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efi: libstub: Factor out EFI stub entrypoint into separate file 

In preparation for allowing the EFI zboot decompressor to reuse most of
the EFI stub machinery, factor out the actual EFI PE/COFF entrypoint
into a separate file.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2022-10-12 12:55:11 +02:00
parent da8dd0c75b
commit 42c8ea3dca
4 changed files with 100 additions and 64 deletions
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2
drivers/firmware/efi/libstub/Makefile
View File

@ -83,7 +83,7 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
$(call if_changed_rule,cc_o_c)
lib-$(CONFIG_EFI_GENERIC_STUB) += efi-stub.o string.o intrinsics.o systable.o \
screen_info.o
screen_info.o efi-stub-entry.o
lib-$(CONFIG_ARM) += arm32-stub.o
lib-$(CONFIG_ARM64) += arm64-stub.o arm64-entry.o

65
drivers/firmware/efi/libstub/efi-stub-entry.c Normal file
View File

@ -0,0 +1,65 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/efi.h>
#include <asm/efi.h>
#include "efistub.h"
/*
* EFI entry point for the generic EFI stub used by ARM, arm64, RISC-V and
* LoongArch. This is the entrypoint that is described in the PE/COFF header
* of the core kernel.
*/
efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
efi_system_table_t *systab)
{
efi_loaded_image_t *image;
efi_status_t status;
unsigned long image_addr;
unsigned long image_size = 0;
/* addr/point and size pairs for memory management*/
char *cmdline_ptr = NULL;
efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
unsigned long reserve_addr = 0;
unsigned long reserve_size = 0;
WRITE_ONCE(efi_system_table, systab);
/* Check if we were booted by the EFI firmware */
if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
return EFI_INVALID_PARAMETER;
/*
* Get a handle to the loaded image protocol. This is used to get
* information about the running image, such as size and the command
* line.
*/
status = efi_bs_call(handle_protocol, handle, &loaded_image_proto,
(void *)&image);
if (status != EFI_SUCCESS) {
efi_err("Failed to get loaded image protocol\n");
return status;
}
status = efi_handle_cmdline(image, &cmdline_ptr);
if (status != EFI_SUCCESS)
return status;
efi_info("Booting Linux Kernel...\n");
status = handle_kernel_image(&image_addr, &image_size,
&reserve_addr,
&reserve_size,
image, handle);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");
return status;
}
status = efi_stub_common(handle, image, image_addr, cmdline_ptr);
efi_free(image_size, image_addr);
efi_free(reserve_size, reserve_addr);
return status;
}

89
drivers/firmware/efi/libstub/efi-stub.c
View File

@ -115,61 +115,21 @@ static u32 get_supported_rt_services(void)
return supported;
}
/*
* EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
* that is described in the PE/COFF header. Most of the code is the same
* for both archictectures, with the arch-specific code provided in the
* handle_kernel_image() function.
*/
efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
efi_system_table_t *sys_table_arg)
efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr)
{
efi_loaded_image_t *image;
efi_status_t status;
unsigned long image_addr;
unsigned long image_size = 0;
/* addr/point and size pairs for memory management*/
char *cmdline_ptr = NULL;
int cmdline_size = 0;
efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
unsigned long reserve_addr = 0;
unsigned long reserve_size = 0;
struct screen_info *si;
efi_system_table = sys_table_arg;
/* Check if we were booted by the EFI firmware */
if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) {
status = EFI_INVALID_PARAMETER;
goto fail;
}
status = check_platform_features();
if (status != EFI_SUCCESS)
goto fail;
/*
* Get a handle to the loaded image protocol. This is used to get
* information about the running image, such as size and the command
* line.
*/
status = efi_bs_call(handle_protocol, handle, &loaded_image_proto,
(void *)&image);
if (status != EFI_SUCCESS) {
efi_err("Failed to get loaded image protocol\n");
goto fail;
}
efi_status_t status;
char *cmdline;
/*
* Get the command line from EFI, using the LOADED_IMAGE
* protocol. We are going to copy the command line into the
* device tree, so this can be allocated anywhere.
*/
cmdline_ptr = efi_convert_cmdline(image, &cmdline_size);
if (!cmdline_ptr) {
cmdline = efi_convert_cmdline(image, &cmdline_size);
if (!cmdline) {
efi_err("getting command line via LOADED_IMAGE_PROTOCOL\n");
status = EFI_OUT_OF_RESOURCES;
goto fail;
return EFI_OUT_OF_RESOURCES;
}
if (IS_ENABLED(CONFIG_CMDLINE_EXTEND) ||
@ -183,26 +143,35 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
}
if (!IS_ENABLED(CONFIG_CMDLINE_FORCE) && cmdline_size > 0) {
status = efi_parse_options(cmdline_ptr);
status = efi_parse_options(cmdline);
if (status != EFI_SUCCESS) {
efi_err("Failed to parse options\n");
goto fail_free_cmdline;
}
}
efi_info("Booting Linux Kernel...\n");
*cmdline_ptr = cmdline;
return EFI_SUCCESS;
fail_free_cmdline:
efi_bs_call(free_pool, cmdline_ptr);
return status;
}
efi_status_t efi_stub_common(efi_handle_t handle,
efi_loaded_image_t *image,
unsigned long image_addr,
char *cmdline_ptr)
{
struct screen_info *si;
efi_status_t status;
status = check_platform_features();
if (status != EFI_SUCCESS)
return status;
si = setup_graphics();
status = handle_kernel_image(&image_addr, &image_size,
&reserve_addr,
&reserve_size,
image, handle);
if (status != EFI_SUCCESS) {
efi_err("Failed to relocate kernel\n");
goto fail_free_screeninfo;
}
efi_retrieve_tpm2_eventlog();
/* Ask the firmware to clear memory on unclean shutdown */
@ -221,13 +190,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
status = efi_boot_kernel(handle, image, image_addr, cmdline_ptr);
efi_free(image_size, image_addr);
efi_free(reserve_size, reserve_addr);
fail_free_screeninfo:
free_screen_info(si);
fail_free_cmdline:
efi_bs_call(free_pool, cmdline_ptr);
fail:
return status;
}

8
drivers/firmware/efi/libstub/efistub.h
View File

@ -958,6 +958,14 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
efi_loaded_image_t *image,
efi_handle_t image_handle);
/* shared entrypoint between the normal stub and the zboot stub */
efi_status_t efi_stub_common(efi_handle_t handle,
efi_loaded_image_t *image,
unsigned long image_addr,
char *cmdline_ptr);
efi_status_t efi_handle_cmdline(efi_loaded_image_t *image, char **cmdline_ptr);
asmlinkage void __noreturn efi_enter_kernel(unsigned long entrypoint,
unsigned long fdt_addr,
unsigned long fdt_size);