4.4-stable review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski luto@kernel.org
commit e63650840e8b053aa09ad934877e87e9941ed135 upstream.
Now that eagerfpu= is gone, remove it from the docs and some comments. Also sync the changes to tools/.
Signed-off-by: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bp@alien8.de Cc: Brian Gerst brgerst@gmail.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Denys Vlasenko dvlasenk@redhat.com Cc: Fenghua Yu fenghua.yu@intel.com Cc: H. Peter Anvin hpa@zytor.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Oleg Nesterov oleg@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Quentin Casasnovas quentin.casasnovas@oracle.com Cc: Rik van Riel riel@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/cf430dd4481d41280e93ac6cf0def1007a67fc8e.1476740397... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Daniel Sangorrin daniel.sangorrin@toshiba.co.jp Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/kernel-parameters.txt | 5 ----- arch/x86/include/asm/cpufeatures.h | 1 - arch/x86/include/asm/fpu/types.h | 23 ----------------------- 3 files changed, 29 deletions(-)
--- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -961,11 +961,6 @@ bytes respectively. Such letter suffixes See Documentation/x86/intel_mpx.txt for more information about the feature.
- eagerfpu= [X86] - on enable eager fpu restore - off disable eager fpu restore - auto selects the default scheme, which automatically - enables eagerfpu restore for xsaveopt.
module.async_probe [KNL] Enable asynchronous probe on this module. --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -104,7 +104,6 @@ #define X86_FEATURE_EXTD_APICID ( 3*32+26) /* has extended APICID (8 bits) */ #define X86_FEATURE_AMD_DCM ( 3*32+27) /* multi-node processor */ #define X86_FEATURE_APERFMPERF ( 3*32+28) /* APERFMPERF */ -/* free, was #define X86_FEATURE_EAGER_FPU ( 3*32+29) * "eagerfpu" Non lazy FPU restore */ #define X86_FEATURE_NONSTOP_TSC_S3 ( 3*32+30) /* TSC doesn't stop in S3 state */
/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -310,29 +310,6 @@ struct fpu { * the registers in the FPU are more recent than this state * copy. If the task context-switches away then they get * saved here and represent the FPU state. - * - * After context switches there may be a (short) time period - * during which the in-FPU hardware registers are unchanged - * and still perfectly match this state, if the tasks - * scheduled afterwards are not using the FPU. - * - * This is the 'lazy restore' window of optimization, which - * we track though 'fpu_fpregs_owner_ctx' and 'fpu->last_cpu'. - * - * We detect whether a subsequent task uses the FPU via setting - * CR0::TS to 1, which causes any FPU use to raise a #NM fault. - * - * During this window, if the task gets scheduled again, we - * might be able to skip having to do a restore from this - * memory buffer to the hardware registers - at the cost of - * incurring the overhead of #NM fault traps. - * - * Note that on modern CPUs that support the XSAVEOPT (or other - * optimized XSAVE instructions), we don't use #NM traps anymore, - * as the hardware can track whether FPU registers need saving - * or not. On such CPUs we activate the non-lazy ('eagerfpu') - * logic, which unconditionally saves/restores all FPU state - * across context switches. (if FPU state exists.) */ union fpregs_state state; /*