,11 @@ typedef struct elf64_shdr { #define NT_PRPSINFO 3 #define NT_TASKSTRUCT 4 #define NT_AUXV 6 +/* + * Although numbers 1 - 6 have been defined here, the user-space include files + * have numbers 1 - 20 taken up. Hence defining NT_MCE as 21. + */ +#define NT_MCE 21 /* Machine Check Exception related data */ #define NT_PRXFPREG 0x46e62b7f /* copied from gdb5.1/include/elf/common.h */ #define NT_PPC_VMX 0x100 /* PowerPC Altivec/VMX registers */ #define NT_PPC_SPE 0x101 /* PowerPC SPE/EVR registers */ Index: linux-2.6.slim_kdump/include/linux/kexec.h =================================================================== --- linux-2.6.slim_kdump.orig/include/linux/kexec.h +++ linux-2.6.slim_kdump/include/linux/kexec.h @@ -125,10 +125,12 @@ extern asmlinkage long compat_sys_kexec_ #endif extern struct page *kimage_alloc_control_pages(struct kimage *image, unsigned int order); -extern void crash_kexec(struct pt_regs *); +extern void crash_kexec(struct pt_regs *, void *arch_info, + size_t arch_info_size, enum panic_flags); int kexec_should_crash(struct task_struct *); void crash_save_cpu(struct pt_regs *regs, int cpu); -void crash_save_vmcoreinfo(void); +void crash_save_vmcoreinfo(void *arch_info, size_t arch_info_size, + enum panic_flags); void arch_crash_save_vmcoreinfo(void); void vmcoreinfo_append_str(const char *fmt, ...) __attribute__ ((format (printf, 1, 2))); @@ -213,7 +215,8 @@ void crash_free_reserved_phys_range(unsi #else /* !CONFIG_KEXEC */ struct pt_regs; struct task_struct; -static inline void crash_kexec(struct pt_regs *regs) { } +static inline void crash_kexec(struct pt_regs *regs, void *arch_info, + size_t arch_info_size, enum panic_flags) { } static inline int kexec_should_crash(struct task_struct *p) { return 0; } #endif /* CONFIG_KEXEC */ #endif /* LINUX_KEXEC_H */ Index: linux-2.6.slim_kdump/kernel/kexec.c =================================================================== --- linux-2.6.slim_kdump.orig/kernel/kexec.c +++ linux-2.6.slim_kdump/kernel/kexec.c @@ -1065,7 +1065,8 @@ asmlinkage long compat_sys_kexec_load(un } #endif -void crash_kexec(struct pt_regs *regs) +void crash_kexec(struct pt_regs *regs, void *arch_info, size_t arch_info_size, + enum panic_flags flags) { /* Take the kexec_mutex here to prevent sys_kexec_load * running on one cpu from replacing the crash kernel @@ -1082,7 +1083,7 @@ void crash_kexec(struct pt_regs *regs) kmsg_dump(KMSG_DUMP_KEXEC); crash_setup_regs(&fixed_regs, regs); - crash_save_vmcoreinfo(); + crash_save_vmcoreinfo(arch_info, arch_info_size, flags); machine_crash_shutdown(&fixed_regs); machine_kexec(kexec_crash_image); } @@ -1381,7 +1382,8 @@ int __init parse_crashkernel(char *cm -void crash_save_vmcoreinfo(void) +void crash_save_vmcoreinfo(void *arch_info, size_t arch_info_size, + enum panic_flags flags) { u32 *buf; @@ -1392,9 +1394,12 @@ void crash_save_vmcoreinfo(void) buf = (u32 *)vmcoreinfo_note; - buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, vmcoreinfo_data, - vmcoreinfo_size); - + if (flags & PANIC_MCE) + buf = append_elf_note(buf, "PANIC_MCE", NT_MCE, arch_info, + arch_info_size); + else + buf = append_elf_note(buf, VMCOREINFO_NOTE_NAME, 0, + vmcoreinfo_data, vmcoreinfo_size); final_note(buf); } _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
