Revert "x86/kexec: Allocate PGD for x86_64 transition page tables separately"
This reverts commit c1adee84ee7ad6ec211a1c275f721201e28b609f.
That commit causes kdump collection to fail. We bisected the kernel to
find it, and after reverting it kdump reliably succeeds as it did
before.
The commit states:
> Now that the following fix:
>
> d0ceea662d45 ("x86/mm: Add _PAGE_NOPTISHADOW bit to avoid updating userspace page tables")
>
> stops kernel_ident_mapping_init() from scribbling over the end of a
> 4KiB PGD by assuming the following 4KiB will be a userspace PGD,
> there's no good reason for the kexec PGD to be part of a single
> 8KiB allocation with the control_code_page.
But d0ceea662d45 is not included in stable, the stable-queue, or our
kernel source, so presumably the assumptions of c1adee84ee7ad6 are
broken.
BUG=b/403014444
TEST=presubmit, verify that kdump fails on VMs without this patch, apply
the patch and verify that kdump succeeds
RELEASE_NOTE=None
cos-patch: bug
Signed-off-by: Kevin Berry <kpberry@google.com>
Change-Id: Id9a2b936bb4c0e0398a32bc5badeb3432b27fa0f
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/99021
Main-Branch-Verified: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Michael Kochera <kochera@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
2 files changed
