diff options
Diffstat (limited to 'arch/arm64/kernel/machine_kexec_file.c')
| -rw-r--r-- | arch/arm64/kernel/machine_kexec_file.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c new file mode 100644 index 000000000000..3c2c8a687149 --- /dev/null +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -0,0 +1,223 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * kexec_file for arm64 + * + * Copyright (C) 2018 Linaro Limited + * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> + * + * Most code is derived from arm64 port of kexec-tools + */ + +#define pr_fmt(fmt) "kexec_file: " fmt + +#include <linux/ioport.h> +#include <linux/kernel.h> +#include <linux/kexec.h> +#include <linux/libfdt.h> +#include <linux/memblock.h> +#include <linux/of_fdt.h> +#include <linux/random.h> +#include <linux/string.h> +#include <linux/types.h> +#include <asm/byteorder.h> + +/* relevant device tree properties */ +#define FDT_PROP_INITRD_START "linux,initrd-start" +#define FDT_PROP_INITRD_END "linux,initrd-end" +#define FDT_PROP_BOOTARGS "bootargs" +#define FDT_PROP_KASLR_SEED "kaslr-seed" + +const struct kexec_file_ops * const kexec_file_loaders[] = { + &kexec_image_ops, + NULL +}; + +int arch_kimage_file_post_load_cleanup(struct kimage *image) +{ + vfree(image->arch.dtb); + image->arch.dtb = NULL; + + return kexec_image_post_load_cleanup_default(image); +} + +static int setup_dtb(struct kimage *image, + unsigned long initrd_load_addr, unsigned long initrd_len, + char *cmdline, void *dtb) +{ + int off, ret; + + ret = fdt_path_offset(dtb, "/chosen"); + if (ret < 0) + goto out; + + off = ret; + + /* add bootargs */ + if (cmdline) { + ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline); + if (ret) + goto out; + } else { + ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS); + if (ret && (ret != -FDT_ERR_NOTFOUND)) + goto out; + } + + /* add initrd-* */ + if (initrd_load_addr) { + ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START, + initrd_load_addr); + if (ret) + goto out; + + ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END, + initrd_load_addr + initrd_len); + if (ret) + goto out; + } else { + ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START); + if (ret && (ret != -FDT_ERR_NOTFOUND)) + goto out; + + ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END); + if (ret && (ret != -FDT_ERR_NOTFOUND)) + goto out; + } + + /* add kaslr-seed */ + ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED); + if (ret && (ret != -FDT_ERR_NOTFOUND)) + goto out; + + if (rng_is_initialized()) { + u64 seed = get_random_u64(); + ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed); + if (ret) + goto out; + } else { + pr_notice("RNG is not initialised: omitting \"%s\" property\n", + FDT_PROP_KASLR_SEED); + } + +out: + if (ret) + return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL; + + return 0; +} + +/* + * More space needed so that we can add initrd, bootargs and kaslr-seed. + */ +#define DTB_EXTRA_SPACE 0x1000 + +static int create_dtb(struct kimage *image, + unsigned long initrd_load_addr, unsigned long initrd_len, + char *cmdline, void **dtb) +{ + void *buf; + size_t buf_size; + int ret; + + buf_size = fdt_totalsize(initial_boot_params) + + strlen(cmdline) + DTB_EXTRA_SPACE; + + for (;;) { + buf = vmalloc(buf_size); + if (!buf) + return -ENOMEM; + + /* duplicate a device tree blob */ + ret = fdt_open_into(initial_boot_params, buf, buf_size); + if (ret) + return -EINVAL; + + ret = setup_dtb(image, initrd_load_addr, initrd_len, + cmdline, buf); + if (ret) { + vfree(buf); + if (ret == -ENOMEM) { + /* unlikely, but just in case */ + buf_size += DTB_EXTRA_SPACE; + continue; + } else { + return ret; + } + } + + /* trim it */ + fdt_pack(buf); + *dtb = buf; + + return 0; + } +} + +int load_other_segments(struct kimage *image, + unsigned long kernel_load_addr, + unsigned long kernel_size, + char *initrd, unsigned long initrd_len, + char *cmdline) +{ + struct kexec_buf kbuf; + void *dtb = NULL; + unsigned long initrd_load_addr = 0, dtb_len; + int ret = 0; + + kbuf.image = image; + /* not allocate anything below the kernel */ + kbuf.buf_min = kernel_load_addr + kernel_size; + + /* load initrd */ + if (initrd) { + kbuf.buffer = initrd; + kbuf.bufsz = initrd_len; + kbuf.mem = 0; + kbuf.memsz = initrd_len; + kbuf.buf_align = 0; + /* within 1GB-aligned window of up to 32GB in size */ + kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) + + (unsigned long)SZ_1G * 32; + kbuf.top_down = false; + + ret = kexec_add_buffer(&kbuf); + if (ret) + goto out_err; + initrd_load_addr = kbuf.mem; + + pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n", + initrd_load_addr, initrd_len, initrd_len); + } + + /* load dtb */ + ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb); + if (ret) { + pr_err("Preparing for new dtb failed\n"); + goto out_err; + } + + dtb_len = fdt_totalsize(dtb); + kbuf.buffer = dtb; + kbuf.bufsz = dtb_len; + kbuf.mem = 0; + kbuf.memsz = dtb_len; + /* not across 2MB boundary */ + kbuf.buf_align = SZ_2M; + kbuf.buf_max = ULONG_MAX; + kbuf.top_down = true; + + ret = kexec_add_buffer(&kbuf); + if (ret) + goto out_err; + image->arch.dtb = dtb; + image->arch.dtb_mem = kbuf.mem; + + pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n", + kbuf.mem, dtb_len, dtb_len); + + return 0; + +out_err: + vfree(dtb); + return ret; +} |