Commit f2dbad36 authored by Rudolf Marek's avatar Rudolf Marek Committed by Ingo Molnar

x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD

[ Note, this is a Git cherry-pick of the following commit:

    2b67799bdf25 ("x86: Make X86_BUG_FXSAVE_LEAK detectable in CPUID on AMD")

  ... for easier x86 PTI code testing and back-porting. ]

The latest AMD AMD64 Architecture Programmer's Manual
adds a CPUID feature XSaveErPtr (CPUID_Fn80000008_EBX[2]).

If this feature is set, the FXSAVE, XSAVE, FXSAVEOPT, XSAVEC, XSAVES
/ FXRSTOR, XRSTOR, XRSTORS always save/restore error pointers,
thus making the X86_BUG_FXSAVE_LEAK workaround obsolete on such CPUs.
Signed-Off-By: default avatarRudolf Marek <r.marek@assembler.cz>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Link: https://lkml.kernel.org/r/bdcebe90-62c5-1f05-083c-eba7f08b2540@assembler.czSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent a8b4db56
...@@ -266,6 +266,7 @@ ...@@ -266,6 +266,7 @@
/* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */ /* AMD-defined CPU features, CPUID level 0x80000008 (EBX), word 13 */
#define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */ #define X86_FEATURE_CLZERO (13*32+ 0) /* CLZERO instruction */
#define X86_FEATURE_IRPERF (13*32+ 1) /* Instructions Retired Count */ #define X86_FEATURE_IRPERF (13*32+ 1) /* Instructions Retired Count */
#define X86_FEATURE_XSAVEERPTR (13*32+ 2) /* Always save/restore FP error pointers */
/* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */ /* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */
#define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */ #define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */
......
...@@ -804,8 +804,11 @@ static void init_amd(struct cpuinfo_x86 *c) ...@@ -804,8 +804,11 @@ static void init_amd(struct cpuinfo_x86 *c)
case 0x17: init_amd_zn(c); break; case 0x17: init_amd_zn(c); break;
} }
/* Enable workaround for FXSAVE leak */ /*
if (c->x86 >= 6) * Enable workaround for FXSAVE leak on CPUs
* without a XSaveErPtr feature
*/
if ((c->x86 >= 6) && (!cpu_has(c, X86_FEATURE_XSAVEERPTR)))
set_cpu_bug(c, X86_BUG_FXSAVE_LEAK); set_cpu_bug(c, X86_BUG_FXSAVE_LEAK);
cpu_detect_cache_sizes(c); cpu_detect_cache_sizes(c);
......
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