linux/arch/arm64/kernel/kexec_image.c
James Morse 394135c1ff arm64: kexec_file: forbid kdump via kexec_file_load()
Now that kexec_walk_memblock() can do the crash-kernel placement itself
architectures that don't support kdump via kexe_file_load() need to
explicitly forbid it.

We don't support this on arm64 until the kernel can add the elfcorehdr
and usable-memory-range fields to the DT. Without these the crash-kernel
overwrites the previous kernel's memory during startup.

Add a check to refuse crash image loading.

Reviewed-by: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-07 15:28:21 +00:00

131 lines
3.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Kexec image loader
* Copyright (C) 2018 Linaro Limited
* Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
*/
#define pr_fmt(fmt) "kexec_file(Image): " 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 <linux/verification.h>
#include <asm/byteorder.h>
#include <asm/cpufeature.h>
#include <asm/image.h>
#include <asm/memory.h>
static int image_probe(const char *kernel_buf, unsigned long kernel_len)
{
const struct arm64_image_header *h =
(const struct arm64_image_header *)(kernel_buf);
if (!h || (kernel_len < sizeof(*h)))
return -EINVAL;
if (memcmp(&h->magic, ARM64_IMAGE_MAGIC, sizeof(h->magic)))
return -EINVAL;
return 0;
}
static void *image_load(struct kimage *image,
char *kernel, unsigned long kernel_len,
char *initrd, unsigned long initrd_len,
char *cmdline, unsigned long cmdline_len)
{
struct arm64_image_header *h;
u64 flags, value;
bool be_image, be_kernel;
struct kexec_buf kbuf;
unsigned long text_offset;
struct kexec_segment *kernel_segment;
int ret;
/* We don't support crash kernels yet. */
if (image->type == KEXEC_TYPE_CRASH)
return ERR_PTR(-EOPNOTSUPP);
/*
* We require a kernel with an unambiguous Image header. Per
* Documentation/booting.txt, this is the case when image_size
* is non-zero (practically speaking, since v3.17).
*/
h = (struct arm64_image_header *)kernel;
if (!h->image_size)
return ERR_PTR(-EINVAL);
/* Check cpu features */
flags = le64_to_cpu(h->flags);
be_image = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_BE);
be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
if ((be_image != be_kernel) && !system_supports_mixed_endian())
return ERR_PTR(-EINVAL);
value = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_PAGE_SIZE);
if (((value == ARM64_IMAGE_FLAG_PAGE_SIZE_4K) &&
!system_supports_4kb_granule()) ||
((value == ARM64_IMAGE_FLAG_PAGE_SIZE_64K) &&
!system_supports_64kb_granule()) ||
((value == ARM64_IMAGE_FLAG_PAGE_SIZE_16K) &&
!system_supports_16kb_granule()))
return ERR_PTR(-EINVAL);
/* Load the kernel */
kbuf.image = image;
kbuf.buf_min = 0;
kbuf.buf_max = ULONG_MAX;
kbuf.top_down = false;
kbuf.buffer = kernel;
kbuf.bufsz = kernel_len;
kbuf.mem = 0;
kbuf.memsz = le64_to_cpu(h->image_size);
text_offset = le64_to_cpu(h->text_offset);
kbuf.buf_align = MIN_KIMG_ALIGN;
/* Adjust kernel segment with TEXT_OFFSET */
kbuf.memsz += text_offset;
ret = kexec_add_buffer(&kbuf);
if (ret)
return ERR_PTR(ret);
kernel_segment = &image->segment[image->nr_segments - 1];
kernel_segment->mem += text_offset;
kernel_segment->memsz -= text_offset;
image->start = kernel_segment->mem;
pr_debug("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
kernel_segment->mem, kbuf.bufsz,
kernel_segment->memsz);
/* Load additional data */
ret = load_other_segments(image,
kernel_segment->mem, kernel_segment->memsz,
initrd, initrd_len, cmdline);
return ERR_PTR(ret);
}
#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
static int image_verify_sig(const char *kernel, unsigned long kernel_len)
{
return verify_pefile_signature(kernel, kernel_len, NULL,
VERIFYING_KEXEC_PE_SIGNATURE);
}
#endif
const struct kexec_file_ops kexec_image_ops = {
.probe = image_probe,
.load = image_load,
#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
.verify_sig = image_verify_sig,
#endif
};