Unverified Commit d7071743 authored by Atish Patra's avatar Atish Patra Committed by Palmer Dabbelt
Browse files

RISC-V: Add EFI stub support. 



Add a RISC-V architecture specific stub code that actually copies the
actual kernel image to a valid address and jump to it after boot services
are terminated. Enable UEFI related kernel configs as well for RISC-V.

Signed-off-by: default avatarAtish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20200421033336.9663-4-atish.patra@wdc.com


[ardb: - move hartid fetch into check_platform_features()
       - use image_size not reserve_size
       - select ISA_C
       - do not use dram_base]
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarPalmer Dabbelt <palmerdabbelt@google.com>
parent cb7d2dd5

arch/riscv/Kconfig

+22 −0
Original line number Diff line number Diff line
@@ -401,6 +401,26 @@ config CMDLINE_FORCE 


endchoice



config EFI_STUB

	bool



config EFI

	bool "UEFI runtime support"

	depends on OF

	select LIBFDT

	select UCS2_STRING

	select EFI_PARAMS_FROM_FDT

	select EFI_STUB

	select EFI_GENERIC_STUB

	select RISCV_ISA_C

	default y

	help

	  This option provides support for runtime services provided

	  by UEFI firmware (such as non-volatile variables, realtime

	  clock, and platform reset). A UEFI stub is also provided to

	  allow the kernel to be booted as an EFI application. This

	  is only useful on systems that have UEFI firmware.



endmenu



config BUILTIN_DTB
@@ -413,3 +433,5 @@ menu "Power management options" 
source "kernel/power/Kconfig"



endmenu



source "drivers/firmware/Kconfig"

arch/riscv/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -80,6 +80,7 @@ head-y := arch/riscv/kernel/head.o 
core-y += arch/riscv/



libs-y += arch/riscv/lib/

libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a



PHONY += vdso_install

vdso_install:

arch/riscv/configs/defconfig

+1 −0
Original line number Diff line number Diff line
@@ -130,3 +130,4 @@ CONFIG_DEBUG_BLOCK_EXT_DEVT=y 
# CONFIG_RUNTIME_TESTING_MENU is not set

CONFIG_MEMTEST=y

# CONFIG_SYSFS_SYSCALL is not set

CONFIG_EFI=y

arch/riscv/include/asm/efi.h

0 → 100644
+35 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * Copyright (C) 2020 Western Digital Corporation or its affiliates.

 */

#ifndef _ASM_EFI_H

#define _ASM_EFI_H



#include <asm/io.h>

#include <asm/mmu_context.h>

#include <asm/ptrace.h>

#include <asm/tlbflush.h>



/* on RISC-V, the FDT may be located anywhere in system RAM */

static inline unsigned long efi_get_max_fdt_addr(unsigned long image_addr)

{

	return ULONG_MAX;

}



/* Load initrd at enough distance from DRAM start */

static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)

{

	return image_addr + SZ_256M;

}



#define alloc_screen_info(x...)		(&screen_info)



static inline void free_screen_info(struct screen_info *si)

{

}



static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)

{

}



#endif /* _ASM_EFI_H */

drivers/firmware/efi/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ config EFI_GENERIC_STUB 


config EFI_ARMSTUB_DTB_LOADER

	bool "Enable the DTB loader"

	depends on EFI_GENERIC_STUB

	depends on EFI_GENERIC_STUB && !RISCV

	default y

	help

	  Select this config option to add support for the dtb= command
@@ -128,6 +128,7 @@ config EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER 
	bool "Enable the command line initrd loader" if !X86

	depends on EFI_STUB && (EFI_GENERIC_STUB || X86)

	default y

	depends on !RISCV

	help

	  Select this config option to add support for the initrd= command

	  line parameter, allowing an initrd that resides on the same volume

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