Many distros are shipping raw kernel images (i.e. vmlinux.efi).
Support booting such image by parsing header as per Linux's
specification [1].
[1]: https://docs.kernel.org/arch/loongarch/booting.html
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
It is based on my previous booting protocol patch
---
hw/loongarch/boot.c | 45
+++++++++++++++++++++++++++++++++++++++++++++
include/hw/loongarch/boot.h | 17 +++++++++++++++++
2 files changed, 62 insertions(+)
diff --git a/hw/loongarch/boot.c b/hw/loongarch/boot.c
index
93847b0eaf8e50ce1a990b91267780e6785e1c2f..5bc889c51fafa9c6d37426b9bee9709c12183927
100644
--- a/hw/loongarch/boot.c
+++ b/hw/loongarch/boot.c
@@ -260,6 +260,43 @@ static uint64_t cpu_loongarch_virt_to_phys(void *opaque,
uint64_t addr)
return addr & MAKE_64BIT_MASK(0, TARGET_PHYS_ADDR_SPACE_BITS);
}
+static int64_t get_linux_image_info(struct loongarch_boot_info *info,
+ uint64_t *kernel_entry,
+ uint64_t *kernel_low,
+ uint64_t *kernel_high)
+{
+ int fd;
+ struct loongarch_linux_hdr hdr;
+ int64_t kernel_size = -1;
+
+ fd = open(info->kernel_filename, O_RDONLY | O_BINARY);
+ if (fd < 0) {
+ return -1;
+ }
+
+ if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) {
+ close(fd);
+ return -1;
+ }
+
+ if ((le32_to_cpu(hdr.mz_magic) & 0xffff) != MZ_MAGIC ||
+ le32_to_cpu(hdr.linux_pe_magic) != LINUX_PE_MAGIC) {
+ close(fd);
+ return -1;
+ }
+
+ *kernel_entry = le64_to_cpu(hdr.kernel_entry);
+ /* Early kernel versions may have those fields in virtual address */
+ *kernel_entry &= MAKE_64BIT_MASK(0, TARGET_PHYS_ADDR_SPACE_BITS);
+ *kernel_low = le64_to_cpu(hdr.load_offset);
+ *kernel_low &= MAKE_64BIT_MASK(0, TARGET_PHYS_ADDR_SPACE_BITS);
+ kernel_size = le64_to_cpu(hdr.kernel_size);
+ *kernel_high = *kernel_low + kernel_size;
+
+ close(fd);
+ return kernel_size;
+}
+
static int64_t load_kernel_info(struct loongarch_boot_info *info)
{
uint64_t kernel_entry, kernel_low, kernel_high;
@@ -270,6 +307,14 @@ static int64_t load_kernel_info(struct loongarch_boot_info
*info)
&kernel_entry, &kernel_low,
&kernel_high, NULL, 0,
EM_LOONGARCH, 1, 0);
+ if (kernel_size < 0) {
+ kernel_size = get_linux_image_info(info, &kernel_entry,
+ &kernel_low, &kernel_high);
+ if (kernel_size >= 0) {
+ kernel_size = load_image_targphys(info->kernel_filename,
+ kernel_low, kernel_size);
+ }
+ }
if (kernel_size < 0) {
error_report("could not load kernel '%s': %s",
diff --git a/include/hw/loongarch/boot.h b/include/hw/loongarch/boot.h
index
96ec15016a314499acf65c6c47e0c4932aa99d01..5e8bd4dd73bbb27abccfa1fa577df52aed15b6a2
100644
--- a/include/hw/loongarch/boot.h
+++ b/include/hw/loongarch/boot.h
@@ -8,6 +8,23 @@
#ifndef HW_LOONGARCH_BOOT_H
#define HW_LOONGARCH_BOOT_H
+/* Linux Image Format */
+#define LINUX_PE_MAGIC 0x818223cd
+#define MZ_MAGIC 0x5a4d /* "MZ" */
+
+struct loongarch_linux_hdr {
+ uint32_t mz_magic;
+ uint32_t res0;
+ uint64_t kernel_entry;
+ uint64_t kernel_size;
+ uint64_t load_offset;
+ uint64_t res1;
+ uint64_t res2;
+ uint64_t res3;
+ uint32_t linux_pe_magic;
+ uint32_t pe_header_offset;
+} QEMU_PACKED;
+
/* UEFI 2.10 */
#define EFI_SYSTEM_TABLE_SIGNATURE 0x5453595320494249
#define EFI_2_100_SYSTEM_TABLE_REVISION ((2<<16) | (100))
---
base-commit: c69612063e1844b76ac01e3a781b979548c3585c
change-id: 20241222-la-direct-kernel-boot-c598264710e7
Best regards,