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arm64: kexec_file: try more regions if loading segments fails

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It's possible that the first region picked for the new kernel will make
it impossible to fit the other segments in the required 32GB window,
especially if we have a very large initrd.

Instead of giving up, we can keep testing other regions for the kernel
until we find one that works.

Suggested-by: Ryan O'Leary <ryanoleary@google.com>
Signed-off-by: Benjamin Gwin <bgwin@google.com>
Link: https://lore.kernel.org/r/20201103201106.2397844-1-bgwin@google.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Benjamin Gwin 2020-11-03 12:11:06 -08:00 committed by Will Deacon
parent 7ee31a3aa8
commit 108aa50365
2 changed files with 40 additions and 12 deletions
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43
arch/arm64/kernel/kexec_image.c
View File

@ -43,7 +43,7 @@ static void *image_load(struct kimage *image,
u64 flags, value;
bool be_image, be_kernel;
struct kexec_buf kbuf;
unsigned long text_offset;
unsigned long text_offset, kernel_segment_number;
struct kexec_segment *kernel_segment;
int ret;
@ -88,11 +88,37 @@ static void *image_load(struct kimage *image,
/* Adjust kernel segment with TEXT_OFFSET */
kbuf.memsz += text_offset;
ret = kexec_add_buffer(&kbuf);
if (ret)
return ERR_PTR(ret);
kernel_segment_number = image->nr_segments;
kernel_segment = &image->segment[image->nr_segments - 1];
/*
* The location of the kernel segment may make it impossible to satisfy
* the other segment requirements, so we try repeatedly to find a
* location that will work.
*/
while ((ret = kexec_add_buffer(&kbuf)) == 0) {
/* Try to load additional data */
kernel_segment = &image->segment[kernel_segment_number];
ret = load_other_segments(image, kernel_segment->mem,
kernel_segment->memsz, initrd,
initrd_len, cmdline);
if (!ret)
break;
/*
* We couldn't find space for the other segments; erase the
* kernel segment and try the next available hole.
*/
image->nr_segments -= 1;
kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz;
kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
}
if (ret) {
pr_err("Could not find any suitable kernel location!");
return ERR_PTR(ret);
}
kernel_segment = &image->segment[kernel_segment_number];
kernel_segment->mem += text_offset;
kernel_segment->memsz -= text_offset;
image->start = kernel_segment->mem;
@ -101,12 +127,7 @@ static void *image_load(struct kimage *image,
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);
return 0;
}
#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG

9
arch/arm64/kernel/machine_kexec_file.c
View File

@ -240,6 +240,11 @@ static int prepare_elf_headers(void **addr, unsigned long *sz)
return ret;
}
/*
* Tries to add the initrd and DTB 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,
@ -248,7 +253,8 @@ int load_other_segments(struct kimage *image,
{
struct kexec_buf kbuf;
void *headers, *dtb = NULL;
unsigned long headers_sz, initrd_load_addr = 0, dtb_len;
unsigned long headers_sz, initrd_load_addr = 0, dtb_len,
orig_segments = image->nr_segments;
int ret = 0;
kbuf.image = image;
@ -334,6 +340,7 @@ int load_other_segments(struct kimage *image,
return 0;
out_err:
image->nr_segments = orig_segments;
vfree(dtb);
return ret;
}