From: Petr Tesarik <ptesarik@xxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxx Signed-off-by: Petr Tesarik <ptesarik@xxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Dave Young <dyoung@xxxxxxxxxx> Cc: David Vrabel <david.vrabel@xxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/kexec.h | 2 ++ kernel/kexec_core.c | 6 ++++++ kernel/ksysfs.c | 2 +- 3 files changed, 9 insertions(+), 1 deletion(-) diff -puN include/linux/kexec.h~add-a-kexec_crash_loaded-function include/linux/kexec.h --- a/include/linux/kexec.h~add-a-kexec_crash_loaded-function +++ a/include/linux/kexec.h @@ -230,6 +230,7 @@ extern void *kexec_purgatory_get_symbol_ 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 -puN kernel/kexec_core.c~add-a-kexec_crash_loaded-function kernel/kexec_core.c --- a/kernel/kexec_core.c~add-a-kexec_crash_loaded-function +++ a/kernel/kexec_core.c @@ -95,6 +95,12 @@ int kexec_should_crash(struct task_struc 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 -puN kernel/ksysfs.c~add-a-kexec_crash_loaded-function kernel/ksysfs.c --- a/kernel/ksysfs.c~add-a-kexec_crash_loaded-function +++ a/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); _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
