From: Sang Yan sangyan@huawei.com
hulk inclusion category: feature bugzilla: 48159 CVE: N/A
------------------------------
In normal kexec, relocating kernel may cost 5 ~ 10 seconds, to copy all segments from vmalloced memory to kernel boot memory, because of disabled mmu.
We introduce quick kexec to save time of copying memory as above, just like kdump(kexec on crash), by using reserved memory "Quick Kexec".
To enable it, we should reserve memory and setup quick_kexec_res.
Constructing quick kimage as the same as crash kernel, then simply copy all segments of kimage to reserved memroy.
We also add this support in syscall kexec_load using flags of KEXEC_QUICK.
Signed-off-by: Sang Yan sangyan@huawei.com Reviewed-by: Kuohai Xu xukuohai@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- arch/Kconfig | 10 +++++++++ include/linux/ioport.h | 1 + include/linux/kexec.h | 24 ++++++++++++++++++---- include/uapi/linux/kexec.h | 1 + kernel/kexec.c | 10 +++++++++ kernel/kexec_core.c | 42 ++++++++++++++++++++++++++++++-------- 6 files changed, 75 insertions(+), 13 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig index f2d65d38f119..2bc2dea38ea4 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -18,6 +18,16 @@ config KEXEC_CORE select CRASH_CORE bool
+config QUICK_KEXEC + bool "Support for quick kexec" + depends on KEXEC_CORE + help + It uses pre-reserved memory to accelerate kexec, just like + crash kexec, loads new kernel and initrd to reserved memory, + and boots new kernel on that memory. It will save the time + of relocating kernel. + + config KEXEC_ELF bool
diff --git a/include/linux/ioport.h b/include/linux/ioport.h index 5135d4b86cd6..84a716fd6029 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -139,6 +139,7 @@ enum { IORES_DESC_DEVICE_PRIVATE_MEMORY = 6, IORES_DESC_RESERVED = 7, IORES_DESC_SOFT_RESERVED = 8, + IORES_DESC_QUICK_KEXEC = 9, };
/* diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 6aca2e51fd8e..bbd8b54753bf 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -269,9 +269,10 @@ struct kimage { unsigned long control_page;
/* Flags to indicate special processing */ - unsigned int type : 1; + unsigned int type : 2; #define KEXEC_TYPE_DEFAULT 0 #define KEXEC_TYPE_CRASH 1 +#define KEXEC_TYPE_QUICK 2 unsigned int preserve_context : 1; /* If set, we are using file mode kexec syscall */ unsigned int file_mode:1; @@ -338,12 +339,24 @@ extern int kexec_load_disabled; #endif
/* List of defined/legal kexec flags */ -#ifndef CONFIG_KEXEC_JUMP -#define KEXEC_FLAGS KEXEC_ON_CRASH +#define __KEXEC_FLAGS_CRASH KEXEC_ON_CRASH + +#ifdef CONFIG_KEXEC_JUMP +#define __KEXEC_FLAGS_JUMP KEXEC_PRESERVE_CONTEXT +#else +#define __KEXEC_FLAGS_JUMP 0 +#endif + +#ifdef CONFIG_QUICK_KEXEC +#define __KEXEC_FLAGS_QUICK KEXEC_QUICK #else -#define KEXEC_FLAGS (KEXEC_ON_CRASH | KEXEC_PRESERVE_CONTEXT) +#define __KEXEC_FLAGS_QUICK 0 #endif
+#define KEXEC_FLAGS \ + (__KEXEC_FLAGS_CRASH | __KEXEC_FLAGS_JUMP | __KEXEC_FLAGS_QUICK) + + /* List of defined/legal kexec file flags */ #define KEXEC_FILE_FLAGS (KEXEC_FILE_UNLOAD | KEXEC_FILE_ON_CRASH | \ KEXEC_FILE_NO_INITRAMFS) @@ -351,6 +364,9 @@ extern int kexec_load_disabled; /* Location of a reserved region to hold the crash kernel. */ extern note_buf_t __percpu *crash_notes; +#ifdef CONFIG_QUICK_KEXEC +extern struct resource quick_kexec_res; +#endif
/* flag to track if kexec reboot is in progress */ extern bool kexec_in_progress; diff --git a/include/uapi/linux/kexec.h b/include/uapi/linux/kexec.h index 05669c87a0af..d891d8009a17 100644 --- a/include/uapi/linux/kexec.h +++ b/include/uapi/linux/kexec.h @@ -12,6 +12,7 @@ /* kexec flags for different usage scenarios */ #define KEXEC_ON_CRASH 0x00000001 #define KEXEC_PRESERVE_CONTEXT 0x00000002 +#define KEXEC_QUICK 0x00000004 #define KEXEC_ARCH_MASK 0xffff0000
/* diff --git a/kernel/kexec.c b/kernel/kexec.c index c82c6c06f051..4acc909940f7 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -44,6 +44,9 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry, int ret; struct kimage *image; bool kexec_on_panic = flags & KEXEC_ON_CRASH; +#ifdef CONFIG_QUICK_KEXEC + bool kexec_on_quick = flags & KEXEC_QUICK; +#endif
if (kexec_on_panic) { /* Verify we have a valid entry point */ @@ -69,6 +72,13 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry, image->type = KEXEC_TYPE_CRASH; }
+#ifdef CONFIG_QUICK_KEXEC + if (kexec_on_quick) { + image->control_page = quick_kexec_res.start; + image->type = KEXEC_TYPE_QUICK; + } +#endif + ret = sanity_check_segment_list(image); if (ret) goto out_free_image; diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 255ec90c6806..b9a6f4658f89 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -52,6 +52,17 @@ note_buf_t __percpu *crash_notes; /* Flag to indicate we are going to kexec a new kernel */ bool kexec_in_progress = false;
+/* Resource for quick kexec */ +#ifdef CONFIG_QUICK_KEXEC +struct resource quick_kexec_res = { + .name = "Quick kexec", + .start = 0, + .end = 0, + .flags = IORESOURCE_BUSY | IORESOURCE_SYSTEM_RAM, + .desc = IORES_DESC_QUICK_KEXEC +}; +#endif + int kexec_should_crash(struct task_struct *p) { /* @@ -395,8 +406,9 @@ static struct page *kimage_alloc_normal_control_pages(struct kimage *image, return pages; }
-static struct page *kimage_alloc_crash_control_pages(struct kimage *image, - unsigned int order) +static struct page *kimage_alloc_special_control_pages(struct kimage *image, + unsigned int order, + unsigned long end) { /* Control pages are special, they are the intermediaries * that are needed while we copy the rest of the pages @@ -426,7 +438,7 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image, size = (1 << order) << PAGE_SHIFT; hole_start = (image->control_page + (size - 1)) & ~(size - 1); hole_end = hole_start + size - 1; - while (hole_end <= crashk_res.end) { + while (hole_end <= end) { unsigned long i;
cond_resched(); @@ -461,7 +473,6 @@ static struct page *kimage_alloc_crash_control_pages(struct kimage *image, return pages; }
- struct page *kimage_alloc_control_pages(struct kimage *image, unsigned int order) { @@ -472,8 +483,15 @@ struct page *kimage_alloc_control_pages(struct kimage *image, pages = kimage_alloc_normal_control_pages(image, order); break; case KEXEC_TYPE_CRASH: - pages = kimage_alloc_crash_control_pages(image, order); + pages = kimage_alloc_special_control_pages(image, order, + crashk_res.end); + break; +#ifdef CONFIG_QUICK_KEXEC + case KEXEC_TYPE_QUICK: + pages = kimage_alloc_special_control_pages(image, order, + quick_kexec_res.end); break; +#endif }
return pages; @@ -829,11 +847,12 @@ static int kimage_load_normal_segment(struct kimage *image, return result; }
-static int kimage_load_crash_segment(struct kimage *image, +static int kimage_load_special_segment(struct kimage *image, struct kexec_segment *segment) { - /* For crash dumps kernels we simply copy the data from - * user space to it's destination. + /* + * For crash dumps kernels and quick kexec kernels + * we simply copy the data from user space to it's destination. * We do things a page at a time for the sake of kmap. */ unsigned long maddr; @@ -907,8 +926,13 @@ int kimage_load_segment(struct kimage *image, result = kimage_load_normal_segment(image, segment); break; case KEXEC_TYPE_CRASH: - result = kimage_load_crash_segment(image, segment); + result = kimage_load_special_segment(image, segment); break; +#ifdef CONFIG_QUICK_KEXEC + case KEXEC_TYPE_QUICK: + result = kimage_load_special_segment(image, segment); + break; +#endif }
return result;