diff options
Diffstat (limited to 'arch/riscv/purgatory')
| -rw-r--r-- | arch/riscv/purgatory/.gitignore | 3 | ||||
| -rw-r--r-- | arch/riscv/purgatory/Makefile | 92 | ||||
| -rw-r--r-- | arch/riscv/purgatory/entry.S | 47 | ||||
| -rw-r--r-- | arch/riscv/purgatory/kexec-purgatory.S | 14 | ||||
| -rw-r--r-- | arch/riscv/purgatory/purgatory.c | 45 |
5 files changed, 201 insertions, 0 deletions
diff --git a/arch/riscv/purgatory/.gitignore b/arch/riscv/purgatory/.gitignore new file mode 100644 index 000000000..6e4dfb024 --- /dev/null +++ b/arch/riscv/purgatory/.gitignore @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only +purgatory.chk +purgatory.ro diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile new file mode 100644 index 000000000..6574c91c9 --- /dev/null +++ b/arch/riscv/purgatory/Makefile @@ -0,0 +1,92 @@ +# 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 profile-guided optimization is enabled, llvm emits two different +# overlapping text sections, which is not supported by kexec. Remove profile +# optimization flags. +KBUILD_CFLAGS := $(filter-out -fprofile-sample-use=% -fprofile-use=%,$(KBUILD_CFLAGS)) + +# 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) + +asflags-remove-y += $(foreach x, -g -gdwarf-4 -gdwarf-5, $(x) -Wa,$(x)) + +$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE + $(call if_changed,ld) + +$(obj)/purgatory.chk: $(obj)/purgatory.ro FORCE + $(call if_changed,ld) + +$(obj)/kexec-purgatory.o: $(obj)/purgatory.ro $(obj)/purgatory.chk + +obj-y += kexec-purgatory.o diff --git a/arch/riscv/purgatory/entry.S b/arch/riscv/purgatory/entry.S new file mode 100644 index 000000000..0194f4554 --- /dev/null +++ b/arch/riscv/purgatory/entry.S @@ -0,0 +1,47 @@ +/* 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 diff --git a/arch/riscv/purgatory/kexec-purgatory.S b/arch/riscv/purgatory/kexec-purgatory.S new file mode 100644 index 000000000..0e9188815 --- /dev/null +++ b/arch/riscv/purgatory/kexec-purgatory.S @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + + .section .rodata, "a" + + .align 8 +kexec_purgatory: + .globl kexec_purgatory + .incbin "arch/riscv/purgatory/purgatory.ro" +.Lkexec_purgatroy_end: + + .align 8 +kexec_purgatory_size: + .globl kexec_purgatory_size + .quad .Lkexec_purgatroy_end - kexec_purgatory diff --git a/arch/riscv/purgatory/purgatory.c b/arch/riscv/purgatory/purgatory.c new file mode 100644 index 000000000..80596ab5f --- /dev/null +++ b/arch/riscv/purgatory/purgatory.c @@ -0,0 +1,45 @@ +// 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) + * + */ + +#include <linux/purgatory.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <asm/string.h> + +u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(".kexec-purgatory"); + +struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(".kexec-purgatory"); + +static int verify_sha256_digest(void) +{ + struct kexec_sha_region *ptr, *end; + struct sha256_state ss; + u8 digest[SHA256_DIGEST_SIZE]; + + sha256_init(&ss); + end = purgatory_sha_regions + ARRAY_SIZE(purgatory_sha_regions); + for (ptr = purgatory_sha_regions; ptr < end; ptr++) + sha256_update(&ss, (uint8_t *)(ptr->start), ptr->len); + sha256_final(&ss, digest); + if (memcmp(digest, purgatory_sha256_digest, sizeof(digest)) != 0) + return 1; + return 0; +} + +/* workaround for a warning with -Wmissing-prototypes */ +void purgatory(void); + +void purgatory(void) +{ + if (verify_sha256_digest()) + for (;;) + /* loop forever */ + ; +} |