From: Youling Tang <tangyoul...@kylinos.cn>
This patch adds support for kexec_file on LoongArch.
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)
This initrd will be passed to the second kernel via the command line
'initrd=start,size'.
Currently, pez(vmlinuz.efi) and pei(vmlinux.efi) format images are supported,
but ELF format is not supported.
Signed-off-by: Youling Tang <tangyoul...@kylinos.cn>
---
arch/loongarch/Kconfig | 9 ++
arch/loongarch/include/asm/image.h | 17 +++
arch/loongarch/include/asm/kexec.h | 12 +++
arch/loongarch/kernel/Makefile | 1 +
arch/loongarch/kernel/kexec_efi.c | 111 +++++++++++++++++++
arch/loongarch/kernel/machine_kexec.c | 33 ++++--
arch/loongarch/kernel/machine_kexec_file.c | 117 +++++++++++++++++++++
7 files changed, 289 insertions(+), 11 deletions(-)
create mode 100644 arch/loongarch/kernel/kexec_efi.c
create mode 100644 arch/loongarch/kernel/machine_kexec_file.c
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index f0abc38c40ac..490dc6eed749 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -625,6 +625,15 @@ config CPU_HAS_PREFETCH
config ARCH_SUPPORTS_KEXEC
def_bool y
+config ARCH_SUPPORTS_KEXEC_FILE
+ def_bool 64BIT
+
+config ARCH_SELECTS_KEXEC_FILE
+ def_bool y
+ depends on KEXEC_FILE
+ select HAVE_IMA_KEXEC if IMA
+ select RELOCATABLE
+
config ARCH_SUPPORTS_CRASH_DUMP
def_bool y
diff --git a/arch/loongarch/include/asm/image.h
b/arch/loongarch/include/asm/image.h
index 1f090736e71d..655d5836c4e8 100644
--- a/arch/loongarch/include/asm/image.h
+++ b/arch/loongarch/include/asm/image.h
@@ -36,5 +36,22 @@ struct loongarch_image_header {
uint32_t pe_header;
};
+static const uint8_t loongarch_image_pe_sig[2] = {'M', 'Z'};
+
+/**
+ * loongarch_header_check_pe_sig - Helper to check the loongarch image header.
+ *
+ * Returns non-zero if 'MZ' signature is found.
+ */
+
+static inline int loongarch_header_check_pe_sig(const struct
loongarch_image_header *h)
+{
+ if (!h)
+ return 0;
+
+ return (h->pe_sig[0] == loongarch_image_pe_sig[0]
+ && h->pe_sig[1] == loongarch_image_pe_sig[1]);
+}
+
#endif /* __ASSEMBLY__ */
#endif /* __ASM_IMAGE_H */
diff --git a/arch/loongarch/include/asm/kexec.h
b/arch/loongarch/include/asm/kexec.h
index cf95cd3eb2de..34799db933fb 100644
--- a/arch/loongarch/include/asm/kexec.h
+++ b/arch/loongarch/include/asm/kexec.h
@@ -41,6 +41,18 @@ struct kimage_arch {
unsigned long systable_ptr;
};
+#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
+
+extern int load_other_segments(struct kimage *image,
+ unsigned long kernel_load_addr, unsigned long kernel_size,
+ char *initrd, unsigned long initrd_len,
+ char *cmdline, unsigned long cmdline_len);
+#endif
+
typedef void (*do_kexec_t)(unsigned long efi_boot,
unsigned long cmdline_ptr,
unsigned long systable_ptr,
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index 6f5a4574a911..dd6183f353e6 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -62,6 +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 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..7741f1139a12
--- /dev/null
+++ b/arch/loongarch/kernel/kexec_efi.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Load EFI vmlinux file for the kexec_file_load syscall.
+ *
+ * Author: Youling Tang <tangyoul...@kylinos.cn>
+ * 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_pe_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->image_size)
+ return ERR_PTR(-EINVAL);
+
+ /* Load the kernel */
+ 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->image_size);
+ 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.c
b/arch/loongarch/kernel/machine_kexec.c
index f9381800e291..ba8d64bc6549 100644
--- a/arch/loongarch/kernel/machine_kexec.c
+++ b/arch/loongarch/kernel/machine_kexec.c
@@ -70,18 +70,28 @@ int machine_kexec_prepare(struct kimage *kimage)
kimage->arch.efi_boot = fw_arg0;
kimage->arch.systable_ptr = fw_arg2;
- /* Find the command line */
- for (i = 0; i < kimage->nr_segments; i++) {
- if (!strncmp(bootloader, (char __user *)kimage->segment[i].buf,
strlen(bootloader))) {
- if (!copy_from_user(cmdline_ptr,
kimage->segment[i].buf, COMMAND_LINE_SIZE))
- kimage->arch.cmdline_ptr = (unsigned
long)cmdline_ptr;
- break;
+ if (kimage->file_mode == 1) {
+ /*
+ * kimage->cmdline_buf will be released in kexec_file_load, so
copy to
+ * the KEXEC_CMDLINE_ADDR safe area.
+ */
+ memcpy((void *)KEXEC_CMDLINE_ADDR, (void
*)kimage->arch.cmdline_ptr,
+ strlen((char
*)kimage->arch.cmdline_ptr) + 1);
+ kimage->arch.cmdline_ptr = (unsigned long)KEXEC_CMDLINE_ADDR;
+ } else {
+ /* Find the command line */
+ for (i = 0; i < kimage->nr_segments; i++) {
+ if (!strncmp(bootloader, (char __user
*)kimage->segment[i].buf, strlen(bootloader))) {
+ if (!copy_from_user(cmdline_ptr,
kimage->segment[i].buf, COMMAND_LINE_SIZE))
+ kimage->arch.cmdline_ptr = (unsigned
long)cmdline_ptr;
+ break;
+ }
}
- }
- if (!kimage->arch.cmdline_ptr) {
- pr_err("Command line not included in the provided image\n");
- return -EINVAL;
+ if (!kimage->arch.cmdline_ptr) {
+ pr_err("Command line not included in the provided
image\n");
+ return -EINVAL;
+ }
}
/* kexec/kdump need a safe page to save reboot_code_buffer */
@@ -288,7 +298,8 @@ void machine_kexec(struct kimage *image)
local_irq_disable();
pr_notice("EFI boot flag 0x%lx\n", efi_boot);
- pr_notice("Command line at 0x%lx\n", cmdline_ptr);
+ pr_notice("Command line addr at 0x%lx\n", cmdline_ptr);
+ pr_notice("Command line: %s\n", (char *)cmdline_ptr);
pr_notice("System table at 0x%lx\n", systable_ptr);
pr_notice("We will call new kernel at 0x%lx\n", start_addr);
pr_notice("Bye ...\n");
diff --git a/arch/loongarch/kernel/machine_kexec_file.c
b/arch/loongarch/kernel/machine_kexec_file.c
new file mode 100644
index 000000000000..a713acf32db8
--- /dev/null
+++ b/arch/loongarch/kernel/machine_kexec_file.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * kexec_file for LoongArch
+ *
+ * Author: Youling Tang <tangyoul...@kylinos.cn>
+ * Copyright (C) 2025 KylinSoft Corporation.
+ *
+ * Most code is derived from LoongArch port of kexec-tools
+ */
+
+#define pr_fmt(fmt) "kexec_file: " fmt
+
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/kexec.h>
+#include <linux/memblock.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <asm/bootinfo.h>
+
+const struct kexec_file_ops * const kexec_file_loaders[] = {
+ &kexec_efi_ops,
+ NULL
+};
+
+int arch_kimage_file_post_load_cleanup(struct kimage *image)
+{
+ vfree(image->elf_headers);
+ image->elf_headers = NULL;
+ image->elf_headers_sz = 0;
+
+ return kexec_image_post_load_cleanup_default(image);
+}
+
+/* Adds the "initrd=start,size" command line parameter to command line. */
+static void cmdline_add_initrd(struct kimage *image, unsigned long
*cmdline_tmplen,
+ char *modified_cmdline, unsigned long initrd)
+{
+ int initrd_strlen;
+
+ initrd_strlen = sprintf(modified_cmdline + (*cmdline_tmplen),
"initrd=0x%lx,0x%lx ",
+ initrd, image->initrd_buf_len);
+ *cmdline_tmplen += initrd_strlen;
+}
+
+/*
+ * Tries to add the initrd to the image. If it is not possible to find
+ * valid locations, this function will undo changes to the image and return non
+ * zero.
+ */
+int load_other_segments(struct kimage *image,
+ unsigned long kernel_load_addr,
+ unsigned long kernel_size,
+ char *initrd, unsigned long initrd_len,
+ char *cmdline, unsigned long cmdline_len)
+{
+ struct kexec_buf kbuf;
+ unsigned long orig_segments = image->nr_segments;
+ char *modified_cmdline = NULL;
+ unsigned long cmdline_tmplen = 0;
+ unsigned long initrd_load_addr = 0;
+ int ret = 0;
+
+
+ kbuf.image = image;
+ /* not allocate anything below the kernel */
+ kbuf.buf_min = kernel_load_addr + kernel_size;
+
+ modified_cmdline = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
+ if (!modified_cmdline)
+ return -EINVAL;
+
+ /* Ensure it's nul terminated */
+ modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
+
+ /* load initrd */
+ if (initrd) {
+ kbuf.buffer = initrd;
+ kbuf.bufsz = initrd_len;
+ kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+ kbuf.memsz = initrd_len;
+ kbuf.buf_align = 0;
+ /* within 1GB-aligned window of up to 32GB in size */
+ kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
+ + (unsigned long)SZ_1G * 32;
+ kbuf.top_down = false;
+
+ ret = kexec_add_buffer(&kbuf);
+ if (ret)
+ goto out_err;
+ initrd_load_addr = kbuf.mem;
+
+ kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx
memsz=0x%lx\n",
+ initrd_load_addr, kbuf.bufsz, kbuf.memsz);
+
+ /* Add the initrd=start,size parameter to the command line */
+ cmdline_add_initrd(image, &cmdline_tmplen, modified_cmdline,
initrd_load_addr);
+ }
+
+ if (cmdline_len + cmdline_tmplen > COMMAND_LINE_SIZE) {
+ pr_err("Appending command line exceeds cmdline size\n");
+ ret = -EINVAL;
+ goto out_err;
+ }
+ memcpy(modified_cmdline + cmdline_tmplen, cmdline, cmdline_len);
+ cmdline = modified_cmdline;
+ image->arch.cmdline_ptr = (unsigned long)cmdline;
+
+ return 0;
+
+out_err:
+ image->nr_segments = orig_segments;
+ kfree(modified_cmdline);
+ return ret;
+}
--
2.43.0
