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| author | Juergen Gross <jgross@suse.com> | 2022-10-04 10:10:08 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-10-19 20:37:23 +0200 |
| commit | 01c97c7303580682751b5aaae043b639bdcbacb3 (patch) | |
| tree | 4dd6d8f0eb87a549e36831dc507c2fcfaea67575 /arch/x86/kernel/cpu/mtrr | |
| parent | x86/bugs: Use sysfs_emit() (diff) | |
| download | linux-01c97c7303580682751b5aaae043b639bdcbacb3.tar.xz linux-01c97c7303580682751b5aaae043b639bdcbacb3.zip | |
x86/mtrr: Add comment for set_mtrr_state() serialization
Add a comment about set_mtrr_state() needing serialization.
[ bp: Touchups. ]
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220820092533.29420-2-jgross@suse.com
Diffstat (limited to 'arch/x86/kernel/cpu/mtrr')
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/generic.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c index 558108296f3c..c8f895157e05 100644 --- a/arch/x86/kernel/cpu/mtrr/generic.c +++ b/arch/x86/kernel/cpu/mtrr/generic.c @@ -684,7 +684,10 @@ static u32 deftype_lo, deftype_hi; /** * set_mtrr_state - Set the MTRR state for this CPU. * - * NOTE: The CPU must already be in a safe state for MTRR changes. + * NOTE: The CPU must already be in a safe state for MTRR changes, including + * measures that only a single CPU can be active in set_mtrr_state() in + * order to not be subject to races for usage of deftype_lo. This is + * accomplished by taking set_atomicity_lock. * RETURNS: 0 if no changes made, else a mask indicating what was changed. */ static unsigned long set_mtrr_state(void) |