From: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx> Subject: kernel/kexec_file.c: allow archs to set purgatory load address For s390 new kernels are loaded to fixed addresses in memory before they are booted. With the current code this is a problem as it assumes the kernel will be loaded to an 'arbitrary' address. In particular, kexec_locate_mem_hole searches for a large enough memory region and sets the load address (kexec_bufer->mem) to it. Luckily there is a simple workaround for this problem. By returning 1 in arch_kexec_walk_mem, kexec_locate_mem_hole is turned off. This allows the architecture to set kbuf->mem by hand. While the trick works fine for the kernel it does not for the purgatory as here the architectures don't have access to its kexec_buffer. Give architectures access to the purgatories kexec_buffer by changing kexec_load_purgatory to take a pointer to it. With this change architectures have access to the buffer and can edit it as they need. A nice side effect of this change is that we can get rid of the purgatory_info->purgatory_load_address field. As now the information stored there can directly be accessed from kbuf->mem. Link: http://lkml.kernel.org/r/20180321112751.22196-11-prudo@xxxxxxxxxxxxxxxxxx Signed-off-by: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx> Reviewed-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Acked-by: Dave Young <dyoung@xxxxxxxxxx> Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/powerpc/kernel/kexec_elf_64.c | 9 ++++---- arch/x86/kernel/kexec-bzimage64.c | 8 +++---- include/linux/kexec.h | 17 +++++---------- kernel/kexec_file.c | 29 ++++++++++++++------------- 4 files changed, 31 insertions(+), 32 deletions(-) diff -puN arch/powerpc/kernel/kexec_elf_64.c~kexec_file-allow-archs-to-set-purgatory-load-address arch/powerpc/kernel/kexec_elf_64.c --- a/arch/powerpc/kernel/kexec_elf_64.c~kexec_file-allow-archs-to-set-purgatory-load-address +++ a/arch/powerpc/kernel/kexec_elf_64.c @@ -572,7 +572,7 @@ static void *elf64_load(struct kimage *i { int ret; unsigned int fdt_size; - unsigned long kernel_load_addr, purgatory_load_addr; + unsigned long kernel_load_addr; unsigned long initrd_load_addr = 0, fdt_load_addr; void *fdt; const void *slave_code; @@ -580,6 +580,8 @@ static void *elf64_load(struct kimage *i struct elf_info elf_info; struct kexec_buf kbuf = { .image = image, .buf_min = 0, .buf_max = ppc64_rma_size }; + struct kexec_buf pbuf = { .image = image, .buf_min = 0, + .buf_max = ppc64_rma_size, .top_down = true }; ret = build_elf_exec_info(kernel_buf, kernel_len, &ehdr, &elf_info); if (ret) @@ -591,14 +593,13 @@ static void *elf64_load(struct kimage *i pr_debug("Loaded the kernel at 0x%lx\n", kernel_load_addr); - ret = kexec_load_purgatory(image, 0, ppc64_rma_size, true, - &purgatory_load_addr); + ret = kexec_load_purgatory(image, &pbuf); if (ret) { pr_err("Loading purgatory failed.\n"); goto out; } - pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr); + pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem); if (initrd != NULL) { kbuf.buffer = initrd; diff -puN arch/x86/kernel/kexec-bzimage64.c~kexec_file-allow-archs-to-set-purgatory-load-address arch/x86/kernel/kexec-bzimage64.c --- a/arch/x86/kernel/kexec-bzimage64.c~kexec_file-allow-archs-to-set-purgatory-load-address +++ a/arch/x86/kernel/kexec-bzimage64.c @@ -334,7 +334,6 @@ static void *bzImage64_load(struct kimag unsigned long setup_header_size, params_cmdline_sz; struct boot_params *params; unsigned long bootparam_load_addr, kernel_load_addr, initrd_load_addr; - unsigned long purgatory_load_addr; struct bzimage64_data *ldata; struct kexec_entry64_regs regs64; void *stack; @@ -342,6 +341,8 @@ static void *bzImage64_load(struct kimag unsigned int efi_map_offset, efi_map_sz, efi_setup_data_offset; struct kexec_buf kbuf = { .image = image, .buf_max = ULONG_MAX, .top_down = true }; + struct kexec_buf pbuf = { .image = image, .buf_min = MIN_PURGATORY_ADDR, + .buf_max = ULONG_MAX, .top_down = true }; header = (struct setup_header *)(kernel + setup_hdr_offset); setup_sects = header->setup_sects; @@ -379,14 +380,13 @@ static void *bzImage64_load(struct kimag * Load purgatory. For 64bit entry point, purgatory code can be * anywhere. */ - ret = kexec_load_purgatory(image, MIN_PURGATORY_ADDR, ULONG_MAX, 1, - &purgatory_load_addr); + ret = kexec_load_purgatory(image, &pbuf); if (ret) { pr_err("Loading purgatory failed\n"); return ERR_PTR(ret); } - pr_debug("Loaded purgatory at 0x%lx\n", purgatory_load_addr); + pr_debug("Loaded purgatory at 0x%lx\n", pbuf.mem); /* diff -puN include/linux/kexec.h~kexec_file-allow-archs-to-set-purgatory-load-address include/linux/kexec.h --- a/include/linux/kexec.h~kexec_file-allow-archs-to-set-purgatory-load-address +++ a/include/linux/kexec.h @@ -114,9 +114,6 @@ struct purgatory_info { * relocation. This memory can be freed post image load. */ void *purgatory_buf; - - /* Address where purgatory is finally loaded and is executed from */ - unsigned long purgatory_load_addr; }; struct kimage; @@ -171,6 +168,12 @@ struct kexec_buf { bool top_down; }; +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, + bool get_value); +void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name); + int __weak arch_kexec_apply_relocations_add(struct purgatory_info *pi, Elf_Shdr *section, const Elf_Shdr *relsec, @@ -266,14 +269,6 @@ extern void machine_kexec_cleanup(struct extern int kernel_kexec(void); extern struct page *kimage_alloc_control_pages(struct kimage *image, unsigned int order); -extern int kexec_load_purgatory(struct kimage *image, unsigned long min, - unsigned long max, int top_down, - unsigned long *load_addr); -extern int kexec_purgatory_get_set_symbol(struct kimage *image, - const char *name, void *buf, - unsigned int size, bool get_value); -extern void *kexec_purgatory_get_symbol_addr(struct kimage *image, - const char *name); extern void __crash_kexec(struct pt_regs *); extern void crash_kexec(struct pt_regs *); int kexec_should_crash(struct task_struct *); diff -puN kernel/kexec_file.c~kexec_file-allow-archs-to-set-purgatory-load-address kernel/kexec_file.c --- a/kernel/kexec_file.c~kexec_file-allow-archs-to-set-purgatory-load-address +++ a/kernel/kexec_file.c @@ -730,8 +730,8 @@ static int kexec_purgatory_setup_kbuf(st int i, ret; sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; - bss_align = 1; - bss_sz = 0; + kbuf->buf_align = bss_align = 1; + kbuf->bufsz = bss_sz = 0; for (i = 0; i < pi->ehdr->e_shnum; i++) { if (!(sechdrs[i].sh_flags & SHF_ALLOC)) @@ -763,7 +763,6 @@ static int kexec_purgatory_setup_kbuf(st ret = kexec_add_buffer(kbuf); if (ret) goto out; - pi->purgatory_load_addr = kbuf->mem; return 0; out: @@ -901,27 +900,32 @@ static int kexec_apply_relocations(struc return 0; } -/* Load relocatable purgatory object and relocate it appropriately */ -int kexec_load_purgatory(struct kimage *image, unsigned long min, - unsigned long max, int top_down, - unsigned long *load_addr) +/* + * kexec_load_purgatory - Load and relocate the purgatory object. + * @image: Image to add the purgatory to. + * @kbuf: Memory parameters to use. + * + * Allocates the memory needed for image->purgatory_info.sechdrs and + * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible + * to free the memory after use. + * + * Return: 0 on success, negative errno on error. + */ +int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) { struct purgatory_info *pi = &image->purgatory_info; int ret; - struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1, - .buf_min = min, .buf_max = max, - .top_down = top_down }; if (kexec_purgatory_size <= 0) return -EINVAL; pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; - ret = kexec_purgatory_setup_kbuf(pi, &kbuf); + ret = kexec_purgatory_setup_kbuf(pi, kbuf); if (ret) return ret; - ret = kexec_purgatory_setup_sechdrs(pi, &kbuf); + ret = kexec_purgatory_setup_sechdrs(pi, kbuf); if (ret) goto out_free_kbuf; @@ -929,7 +933,6 @@ int kexec_load_purgatory(struct kimage * if (ret) goto out; - *load_addr = pi->purgatory_load_addr; return 0; out: vfree(pi->sechdrs); _ -- 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
