summaryrefslogtreecommitdiffstats
path: root/arch/riscv/purgatory
diff options
context:
space:
mode:
Diffstat (limited to 'arch/riscv/purgatory')
-rw-r--r--arch/riscv/purgatory/.gitignore3
-rw-r--r--arch/riscv/purgatory/Makefile92
-rw-r--r--arch/riscv/purgatory/entry.S47
-rw-r--r--arch/riscv/purgatory/kexec-purgatory.S14
-rw-r--r--arch/riscv/purgatory/purgatory.c45
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 */
+ ;
+}