/* SPDX-License-Identifier: GPL-2.0-or-later */ #include #include #include #include #include #include #include #include #define MAX_KERNEL_SIZE (64*MiB) struct arm64_kernel_header { u32 code0; u32 code1; u64 text_offset; u64 image_size; u64 flags; u64 res2; u64 res3; u64 res4; u32 magic; #define KERNEL_HEADER_MAGIC 0x644d5241 u32 res5; }; static struct { union { struct arm64_kernel_header header; u8 raw[sizeof(struct arm64_kernel_header) + 0x100]; }; #define SCRATCH_CANARY_VALUE 0xdeadbeef u32 canary; } scratch; /* Returns true if decompressing was successful and it looks like a kernel. */ static bool decompress_kernel_header(const struct fit_image_node *node) { /* Partially decompress to get text_offset. Can't check for errors. */ scratch.canary = SCRATCH_CANARY_VALUE; switch (node->compression) { case CBFS_COMPRESS_NONE: memcpy(scratch.raw, node->data, sizeof(scratch.raw)); break; case CBFS_COMPRESS_LZMA: ulzman(node->data, node->size, scratch.raw, sizeof(scratch.raw)); break; case CBFS_COMPRESS_LZ4: ulz4fn(node->data, node->size, scratch.raw, sizeof(scratch.raw)); break; default: printk(BIOS_ERR, "ERROR: Unsupported compression algorithm!\n"); return false; } /* Should never happen, but if it does we'll want to know. */ if (scratch.canary != SCRATCH_CANARY_VALUE) die("ERROR: Partial decompression ran over scratchbuf!\n"); if (scratch.header.magic != KERNEL_HEADER_MAGIC) { printk(BIOS_ERR, "ERROR: Invalid kernel magic: %#.8x\n != %#.8x\n", scratch.header.magic, KERNEL_HEADER_MAGIC); return false; } /** * Prior to v3.17, the endianness of text_offset was not specified. In * these cases image_size is zero and text_offset is 0x80000 in the * endianness of the kernel. Where image_size is non-zero image_size is * little-endian and must be respected. Where image_size is zero, * text_offset can be assumed to be 0x80000. */ if (!scratch.header.image_size) scratch.header.text_offset = cpu_to_le64(0x80000); return true; } static size_t get_kernel_size(const struct fit_image_node *node) { if (scratch.header.image_size) return le64_to_cpu(scratch.header.image_size); /** * When image_size is zero, a bootloader should attempt to keep as much * memory as possible free for use by the kernel immediately after the * end of the kernel image. The amount of space required will vary * depending on selected features, and is effectively unbound. */ printk(BIOS_WARNING, "FIT: image_size not set in kernel header.\n" "Leaving additional %u MiB of free space after kernel.\n", MAX_KERNEL_SIZE >> 20); return node->size + MAX_KERNEL_SIZE; } static bool fit_place_kernel(const struct range_entry *r, void *arg) { struct region *region = arg; resource_t start; if (range_entry_tag(r) != BM_MEM_RAM) return true; /** * The Image must be placed text_offset bytes from a 2MB aligned base * address anywhere in usable system RAM and called there. The region * between the 2 MB aligned base address and the start of the image has * no special significance to the kernel, and may be used for other * purposes. * * If the reserved memory (BL31 for example) is smaller than text_offset * we can use the 2 MiB base address, otherwise use the next 2 MiB page. * It's not mandatory, but wastes less memory below the kernel. */ start = ALIGN_DOWN(range_entry_base(r), 2 * MiB) + le64_to_cpu(scratch.header.text_offset); if (start < range_entry_base(r)) start += 2 * MiB; /** * At least image_size bytes from the start of the image must be free * for use by the kernel. */ if (start + region->size < range_entry_end(r)) { region->offset = (size_t)start; return false; } return true; } /** * Place the region in free memory range. * * The caller has to set region->offset to the minimum allowed address. * The region->offset is usually 0 on kernel >v4.6 and kernel_base + kernel_size * on kernel offset, range_entry_base(r)), 1 * MiB); if (start + region->size < range_entry_end(r)) { region->offset = (size_t)start; return false; } return true; } bool fit_payload_arch(struct prog *payload, struct fit_config_node *config, struct region *kernel, struct region *fdt, struct region *initrd) { bool place_anywhere; void *arg = NULL; if (!decompress_kernel_header(config->kernel)) { printk(BIOS_CRIT, "CRIT: Payload doesn't look like an ARM64" " kernel Image.\n"); return false; } /* Update kernel size from image header, if possible */ kernel->size = get_kernel_size(config->kernel); printk(BIOS_DEBUG, "FIT: Using kernel size of 0x%zx bytes\n", kernel->size); /** * The code assumes that bootmem_walk provides a sorted list of memory * regions, starting from the lowest address. * The order of the calls here doesn't matter, as the placement is * enforced in the called functions. * For details check code on top. */ if (!bootmem_walk(fit_place_kernel, kernel)) return false; /* Mark as reserved for future allocations. */ bootmem_add_range(kernel->offset, kernel->size, BM_MEM_PAYLOAD); /** * NOTE: versions prior to v4.6 cannot make use of memory below the * physical offset of the Image so it is recommended that the Image be * placed as close as possible to the start of system RAM. * * For kernel ramdisk) { if (place_anywhere) initrd->offset = 0; else initrd->offset = kernel->offset + kernel->size; if (!bootmem_walk(fit_place_mem, initrd)) return false; /* Mark as reserved for future allocations. */ bootmem_add_range(initrd->offset, initrd->size, BM_MEM_PAYLOAD); } /* Place FDT */ if (place_anywhere) fdt->offset = 0; else fdt->offset = kernel->offset + kernel->size; if (!bootmem_walk(fit_place_mem, fdt)) return false; /* Mark as reserved for future allocations. */ bootmem_add_range(fdt->offset, fdt->size, BM_MEM_PAYLOAD); /* Kernel expects FDT as argument */ arg = (void *)fdt->offset; prog_set_entry(payload, (void *)kernel->offset, arg); bootmem_dump_ranges(); return true; }