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ARM: kexec: fix oops after TLB are invalidated

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[ Upstream commit 4d62e81b60d4025e2dfcd5ea531cc1394ce9226f ]

Giancarlo Ferrari reports the following oops while trying to use kexec:

 Unable to handle kernel paging request at virtual address 80112f38
 pgd = fd7ef03e
 [80112f38] *pgd=0001141e(bad)
 Internal error: Oops: 80d [#1] PREEMPT SMP ARM
 ...

This is caused by machine_kexec() trying to set the kernel text to be
read/write, so it can poke values into the relocation code before
copying it - and an interrupt occuring which changes the page tables.
The subsequent writes then hit read-only sections that trigger a
data abort resulting in the above oops.

Fix this by copying the relocation code, and then writing the variables
into the destination, thereby avoiding the need to make the kernel text
read/write.

Reported-by: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com>
Tested-by: Giancarlo Ferrari <giancarlo.ferrari89@gmail.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Russell King
2021-02-01 19:40:01 +00:00
committed by Greg Kroah-Hartman
parent 7913ec05fc
commit 249735b011
4 changed files with 36 additions and 39 deletions
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12
arch/arm/include/asm/kexec-internal.h Normal file
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@@ -0,0 +1,12 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ARM_KEXEC_INTERNAL_H
#define _ARM_KEXEC_INTERNAL_H
struct kexec_relocate_data {
unsigned long kexec_start_address;
unsigned long kexec_indirection_page;
unsigned long kexec_mach_type;
unsigned long kexec_r2;
};
#endif