[PATCH 1/1] x86, efi: EFI boot stub config file support

[Shea Levy]

When booting via the EFI boot stub, search for a file named 'linux.conf' in
the same directory as the bzImage and read the kernel command line from it
when no load options are passed.

The file search should only be triggered when the bzImage is loaded from the
firmware's boot process. When loaded via an EFI shell, the load options always
contain at least one character, even if no parameters were passed at the
prompt.

Signed-off-by: Shea Levy <shea@xxxxxxxxxxxx>
---
 arch/x86/boot/compressed/eboot.c |  146 ++++++++++++++++++++++++++++++++++++--
 arch/x86/boot/compressed/eboot.h |    2 +
 2 files changed, 143 insertions(+), 5 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index fec216f..672ecfe 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -486,14 +486,14 @@ struct initrd {
  * kernel image.
  */
 static efi_status_t handle_ramdisks(efi_loaded_image_t *image,
-				    struct setup_header *hdr)
+				    struct setup_header *hdr,
+				    efi_file_handle_t *fh)
 {
 	struct initrd *initrds;
 	unsigned long initrd_addr;
 	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
 	u64 initrd_total;
 	efi_file_io_interface_t *io;
-	efi_file_handle_t *fh;
 	efi_status_t status;
 	int nr_initrds;
 	char *str;
@@ -568,7 +568,7 @@ static efi_status_t handle_ramdisks(efi_loaded_image_t *image,
 		*p = '\0';
 
 		/* Only open the volume once. */
-		if (!i) {
+		if (!fh) {
 			efi_boot_services_t *boottime;
 
 			boottime = sys_table->boottime;
@@ -712,6 +712,7 @@ static efi_status_t make_boot_params(struct boot_params *boot_params,
 	u16 *s2;
 	u8 *s1;
 	int i;
+	efi_file_handle_t *fh = NULL;
 
 	hdr->type_of_loader = 0x21;
 
@@ -743,14 +744,149 @@ static efi_status_t make_boot_params(struct boot_params *boot_params,
 
 			*s1 = '\0';
 		}
-	}
+	} else {
+		efi_char16_t config_file_name[
+			sizeof CONFIG_FILE_NAME * sizeof(efi_char16_t)];
+		u16 *file_path = (u16 *)image->file_path;
+		efi_char16_t config_path[256], *config_path_position;
+		efi_boot_services_t *boottime;
+		efi_file_info_t *info;
+		unsigned long info_sz = 0;
+		u64 file_sz;
+		efi_guid_t info_guid = EFI_FILE_INFO_ID;
+		efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
+		efi_file_io_interface_t *io;
+		efi_file_handle_t *h;
+
+		boottime = sys_table->boottime;
+
+		config_path_position = config_path;
+
+		for (i = 0; i < sizeof CONFIG_FILE_NAME; i++)
+			config_file_name[i] = CONFIG_FILE_NAME[i];
+
+		while (*file_path == 0x404) {
+			u16 node_size = *(file_path + 1)/sizeof *file_path;
+
+			if (config_path_position - config_path) {
+				if (*(file_path + 2) == '\\' &&
+						*(file_path - 2) == '\\') {
+					config_path_position--;
+				} else if (*(file_path + 2) != '\\' &&
+						*(file_path - 2) != '\\') {
+					*config_path_position++ = '\\';
+				}
+			}
+
+			if ((config_path_position - config_path) + node_size - 3
+					+ sizeof config_file_name
+					/ sizeof *config_file_name
+					> sizeof config_path
+					/ sizeof *config_path)
+				goto end;
+
+			memcpy((void *)config_path_position, file_path + 2,
+					(node_size - 3) * sizeof *config_path);
 
+			config_path_position += node_size - 3;
+			file_path += node_size;
+		}
+
+		while (*config_path_position != '\\' && config_path_position !=
+				config_path)
+			config_path_position--;
+
+		*config_path_position = '\\';
+
+		memcpy((void *)(config_path_position + 1),
+				config_file_name,
+				sizeof config_file_name);
+
+		status = efi_call_phys3(boottime->handle_protocol,
+				image->device_handle, &fs_proto, &io);
+
+		if (status != EFI_SUCCESS)
+			goto end;
+
+		status = efi_call_phys2(io->open_volume, io, &fh);
+
+		if (status != EFI_SUCCESS) {
+			fh = NULL;
+			goto end;
+		}
+
+		status = efi_call_phys5(fh->open,
+				fh,
+				&h,
+				config_path,
+				EFI_FILE_MODE_READ, (u64)0);
+
+		if (status != EFI_SUCCESS)
+			goto end;
+
+		status = efi_call_phys4(h->get_info, h, &info_guid,
+					&info_sz, NULL);
+
+		if (status != EFI_BUFFER_TOO_SMALL)
+			goto close_config_file;
+
+		while (status == EFI_BUFFER_TOO_SMALL) {
+			status = efi_call_phys3(boottime->allocate_pool,
+					EFI_LOADER_DATA, info_sz, &info);
+
+			if (status != EFI_SUCCESS)
+				goto close_config_file;
+
+			status = efi_call_phys4(h->get_info, h, &info_guid,
+						&info_sz, info);
+
+			if (status == EFI_BUFFER_TOO_SMALL)
+				efi_call_phys1(boottime->free_pool, info);
+		}
+
+		if (status != EFI_SUCCESS)
+			goto free_config_file_info;
+
+		file_sz = info->file_size;
+
+		if (file_sz > hdr->cmdline_size)
+			file_sz = hdr->cmdline_size;
+
+		options_size = file_sz + 1;
+
+		status = low_alloc(options_size, 1, &cmdline);
+
+		if (status != EFI_SUCCESS)
+			goto free_config_file_info;
+
+		status = efi_call_phys3(h->read, h, &file_sz, cmdline);
+
+		if (status != EFI_SUCCESS)
+			goto free_config_file_cmdline;
+
+		*((u8 *)cmdline + file_sz) = 0;
+
+		goto free_config_file_info;
+free_config_file_cmdline:
+		low_free(options_size, cmdline);
+		cmdline = 0;
+		options_size = 0;
+free_config_file_info:
+		efi_call_phys1(boottime->free_pool, info);
+close_config_file:
+		efi_call_phys1(h->close, h);
+	}
+end:
 	hdr->cmd_line_ptr = cmdline;
 
 	hdr->ramdisk_image = 0;
 	hdr->ramdisk_size = 0;
 
-	status = handle_ramdisks(image, hdr);
+	status = handle_ramdisks(image, hdr, fh);
+
+	if (fh)
+		efi_call_phys1(fh->close, fh);
+
 	if (status != EFI_SUCCESS)
 		goto free_cmdline;
 
diff --git a/arch/x86/boot/compressed/eboot.h b/arch/x86/boot/compressed/eboot.h
index 3925166..186b4c6 100644
--- a/arch/x86/boot/compressed/eboot.h
+++ b/arch/x86/boot/compressed/eboot.h
@@ -20,6 +20,8 @@
 #define PIXEL_BLT_ONLY					3
 #define PIXEL_FORMAT_MAX				4
 
+#define CONFIG_FILE_NAME "linux.conf"
+
 struct efi_pixel_bitmask {
 	u32 red_mask;
 	u32 green_mask;
-- 
1.7.9.4


--------------030304090700030201070807--
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/