On Sun, Aug 3, 2014 at 1:45 AM, Richard W.M. Jones <rjo...@redhat.com> wrote:
> 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 +
There's two patches here, one adding the generic gzip loader (which
has wider review audience than just ARM people), and a second one
adding the AArch64 usage.
> 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). */
No need to refer to "aarch64" in generic code (this comment is likely
to go stale).
> +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;
Why does u-boot's maximum size limit apply here?
Regards,
Peter
> + 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
>
>
