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Date: Sun, 18 Mar 2012 11:49:22 -0400
From: Shea Levy <shea@...alevy.com>
To: linux-kernel@...r.kernel.org
CC: "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
Matt Fleming <matt.fleming@...el.com>,
Maarten Lankhorst <m.b.lankhorst@...il.com>
Subject: Re: [RFC][PATCH 1/1] x86, efi: EFI boot stub config file support
On 3/18/12 11:45 AM, Shea Levy wrote:
> Hello,
>
> Inlined is a patch to have the kernel read its parameters from a
> config file when booted via the EFI boot stub without any parameters
> passed. This patch roughly follows the plan I discussed when proposing
> this idea, except now the file is found relative to the location of
> the bzImage and there is no additional check to see if
> image->parent_handle is NULL (despite the spec saying it will be NULL
> when the image was loaded by the firmware itself, it was never NULL on
> any of the systems I tested).
>
> Cheers,
> Shea Levy
>
> ---
>
> From 2c12b0f49831d2d96b6bdcef931794178312c288 Mon Sep 17 00:00:00 2001
> From: Shea Levy <shea@...alevy.com>
> Date: Sun, 18 Mar 2012 16:17:04 +0100
> Subject: [PATCH 1/1] x86, efi: EFI boot stub config file support
>
> 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@...alevy.com>
> ---
> 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;
Hmm, my mail client seems to have mangled the patch. I've attached it here.
View attachment "0001-x86-efi-EFI-boot-stub-config-file-support.patch" of type "text/plain" (6041 bytes)
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