]> git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/commit - arch/x86/kernel/cpu/common.c
x86/CPU: Change query logic so CPUID is enabled before testing
authorMatthew Whitehead <tedheadster@gmail.com>
Fri, 21 Sep 2018 21:20:41 +0000 (17:20 -0400)
committerBorislav Petkov <bp@suse.de>
Sat, 22 Sep 2018 09:47:39 +0000 (11:47 +0200)
commit2893cc8ff892fa74972d8dc0e1d0dc65116daaa3
tree849969e84a3b820861b15734b52f37458805fb74
parent03b099bdcdf7125d4a63dc9ddeefdd454e05123d
x86/CPU: Change query logic so CPUID is enabled before testing

Presently we check first if CPUID is enabled. If it is not already
enabled, then we next call identify_cpu_without_cpuid() and clear
X86_FEATURE_CPUID.

Unfortunately, identify_cpu_without_cpuid() is the function where CPUID
becomes _enabled_ on Cyrix 6x86/6x86L CPUs.

Reverse the calling sequence so that CPUID is first enabled, and then
check a second time to see if the feature has now been activated.

[ bp: Massage commit message and remove trailing whitespace. ]

Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@amacapital.net>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180921212041.13096-3-tedheadster@gmail.com
arch/x86/kernel/cpu/common.c