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// 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>
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;
kbuf.buf_align = PAGE_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;
unsigned long initrd_pbase = 0UL;
void *fdt;
struct elfhdr ehdr;
struct kexec_buf kbuf;
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;
pr_notice("The entry point of kernel at 0x%lx\n", 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;
/* 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 = false;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
ret = kexec_add_buffer(&kbuf);
if (ret)
goto out;
initrd_pbase = kbuf.mem;
pr_notice("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;
}
pr_notice("Loaded device tree at 0x%lx\n", kbuf.mem);
goto out;
out_free_fdt:
kvfree(fdt);
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,
};
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