Commit d162feec authored by Youling Tang's avatar Youling Tang Committed by Huacai Chen
Browse files

LoongArch: Add preparatory infrastructure for kexec_file 



Add some preparatory infrastructure:
- Add command line processing.
- Add support for loading other segments.
- Other minor modifications.

This initrd will be passed to the second kernel via the command line
'initrd=start,size'.

The 'kexec_file' command line parameter indicates that the kernel is
loaded via kexec_file.

Signed-off-by: default avatarYouling Tang <tangyouling@kylinos.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 30ade4fe

arch/loongarch/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -633,6 +633,15 @@ 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 64BIT

	depends on KEXEC_FILE

	select RELOCATABLE

	select HAVE_IMA_KEXEC if IMA



config ARCH_SUPPORTS_CRASH_DUMP

	def_bool y

arch/loongarch/include/asm/kexec.h

+10 −0
Original line number Diff line number Diff line
@@ -41,6 +41,16 @@ struct kimage_arch { 
	unsigned long systable_ptr;

};



#ifdef CONFIG_KEXEC_FILE



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,

arch/loongarch/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o



obj-$(CONFIG_UNWINDER_GUESS)	+= unwind_guess.o

arch/loongarch/kernel/machine_kexec.c

+24 −13
Original line number Diff line number Diff line
@@ -70,6 +70,15 @@ int machine_kexec_prepare(struct kimage *kimage) 
	kimage->arch.efi_boot = fw_arg0;

	kimage->arch.systable_ptr = fw_arg2;



	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))) {
@@ -83,6 +92,7 @@ int machine_kexec_prepare(struct kimage *kimage) 
			pr_err("Command line not included in the provided image\n");

			return -EINVAL;

		}

	}



	/* kexec/kdump need a safe page to save reboot_code_buffer */

	kimage->control_code_page = virt_to_page((void *)KEXEC_CONTROL_CODE);
@@ -287,9 +297,10 @@ void machine_kexec(struct kimage *image) 
	/* We do not want to be bothered. */

	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("System table at 0x%lx\n", systable_ptr);

	pr_notice("EFI boot flag: 0x%lx\n", efi_boot);

	pr_notice("Command line addr: 0x%lx\n", cmdline_ptr);

	pr_notice("Command line string: %s\n", (char *)cmdline_ptr);

	pr_notice("System table addr: 0x%lx\n", systable_ptr);

	pr_notice("We will call new kernel at 0x%lx\n", start_addr);

	pr_notice("Bye ...\n");

arch/loongarch/kernel/machine_kexec_file.c

0 → 100644
+122 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * kexec_file for LoongArch

 *

 * Author: Youling Tang <tangyouling@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[] = {

	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);

}



/* Add the "kexec_file" command line parameter to command line. */

static void cmdline_add_loader(unsigned long *cmdline_tmplen, char *modified_cmdline)

{

	int loader_strlen;



	loader_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "kexec_file ");

	*cmdline_tmplen += loader_strlen;

}



/* Add 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;

}



/*

 * Try 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)

{

	int ret = 0;

	unsigned long cmdline_tmplen = 0;

	unsigned long initrd_load_addr = 0;

	unsigned long orig_segments = image->nr_segments;

	char *modified_cmdline = NULL;

	struct kexec_buf kbuf;



	kbuf.image = image;

	/* Don't 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;



	cmdline_add_loader(&cmdline_tmplen, modified_cmdline);

	/* Ensure it's null 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 < 0)

			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 COMMAND_LINE_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;

}