From: Cong Wang <[email protected]> Replace static kexec_image and kexec_crash_image globals with a dynamic linked list infrastructure to support multiple kernel images. This change enables multikernel functionality while maintaining backward compatibility.
Key changes: - Add list_head member to kimage structure for chaining - Implement thread-safe linked list management with global mutex - Update kexec load/unload logic to use list-based APIs for multikernel - Add helper functions for finding and managing multiple kimages - Preserve existing kexec_image/kexec_crash_image pointers for compatibility - Update architecture-specific crash handling to use new APIs The multikernel case now properly uses list-based management instead of overwriting compatibility pointers, allowing multiple multikernel images to coexist in the system. Signed-off-by: Cong Wang <[email protected]> --- arch/powerpc/kexec/crash.c | 8 +- arch/x86/kernel/crash.c | 4 +- include/linux/kexec.h | 16 ++++ kernel/kexec.c | 62 +++++++++++++- kernel/kexec_core.c | 165 ++++++++++++++++++++++++++++++++++++- kernel/kexec_file.c | 33 +++++++- 6 files changed, 274 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c index a325c1c02f96..af190fad4f22 100644 --- a/arch/powerpc/kexec/crash.c +++ b/arch/powerpc/kexec/crash.c @@ -477,13 +477,13 @@ static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify * ptr = __va(mem); if (ptr) { /* Temporarily invalidate the crash image while it is replaced */ - xchg(&kexec_crash_image, NULL); + kimage_update_compat_pointers(NULL, KEXEC_TYPE_CRASH); /* Replace the old elfcorehdr with newly prepared elfcorehdr */ memcpy((void *)ptr, elfbuf, elfsz); /* The crash image is now valid once again */ - xchg(&kexec_crash_image, image); + kimage_update_compat_pointers(image, KEXEC_TYPE_CRASH); } out: kvfree(cmem); @@ -537,14 +537,14 @@ static void update_crash_fdt(struct kimage *image) fdt = __va((void *)image->segment[fdt_index].mem); /* Temporarily invalidate the crash image while it is replaced */ - xchg(&kexec_crash_image, NULL); + kimage_update_compat_pointers(NULL, KEXEC_TYPE_CRASH); /* update FDT to reflect changes in CPU resources */ if (update_cpus_node(fdt)) pr_err("Failed to update crash FDT"); /* The crash image is now valid once again */ - xchg(&kexec_crash_image, image); + kimage_update_compat_pointers(image, KEXEC_TYPE_CRASH); } int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags) diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index c6b12bed173d..fc561d5e058e 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -546,9 +546,9 @@ void arch_crash_handle_hotplug_event(struct kimage *image, void *arg) * Temporarily invalidate the crash image while the * elfcorehdr is updated. */ - xchg(&kexec_crash_image, NULL); + kimage_update_compat_pointers(NULL, KEXEC_TYPE_CRASH); memcpy_flushcache(old_elfcorehdr, elfbuf, elfsz); - xchg(&kexec_crash_image, image); + kimage_update_compat_pointers(image, KEXEC_TYPE_CRASH); kunmap_local(old_elfcorehdr); pr_debug("updated elfcorehdr\n"); diff --git a/include/linux/kexec.h b/include/linux/kexec.h index a3ae3e561109..3bcbbacc0108 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -428,6 +428,9 @@ struct kimage { /* dm crypt keys buffer */ unsigned long dm_crypt_keys_addr; unsigned long dm_crypt_keys_sz; + + /* For multikernel support: linked list node */ + struct list_head list; }; /* kexec interface functions */ @@ -531,6 +534,19 @@ extern bool kexec_file_dbg_print; extern void *kimage_map_segment(struct kimage *image, unsigned long addr, unsigned long size); extern void kimage_unmap_segment(void *buffer); + +/* Multikernel support functions */ +extern struct kimage *kimage_find_by_type(int type); +extern void kimage_add_to_list(struct kimage *image); +extern void kimage_remove_from_list(struct kimage *image); +extern void kimage_update_compat_pointers(struct kimage *new_image, int type); +extern int kimage_get_all_by_type(int type, struct kimage **images, int max_count); +extern void kimage_list_lock(void); +extern void kimage_list_unlock(void); +extern struct kimage *kimage_find_multikernel_by_entry(unsigned long entry); +extern struct kimage *kimage_get_multikernel_by_index(int index); +extern int multikernel_kexec_by_entry(int cpu, unsigned long entry); +extern void kimage_list_multikernel_images(void); #else /* !CONFIG_KEXEC_CORE */ struct pt_regs; struct task_struct; diff --git a/kernel/kexec.c b/kernel/kexec.c index 49e62f804674..3d37925ee15a 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -147,7 +147,31 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, if (nr_segments == 0) { /* Uninstall image */ - kimage_free(xchg(dest_image, NULL)); + if (flags & KEXEC_ON_CRASH) { + struct kimage *old_image = xchg(&kexec_crash_image, NULL); + if (old_image) { + kimage_remove_from_list(old_image); + kimage_free(old_image); + } + } else if (flags & KEXEC_MULTIKERNEL) { + /* For multikernel unload, we need to specify which image to remove */ + /* For now, remove all multikernel images - this could be enhanced */ + struct kimage *images[10]; + int count, i; + + count = kimage_get_all_by_type(KEXEC_TYPE_MULTIKERNEL, images, 10); + for (i = 0; i < count; i++) { + kimage_remove_from_list(images[i]); + kimage_free(images[i]); + } + pr_info("Unloaded %d multikernel images\n", count); + } else { + struct kimage *old_image = xchg(&kexec_image, NULL); + if (old_image) { + kimage_remove_from_list(old_image); + kimage_free(old_image); + } + } ret = 0; goto out_unlock; } @@ -157,7 +181,11 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, * crashes. Free any current crash dump kernel before * we corrupt it. */ - kimage_free(xchg(&kexec_crash_image, NULL)); + struct kimage *old_crash_image = xchg(&kexec_crash_image, NULL); + if (old_crash_image) { + kimage_remove_from_list(old_crash_image); + kimage_free(old_crash_image); + } } ret = kimage_alloc_init(&image, entry, nr_segments, segments, flags); @@ -199,7 +227,35 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, goto out; /* Install the new kernel and uninstall the old */ - image = xchg(dest_image, image); + if (flags & KEXEC_ON_CRASH) { + struct kimage *old_image = xchg(&kexec_crash_image, image); + if (old_image) { + kimage_remove_from_list(old_image); + kimage_free(old_image); + } + if (image) { + kimage_add_to_list(image); + kimage_update_compat_pointers(image, KEXEC_TYPE_CRASH); + } + image = NULL; /* Don't free the new image */ + } else if (flags & KEXEC_MULTIKERNEL) { + if (image) { + kimage_add_to_list(image); + pr_info("Added multikernel image to list (entry: 0x%lx)\n", image->start); + } + image = NULL; /* Don't free the new image */ + } else { + struct kimage *old_image = xchg(&kexec_image, image); + if (old_image) { + kimage_remove_from_list(old_image); + kimage_free(old_image); + } + if (image) { + kimage_add_to_list(image); + kimage_update_compat_pointers(image, KEXEC_TYPE_DEFAULT); + } + image = NULL; /* Don't free the new image */ + } out: #ifdef CONFIG_CRASH_DUMP diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 35a66c8dd78b..4e489a7031e6 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -56,6 +56,10 @@ bool kexec_in_progress = false; bool kexec_file_dbg_print; +/* Linked list of dynamically allocated kimages */ +static LIST_HEAD(kexec_image_list); +static DEFINE_MUTEX(kexec_image_mutex); + /* * When kexec transitions to the new kernel there is a one-to-one * mapping between physical and virtual addresses. On processors @@ -275,6 +279,9 @@ struct kimage *do_kimage_alloc_init(void) /* Initialize the list of unusable pages */ INIT_LIST_HEAD(&image->unusable_pages); + /* Initialize the list node for multikernel support */ + INIT_LIST_HEAD(&image->list); + #ifdef CONFIG_CRASH_HOTPLUG image->hp_action = KEXEC_CRASH_HP_NONE; image->elfcorehdr_index = -1; @@ -607,6 +614,13 @@ void kimage_free(struct kimage *image) if (!image) return; + /* Remove from linked list and update compatibility pointers */ + kimage_remove_from_list(image); + if (image == kexec_image) + kimage_update_compat_pointers(NULL, KEXEC_TYPE_DEFAULT); + else if (image == kexec_crash_image) + kimage_update_compat_pointers(NULL, KEXEC_TYPE_CRASH); + #ifdef CONFIG_CRASH_DUMP if (image->vmcoreinfo_data_copy) { crash_update_vmcoreinfo_safecopy(NULL); @@ -1123,6 +1137,72 @@ void kimage_unmap_segment(void *segment_buffer) vunmap(segment_buffer); } +void kimage_add_to_list(struct kimage *image) +{ + mutex_lock(&kexec_image_mutex); + list_add_tail(&image->list, &kexec_image_list); + mutex_unlock(&kexec_image_mutex); +} + +void kimage_remove_from_list(struct kimage *image) +{ + mutex_lock(&kexec_image_mutex); + if (!list_empty(&image->list)) + list_del_init(&image->list); + mutex_unlock(&kexec_image_mutex); +} + +struct kimage *kimage_find_by_type(int type) +{ + struct kimage *image; + + mutex_lock(&kexec_image_mutex); + list_for_each_entry(image, &kexec_image_list, list) { + if (image->type == type) { + mutex_unlock(&kexec_image_mutex); + return image; + } + } + mutex_unlock(&kexec_image_mutex); + return NULL; +} + +void kimage_update_compat_pointers(struct kimage *new_image, int type) +{ + mutex_lock(&kexec_image_mutex); + if (type == KEXEC_TYPE_CRASH) { + kexec_crash_image = new_image; + } else if (type == KEXEC_TYPE_DEFAULT) { + kexec_image = new_image; + } + mutex_unlock(&kexec_image_mutex); +} + +int kimage_get_all_by_type(int type, struct kimage **images, int max_count) +{ + struct kimage *image; + int count = 0; + + mutex_lock(&kexec_image_mutex); + list_for_each_entry(image, &kexec_image_list, list) { + if (image->type == type && count < max_count) { + images[count++] = image; + } + } + mutex_unlock(&kexec_image_mutex); + return count; +} + +void kimage_list_lock(void) +{ + mutex_lock(&kexec_image_mutex); +} + +void kimage_list_unlock(void) +{ + mutex_unlock(&kexec_image_mutex); +} + struct kexec_load_limit { /* Mutex protects the limit count. */ struct mutex mutex; @@ -1139,6 +1219,7 @@ static struct kexec_load_limit load_limit_panic = { .limit = -1, }; +/* Compatibility: maintain pointers to current default and crash images */ struct kimage *kexec_image; struct kimage *kexec_crash_image; static int kexec_load_disabled; @@ -1339,8 +1420,49 @@ int kernel_kexec(void) return error; } +/* + * Find a multikernel image by entry point + */ +struct kimage *kimage_find_multikernel_by_entry(unsigned long entry) +{ + struct kimage *image; + + kimage_list_lock(); + list_for_each_entry(image, &kexec_image_list, list) { + if (image->type == KEXEC_TYPE_MULTIKERNEL && image->start == entry) { + kimage_list_unlock(); + return image; + } + } + kimage_list_unlock(); + return NULL; +} + +/* + * Get multikernel image by index (0-based) + */ +struct kimage *kimage_get_multikernel_by_index(int index) +{ + struct kimage *image; + int count = 0; + + kimage_list_lock(); + list_for_each_entry(image, &kexec_image_list, list) { + if (image->type == KEXEC_TYPE_MULTIKERNEL) { + if (count == index) { + kimage_list_unlock(); + return image; + } + count++; + } + } + kimage_list_unlock(); + return NULL; +} + int multikernel_kexec(int cpu) { + struct kimage *mk_image; int rc; pr_info("multikernel kexec: cpu %d\n", cpu); @@ -1352,13 +1474,52 @@ int multikernel_kexec(int cpu) if (!kexec_trylock()) return -EBUSY; - if (!kexec_image) { + + mk_image = kimage_find_by_type(KEXEC_TYPE_MULTIKERNEL); + if (!mk_image) { + pr_err("No multikernel image loaded\n"); rc = -EINVAL; goto unlock; } + pr_info("Found multikernel image with entry point: 0x%lx\n", mk_image->start); + + cpus_read_lock(); + rc = multikernel_kick_ap(cpu, mk_image->start); + cpus_read_unlock(); + +unlock: + kexec_unlock(); + return rc; +} + +int multikernel_kexec_by_entry(int cpu, unsigned long entry) +{ + struct kimage *mk_image; + int rc; + + pr_info("multikernel kexec: cpu %d, entry 0x%lx\n", cpu, entry); + + if (cpu_online(cpu)) { + pr_err("The CPU is currently running with this kernel instance."); + return -EBUSY; + } + + if (!kexec_trylock()) + return -EBUSY; + + /* Find the specific multikernel image by entry point */ + mk_image = kimage_find_multikernel_by_entry(entry); + if (!mk_image) { + pr_err("No multikernel image found with entry point 0x%lx\n", entry); + rc = -EINVAL; + goto unlock; + } + + pr_info("Using multikernel image with entry point: 0x%lx\n", mk_image->start); + cpus_read_lock(); - rc = multikernel_kick_ap(cpu, kexec_image->start); + rc = multikernel_kick_ap(cpu, mk_image->start); cpus_read_unlock(); unlock: diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 91d46502a817..d4b8831eb59c 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -399,8 +399,13 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, * same memory where old crash kernel might be loaded. Free any * current crash dump kernel before we corrupt it. */ - if (flags & KEXEC_FILE_ON_CRASH) - kimage_free(xchg(&kexec_crash_image, NULL)); + if (flags & KEXEC_FILE_ON_CRASH) { + struct kimage *old_crash_image = xchg(&kexec_crash_image, NULL); + if (old_crash_image) { + kimage_remove_from_list(old_crash_image); + kimage_free(old_crash_image); + } + } ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, cmdline_len, flags); @@ -456,7 +461,29 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, */ kimage_file_post_load_cleanup(image); exchange: - image = xchg(dest_image, image); + if (image_type == KEXEC_TYPE_CRASH) { + struct kimage *old_image = xchg(&kexec_crash_image, image); + if (old_image) { + kimage_remove_from_list(old_image); + kimage_free(old_image); + } + if (image) { + kimage_add_to_list(image); + kimage_update_compat_pointers(image, KEXEC_TYPE_CRASH); + } + image = NULL; /* Don't free the new image */ + } else { + struct kimage *old_image = xchg(&kexec_image, image); + if (old_image) { + kimage_remove_from_list(old_image); + kimage_free(old_image); + } + if (image) { + kimage_add_to_list(image); + kimage_update_compat_pointers(image, KEXEC_TYPE_DEFAULT); + } + image = NULL; /* Don't free the new image */ + } out: #ifdef CONFIG_CRASH_DUMP if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) -- 2.34.1
