Unverified Commit 9eb9ea31 authored by Palmer Dabbelt's avatar Palmer Dabbelt
Browse files

Merge patch series "riscv: kexec_file: Support loading Image binary file" 

Björn Töpel <bjorn@kernel.org> says:

From: Björn Töpel <bjorn@rivosinc.com>

Hi!

For over a year ago, Daniel and I was testing the V2 of Song's series.
I also promised to take the V2, that had been sitting on the lists for
too long, to rebase it on a new kernel, and re-test it.

One year later, here's the V3! ;-)

There are no changes from V2 other, than some simple checkpatch
cleanups.

Song's original cover:
  | This series makes the kexec_file_load() syscall support to load
  | Image binary file. At the same time, corresponding support for
  | kexec-tools had been pushed to my repo[2].
  |
  | Now, we can leverage that kexec-tools and this series to use the
  | kexec_load() or kexec_file_load() syscall to boot both vmlinux and
  | Image file, as seen in these combo tests:
  |
  | ```
  | 1. kexec -l vmlinux
  | 2. kexec -l Image
  | 3. kexec -s -l vmlinux
  | 4. kexec -s -l Image
  | ```

Notably, kexec-tools has still not made it upstream. I've prepared a
branch on my GH [3], that I indend to post ASAP. That branch is a
collection of fixes/features, including Song's userland Image loading.

The V2 is here [2], and V1 [1].

I've tested the kexec-file/Image on qemu-rv64, with following
combinations:
 * ACPI/UEFI
 * DT/UEFI
 * DT

both "regular" kexec (-s + -e), and crashkernels (-p).

Note that there are two purgatory patches that has to be present (part
of -rc1, so all good):
  commit 28093cfe ("riscv/kexec_file: Handle R_RISCV_64 in purgatory relocator")
  commit 3f702317 ("riscv/purgatory: 4B align purgatory_start")

[1] https://lore.kernel.org/linux-riscv/20230914020044.1397356-1-songshuaishuai@tinylab.org/
[2] https://lore.kernel.org/linux-riscv/20231016092006.3347632-1-songshuaishuai@tinylab.org/
[3] https://github.com/bjoto/kexec-tools/tree/rv-on-master

* patches from https://lore.kernel.org/r/20250409193004.643839-1-bjorn@kernel.org:
  riscv: kexec_file: Support loading Image binary file
  riscv: kexec_file: Split the loading of kernel and others

Link: https://lore.kernel.org/r/20250409193004.643839-1-bjorn@kernel.org


Signed-off-by: default avatarAlexandre Ghiti <alexghiti@rivosinc.com>
Signed-off-by: default avatarPalmer Dabbelt <palmer@dabbelt.com>
parents 48d9aabf 809a11ee

arch/riscv/include/asm/image.h

+2 −0
Original line number Diff line number Diff line
@@ -30,6 +30,8 @@ 
			      RISCV_HEADER_VERSION_MINOR)



#ifndef __ASSEMBLY__

#define riscv_image_flag_field(flags, field)\

			       (((flags) >> field##_SHIFT) & field##_MASK)

/**

 * struct riscv_image_header - riscv kernel image header

 * @code0:		Executable code

arch/riscv/include/asm/kexec.h

+6 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ extern riscv_kexec_method riscv_kexec_norelocate; 


#ifdef CONFIG_KEXEC_FILE

extern const struct kexec_file_ops elf_kexec_ops;

extern const struct kexec_file_ops image_kexec_ops;



struct purgatory_info;

int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
@@ -67,6 +68,11 @@ int arch_kexec_apply_relocations_add(struct purgatory_info *pi, 
struct kimage;

int arch_kimage_file_post_load_cleanup(struct kimage *image);

#define arch_kimage_file_post_load_cleanup arch_kimage_file_post_load_cleanup



int load_extra_segments(struct kimage *image, unsigned long kernel_start,

			unsigned long kernel_len, char *initrd,

			unsigned long initrd_len, char *cmdline,

			unsigned long cmdline_len);

#endif



#endif

arch/riscv/kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -107,7 +107,7 @@ obj-$(CONFIG_HOTPLUG_CPU) += cpu-hotplug.o 
obj-$(CONFIG_PARAVIRT)		+= paravirt.o

obj-$(CONFIG_KGDB)		+= kgdb.o

obj-$(CONFIG_KEXEC_CORE)	+= kexec_relocate.o crash_save_regs.o machine_kexec.o

obj-$(CONFIG_KEXEC_FILE)	+= elf_kexec.o machine_kexec_file.o

obj-$(CONFIG_KEXEC_FILE)	+= kexec_elf.o kexec_image.o machine_kexec_file.o

obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o

obj-$(CONFIG_VMCORE_INFO)	+= vmcore_info.o

arch/riscv/kernel/elf_kexec.c

deleted100644 → 0
+0 −485
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Load ELF vmlinux file for the kexec_file_load syscall.

 *

 * Copyright (C) 2021 Huawei Technologies Co, Ltd.

 *

 * Author: Liao Chang (liaochang1@huawei.com)

 *

 * Based on kexec-tools' kexec-elf-riscv.c, heavily modified

 * for kernel.

 */



#define pr_fmt(fmt)	"kexec_image: " fmt



#include <linux/elf.h>

#include <linux/kexec.h>

#include <linux/slab.h>

#include <linux/of.h>

#include <linux/libfdt.h>

#include <linux/types.h>

#include <linux/memblock.h>

#include <linux/vmalloc.h>

#include <asm/setup.h>



int arch_kimage_file_post_load_cleanup(struct kimage *image)

{

	kvfree(image->arch.fdt);

	image->arch.fdt = NULL;



	vfree(image->elf_headers);

	image->elf_headers = NULL;

	image->elf_headers_sz = 0;



	return kexec_image_post_load_cleanup_default(image);

}



static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,

				struct kexec_elf_info *elf_info, unsigned long old_pbase,

				unsigned long new_pbase)

{

	int i;

	int ret = 0;

	size_t size;

	struct kexec_buf kbuf;

	const struct elf_phdr *phdr;



	kbuf.image = image;



	for (i = 0; i < ehdr->e_phnum; i++) {

		phdr = &elf_info->proghdrs[i];

		if (phdr->p_type != PT_LOAD)

			continue;



		size = phdr->p_filesz;

		if (size > phdr->p_memsz)

			size = phdr->p_memsz;



		kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset;

		kbuf.bufsz = size;

		kbuf.buf_align = phdr->p_align;

		kbuf.mem = phdr->p_paddr - old_pbase + new_pbase;

		kbuf.memsz = phdr->p_memsz;

		kbuf.top_down = false;

		ret = kexec_add_buffer(&kbuf);

		if (ret)

			break;

	}



	return ret;

}



/*

 * Go through the available phsyical memory regions and find one that hold

 * an image of the specified size.

 */

static int elf_find_pbase(struct kimage *image, unsigned long kernel_len,

			  struct elfhdr *ehdr, struct kexec_elf_info *elf_info,

			  unsigned long *old_pbase, unsigned long *new_pbase)

{

	int i;

	int ret;

	struct kexec_buf kbuf;

	const struct elf_phdr *phdr;

	unsigned long lowest_paddr = ULONG_MAX;

	unsigned long lowest_vaddr = ULONG_MAX;



	for (i = 0; i < ehdr->e_phnum; i++) {

		phdr = &elf_info->proghdrs[i];

		if (phdr->p_type != PT_LOAD)

			continue;



		if (lowest_paddr > phdr->p_paddr)

			lowest_paddr = phdr->p_paddr;



		if (lowest_vaddr > phdr->p_vaddr)

			lowest_vaddr = phdr->p_vaddr;

	}



	kbuf.image = image;

	kbuf.buf_min = lowest_paddr;

	kbuf.buf_max = ULONG_MAX;



	/*

	 * Current riscv boot protocol requires 2MB alignment for

	 * RV64 and 4MB alignment for RV32

	 *

	 */

	kbuf.buf_align = PMD_SIZE;

	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

	kbuf.memsz = ALIGN(kernel_len, PAGE_SIZE);

	kbuf.top_down = false;

	ret = arch_kexec_locate_mem_hole(&kbuf);

	if (!ret) {

		*old_pbase = lowest_paddr;

		*new_pbase = kbuf.mem;

		image->start = ehdr->e_entry - lowest_vaddr + kbuf.mem;

	}

	return ret;

}



#ifdef CONFIG_CRASH_DUMP

static int get_nr_ram_ranges_callback(struct resource *res, void *arg)

{

	unsigned int *nr_ranges = arg;



	(*nr_ranges)++;

	return 0;

}



static int prepare_elf64_ram_headers_callback(struct resource *res, void *arg)

{

	struct crash_mem *cmem = arg;



	cmem->ranges[cmem->nr_ranges].start = res->start;

	cmem->ranges[cmem->nr_ranges].end = res->end;

	cmem->nr_ranges++;



	return 0;

}



static int prepare_elf_headers(void **addr, unsigned long *sz)

{

	struct crash_mem *cmem;

	unsigned int nr_ranges;

	int ret;



	nr_ranges = 1; /* For exclusion of crashkernel region */

	walk_system_ram_res(0, -1, &nr_ranges, get_nr_ram_ranges_callback);



	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);

	if (!cmem)

		return -ENOMEM;



	cmem->max_nr_ranges = nr_ranges;

	cmem->nr_ranges = 0;

	ret = walk_system_ram_res(0, -1, cmem, prepare_elf64_ram_headers_callback);

	if (ret)

		goto out;



	/* Exclude crashkernel region */

	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

	if (!ret)

		ret = crash_prepare_elf64_headers(cmem, true, addr, sz);



out:

	kfree(cmem);

	return ret;

}



static char *setup_kdump_cmdline(struct kimage *image, char *cmdline,

				 unsigned long cmdline_len)

{

	int elfcorehdr_strlen;

	char *cmdline_ptr;



	cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);

	if (!cmdline_ptr)

		return NULL;



	elfcorehdr_strlen = sprintf(cmdline_ptr, "elfcorehdr=0x%lx ",

		image->elf_load_addr);



	if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) {

		pr_err("Appending elfcorehdr=<addr> exceeds cmdline size\n");

		kfree(cmdline_ptr);

		return NULL;

	}



	memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len);

	/* Ensure it's nul terminated */

	cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0';

	return cmdline_ptr;

}

#endif



static void *elf_kexec_load(struct kimage *image, char *kernel_buf,

			    unsigned long kernel_len, char *initrd,

			    unsigned long initrd_len, char *cmdline,

			    unsigned long cmdline_len)

{

	int ret;

	void *fdt;

	unsigned long old_kernel_pbase = ULONG_MAX;

	unsigned long new_kernel_pbase = 0UL;

	unsigned long initrd_pbase = 0UL;

	unsigned long kernel_start;

	struct elfhdr ehdr;

	struct kexec_buf kbuf;

	struct kexec_elf_info elf_info;

	char *modified_cmdline = NULL;



	ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);

	if (ret)

		return ERR_PTR(ret);



	ret = elf_find_pbase(image, kernel_len, &ehdr, &elf_info,

			     &old_kernel_pbase, &new_kernel_pbase);

	if (ret)

		goto out;

	kernel_start = image->start;



	/* Add the kernel binary to the image */

	ret = riscv_kexec_elf_load(image, &ehdr, &elf_info,

				   old_kernel_pbase, new_kernel_pbase);

	if (ret)

		goto out;



	kbuf.image = image;

	kbuf.buf_min = new_kernel_pbase + kernel_len;

	kbuf.buf_max = ULONG_MAX;



#ifdef CONFIG_CRASH_DUMP

	/* Add elfcorehdr */

	if (image->type == KEXEC_TYPE_CRASH) {

		void *headers;

		unsigned long headers_sz;

		ret = prepare_elf_headers(&headers, &headers_sz);

		if (ret) {

			pr_err("Preparing elf core header failed\n");

			goto out;

		}



		kbuf.buffer = headers;

		kbuf.bufsz = headers_sz;

		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

		kbuf.memsz = headers_sz;

		kbuf.buf_align = ELF_CORE_HEADER_ALIGN;

		kbuf.top_down = true;



		ret = kexec_add_buffer(&kbuf);

		if (ret) {

			vfree(headers);

			goto out;

		}

		image->elf_headers = headers;

		image->elf_load_addr = kbuf.mem;

		image->elf_headers_sz = headers_sz;



		kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",

			      image->elf_load_addr, kbuf.bufsz, kbuf.memsz);



		/* Setup cmdline for kdump kernel case */

		modified_cmdline = setup_kdump_cmdline(image, cmdline,

						       cmdline_len);

		if (!modified_cmdline) {

			pr_err("Setting up cmdline for kdump kernel failed\n");

			ret = -EINVAL;

			goto out;

		}

		cmdline = modified_cmdline;

	}

#endif



#ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY

	/* Add purgatory to the image */

	kbuf.top_down = true;

	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

	ret = kexec_load_purgatory(image, &kbuf);

	if (ret) {

		pr_err("Error loading purgatory ret=%d\n", ret);

		goto out;

	}

	kexec_dprintk("Loaded purgatory at 0x%lx\n", kbuf.mem);



	ret = kexec_purgatory_get_set_symbol(image, "riscv_kernel_entry",

					     &kernel_start,

					     sizeof(kernel_start), 0);

	if (ret)

		pr_err("Error update purgatory ret=%d\n", ret);

#endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */



	/* Add the initrd to the image */

	if (initrd != NULL) {

		kbuf.buffer = initrd;

		kbuf.bufsz = kbuf.memsz = initrd_len;

		kbuf.buf_align = PAGE_SIZE;

		kbuf.top_down = true;

		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

		ret = kexec_add_buffer(&kbuf);

		if (ret)

			goto out;

		initrd_pbase = kbuf.mem;

		kexec_dprintk("Loaded initrd at 0x%lx\n", initrd_pbase);

	}



	/* Add the DTB to the image */

	fdt = of_kexec_alloc_and_setup_fdt(image, initrd_pbase,

					   initrd_len, cmdline, 0);

	if (!fdt) {

		pr_err("Error setting up the new device tree.\n");

		ret = -EINVAL;

		goto out;

	}



	fdt_pack(fdt);

	kbuf.buffer = fdt;

	kbuf.bufsz = kbuf.memsz = fdt_totalsize(fdt);

	kbuf.buf_align = PAGE_SIZE;

	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

	kbuf.top_down = true;

	ret = kexec_add_buffer(&kbuf);

	if (ret) {

		pr_err("Error add DTB kbuf ret=%d\n", ret);

		goto out_free_fdt;

	}

	/* Cache the fdt buffer address for memory cleanup */

	image->arch.fdt = fdt;

	kexec_dprintk("Loaded device tree at 0x%lx\n", kbuf.mem);

	goto out;



out_free_fdt:

	kvfree(fdt);

out:

	kfree(modified_cmdline);

	kexec_free_elf_info(&elf_info);

	return ret ? ERR_PTR(ret) : NULL;

}



#define RV_X(x, s, n)  (((x) >> (s)) & ((1 << (n)) - 1))

#define RISCV_IMM_BITS 12

#define RISCV_IMM_REACH (1LL << RISCV_IMM_BITS)

#define RISCV_CONST_HIGH_PART(x) \

	(((x) + (RISCV_IMM_REACH >> 1)) & ~(RISCV_IMM_REACH - 1))

#define RISCV_CONST_LOW_PART(x) ((x) - RISCV_CONST_HIGH_PART(x))



#define ENCODE_ITYPE_IMM(x) \

	(RV_X(x, 0, 12) << 20)

#define ENCODE_BTYPE_IMM(x) \

	((RV_X(x, 1, 4) << 8) | (RV_X(x, 5, 6) << 25) | \

	(RV_X(x, 11, 1) << 7) | (RV_X(x, 12, 1) << 31))

#define ENCODE_UTYPE_IMM(x) \

	(RV_X(x, 12, 20) << 12)

#define ENCODE_JTYPE_IMM(x) \

	((RV_X(x, 1, 10) << 21) | (RV_X(x, 11, 1) << 20) | \

	(RV_X(x, 12, 8) << 12) | (RV_X(x, 20, 1) << 31))

#define ENCODE_CBTYPE_IMM(x) \

	((RV_X(x, 1, 2) << 3) | (RV_X(x, 3, 2) << 10) | (RV_X(x, 5, 1) << 2) | \

	(RV_X(x, 6, 2) << 5) | (RV_X(x, 8, 1) << 12))

#define ENCODE_CJTYPE_IMM(x) \

	((RV_X(x, 1, 3) << 3) | (RV_X(x, 4, 1) << 11) | (RV_X(x, 5, 1) << 2) | \

	(RV_X(x, 6, 1) << 7) | (RV_X(x, 7, 1) << 6) | (RV_X(x, 8, 2) << 9) | \

	(RV_X(x, 10, 1) << 8) | (RV_X(x, 11, 1) << 12))

#define ENCODE_UJTYPE_IMM(x) \

	(ENCODE_UTYPE_IMM(RISCV_CONST_HIGH_PART(x)) | \

	(ENCODE_ITYPE_IMM(RISCV_CONST_LOW_PART(x)) << 32))

#define ENCODE_UITYPE_IMM(x) \

	(ENCODE_UTYPE_IMM(x) | (ENCODE_ITYPE_IMM(x) << 32))



#define CLEAN_IMM(type, x) \

	((~ENCODE_##type##_IMM((uint64_t)(-1))) & (x))



int arch_kexec_apply_relocations_add(struct purgatory_info *pi,

				     Elf_Shdr *section,

				     const Elf_Shdr *relsec,

				     const Elf_Shdr *symtab)

{

	const char *strtab, *name, *shstrtab;

	const Elf_Shdr *sechdrs;

	Elf64_Rela *relas;

	int i, r_type;



	/* String & section header string table */

	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;

	strtab = (char *)pi->ehdr + sechdrs[symtab->sh_link].sh_offset;

	shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;



	relas = (void *)pi->ehdr + relsec->sh_offset;



	for (i = 0; i < relsec->sh_size / sizeof(*relas); i++) {

		const Elf_Sym *sym;	/* symbol to relocate */

		unsigned long addr;	/* final location after relocation */

		unsigned long val;	/* relocated symbol value */

		unsigned long sec_base;	/* relocated section base address */

		void *loc;		/* tmp location to modify */



		sym = (void *)pi->ehdr + symtab->sh_offset;

		sym += ELF64_R_SYM(relas[i].r_info);



		if (sym->st_name)

			name = strtab + sym->st_name;

		else

			name = shstrtab + sechdrs[sym->st_shndx].sh_name;



		loc = pi->purgatory_buf;

		loc += section->sh_offset;

		loc += relas[i].r_offset;



		if (sym->st_shndx == SHN_ABS)

			sec_base = 0;

		else if (sym->st_shndx >= pi->ehdr->e_shnum) {

			pr_err("Invalid section %d for symbol %s\n",

			       sym->st_shndx, name);

			return -ENOEXEC;

		} else

			sec_base = pi->sechdrs[sym->st_shndx].sh_addr;



		val = sym->st_value;

		val += sec_base;

		val += relas[i].r_addend;



		addr = section->sh_addr + relas[i].r_offset;



		r_type = ELF64_R_TYPE(relas[i].r_info);



		switch (r_type) {

		case R_RISCV_BRANCH:

			*(u32 *)loc = CLEAN_IMM(BTYPE, *(u32 *)loc) |

				 ENCODE_BTYPE_IMM(val - addr);

			break;

		case R_RISCV_JAL:

			*(u32 *)loc = CLEAN_IMM(JTYPE, *(u32 *)loc) |

				 ENCODE_JTYPE_IMM(val - addr);

			break;

		/*

		 * With no R_RISCV_PCREL_LO12_S, R_RISCV_PCREL_LO12_I

		 * sym is expected to be next to R_RISCV_PCREL_HI20

		 * in purgatory relsec. Handle it like R_RISCV_CALL

		 * sym, instead of searching the whole relsec.

		 */

		case R_RISCV_PCREL_HI20:

		case R_RISCV_CALL_PLT:

		case R_RISCV_CALL:

			*(u64 *)loc = CLEAN_IMM(UITYPE, *(u64 *)loc) |

				 ENCODE_UJTYPE_IMM(val - addr);

			break;

		case R_RISCV_RVC_BRANCH:

			*(u32 *)loc = CLEAN_IMM(CBTYPE, *(u32 *)loc) |

				 ENCODE_CBTYPE_IMM(val - addr);

			break;

		case R_RISCV_RVC_JUMP:

			*(u32 *)loc = CLEAN_IMM(CJTYPE, *(u32 *)loc) |

				 ENCODE_CJTYPE_IMM(val - addr);

			break;

		case R_RISCV_ADD16:

			*(u16 *)loc += val;

			break;

		case R_RISCV_SUB16:

			*(u16 *)loc -= val;

			break;

		case R_RISCV_ADD32:

			*(u32 *)loc += val;

			break;

		case R_RISCV_SUB32:

			*(u32 *)loc -= val;

			break;

		/* It has been applied by R_RISCV_PCREL_HI20 sym */

		case R_RISCV_PCREL_LO12_I:

		case R_RISCV_ALIGN:

		case R_RISCV_RELAX:

			break;

		case R_RISCV_64:

			*(u64 *)loc = val;

			break;

		default:

			pr_err("Unknown rela relocation: %d\n", r_type);

			return -ENOEXEC;

		}

	}

	return 0;

}



const struct kexec_file_ops elf_kexec_ops = {

	.probe = kexec_elf_probe,

	.load  = elf_kexec_load,

};

arch/riscv/kernel/kexec_elf.c

0 → 100644
+144 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Load ELF vmlinux file for the kexec_file_load syscall.

 *

 * Copyright (C) 2021 Huawei Technologies Co, Ltd.

 *

 * Author: Liao Chang (liaochang1@huawei.com)

 *

 * Based on kexec-tools' kexec-elf-riscv.c, heavily modified

 * for kernel.

 */



#define pr_fmt(fmt)	"kexec_image: " fmt



#include <linux/elf.h>

#include <linux/kexec.h>

#include <linux/slab.h>

#include <linux/of.h>

#include <linux/libfdt.h>

#include <linux/types.h>

#include <linux/memblock.h>

#include <asm/setup.h>



static int riscv_kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,

				struct kexec_elf_info *elf_info, unsigned long old_pbase,

				unsigned long new_pbase)

{

	int i;

	int ret = 0;

	size_t size;

	struct kexec_buf kbuf;

	const struct elf_phdr *phdr;



	kbuf.image = image;



	for (i = 0; i < ehdr->e_phnum; i++) {

		phdr = &elf_info->proghdrs[i];

		if (phdr->p_type != PT_LOAD)

			continue;



		size = phdr->p_filesz;

		if (size > phdr->p_memsz)

			size = phdr->p_memsz;



		kbuf.buffer = (void *) elf_info->buffer + phdr->p_offset;

		kbuf.bufsz = size;

		kbuf.buf_align = phdr->p_align;

		kbuf.mem = phdr->p_paddr - old_pbase + new_pbase;

		kbuf.memsz = phdr->p_memsz;

		kbuf.top_down = false;

		ret = kexec_add_buffer(&kbuf);

		if (ret)

			break;

	}



	return ret;

}



/*

 * Go through the available phsyical memory regions and find one that hold

 * an image of the specified size.

 */

static int elf_find_pbase(struct kimage *image, unsigned long kernel_len,

			  struct elfhdr *ehdr, struct kexec_elf_info *elf_info,

			  unsigned long *old_pbase, unsigned long *new_pbase)

{

	int i;

	int ret;

	struct kexec_buf kbuf;

	const struct elf_phdr *phdr;

	unsigned long lowest_paddr = ULONG_MAX;

	unsigned long lowest_vaddr = ULONG_MAX;



	for (i = 0; i < ehdr->e_phnum; i++) {

		phdr = &elf_info->proghdrs[i];

		if (phdr->p_type != PT_LOAD)

			continue;



		if (lowest_paddr > phdr->p_paddr)

			lowest_paddr = phdr->p_paddr;



		if (lowest_vaddr > phdr->p_vaddr)

			lowest_vaddr = phdr->p_vaddr;

	}



	kbuf.image = image;

	kbuf.buf_min = lowest_paddr;

	kbuf.buf_max = ULONG_MAX;



	/*

	 * Current riscv boot protocol requires 2MB alignment for

	 * RV64 and 4MB alignment for RV32

	 *

	 */

	kbuf.buf_align = PMD_SIZE;

	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;

	kbuf.memsz = ALIGN(kernel_len, PAGE_SIZE);

	kbuf.top_down = false;

	ret = arch_kexec_locate_mem_hole(&kbuf);

	if (!ret) {

		*old_pbase = lowest_paddr;

		*new_pbase = kbuf.mem;

		image->start = ehdr->e_entry - lowest_vaddr + kbuf.mem;

	}

	return ret;

}



static void *elf_kexec_load(struct kimage *image, char *kernel_buf,

			    unsigned long kernel_len, char *initrd,

			    unsigned long initrd_len, char *cmdline,

			    unsigned long cmdline_len)

{

	int ret;

	unsigned long old_kernel_pbase = ULONG_MAX;

	unsigned long new_kernel_pbase = 0UL;

	struct elfhdr ehdr;

	struct kexec_elf_info elf_info;



	ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);

	if (ret)

		return ERR_PTR(ret);



	ret = elf_find_pbase(image, kernel_len, &ehdr, &elf_info,

			     &old_kernel_pbase, &new_kernel_pbase);

	if (ret)

		goto out;



	/* Add the kernel binary to the image */

	ret = riscv_kexec_elf_load(image, &ehdr, &elf_info,

				   old_kernel_pbase, new_kernel_pbase);

	if (ret)

		goto out;



	ret = load_extra_segments(image, image->start, kernel_len,

				  initrd, initrd_len, cmdline, cmdline_len);

out:

	kexec_free_elf_info(&elf_info);

	return ret ? ERR_PTR(ret) : NULL;

}



const struct kexec_file_ops elf_kexec_ops = {

	.probe = kexec_elf_probe,

	.load  = elf_kexec_load,

};