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// SPDX-License-Identifier: GPL-2.0
/*
* kexec_file for arm64
*
* Copyright (C) 2018 Linaro Limited
* Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
*
* Most code is derived from arm64 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/libfdt.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/random.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>
/* relevant device tree properties */
#define FDT_PROP_INITRD_START "linux,initrd-start"
#define FDT_PROP_INITRD_END "linux,initrd-end"
#define FDT_PROP_BOOTARGS "bootargs"
#define FDT_PROP_KASLR_SEED "kaslr-seed"
#define FDT_PROP_RNG_SEED "rng-seed"
#define RNG_SEED_SIZE 128
const struct kexec_file_ops * const kexec_file_loaders[] = {
&kexec_image_ops,
NULL
};
int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
vfree(image->arch.dtb);
image->arch.dtb = NULL;
return kexec_image_post_load_cleanup_default(image);
}
static int setup_dtb(struct kimage *image,
unsigned long initrd_load_addr, unsigned long initrd_len,
char *cmdline, void *dtb)
{
int off, ret;
ret = fdt_path_offset(dtb, "/chosen");
if (ret < 0)
goto out;
off = ret;
/* add bootargs */
if (cmdline) {
ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
if (ret)
goto out;
} else {
ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS);
if (ret && (ret != -FDT_ERR_NOTFOUND))
goto out;
}
/* add initrd-* */
if (initrd_load_addr) {
ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START,
initrd_load_addr);
if (ret)
goto out;
ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END,
initrd_load_addr + initrd_len);
if (ret)
goto out;
} else {
ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START);
if (ret && (ret != -FDT_ERR_NOTFOUND))
goto out;
ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END);
if (ret && (ret != -FDT_ERR_NOTFOUND))
goto out;
}
/* add kaslr-seed */
ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED);
if (ret == -FDT_ERR_NOTFOUND)
ret = 0;
else if (ret)
goto out;
if (rng_is_initialized()) {
u64 seed = get_random_u64();
ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed);
if (ret)
goto out;
} else {
pr_notice("RNG is not initialised: omitting \"%s\" property\n",
FDT_PROP_KASLR_SEED);
}
/* add rng-seed */
if (rng_is_initialized()) {
u8 rng_seed[RNG_SEED_SIZE];
get_random_bytes(rng_seed, RNG_SEED_SIZE);
ret = fdt_setprop(dtb, off, FDT_PROP_RNG_SEED, rng_seed,
RNG_SEED_SIZE);
if (ret)
goto out;
} else {
pr_notice("RNG is not initialised: omitting \"%s\" property\n",
FDT_PROP_RNG_SEED);
}
out:
if (ret)
return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;
return 0;
}
/*
* More space needed so that we can add initrd, bootargs, kaslr-seed, and
* rng-seed.
*/
#define DTB_EXTRA_SPACE 0x1000
static int create_dtb(struct kimage *image,
unsigned long initrd_load_addr, unsigned long initrd_len,
char *cmdline, void **dtb)
{
void *buf;
size_t buf_size;
size_t cmdline_len;
int ret;
cmdline_len = cmdline ? strlen(cmdline) : 0;
buf_size = fdt_totalsize(initial_boot_params)
+ cmdline_len + DTB_EXTRA_SPACE;
for (;;) {
buf = vmalloc(buf_size);
if (!buf)
return -ENOMEM;
/* duplicate a device tree blob */
ret = fdt_open_into(initial_boot_params, buf, buf_size);
if (ret)
return -EINVAL;
ret = setup_dtb(image, initrd_load_addr, initrd_len,
cmdline, buf);
if (ret) {
vfree(buf);
if (ret == -ENOMEM) {
/* unlikely, but just in case */
buf_size += DTB_EXTRA_SPACE;
continue;
} else {
return ret;
}
}
/* trim it */
fdt_pack(buf);
*dtb = buf;
return 0;
}
}
int load_other_segments(struct kimage *image,
unsigned long kernel_load_addr,
unsigned long kernel_size,
char *initrd, unsigned long initrd_len,
char *cmdline)
{
struct kexec_buf kbuf;
void *dtb = NULL;
unsigned long initrd_load_addr = 0, dtb_len;
int ret = 0;
kbuf.image = image;
/* not allocate anything below the kernel */
kbuf.buf_min = kernel_load_addr + kernel_size;
/* 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;
pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
initrd_load_addr, initrd_len, initrd_len);
}
/* load dtb */
ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
if (ret) {
pr_err("Preparing for new dtb failed\n");
goto out_err;
}
dtb_len = fdt_totalsize(dtb);
kbuf.buffer = dtb;
kbuf.bufsz = dtb_len;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
kbuf.memsz = dtb_len;
/* not across 2MB boundary */
kbuf.buf_align = SZ_2M;
kbuf.buf_max = ULONG_MAX;
kbuf.top_down = true;
ret = kexec_add_buffer(&kbuf);
if (ret)
goto out_err;
image->arch.dtb = dtb;
image->arch.dtb_mem = kbuf.mem;
pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
kbuf.mem, dtb_len, dtb_len);
return 0;
out_err:
vfree(dtb);
return ret;
}
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