diff options
| -rw-r--r-- | include/linux/kexec.h | 2 | ||||
| -rw-r--r-- | kernel/kexec.c | 59 | ||||
| -rw-r--r-- | kernel/ksysfs.c | 21 |
3 files changed, 82 insertions, 0 deletions
diff --git a/include/linux/kexec.h b/include/linux/kexec.h index adc34f2c6eff..c356b6914ffd 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -206,6 +206,8 @@ extern size_t vmcoreinfo_max_size; int __init parse_crashkernel(char *cmdline, unsigned long long system_ram, unsigned long long *crash_size, unsigned long long *crash_base); +int crash_shrink_memory(unsigned long new_size); +size_t crash_get_memory_size(void); #else /* !CONFIG_KEXEC */ struct pt_regs; diff --git a/kernel/kexec.c b/kernel/kexec.c index f336e2107f98..433e9fcc1fc5 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -31,6 +31,7 @@ #include <linux/cpu.h> #include <linux/console.h> #include <linux/vmalloc.h> +#include <linux/swap.h> #include <asm/page.h> #include <asm/uaccess.h> @@ -1082,6 +1083,64 @@ void crash_kexec(struct pt_regs *regs) } } +size_t crash_get_memory_size(void) +{ + size_t size; + mutex_lock(&kexec_mutex); + size = crashk_res.end - crashk_res.start + 1; + mutex_unlock(&kexec_mutex); + return size; +} + +static void free_reserved_phys_range(unsigned long begin, unsigned long end) +{ + unsigned long addr; + + for (addr = begin; addr < end; addr += PAGE_SIZE) { + ClearPageReserved(pfn_to_page(addr >> PAGE_SHIFT)); + init_page_count(pfn_to_page(addr >> PAGE_SHIFT)); + free_page((unsigned long)__va(addr)); + totalram_pages++; + } +} + +int crash_shrink_memory(unsigned long new_size) +{ + int ret = 0; + unsigned long start, end; + + mutex_lock(&kexec_mutex); + + if (kexec_crash_image) { + ret = -ENOENT; + goto unlock; + } + start = crashk_res.start; + end = crashk_res.end; + + if (new_size >= end - start + 1) { + ret = -EINVAL; + if (new_size == end - start + 1) + ret = 0; + goto unlock; + } + + start = roundup(start, PAGE_SIZE); + end = roundup(start + new_size, PAGE_SIZE); + + free_reserved_phys_range(end, crashk_res.end); + + if (start == end) { + crashk_res.end = end; + release_resource(&crashk_res); + } else + crashk_res.end = end - 1; + +unlock: + mutex_unlock(&kexec_mutex); + return ret; +} + static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data, size_t data_len) { diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index 528dd78e7e7e..3feaf5a74514 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -100,6 +100,26 @@ static ssize_t kexec_crash_loaded_show(struct kobject *kobj, } KERNEL_ATTR_RO(kexec_crash_loaded); +static ssize_t kexec_crash_size_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%zu\n", crash_get_memory_size()); +} +static ssize_t kexec_crash_size_store(struct kobject *kobj, + struct kobj_attribute *attr, + const char *buf, size_t count) +{ + unsigned long cnt; + int ret; + + if (strict_strtoul(buf, 0, &cnt)) + return -EINVAL; + + ret = crash_shrink_memory(cnt); + return ret < 0 ? ret : count; +} +KERNEL_ATTR_RW(kexec_crash_size); + static ssize_t vmcoreinfo_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -147,6 +167,7 @@ static struct attribute * kernel_attrs[] = { #ifdef CONFIG_KEXEC &kexec_loaded_attr.attr, &kexec_crash_loaded_attr.attr, + &kexec_crash_size_attr.attr, &vmcoreinfo_attr.attr, #endif NULL |