From 8acea455fafaf2620b247de6c00774828b618a82 Mon Sep 17 00:00:00 2001 From: Li Zhengyu Date: Fri, 8 Apr 2022 18:09:12 +0800 Subject: RISC-V: Support for kexec_file on panic This patch adds support for loading a kexec on panic (kdump) kernel. It has been tested with vmcore-dmesg on riscv64 QEMU on both an smp and a non-smp system. Signed-off-by: Li Zhengyu Link: https://lore.kernel.org/r/20220408100914.150110-5-lizhengyu3@huawei.com Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/elf_kexec.c | 119 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 118 insertions(+), 1 deletion(-) (limited to 'arch/riscv') diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c index 2d442a849871..911d65d5a123 100644 --- a/arch/riscv/kernel/elf_kexec.c +++ b/arch/riscv/kernel/elf_kexec.c @@ -18,6 +18,8 @@ #include #include #include +#include +#include static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr, struct kexec_elf_info *elf_info, unsigned long old_pbase, @@ -97,6 +99,79 @@ static int elf_find_pbase(struct kimage *image, unsigned long kernel_len, return ret; } +static int get_nr_ram_ranges_callback(struct resource *res, void *arg) +{ + unsigned int *nr_ranges = arg; + + (*nr_ranges)++; + return 0; +} + +static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg) +{ + struct crash_mem *cmem = arg; + + cmem->ranges[cmem->nr_ranges].start = res->start; + cmem->ranges[cmem->nr_ranges].end = res->end; + cmem->nr_ranges++; + + return 0; +} + +static int prepare_elf_headers(void **addr, unsigned long *sz) +{ + struct crash_mem *cmem; + unsigned int nr_ranges; + int ret; + + nr_ranges = 1; /* For exclusion of crashkernel region */ + walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback); + + cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL); + if (!cmem) + return -ENOMEM; + + cmem->max_nr_ranges = nr_ranges; + cmem->nr_ranges = 0; + ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback); + if (ret) + goto out; + + /* Exclude crashkernel region */ + ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end); + if (!ret) + ret = crash_prepare_elf64_headers(cmem, true, addr, sz); + +out: + kfree(cmem); + return ret; +} + +static char *setup_kdump_cmdline(struct kimage *image, char *cmdline, + unsigned long cmdline_len) +{ + int elfcorehdr_strlen; + char *cmdline_ptr; + + cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL); + if (!cmdline_ptr) + return NULL; + + elfcorehdr_strlen = sprintf(cmdline_ptr, "elfcorehdr=0x%lx ", + image->elf_load_addr); + + if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) { + pr_err("Appending elfcorehdr= exceeds cmdline size\n"); + kfree(cmdline_ptr); + return NULL; + } + + memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len); + /* Ensure it's nul terminated */ + cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0'; + return cmdline_ptr; +} + static void *elf_kexec_load(struct kimage *image, char *kernel_buf, unsigned long kernel_len, char *initrd, unsigned long initrd_len, char *cmdline, @@ -106,10 +181,12 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf, unsigned long old_kernel_pbase = ULONG_MAX; unsigned long new_kernel_pbase = 0UL; unsigned long initrd_pbase = 0UL; - void *fdt; + unsigned long headers_sz; + void *fdt, *headers; struct elfhdr ehdr; struct kexec_buf kbuf; struct kexec_elf_info elf_info; + char *modified_cmdline = NULL; ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info); if (ret) @@ -130,6 +207,45 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf, kbuf.image = image; kbuf.buf_min = new_kernel_pbase + kernel_len; kbuf.buf_max = ULONG_MAX; + + /* Add elfcorehdr */ + if (image->type == KEXEC_TYPE_CRASH) { + ret = prepare_elf_headers(&headers, &headers_sz); + if (ret) { + pr_err("Preparing elf core header failed\n"); + goto out; + } + + kbuf.buffer = headers; + kbuf.bufsz = headers_sz; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + kbuf.memsz = headers_sz; + kbuf.buf_align = ELF_CORE_HEADER_ALIGN; + kbuf.top_down = true; + + ret = kexec_add_buffer(&kbuf); + if (ret) { + vfree(headers); + goto out; + } + image->elf_headers = headers; + image->elf_load_addr = kbuf.mem; + image->elf_headers_sz = headers_sz; + + pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", + image->elf_load_addr, kbuf.bufsz, kbuf.memsz); + + /* Setup cmdline for kdump kernel case */ + modified_cmdline = setup_kdump_cmdline(image, cmdline, + cmdline_len); + if (!modified_cmdline) { + pr_err("Setting up cmdline for kdump kernel failed\n"); + ret = -EINVAL; + goto out; + } + cmdline = modified_cmdline; + } + /* Add the initrd to the image */ if (initrd != NULL) { kbuf.buffer = initrd; @@ -170,6 +286,7 @@ static void *elf_kexec_load(struct kimage *image, char *kernel_buf, out_free_fdt: kvfree(fdt); out: + kfree(modified_cmdline); kexec_free_elf_info(&elf_info); return ret ? ERR_PTR(ret) : NULL; } -- cgit v1.2.3