diff options
| -rw-r--r-- | include/linux/kexec.h | 30 | ||||
| -rw-r--r-- | kernel/kexec_file.c | 3 |
2 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/kexec.h b/include/linux/kexec.h index c8971861521a..1871eaa95432 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -25,6 +25,10 @@ extern note_buf_t __percpu *crash_notes; +#ifdef CONFIG_CRASH_DUMP +#include <linux/prandom.h> +#endif + #ifdef CONFIG_KEXEC_CORE #include <linux/list.h> #include <linux/compat.h> @@ -169,6 +173,7 @@ int kexec_image_post_load_cleanup_default(struct kimage *image); * @buf_min: The buffer can't be placed below this address. * @buf_max: The buffer can't be placed above this address. * @top_down: Allocate from top of memory. + * @random: Place the buffer at a random position. */ struct kexec_buf { struct kimage *image; @@ -180,8 +185,33 @@ struct kexec_buf { unsigned long buf_min; unsigned long buf_max; bool top_down; +#ifdef CONFIG_CRASH_DUMP + bool random; +#endif }; + +#ifdef CONFIG_CRASH_DUMP +static inline void kexec_random_range_start(unsigned long start, + unsigned long end, + struct kexec_buf *kbuf, + unsigned long *temp_start) +{ + unsigned short i; + + if (kbuf->random) { + get_random_bytes(&i, sizeof(unsigned short)); + *temp_start = start + (end - start) / USHRT_MAX * i; + } +} +#else +static inline void kexec_random_range_start(unsigned long start, + unsigned long end, + struct kexec_buf *kbuf, + unsigned long *temp_start) +{} +#endif + int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf); int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, void *buf, unsigned int size, diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 14e5087b4277..4a88bfc33824 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -444,6 +444,7 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end, temp_end = min(end, kbuf->buf_max); temp_start = temp_end - kbuf->memsz + 1; + kexec_random_range_start(temp_start, temp_end, kbuf, &temp_start); do { /* align down start */ @@ -488,6 +489,8 @@ static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, temp_start = max(start, kbuf->buf_min); + kexec_random_range_start(temp_start, end, kbuf, &temp_start); + do { temp_start = ALIGN(temp_start, kbuf->buf_align); temp_end = temp_start + kbuf->memsz - 1; |