[PATCH v2 10/10] efi: payload: bootm: add x86 efi stub boot support.
chalianis1 at gmail.com
chalianis1 at gmail.com
Mon Sep 15 20:54:37 PDT 2025
From: Chali Anis <chalianis1 at gmail.com>
implement the efi stub boot on x86, this code is tested on qemu,
and dell latitude 7490. the EFI_ALLOCATE_MAX_PAGES cause an xfuncs
issue on real hardware so I transformed it to allocate any pages.
Signed-off-by: Chali Anis <chalianis1 at gmail.com>
---
efi/payload/bootm.c | 143 +++++++++++++-------------------------------
1 file changed, 40 insertions(+), 103 deletions(-)
diff --git a/efi/payload/bootm.c b/efi/payload/bootm.c
index ce225ab949c9..3d2eaf915f4c 100644
--- a/efi/payload/bootm.c
+++ b/efi/payload/bootm.c
@@ -133,101 +133,6 @@ static int efi_load_file_image(const char *file,
return ret;
}
-typedef void(*handover_fn)(void *image, struct efi_system_table *table,
- struct x86_setup_header *header);
-
-static inline void linux_efi_handover(efi_handle_t handle,
- struct x86_setup_header *header)
-{
- handover_fn handover;
- uintptr_t addr;
-
- addr = header->code32_start + header->handover_offset;
- if (IS_ENABLED(CONFIG_X86_64))
- addr += 512;
-
- handover = efi_phys_to_virt(addr);
- handover(handle, efi_sys_table, header);
-}
-
-static int do_bootm_efi(struct image_data *data)
-{
- void *tmp;
- void *initrd = NULL;
- size_t size;
- efi_handle_t handle;
- int ret;
- const char *options;
- struct efi_loaded_image *loaded_image;
- struct x86_setup_header *image_header, *boot_header;
-
- ret = efi_load_file_image(data->os_file, &loaded_image, &handle);
- if (ret)
- return ret;
-
- image_header = (struct x86_setup_header *)loaded_image->image_base;
-
- if (image_header->boot_flag != 0xAA55 ||
- image_header->header != 0x53726448 ||
- image_header->version < 0x20b ||
- !image_header->relocatable_kernel) {
- pr_err("Not a valid kernel image!\n");
- BS->unload_image(handle);
- return -EINVAL;
- }
-
- boot_header = xmalloc(0x4000);
- memset(boot_header, 0, 0x4000);
- memcpy(boot_header, image_header, sizeof(*image_header));
-
- /* Refer to Linux kernel commit a27e292b8a54
- * ("Documentation/x86/boot: Reserve type_of_loader=13 for barebox")
- */
- boot_header->type_of_loader = 0x13;
-
- if (data->initrd_file) {
- tmp = read_file(data->initrd_file, &size);
- initrd = xmemalign(PAGE_SIZE, PAGE_ALIGN(size));
- memcpy(initrd, tmp, size);
- memset(initrd + size, 0, PAGE_ALIGN(size) - size);
- free(tmp);
- boot_header->ramdisk_image = efi_virt_to_phys(initrd);
- boot_header->ramdisk_size = PAGE_ALIGN(size);
- }
-
- options = linux_bootargs_get();
- if (options) {
- boot_header->cmd_line_ptr = efi_virt_to_phys(options);
- boot_header->cmdline_size = strlen(options);
- }
-
- boot_header->code32_start = efi_virt_to_phys(loaded_image->image_base +
- (image_header->setup_sects+1) * 512);
-
- if (bootm_verbose(data)) {
- printf("\nStarting kernel at 0x%p", loaded_image->image_base);
- if (data->initrd_file)
- printf(", initrd at 0x%08x",
- boot_header->ramdisk_image);
- printf("...\n");
- }
-
- if (data->dryrun) {
- BS->unload_image(handle);
- free(boot_header);
- free(initrd);
- return 0;
- }
-
- efi_set_variable_usec("LoaderTimeExecUSec", &efi_systemd_vendor_guid,
- ktime_to_us(ktime_get()));
-
- shutdown_barebox();
- linux_efi_handover(handle, boot_header);
-
- return 0;
-}
-
static bool ramdisk_is_fit(struct image_data *data)
{
struct stat st;
@@ -368,9 +273,9 @@ static int efi_load_ramdisk(struct efi_image_data *e)
}
vmem = efi_allocate_pages(&mem, initrd_size,
- EFI_ALLOCATE_MAX_ADDRESS, EFI_LOADER_DATA);
+ EFI_ALLOCATE_ANY_PAGES, EFI_LOADER_DATA);
if (!vmem) {
- pr_err("Failed to allocate pages for initrd data\n");
+ pr_err("Failed to allocate pages for initrd data: %s\n", strerror(errno));
ret = -ENOMEM;
goto free_pool;
}
@@ -498,6 +403,9 @@ static int efi_load_fdt(struct efi_image_data *e)
static void efi_unload_fdt(struct efi_image_data *e)
{
+ if (IS_ENABLED(CONFIG_EFI_FDT_FORCE))
+ return;
+
BS->install_configuration_table(&efi_fdt_guid, NULL);
efi_free_pages(efi_phys_to_virt(e->oftree_res.base),
@@ -539,12 +447,33 @@ static int do_bootm_efi_stub(struct image_data *data)
return ret;
}
-static struct image_handler efi_handle_tr = {
+static int efi_app_execute(struct image_data *data)
+{
+ int ret;
+ struct efi_image_data e = { .data = data };
+ enum filetype type;
+
+ ret = efi_load_file_image(data->os_file, &e.loaded_image, &e.handle);
+ if (ret)
+ return ret;
+
+ type = file_detect_type(e.loaded_image->image_base, PAGE_SIZE);
+
+ return efi_execute_image(e.handle, e.loaded_image, type);
+}
+
+static struct image_handler efi_app_handle_tr = {
.name = "EFI Application",
- .bootm = do_bootm_efi,
+ .bootm = efi_app_execute,
.filetype = filetype_exe,
};
+static struct image_handler efi_x86_linux_handle_tr = {
+ .name = "EFI X86 Linux kernel",
+ .bootm = do_bootm_efi_stub,
+ .filetype = filetype_x86_efi_linux_image,
+};
+
static struct image_handler efi_arm64_handle_tr = {
.name = "EFI ARM64 Linux kernel",
.bootm = do_bootm_efi_stub,
@@ -594,14 +523,22 @@ static struct binfmt_hook binfmt_arm64_efi_hook = {
.hook = efi_execute,
};
+static struct binfmt_hook binfmt_x86_efi_hook = {
+ .type = filetype_x86_efi_linux_image,
+ .hook = efi_execute,
+};
+
static int efi_register_image_handler(void)
{
- register_image_handler(&efi_handle_tr);
+ register_image_handler(&efi_app_handle_tr);
binfmt_register(&binfmt_efi_hook);
-
- if (IS_ENABLED(CONFIG_X86))
+
+ if (IS_ENABLED(CONFIG_X86)) {
register_image_handler(&non_efi_handle_linux_x86);
-
+ register_image_handler(&efi_x86_linux_handle_tr);
+ binfmt_register(&binfmt_x86_efi_hook);
+ }
+
if (IS_ENABLED(CONFIG_ARM64)) {
register_image_handler(&efi_arm64_handle_tr);
binfmt_register(&binfmt_arm64_efi_hook);
--
2.34.1
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