diff options
| author | Janakarajan Natarajan <Janakarajan.Natarajan@amd.com> | 2019-10-07 19:00:22 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-17 13:42:46 -0700 |
| commit | 1cf08650c04a6d6a6356613dec712fbf97f91fb3 (patch) | |
| tree | afffc966abc6c7aba86778bac6b5a159601c6bdd /arch/x86/include | |
| parent | 5e402bab5fc3c96a72e590b614e0c86b06423588 (diff) | |
x86/asm: Fix MWAITX C-state hint value
commit 454de1e7d970d6bc567686052329e4814842867c upstream.
As per "AMD64 Architecture Programmer's Manual Volume 3: General-Purpose
and System Instructions", MWAITX EAX[7:4]+1 specifies the optional hint
of the optimized C-state. For C0 state, EAX[7:4] should be set to 0xf.
Currently, a value of 0xf is set for EAX[3:0] instead of EAX[7:4]. Fix
this by changing MWAITX_DISABLE_CSTATES from 0xf to 0xf0.
This hasn't had any implications so far because setting reserved bits in
EAX is simply ignored by the CPU.
[ bp: Fixup comment in delay_mwaitx() and massage. ]
Signed-off-by: Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "x86@kernel.org" <x86@kernel.org>
Cc: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20191007190011.4859-1-Janakarajan.Natarajan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/mwait.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h index 0b40cc442bda..58b1b766e84e 100644 --- a/arch/x86/include/asm/mwait.h +++ b/arch/x86/include/asm/mwait.h @@ -19,7 +19,7 @@ #define MWAIT_ECX_INTERRUPT_BREAK 0x1 #define MWAITX_ECX_TIMER_ENABLE BIT(1) #define MWAITX_MAX_LOOPS ((u32)-1) -#define MWAITX_DISABLE_CSTATES 0xf +#define MWAITX_DISABLE_CSTATES 0xf0 static inline void __monitor(const void *eax, unsigned long ecx, unsigned long edx) |