On aarch64 it is the bootloader's job to uncompress the kernel. UEFI and u-boot bootloaders do this automatically when the kernel is gzip-compressed.
However the qemu -kernel option does not do this. The following command does not work: qemu-system-aarch64 [...] -kernel /boot/vmlinuz because it tries to execute the gzip-compressed data. This commit lets gzip-compressed kernels be uncompressed transparently. Currently this is only done when emulating aarch64. Signed-off-by: Richard W.M. Jones <rjo...@redhat.com> --- hw/arm/boot.c | 9 +++++++++ hw/core/loader.c | 43 +++++++++++++++++++++++++++++++++++++++++++ include/hw/loader.h | 1 + 3 files changed, 53 insertions(+) diff --git a/hw/arm/boot.c b/hw/arm/boot.c index 3d1f4a2..1d541db 100644 --- a/hw/arm/boot.c +++ b/hw/arm/boot.c @@ -444,6 +444,7 @@ static void do_cpu_reset(void *opaque) void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) { CPUState *cs = CPU(cpu); + int allow_compressed_kernels = 0; int kernel_size; int initrd_size; int is_linux = 0; @@ -465,6 +466,7 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) primary_loader = bootloader_aarch64; kernel_load_offset = KERNEL64_LOAD_ADDR; elf_machine = EM_AARCH64; + allow_compressed_kernels = 1; } else { primary_loader = bootloader; kernel_load_offset = KERNEL_LOAD_ADDR; @@ -510,6 +512,13 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info) kernel_size = load_uimage(info->kernel_filename, &entry, NULL, &is_linux); } + /* On aarch64, it's the bootloader's job to uncompress the kernel. */ + if (allow_compressed_kernels && kernel_size < 0) { + entry = info->loader_start + kernel_load_offset; + kernel_size = load_image_gzipped(info->kernel_filename, entry, + info->ram_size - kernel_load_offset); + is_linux = 1; + } if (kernel_size < 0) { entry = info->loader_start + kernel_load_offset; kernel_size = load_image_targphys(info->kernel_filename, entry, diff --git a/hw/core/loader.c b/hw/core/loader.c index 2bf6b8f..1cbe733 100644 --- a/hw/core/loader.c +++ b/hw/core/loader.c @@ -577,6 +577,49 @@ int load_ramdisk(const char *filename, hwaddr addr, uint64_t max_sz) return load_uboot_image(filename, NULL, &addr, NULL, IH_TYPE_RAMDISK); } +/* Load a gzip-compressed kernel (currently used by aarch64). */ +int load_image_gzipped(const char *filename, hwaddr addr, uint64_t max_sz) +{ + uint8_t *compressed_data = NULL; + uint8_t *data = NULL; + gsize len; + size_t max_bytes; + ssize_t bytes; + int ret = -1; + + if (!g_file_get_contents(filename, (char **) &compressed_data, &len, + NULL)) { + goto out; + } + + /* Is it a gzip-compressed file? */ + if (len < 2 || + compressed_data[0] != '\x1f' || + compressed_data[1] != '\x8b') { + goto out; + } + + max_bytes = UBOOT_MAX_GUNZIP_BYTES; + if (max_bytes > max_sz) { + max_bytes = max_sz; + } + data = g_malloc(max_bytes); + bytes = gunzip(data, max_bytes, compressed_data, len); + if (bytes < 0) { + fprintf(stderr, "%s: unable to decompress gzipped kernel file\n", + filename); + goto out; + } + + rom_add_blob_fixed(filename, data, bytes, addr); + ret = bytes; + + out: + g_free(compressed_data); + g_free(data); + return ret; +} + /* * Functions for reboot-persistent memory regions. * - used for vga bios and option roms. diff --git a/include/hw/loader.h b/include/hw/loader.h index 796cbf9..00c9117 100644 --- a/include/hw/loader.h +++ b/include/hw/loader.h @@ -15,6 +15,7 @@ int get_image_size(const char *filename); int load_image(const char *filename, uint8_t *addr); /* deprecated */ int load_image_targphys(const char *filename, hwaddr, uint64_t max_sz); +int load_image_gzipped(const char *filename, hwaddr addr, uint64_t max_sz); #define ELF_LOAD_FAILED -1 #define ELF_LOAD_NOT_ELF -2 -- 2.0.1