Unverified Commit 736e30af authored by Li Zhengyu's avatar Li Zhengyu Committed by Palmer Dabbelt
Browse files

RISC-V: Add purgatory 



This patch adds purgatory, the name and concept have been taken
from kexec-tools. Purgatory runs between two kernels, and do
verify sha256 hash to ensure the kernel to jump to is fine and
has not been corrupted after loading. Makefile is modified based
on x86 platform.

Signed-off-by: default avatarLi Zhengyu <lizhengyu3@huawei.com>
Link: https://lore.kernel.org/r/20220408100914.150110-6-lizhengyu3@huawei.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 8acea455

arch/riscv/Kbuild

+2 −0
Original line number Diff line number Diff line
@@ -3,5 +3,7 @@ 
obj-y += kernel/ mm/ net/

obj-$(CONFIG_BUILTIN_DTB) += boot/dts/



obj-$(CONFIG_ARCH_HAS_KEXEC_PURGATORY) += purgatory/



# for cleaning

subdir- += boot

arch/riscv/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -397,6 +397,12 @@ config KEXEC_FILE 


	  If you don't know what to do here, say Y.



config ARCH_HAS_KEXEC_PURGATORY

	def_bool KEXEC_FILE

	select BUILD_BIN2C

	depends on CRYPTO=y

	depends on CRYPTO_SHA256=y



config CRASH_DUMP

	bool "Build kdump crash kernel"

	help

arch/riscv/purgatory/.gitignore

0 → 100644
+4 −0
Original line number Diff line number Diff line 
# SPDX-License-Identifier: GPL-2.0-only

purgatory.chk

purgatory.ro

kexec-purgatory.c

arch/riscv/purgatory/Makefile

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# SPDX-License-Identifier: GPL-2.0

OBJECT_FILES_NON_STANDARD := y



purgatory-y := purgatory.o sha256.o entry.o string.o ctype.o memcpy.o memset.o



targets += $(purgatory-y)

PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y))



$(obj)/string.o: $(srctree)/lib/string.c FORCE

	$(call if_changed_rule,cc_o_c)



$(obj)/ctype.o: $(srctree)/lib/ctype.c FORCE

	$(call if_changed_rule,cc_o_c)



$(obj)/memcpy.o: $(srctree)/arch/riscv/lib/memcpy.S FORCE

	$(call if_changed_rule,as_o_S)



$(obj)/memset.o: $(srctree)/arch/riscv/lib/memset.S FORCE

	$(call if_changed_rule,as_o_S)



$(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE

	$(call if_changed_rule,cc_o_c)



CFLAGS_sha256.o := -D__DISABLE_EXPORTS

CFLAGS_string.o := -D__DISABLE_EXPORTS

CFLAGS_ctype.o := -D__DISABLE_EXPORTS



# When linking purgatory.ro with -r unresolved symbols are not checked,

# also link a purgatory.chk binary without -r to check for unresolved symbols.

PURGATORY_LDFLAGS := -e purgatory_start -z nodefaultlib

LDFLAGS_purgatory.ro := -r $(PURGATORY_LDFLAGS)

LDFLAGS_purgatory.chk := $(PURGATORY_LDFLAGS)

targets += purgatory.ro purgatory.chk



# Sanitizer, etc. runtimes are unavailable and cannot be linked here.

GCOV_PROFILE	:= n

KASAN_SANITIZE	:= n

UBSAN_SANITIZE	:= n

KCSAN_SANITIZE	:= n

KCOV_INSTRUMENT := n



# These are adjustments to the compiler flags used for objects that

# make up the standalone purgatory.ro



PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel

PURGATORY_CFLAGS := -mcmodel=medany -ffreestanding -fno-zero-initialized-in-bss

PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING

PURGATORY_CFLAGS += -fno-stack-protector -g0



# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That

# in turn leaves some undefined symbols like __fentry__ in purgatory and not

# sure how to relocate those.

ifdef CONFIG_FUNCTION_TRACER

PURGATORY_CFLAGS_REMOVE		+= $(CC_FLAGS_FTRACE)

endif



ifdef CONFIG_STACKPROTECTOR

PURGATORY_CFLAGS_REMOVE		+= -fstack-protector

endif



ifdef CONFIG_STACKPROTECTOR_STRONG

PURGATORY_CFLAGS_REMOVE		+= -fstack-protector-strong

endif



CFLAGS_REMOVE_purgatory.o	+= $(PURGATORY_CFLAGS_REMOVE)

CFLAGS_purgatory.o		+= $(PURGATORY_CFLAGS)



CFLAGS_REMOVE_sha256.o		+= $(PURGATORY_CFLAGS_REMOVE)

CFLAGS_sha256.o			+= $(PURGATORY_CFLAGS)



CFLAGS_REMOVE_string.o		+= $(PURGATORY_CFLAGS_REMOVE)

CFLAGS_string.o			+= $(PURGATORY_CFLAGS)



CFLAGS_REMOVE_ctype.o		+= $(PURGATORY_CFLAGS_REMOVE)

CFLAGS_ctype.o			+= $(PURGATORY_CFLAGS)



AFLAGS_REMOVE_entry.o		+= -Wa,-gdwarf-2

AFLAGS_REMOVE_memcpy.o		+= -Wa,-gdwarf-2

AFLAGS_REMOVE_memset.o		+= -Wa,-gdwarf-2



$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE

		$(call if_changed,ld)



$(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE

		$(call if_changed,ld)



targets += kexec-purgatory.c



quiet_cmd_bin2c = BIN2C   $@

      cmd_bin2c = $(objtree)/scripts/bin2c kexec_purgatory < $< > $@



$(obj)/kexec-purgatory.c: $(obj)/purgatory.ro $(obj)/purgatory.chk FORCE

	$(call if_changed,bin2c)



obj-$(CONFIG_ARCH_HAS_KEXEC_PURGATORY)	+= kexec-purgatory.o

arch/riscv/purgatory/entry.S

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+47 −0
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/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * purgatory: Runs between two kernels

 *

 * Copyright (C) 2022 Huawei Technologies Co, Ltd.

 *

 * Author: Li Zhengyu (lizhengyu3@huawei.com)

 *

 */



.macro	size, sym:req

	.size \sym, . - \sym

.endm



.text



.globl purgatory_start

purgatory_start:



	lla	sp, .Lstack

	mv	s0, a0	/* The hartid of the current hart */

	mv	s1, a1	/* Phys address of the FDT image */



	jal	purgatory



	/* Start new image. */

	mv	a0, s0

	mv	a1, s1

	ld	a2, riscv_kernel_entry

	jr	a2



size purgatory_start



.align 4

	.rept	256

	.quad	0

	.endr

.Lstack:



.data



.globl riscv_kernel_entry

riscv_kernel_entry:

	.quad	0

size riscv_kernel_entry



.end