[PATCH v6 06/10] arm64: kexec_file: create purgatory
From: AKASHI Takahiro <hidden>
Date: 2017-10-24 06:22:16
Also in:
kexec, lkml
Subsystem:
arm64 port (aarch64 architecture), the rest · Maintainers:
Catalin Marinas, Will Deacon, Linus Torvalds
This is a basic purgatory, or a kind of glue code between the two kernels, for arm64. Since purgatory is assumed to be relocatable (not executable) object by kexec generic code, arch_kexec_apply_relocations_add() is required in general. Arm64's purgatory, however, is a simple asm and all the references can be resolved as local, no re-linking is needed here. Please note that even if we don't support digest check at purgatory we need purgatory_sha_regions and purgatory_sha256_digest as they are referenced by generic kexec code. Signed-off-by: AKASHI Takahiro <redacted> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <redacted> --- arch/arm64/Makefile | 1 + arch/arm64/purgatory/Makefile | 24 +++++++++++++++++++ arch/arm64/purgatory/entry.S | 55 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 80 insertions(+) create mode 100644 arch/arm64/purgatory/Makefile create mode 100644 arch/arm64/purgatory/entry.S
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 939b310913cf..cf39ec3baf5a 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile@@ -110,6 +110,7 @@ core-$(CONFIG_XEN) += arch/arm64/xen/ core-$(CONFIG_CRYPTO) += arch/arm64/crypto/ libs-y := arch/arm64/lib/ $(libs-y) core-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a +core-$(CONFIG_KEXEC_FILE) += arch/arm64/purgatory/ # Default target when executing plain make boot := arch/arm64/boot
diff --git a/arch/arm64/purgatory/Makefile b/arch/arm64/purgatory/Makefile
new file mode 100644
index 000000000000..c2127a2cbd51
--- /dev/null
+++ b/arch/arm64/purgatory/Makefile@@ -0,0 +1,24 @@ +OBJECT_FILES_NON_STANDARD := y + +purgatory-y := entry.o + +targets += $(purgatory-y) +PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y)) + +LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined \ + -nostdlib -z nodefaultlib +targets += purgatory.ro + +$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE + $(call if_changed,ld) + +targets += kexec_purgatory.c + +CMD_BIN2C = $(objtree)/scripts/basic/bin2c +quiet_cmd_bin2c = BIN2C $@ + cmd_bin2c = $(CMD_BIN2C) kexec_purgatory < $< > $@ + +$(obj)/kexec_purgatory.c: $(obj)/purgatory.ro FORCE + $(call if_changed,bin2c) + +obj-${CONFIG_KEXEC_FILE} += kexec_purgatory.o
diff --git a/arch/arm64/purgatory/entry.S b/arch/arm64/purgatory/entry.S
new file mode 100644
index 000000000000..fe6e968076db
--- /dev/null
+++ b/arch/arm64/purgatory/entry.S@@ -0,0 +1,55 @@ +/* + * kexec core purgatory + */ +#include <linux/linkage.h> +#include <uapi/linux/kexec.h> + +#define SHA256_DIGEST_SIZE 32 /* defined in crypto/sha.h */ + +.text + +ENTRY(purgatory_start) + /* Start new image. */ + ldr x17, __kernel_entry + ldr x0, __dtb_addr + mov x1, xzr + mov x2, xzr + mov x3, xzr + br x17 +END(purgatory_start) + +/* + * data section: + * kernel_entry and dtb_addr are global but also labelled as local, + * "__xxx:", to avoid unwanted re-linking. + * + * purgatory_sha_regions and purgatory_sha256_digest are referenced + * by kexec generic code and so must exist, but not actually used + * here because hash check is not that useful in purgatory. + */ +.align 3 + +.globl kernel_entry +kernel_entry: +__kernel_entry: + .quad 0 +END(kernel_entry) + +.globl dtb_addr +dtb_addr: +__dtb_addr: + .quad 0 +END(dtb_addr) + +.globl purgatory_sha_regions +purgatory_sha_regions: + .rept KEXEC_SEGMENT_MAX + .quad 0 + .quad 0 + .endr +END(purgatory_sha_regions) + +.globl purgatory_sha256_digest +purgatory_sha256_digest: + .skip SHA256_DIGEST_SIZE +END(purgatory_sha256_digest)
--
2.14.1