From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Subject: x86: kexec_file: purge system-ram walking from prepare_elf64_headers() While prepare_elf64_headers() in x86 looks pretty generic for other architectures' use, it contains some code which tries to list crash memory regions by walking through system resources, which is not always architecture agnostic. To make this function more generic, the related code should be purged. In this patch, prepare_elf64_headers() simply scans crash_mem buffer passed and add all the listed regions to elf header as a PT_LOAD segment. So walk_system_ram_res(prepare_elf64_headers_callback) have been moved forward before prepare_elf64_headers() where the callback, prepare_elf64_headers_callback(), is now responsible for filling up crash_mem buffer. Meanwhile exclude_elf_header_ranges() used to be called every time in this callback it is rather redundant and now called only once in prepare_elf_headers() as well. Link: http://lkml.kernel.org/r/20180306102303.9063-4-takahiro.akashi@xxxxxxxxxx Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Acked-by: Dave Young <dyoung@xxxxxxxxxx> Tested-by: Dave Young <dyoung@xxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Cc: Baoquan He <bhe@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/crash.c | 121 ++++++++++++++++++-------------------- 1 file changed, 58 insertions(+), 63 deletions(-) diff -puN arch/x86/kernel/crash.c~x86-kexec_file-purge-system-ram-walking-from-prepare_elf64_headers arch/x86/kernel/crash.c --- a/arch/x86/kernel/crash.c~x86-kexec_file-purge-system-ram-walking-from-prepare_elf64_headers +++ a/arch/x86/kernel/crash.c @@ -317,18 +317,11 @@ static int exclude_mem_range(struct cras * Look for any unwanted ranges between mstart, mend and remove them. This * might lead to split and split ranges are put in ced->mem.ranges[] array */ -static int elf_header_exclude_ranges(struct crash_elf_data *ced, - unsigned long long mstart, unsigned long long mend) +static int elf_header_exclude_ranges(struct crash_elf_data *ced) { struct crash_mem *cmem = &ced->mem; int ret = 0; - memset(cmem->ranges, 0, sizeof(cmem->ranges)); - - cmem->ranges[0].start = mstart; - cmem->ranges[0].end = mend; - cmem->nr_ranges = 1; - /* Exclude crashkernel region */ ret = exclude_mem_range(cmem, crashk_res.start, crashk_res.end); if (ret) @@ -346,53 +339,13 @@ static int elf_header_exclude_ranges(str static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) { struct crash_elf_data *ced = arg; - Elf64_Ehdr *ehdr; - Elf64_Phdr *phdr; - unsigned long mstart, mend; - struct kimage *image = ced->image; - struct crash_mem *cmem; - int ret, i; - - ehdr = ced->ehdr; - - /* Exclude unwanted mem ranges */ - ret = elf_header_exclude_ranges(ced, res->start, res->end); - if (ret) - return ret; - - /* Go through all the ranges in ced->mem.ranges[] and prepare phdr */ - cmem = &ced->mem; - - for (i = 0; i < cmem->nr_ranges; i++) { - mstart = cmem->ranges[i].start; - mend = cmem->ranges[i].end; - - phdr = ced->bufp; - ced->bufp += sizeof(Elf64_Phdr); - - phdr->p_type = PT_LOAD; - phdr->p_flags = PF_R|PF_W|PF_X; - phdr->p_offset = mstart; + struct crash_mem *cmem = &ced->mem; - /* - * If a range matches backup region, adjust offset to backup - * segment. - */ - if (mstart == image->arch.backup_src_start && - (mend - mstart + 1) == image->arch.backup_src_sz) - phdr->p_offset = image->arch.backup_load_addr; + cmem->ranges[cmem->nr_ranges].start = res->start; + cmem->ranges[cmem->nr_ranges].end = res->end; + cmem->nr_ranges++; - phdr->p_paddr = mstart; - phdr->p_vaddr = (unsigned long long) __va(mstart); - phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; - phdr->p_align = 0; - ehdr->e_phnum++; - pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n", - phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, - ehdr->e_phnum, phdr->p_offset); - } - - return ret; + return 0; } static int prepare_elf64_headers(struct crash_elf_data *ced, @@ -402,9 +355,10 @@ static int prepare_elf64_headers(struct Elf64_Phdr *phdr; unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz; unsigned char *buf, *bufp; - unsigned int cpu; + unsigned int cpu, i; unsigned long long notes_addr; - int ret; + struct crash_mem *cmem = &ced->mem; + unsigned long mstart, mend; /* extra phdr for vmcoreinfo elf note */ nr_phdr = nr_cpus + 1; @@ -473,13 +427,25 @@ static int prepare_elf64_headers(struct (ehdr->e_phnum)++; #endif - /* Prepare PT_LOAD headers for system ram chunks. */ - ced->ehdr = ehdr; - ced->bufp = bufp; - ret = walk_system_ram_res(0, -1, ced, - prepare_elf64_ram_headers_callback); - if (ret < 0) - return ret; + /* Go through all the ranges in cmem->ranges[] and prepare phdr */ + for (i = 0; i < cmem->nr_ranges; i++) { + mstart = cmem->ranges[i].start; + mend = cmem->ranges[i].end; + + phdr->p_type = PT_LOAD; + phdr->p_flags = PF_R|PF_W|PF_X; + phdr->p_offset = mstart; + + phdr->p_paddr = mstart; + phdr->p_vaddr = (unsigned long long) __va(mstart); + phdr->p_filesz = phdr->p_memsz = mend - mstart + 1; + phdr->p_align = 0; + ehdr->e_phnum++; + phdr++; + pr_debug("Crash PT_LOAD elf header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n", + phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz, + ehdr->e_phnum, phdr->p_offset); + } *addr = buf; *sz = elf_sz; @@ -491,7 +457,9 @@ static int prepare_elf_headers(struct ki unsigned long *sz) { struct crash_elf_data *ced; - int ret; + Elf64_Ehdr *ehdr; + Elf64_Phdr *phdr; + int ret, i; ced = kzalloc(sizeof(*ced), GFP_KERNEL); if (!ced) @@ -499,8 +467,35 @@ static int prepare_elf_headers(struct ki fill_up_crash_elf_data(ced, image); + ret = walk_system_ram_res(0, -1, ced, + prepare_elf64_ram_headers_callback); + if (ret) + goto out; + + /* Exclude unwanted mem ranges */ + ret = elf_header_exclude_ranges(ced); + if (ret) + goto out; + /* By default prepare 64bit headers */ ret = prepare_elf64_headers(ced, addr, sz); + if (ret) + goto out; + + /* + * If a range matches backup region, adjust offset to backup + * segment. + */ + ehdr = (Elf64_Ehdr *)*addr; + phdr = (Elf64_Phdr *)(ehdr + 1); + for (i = 0; i < ehdr->e_phnum; phdr++, i++) + if (phdr->p_type == PT_LOAD && + phdr->p_paddr == image->arch.backup_src_start && + phdr->p_memsz == image->arch.backup_src_sz) { + phdr->p_offset = image->arch.backup_load_addr; + break; + } +out: kfree(ced); return ret; } _ -- 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
