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linux/arch/x86/boot
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Kairui Song bdec8d7fa5 x86/boot: Fix kexec booting failure in the SEV bit detection code 
Commit

  1958b5fc40 ("x86/boot: Add early boot support when running with SEV active")

can occasionally cause system resets when kexec-ing a second kernel even
if SEV is not active.

That's because get_sev_encryption_bit() uses 32-bit rIP-relative
addressing to read the value of enc_bit - a variable which caches a
previously detected encryption bit position - but kexec may allocate
the early boot code to a higher location, beyond the 32-bit addressing
limit.

In this case, garbage will be read and get_sev_encryption_bit() will
return the wrong value, leading to accessing memory with the wrong
encryption setting.

Therefore, remove enc_bit, and thus get rid of the need to do 32-bit
rIP-relative addressing in the first place.

 [ bp: massage commit message heavily. ]

Fixes: 1958b5fc40 ("x86/boot: Add early boot support when running with SEV active")
Suggested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Kairui Song <kasong@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: brijesh.singh@amd.com
Cc: kexec@lists.infradead.org
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: ghook@redhat.com
Link: https://lkml.kernel.org/r/20180927123845.32052-1-kasong@redhat.com
2018-09-27 19:35:03 +02:00
..
compressed x86/boot: Fix kexec booting failure in the SEV bit detection code 2018-09-27 19:35:03 +02:00
tools License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
.gitignore x86/build: Add more generated files to the .gitignore file 2017-11-07 11:22:21 +01:00
a20.c
apm.c
bioscall.S
bitops.h x86/boot: Use CC_SET()/CC_OUT() instead of open coding it 2018-08-02 14:30:42 +02:00
boot.h x86/boot: Fix BSS corruption/overwrite bug in early x86 kernel startup 2017-04-20 10:05:23 +02:00
cmdline.c
code16gcc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
copy.S x86/boot: Remove unused copy_*_gs() functions 2017-06-05 09:35:16 +02:00
cpu.c Revert "x86/boot: Fail the boot if !M486 and CPUID is missing" 2016-12-19 11:54:20 +01:00
cpucheck.c x86/boot: Detect 5-level paging support 2017-04-04 08:22:33 +02:00
cpuflags.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cpuflags.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ctype.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
early_serial_console.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
edd.c
genimage.sh x86/build: Make isoimage work on Debian 2017-12-16 16:23:31 +01:00
header.S Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-13 16:32:30 -08:00
install.sh
main.c
Makefile x86/build: Factor out fdimage/isoimage generation commands to standalone script 2017-11-07 11:22:20 +01:00
memory.c x86/boot/e820: Separate the E820 ABI structures from the in-kernel structures 2017-01-29 13:39:32 +01:00
mkcpustr.c
mtools.conf.in
pm.c
pmjump.S
printf.c
regs.c
setup.ld
string.c x86/boot: Use CC_SET()/CC_OUT() instead of open coding it 2018-08-02 14:30:42 +02:00
string.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tty.c
version.c
vesa.h
video-bios.c
video-mode.c
video-vesa.c
video-vga.c x86: Use ARRAY_SIZE 2017-10-19 16:15:47 +02:00
video.c
video.h