From: Youling Tang <[email protected]> This patch creates kexec_efi_ops to load EFI binary file for kexec_file_load() syscall.
The efi_kexec_load() as two parts: - the first part loads the kernel image (vmlinuz.efi or vmlinux.efi) - the second part loads other segments (eg: initrd, cmdline) Currently, pez(vmlinuz.efi) and pei(vmlinux.efi) format images are supported. The basic usage (vmlinuz.efi or vmlinux.efi): 1) Load second kernel image: # kexec -s -l vmlinuz.efi --initrd=initrd.img --reuse-cmdline 2) Startup second kernel: # kexec -e Signed-off-by: Youling Tang <[email protected]> --- arch/loongarch/include/asm/image.h | 17 +++ arch/loongarch/include/asm/kexec.h | 1 + arch/loongarch/kernel/Makefile | 2 +- arch/loongarch/kernel/kexec_efi.c | 114 +++++++++++++++++++++ arch/loongarch/kernel/machine_kexec_file.c | 1 + 5 files changed, 134 insertions(+), 1 deletion(-) create mode 100644 arch/loongarch/kernel/kexec_efi.c diff --git a/arch/loongarch/include/asm/image.h b/arch/loongarch/include/asm/image.h index ff539711c9ea..982cebd31cac 100644 --- a/arch/loongarch/include/asm/image.h +++ b/arch/loongarch/include/asm/image.h @@ -32,5 +32,22 @@ struct loongarch_image_header { uint32_t pe_header; }; +static const uint8_t loongarch_image_dos_sig[2] = {'M', 'Z'}; + +/** + * loongarch_header_check_dos_sig - Helper to check the loongarch image header. + * + * Returns non-zero if 'MZ' signature is found. + */ + +static inline int loongarch_header_check_dos_sig(const struct loongarch_image_header *h) +{ + if (!h) + return 0; + + return (h->dos_sig[0] == loongarch_image_dos_sig[0] + && h->dos_sig[1] == loongarch_image_dos_sig[1]); +} + #endif /* __ASSEMBLER__ */ #endif /* __ASM_IMAGE_H */ diff --git a/arch/loongarch/include/asm/kexec.h b/arch/loongarch/include/asm/kexec.h index ed7e3fc8571e..34799db933fb 100644 --- a/arch/loongarch/include/asm/kexec.h +++ b/arch/loongarch/include/asm/kexec.h @@ -42,6 +42,7 @@ struct kimage_arch { }; #ifdef CONFIG_KEXEC_FILE +extern const struct kexec_file_ops kexec_efi_ops; int arch_kimage_file_post_load_cleanup(struct kimage *image); #define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile index 67b9b214d212..dd6183f353e6 100644 --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -62,7 +62,7 @@ obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o obj-$(CONFIG_RELOCATABLE) += relocate.o obj-$(CONFIG_KEXEC_CORE) += machine_kexec.o relocate_kernel.o -obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o +obj-$(CONFIG_KEXEC_FILE) += machine_kexec_file.o kexec_efi.o obj-$(CONFIG_CRASH_DUMP) += crash_dump.o obj-$(CONFIG_UNWINDER_GUESS) += unwind_guess.o diff --git a/arch/loongarch/kernel/kexec_efi.c b/arch/loongarch/kernel/kexec_efi.c new file mode 100644 index 000000000000..e02fd88cf5d0 --- /dev/null +++ b/arch/loongarch/kernel/kexec_efi.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Load EFI vmlinux file for the kexec_file_load syscall. + * + * Author: Youling Tang <[email protected]> + * Copyright (C) 2025 KylinSoft Corporation. + */ + +#define pr_fmt(fmt) "kexec_file(EFI): " fmt + +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/kexec.h> +#include <linux/pe.h> +#include <linux/string.h> +#include <asm/byteorder.h> +#include <asm/cpufeature.h> +#include <asm/image.h> + +static int efi_kexec_probe(const char *kernel_buf, unsigned long kernel_len) +{ + const struct loongarch_image_header *h = (const struct loongarch_image_header *)kernel_buf; + + if (!h || (kernel_len < sizeof(*h))) { + pr_err("No loongarch image header.\n"); + return -EINVAL; + } + + if (!loongarch_header_check_dos_sig(h)) { + pr_warn("No loongarch PE image header.\n"); + return -EINVAL; + } + + return 0; +} + +static void *efi_kexec_load(struct kimage *image, + char *kernel, unsigned long kernel_len, + char *initrd, unsigned long initrd_len, + char *cmdline, unsigned long cmdline_len) +{ + struct loongarch_image_header *h; + struct kexec_buf kbuf; + unsigned long text_offset, kernel_segment_number; + struct kexec_segment *kernel_segment; + int ret; + + h = (struct loongarch_image_header *)kernel; + if (!h->kernel_asize) + return ERR_PTR(-EINVAL); + + /* + * Load the kernel + * FIXME: Non-relocatable kernel rejected for kexec_file (require CONFIG_RELOCATABLE) + */ + kbuf.image = image; + kbuf.buf_max = ULONG_MAX; + kbuf.top_down = false; + + kbuf.buffer = kernel; + kbuf.bufsz = kernel_len; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + kbuf.memsz = le64_to_cpu(h->kernel_asize); + text_offset = le64_to_cpu(h->text_offset); + kbuf.buf_min = text_offset; + kbuf.buf_align = SZ_2M; + + kernel_segment_number = image->nr_segments; + + /* + * The location of the kernel segment may make it impossible to satisfy + * the other segment requirements, so we try repeatedly to find a + * location that will work. + */ + while ((ret = kexec_add_buffer(&kbuf)) == 0) { + /* Try to load additional data */ + kernel_segment = &image->segment[kernel_segment_number]; + ret = load_other_segments(image, kernel_segment->mem, + kernel_segment->memsz, initrd, + initrd_len, cmdline, cmdline_len); + if (!ret) + break; + + /* + * We couldn't find space for the other segments; erase the + * kernel segment and try the next available hole. + */ + image->nr_segments -= 1; + kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz; + kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; + } + + if (ret) { + pr_err("Could not find any suitable kernel location!"); + return ERR_PTR(ret); + } + + kernel_segment = &image->segment[kernel_segment_number]; + + /* Make sure the second kernel jumps to the correct "kernel_entry". */ + image->start = kernel_segment->mem + h->kernel_entry - text_offset; + + kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n", + kernel_segment->mem, kbuf.bufsz, + kernel_segment->memsz); + + return NULL; +} + +const struct kexec_file_ops kexec_efi_ops = { + .probe = efi_kexec_probe, + .load = efi_kexec_load, +}; diff --git a/arch/loongarch/kernel/machine_kexec_file.c b/arch/loongarch/kernel/machine_kexec_file.c index 584ce9471e93..a454e9dfc339 100644 --- a/arch/loongarch/kernel/machine_kexec_file.c +++ b/arch/loongarch/kernel/machine_kexec_file.c @@ -21,6 +21,7 @@ #include <asm/bootinfo.h> const struct kexec_file_ops * const kexec_file_loaders[] = { + &kexec_efi_ops, NULL }; -- 2.43.0
