From 21db79e8bb054d0351a6b1b464f1c9c47a2e6e8d Mon Sep 17 00:00:00 2001 From: Petr Tesarik Date: Tue, 2 Aug 2016 14:06:16 -0700 Subject: [PATCH] kexec: add a kexec_crash_loaded() function Provide a wrapper function to be used by kernel code to check whether a crash kernel is loaded. It returns the same value that can be seen in /sys/kernel/kexec_crash_loaded by userspace programs. I'm exporting the function, because it will be used by Xen, and it is possible to compile Xen modules separately to enable the use of PV drivers with unmodified bare-metal kernels. Link: http://lkml.kernel.org/r/20160713121955.14969.69080.stgit@hananiah.suse.cz Signed-off-by: Petr Tesarik Cc: Juergen Gross Cc: Josh Triplett Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Eric Biederman Cc: "H. Peter Anvin" Cc: Boris Ostrovsky Cc: "Paul E. McKenney" Cc: Dave Young Cc: David Vrabel Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kexec.h | 2 ++ kernel/kexec_core.c | 6 ++++++ kernel/ksysfs.c | 2 +- 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 23e14a460cfb..d7437777baaa 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -230,6 +230,7 @@ extern void *kexec_purgatory_get_symbol_addr(struct kimage *image, extern void __crash_kexec(struct pt_regs *); extern void crash_kexec(struct pt_regs *); int kexec_should_crash(struct task_struct *); +int kexec_crash_loaded(void); void crash_save_cpu(struct pt_regs *regs, int cpu); void crash_save_vmcoreinfo(void); void arch_crash_save_vmcoreinfo(void); @@ -364,6 +365,7 @@ struct task_struct; static inline void __crash_kexec(struct pt_regs *regs) { } static inline void crash_kexec(struct pt_regs *regs) { } static inline int kexec_should_crash(struct task_struct *p) { return 0; } +static inline int kexec_crash_loaded(void) { return 0; } #define kexec_in_progress false #endif /* CONFIG_KEXEC_CORE */ diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 73d4c5f57dd8..704534029a00 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -95,6 +95,12 @@ int kexec_should_crash(struct task_struct *p) return 0; } +int kexec_crash_loaded(void) +{ + return !!kexec_crash_image; +} +EXPORT_SYMBOL_GPL(kexec_crash_loaded); + /* * When kexec transitions to the new kernel there is a one-to-one * mapping between physical and virtual addresses. On processors diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 9f1920d2d0c6..ee1bc1bb8feb 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -101,7 +101,7 @@ KERNEL_ATTR_RO(kexec_loaded); static ssize_t kexec_crash_loaded_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { - return sprintf(buf, "%d\n", !!kexec_crash_image); + return sprintf(buf, "%d\n", kexec_crash_loaded()); } KERNEL_ATTR_RO(kexec_crash_loaded); -- 2.20.1