OpenCloudOS-Kernel/arch/x86/include/asm/cpufeatures.h

301 lines
17 KiB
C
Raw Normal View History

#ifndef _ASM_X86_CPUFEATURES_H
#define _ASM_X86_CPUFEATURES_H
#ifndef _ASM_X86_REQUIRED_FEATURES_H
#include <asm/required-features.h>
#endif
#ifndef _ASM_X86_DISABLED_FEATURES_H
#include <asm/disabled-features.h>
#endif
/*
* Defines x86 CPU feature bits
*/
#define NCAPINTS 16 /* N 32-bit words worth of info */
#define NBUGINTS 1 /* N 32-bit bug flags */
/*
* Note: If the comment begins with a quoted string, that string is used
* in /proc/cpuinfo instead of the macro name. If the string is "",
* this feature bit is not displayed in /proc/cpuinfo at all.
*/
/* Intel-defined CPU features, CPUID level 0x00000001 (edx), word 0 */
#define X86_FEATURE_FPU ( 0*32+ 0) /* Onboard FPU */
#define X86_FEATURE_VME ( 0*32+ 1) /* Virtual Mode Extensions */
#define X86_FEATURE_DE ( 0*32+ 2) /* Debugging Extensions */
#define X86_FEATURE_PSE ( 0*32+ 3) /* Page Size Extensions */
#define X86_FEATURE_TSC ( 0*32+ 4) /* Time Stamp Counter */
#define X86_FEATURE_MSR ( 0*32+ 5) /* Model-Specific Registers */
#define X86_FEATURE_PAE ( 0*32+ 6) /* Physical Address Extensions */
#define X86_FEATURE_MCE ( 0*32+ 7) /* Machine Check Exception */
#define X86_FEATURE_CX8 ( 0*32+ 8) /* CMPXCHG8 instruction */
#define X86_FEATURE_APIC ( 0*32+ 9) /* Onboard APIC */
#define X86_FEATURE_SEP ( 0*32+11) /* SYSENTER/SYSEXIT */
#define X86_FEATURE_MTRR ( 0*32+12) /* Memory Type Range Registers */
#define X86_FEATURE_PGE ( 0*32+13) /* Page Global Enable */
#define X86_FEATURE_MCA ( 0*32+14) /* Machine Check Architecture */
#define X86_FEATURE_CMOV ( 0*32+15) /* CMOV instructions */
/* (plus FCMOVcc, FCOMI with FPU) */
#define X86_FEATURE_PAT ( 0*32+16) /* Page Attribute Table */
#define X86_FEATURE_PSE36 ( 0*32+17) /* 36-bit PSEs */
#define X86_FEATURE_PN ( 0*32+18) /* Processor serial number */
#define X86_FEATURE_CLFLUSH ( 0*32+19) /* CLFLUSH instruction */
#define X86_FEATURE_DS ( 0*32+21) /* "dts" Debug Store */
#define X86_FEATURE_ACPI ( 0*32+22) /* ACPI via MSR */
#define X86_FEATURE_MMX ( 0*32+23) /* Multimedia Extensions */
#define X86_FEATURE_FXSR ( 0*32+24) /* FXSAVE/FXRSTOR, CR4.OSFXSR */
#define X86_FEATURE_XMM ( 0*32+25) /* "sse" */
#define X86_FEATURE_XMM2 ( 0*32+26) /* "sse2" */
#define X86_FEATURE_SELFSNOOP ( 0*32+27) /* "ss" CPU self snoop */
#define X86_FEATURE_HT ( 0*32+28) /* Hyper-Threading */
#define X86_FEATURE_ACC ( 0*32+29) /* "tm" Automatic clock control */
#define X86_FEATURE_IA64 ( 0*32+30) /* IA-64 processor */
#define X86_FEATURE_PBE ( 0*32+31) /* Pending Break Enable */
/* AMD-defined CPU features, CPUID level 0x80000001, word 1 */
/* Don't duplicate feature flags which are redundant with Intel! */
#define X86_FEATURE_SYSCALL ( 1*32+11) /* SYSCALL/SYSRET */
#define X86_FEATURE_MP ( 1*32+19) /* MP Capable. */
#define X86_FEATURE_NX ( 1*32+20) /* Execute Disable */
#define X86_FEATURE_MMXEXT ( 1*32+22) /* AMD MMX extensions */
#define X86_FEATURE_FXSR_OPT ( 1*32+25) /* FXSAVE/FXRSTOR optimizations */
#define X86_FEATURE_GBPAGES ( 1*32+26) /* "pdpe1gb" GB pages */
#define X86_FEATURE_RDTSCP ( 1*32+27) /* RDTSCP */
#define X86_FEATURE_LM ( 1*32+29) /* Long Mode (x86-64) */
#define X86_FEATURE_3DNOWEXT ( 1*32+30) /* AMD 3DNow! extensions */
#define X86_FEATURE_3DNOW ( 1*32+31) /* 3DNow! */
/* Transmeta-defined CPU features, CPUID level 0x80860001, word 2 */
#define X86_FEATURE_RECOVERY ( 2*32+ 0) /* CPU in recovery mode */
#define X86_FEATURE_LONGRUN ( 2*32+ 1) /* Longrun power control */
#define X86_FEATURE_LRTI ( 2*32+ 3) /* LongRun table interface */
/* Other features, Linux-defined mapping, word 3 */
/* This range is used for feature bits which conflict or are synthesized */
#define X86_FEATURE_CXMMX ( 3*32+ 0) /* Cyrix MMX extensions */
#define X86_FEATURE_K6_MTRR ( 3*32+ 1) /* AMD K6 nonstandard MTRRs */
#define X86_FEATURE_CYRIX_ARR ( 3*32+ 2) /* Cyrix ARRs (= MTRRs) */
#define X86_FEATURE_CENTAUR_MCR ( 3*32+ 3) /* Centaur MCRs (= MTRRs) */
/* cpu types for specific tunings: */
#define X86_FEATURE_K8 ( 3*32+ 4) /* "" Opteron, Athlon64 */
#define X86_FEATURE_K7 ( 3*32+ 5) /* "" Athlon */
#define X86_FEATURE_P3 ( 3*32+ 6) /* "" P3 */
#define X86_FEATURE_P4 ( 3*32+ 7) /* "" P4 */
#define X86_FEATURE_CONSTANT_TSC ( 3*32+ 8) /* TSC ticks at a constant rate */
#define X86_FEATURE_UP ( 3*32+ 9) /* smp kernel running on up */
/* free, was #define X86_FEATURE_FXSAVE_LEAK ( 3*32+10) * "" FXSAVE leaks FOP/FIP/FOP */
#define X86_FEATURE_ARCH_PERFMON ( 3*32+11) /* Intel Architectural PerfMon */
#define X86_FEATURE_PEBS ( 3*32+12) /* Precise-Event Based Sampling */
#define X86_FEATURE_BTS ( 3*32+13) /* Branch Trace Store */
#define X86_FEATURE_SYSCALL32 ( 3*32+14) /* "" syscall in ia32 userspace */
#define X86_FEATURE_SYSENTER32 ( 3*32+15) /* "" sysenter in ia32 userspace */
#define X86_FEATURE_REP_GOOD ( 3*32+16) /* rep microcode works well */
#define X86_FEATURE_MFENCE_RDTSC ( 3*32+17) /* "" Mfence synchronizes RDTSC */
#define X86_FEATURE_LFENCE_RDTSC ( 3*32+18) /* "" Lfence synchronizes RDTSC */
/* free, was #define X86_FEATURE_11AP ( 3*32+19) * "" Bad local APIC aka 11AP */
#define X86_FEATURE_NOPL ( 3*32+20) /* The NOPL (0F 1F) instructions */
#define X86_FEATURE_ALWAYS ( 3*32+21) /* "" Always-present feature */
#define X86_FEATURE_XTOPOLOGY ( 3*32+22) /* cpu topology enum extensions */
#define X86_FEATURE_TSC_RELIABLE ( 3*32+23) /* TSC is known to be reliable */
#define X86_FEATURE_NONSTOP_TSC ( 3*32+24) /* TSC does not stop in C states */
/* free, was #define X86_FEATURE_CLFLUSH_MONITOR ( 3*32+25) * "" clflush reqd with monitor */
#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 */
#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 */
#define X86_FEATURE_MCE_RECOVERY ( 3*32+31) /* cpu has recoverable machine checks */
/* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
#define X86_FEATURE_XMM3 ( 4*32+ 0) /* "pni" SSE-3 */
#define X86_FEATURE_PCLMULQDQ ( 4*32+ 1) /* PCLMULQDQ instruction */
#define X86_FEATURE_DTES64 ( 4*32+ 2) /* 64-bit Debug Store */
#define X86_FEATURE_MWAIT ( 4*32+ 3) /* "monitor" Monitor/Mwait support */
#define X86_FEATURE_DSCPL ( 4*32+ 4) /* "ds_cpl" CPL Qual. Debug Store */
#define X86_FEATURE_VMX ( 4*32+ 5) /* Hardware virtualization */
#define X86_FEATURE_SMX ( 4*32+ 6) /* Safer mode */
#define X86_FEATURE_EST ( 4*32+ 7) /* Enhanced SpeedStep */
#define X86_FEATURE_TM2 ( 4*32+ 8) /* Thermal Monitor 2 */
#define X86_FEATURE_SSSE3 ( 4*32+ 9) /* Supplemental SSE-3 */
#define X86_FEATURE_CID ( 4*32+10) /* Context ID */
#define X86_FEATURE_SDBG ( 4*32+11) /* Silicon Debug */
#define X86_FEATURE_FMA ( 4*32+12) /* Fused multiply-add */
#define X86_FEATURE_CX16 ( 4*32+13) /* CMPXCHG16B */
#define X86_FEATURE_XTPR ( 4*32+14) /* Send Task Priority Messages */
#define X86_FEATURE_PDCM ( 4*32+15) /* Performance Capabilities */
#define X86_FEATURE_PCID ( 4*32+17) /* Process Context Identifiers */
#define X86_FEATURE_DCA ( 4*32+18) /* Direct Cache Access */
#define X86_FEATURE_XMM4_1 ( 4*32+19) /* "sse4_1" SSE-4.1 */
#define X86_FEATURE_XMM4_2 ( 4*32+20) /* "sse4_2" SSE-4.2 */
#define X86_FEATURE_X2APIC ( 4*32+21) /* x2APIC */
#define X86_FEATURE_MOVBE ( 4*32+22) /* MOVBE instruction */
#define X86_FEATURE_POPCNT ( 4*32+23) /* POPCNT instruction */
#define X86_FEATURE_TSC_DEADLINE_TIMER ( 4*32+24) /* Tsc deadline timer */
#define X86_FEATURE_AES ( 4*32+25) /* AES instructions */
#define X86_FEATURE_XSAVE ( 4*32+26) /* XSAVE/XRSTOR/XSETBV/XGETBV */
#define X86_FEATURE_OSXSAVE ( 4*32+27) /* "" XSAVE enabled in the OS */
#define X86_FEATURE_AVX ( 4*32+28) /* Advanced Vector Extensions */
#define X86_FEATURE_F16C ( 4*32+29) /* 16-bit fp conversions */
#define X86_FEATURE_RDRAND ( 4*32+30) /* The RDRAND instruction */
#define X86_FEATURE_HYPERVISOR ( 4*32+31) /* Running on a hypervisor */
/* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */
#define X86_FEATURE_XSTORE ( 5*32+ 2) /* "rng" RNG present (xstore) */
#define X86_FEATURE_XSTORE_EN ( 5*32+ 3) /* "rng_en" RNG enabled */
#define X86_FEATURE_XCRYPT ( 5*32+ 6) /* "ace" on-CPU crypto (xcrypt) */
#define X86_FEATURE_XCRYPT_EN ( 5*32+ 7) /* "ace_en" on-CPU crypto enabled */
#define X86_FEATURE_ACE2 ( 5*32+ 8) /* Advanced Cryptography Engine v2 */
#define X86_FEATURE_ACE2_EN ( 5*32+ 9) /* ACE v2 enabled */
#define X86_FEATURE_PHE ( 5*32+10) /* PadLock Hash Engine */
#define X86_FEATURE_PHE_EN ( 5*32+11) /* PHE enabled */
#define X86_FEATURE_PMM ( 5*32+12) /* PadLock Montgomery Multiplier */
#define X86_FEATURE_PMM_EN ( 5*32+13) /* PMM enabled */
/* More extended AMD flags: CPUID level 0x80000001, ecx, word 6 */
#define X86_FEATURE_LAHF_LM ( 6*32+ 0) /* LAHF/SAHF in long mode */
#define X86_FEATURE_CMP_LEGACY ( 6*32+ 1) /* If yes HyperThreading not valid */
#define X86_FEATURE_SVM ( 6*32+ 2) /* Secure virtual machine */
#define X86_FEATURE_EXTAPIC ( 6*32+ 3) /* Extended APIC space */
#define X86_FEATURE_CR8_LEGACY ( 6*32+ 4) /* CR8 in 32-bit mode */
#define X86_FEATURE_ABM ( 6*32+ 5) /* Advanced bit manipulation */
#define X86_FEATURE_SSE4A ( 6*32+ 6) /* SSE-4A */
#define X86_FEATURE_MISALIGNSSE ( 6*32+ 7) /* Misaligned SSE mode */
#define X86_FEATURE_3DNOWPREFETCH ( 6*32+ 8) /* 3DNow prefetch instructions */
#define X86_FEATURE_OSVW ( 6*32+ 9) /* OS Visible Workaround */
#define X86_FEATURE_IBS ( 6*32+10) /* Instruction Based Sampling */
#define X86_FEATURE_XOP ( 6*32+11) /* extended AVX instructions */
#define X86_FEATURE_SKINIT ( 6*32+12) /* SKINIT/STGI instructions */
#define X86_FEATURE_WDT ( 6*32+13) /* Watchdog timer */
#define X86_FEATURE_LWP ( 6*32+15) /* Light Weight Profiling */
#define X86_FEATURE_FMA4 ( 6*32+16) /* 4 operands MAC instructions */
#define X86_FEATURE_TCE ( 6*32+17) /* translation cache extension */
#define X86_FEATURE_NODEID_MSR ( 6*32+19) /* NodeId MSR */
#define X86_FEATURE_TBM ( 6*32+21) /* trailing bit manipulations */
#define X86_FEATURE_TOPOEXT ( 6*32+22) /* topology extensions CPUID leafs */
#define X86_FEATURE_PERFCTR_CORE ( 6*32+23) /* core performance counter extensions */
#define X86_FEATURE_PERFCTR_NB ( 6*32+24) /* NB performance counter extensions */
#define X86_FEATURE_BPEXT (6*32+26) /* data breakpoint extension */
#define X86_FEATURE_PERFCTR_L2 ( 6*32+28) /* L2 performance counter extensions */
#define X86_FEATURE_MWAITX ( 6*32+29) /* MWAIT extension (MONITORX/MWAITX) */
/*
* Auxiliary flags: Linux defined - For features scattered in various
* CPUID levels like 0x6, 0xA etc, word 7.
*
* Reuse free bits when adding new feature flags!
*/
#define X86_FEATURE_CPB ( 7*32+ 2) /* AMD Core Performance Boost */
#define X86_FEATURE_EPB ( 7*32+ 3) /* IA32_ENERGY_PERF_BIAS support */
#define X86_FEATURE_HW_PSTATE ( 7*32+ 8) /* AMD HW-PState */
#define X86_FEATURE_PROC_FEEDBACK ( 7*32+ 9) /* AMD ProcFeedbackInterface */
#define X86_FEATURE_INTEL_PT ( 7*32+15) /* Intel Processor Trace */
/* Virtualization flags: Linux defined, word 8 */
#define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */
#define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */
#define X86_FEATURE_FLEXPRIORITY ( 8*32+ 2) /* Intel FlexPriority */
#define X86_FEATURE_EPT ( 8*32+ 3) /* Intel Extended Page Table */
#define X86_FEATURE_VPID ( 8*32+ 4) /* Intel Virtual Processor ID */
#define X86_FEATURE_VMMCALL ( 8*32+15) /* Prefer vmmcall to vmcall */
#define X86_FEATURE_XENPV ( 8*32+16) /* "" Xen paravirtual guest */
/* Intel-defined CPU features, CPUID level 0x00000007:0 (ebx), word 9 */
#define X86_FEATURE_FSGSBASE ( 9*32+ 0) /* {RD/WR}{FS/GS}BASE instructions*/
#define X86_FEATURE_TSC_ADJUST ( 9*32+ 1) /* TSC adjustment MSR 0x3b */
#define X86_FEATURE_BMI1 ( 9*32+ 3) /* 1st group bit manipulation extensions */
#define X86_FEATURE_HLE ( 9*32+ 4) /* Hardware Lock Elision */
#define X86_FEATURE_AVX2 ( 9*32+ 5) /* AVX2 instructions */
#define X86_FEATURE_SMEP ( 9*32+ 7) /* Supervisor Mode Execution Protection */
#define X86_FEATURE_BMI2 ( 9*32+ 8) /* 2nd group bit manipulation extensions */
#define X86_FEATURE_ERMS ( 9*32+ 9) /* Enhanced REP MOVSB/STOSB */
#define X86_FEATURE_INVPCID ( 9*32+10) /* Invalidate Processor Context ID */
#define X86_FEATURE_RTM ( 9*32+11) /* Restricted Transactional Memory */
#define X86_FEATURE_CQM ( 9*32+12) /* Cache QoS Monitoring */
#define X86_FEATURE_MPX ( 9*32+14) /* Memory Protection Extension */
#define X86_FEATURE_AVX512F ( 9*32+16) /* AVX-512 Foundation */
#define X86_FEATURE_AVX512DQ ( 9*32+17) /* AVX-512 DQ (Double/Quad granular) Instructions */
#define X86_FEATURE_RDSEED ( 9*32+18) /* The RDSEED instruction */
#define X86_FEATURE_ADX ( 9*32+19) /* The ADCX and ADOX instructions */
#define X86_FEATURE_SMAP ( 9*32+20) /* Supervisor Mode Access Prevention */
#define X86_FEATURE_PCOMMIT ( 9*32+22) /* PCOMMIT instruction */
#define X86_FEATURE_CLFLUSHOPT ( 9*32+23) /* CLFLUSHOPT instruction */
#define X86_FEATURE_CLWB ( 9*32+24) /* CLWB instruction */
#define X86_FEATURE_AVX512PF ( 9*32+26) /* AVX-512 Prefetch */
#define X86_FEATURE_AVX512ER ( 9*32+27) /* AVX-512 Exponential and Reciprocal */
#define X86_FEATURE_AVX512CD ( 9*32+28) /* AVX-512 Conflict Detection */
#define X86_FEATURE_SHA_NI ( 9*32+29) /* SHA1/SHA256 Instruction Extensions */
#define X86_FEATURE_AVX512BW ( 9*32+30) /* AVX-512 BW (Byte/Word granular) Instructions */
#define X86_FEATURE_AVX512VL ( 9*32+31) /* AVX-512 VL (128/256 Vector Length) Extensions */
/* Extended state features, CPUID level 0x0000000d:1 (eax), word 10 */
#define X86_FEATURE_XSAVEOPT (10*32+ 0) /* XSAVEOPT */
#define X86_FEATURE_XSAVEC (10*32+ 1) /* XSAVEC */
#define X86_FEATURE_XGETBV1 (10*32+ 2) /* XGETBV with ECX = 1 */
#define X86_FEATURE_XSAVES (10*32+ 3) /* XSAVES/XRSTORS */
/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:0 (edx), word 11 */
#define X86_FEATURE_CQM_LLC (11*32+ 1) /* LLC QoS if 1 */
/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:1 (edx), word 12 */
#define X86_FEATURE_CQM_OCCUP_LLC (12*32+ 0) /* LLC occupancy monitoring if 1 */
/* AMD-defined CPU features, CPUID level 0x80000008 (ebx), word 13 */
#define X86_FEATURE_CLZERO (13*32+0) /* CLZERO instruction */
/* Thermal and Power Management Leaf, CPUID level 0x00000006 (eax), word 14 */
#define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */
#define X86_FEATURE_IDA (14*32+ 1) /* Intel Dynamic Acceleration */
#define X86_FEATURE_ARAT (14*32+ 2) /* Always Running APIC Timer */
#define X86_FEATURE_PLN (14*32+ 4) /* Intel Power Limit Notification */
#define X86_FEATURE_PTS (14*32+ 6) /* Intel Package Thermal Status */
#define X86_FEATURE_HWP (14*32+ 7) /* Intel Hardware P-states */
#define X86_FEATURE_HWP_NOTIFY (14*32+ 8) /* HWP Notification */
#define X86_FEATURE_HWP_ACT_WINDOW (14*32+ 9) /* HWP Activity Window */
#define X86_FEATURE_HWP_EPP (14*32+10) /* HWP Energy Perf. Preference */
#define X86_FEATURE_HWP_PKG_REQ (14*32+11) /* HWP Package Level Request */
/* AMD SVM Feature Identification, CPUID level 0x8000000a (edx), word 15 */
#define X86_FEATURE_NPT (15*32+ 0) /* Nested Page Table support */
#define X86_FEATURE_LBRV (15*32+ 1) /* LBR Virtualization support */
#define X86_FEATURE_SVML (15*32+ 2) /* "svm_lock" SVM locking MSR */
#define X86_FEATURE_NRIPS (15*32+ 3) /* "nrip_save" SVM next_rip save */
#define X86_FEATURE_TSCRATEMSR (15*32+ 4) /* "tsc_scale" TSC scaling support */
#define X86_FEATURE_VMCBCLEAN (15*32+ 5) /* "vmcb_clean" VMCB clean bits support */
#define X86_FEATURE_FLUSHBYASID (15*32+ 6) /* flush-by-ASID support */
#define X86_FEATURE_DECODEASSISTS (15*32+ 7) /* Decode Assists support */
#define X86_FEATURE_PAUSEFILTER (15*32+10) /* filtered pause intercept */
#define X86_FEATURE_PFTHRESHOLD (15*32+12) /* pause filter threshold */
#define X86_FEATURE_AVIC (15*32+13) /* Virtual Interrupt Controller */
/*
* BUG word(s)
*/
#define X86_BUG(x) (NCAPINTS*32 + (x))
#define X86_BUG_F00F X86_BUG(0) /* Intel F00F */
#define X86_BUG_FDIV X86_BUG(1) /* FPU FDIV */
#define X86_BUG_COMA X86_BUG(2) /* Cyrix 6x86 coma */
#define X86_BUG_AMD_TLB_MMATCH X86_BUG(3) /* "tlb_mmatch" AMD Erratum 383 */
#define X86_BUG_AMD_APIC_C1E X86_BUG(4) /* "apic_c1e" AMD Erratum 400 */
#define X86_BUG_11AP X86_BUG(5) /* Bad local APIC aka 11AP */
#define X86_BUG_FXSAVE_LEAK X86_BUG(6) /* FXSAVE leaks FOP/FIP/FOP */
#define X86_BUG_CLFLUSH_MONITOR X86_BUG(7) /* AAI65, CLFLUSH required before MONITOR */
#define X86_BUG_SYSRET_SS_ATTRS X86_BUG(8) /* SYSRET doesn't fix up SS attrs */
x86/entry/32: Introduce and use X86_BUG_ESPFIX instead of paravirt_enabled x86_64 has very clean espfix handling on paravirt: espfix64 is set up in native_iret, so paravirt systems that override iret bypass espfix64 automatically. This is robust and straightforward. x86_32 is messier. espfix is set up before the IRET paravirt patch point, so it can't be directly conditionalized on whether we use native_iret. We also can't easily move it into native_iret without regressing performance due to a bizarre consideration. Specifically, on 64-bit kernels, the logic is: if (regs->ss & 0x4) setup_espfix; On 32-bit kernels, the logic is: if ((regs->ss & 0x4) && (regs->cs & 0x3) == 3 && (regs->flags & X86_EFLAGS_VM) == 0) setup_espfix; The performance of setup_espfix itself is essentially irrelevant, but the comparison happens on every IRET so its performance matters. On x86_64, there's no need for any registers except flags to implement the comparison, so we fold the whole thing into native_iret. On x86_32, we don't do that because we need a free register to implement the comparison efficiently. We therefore do espfix setup before restoring registers on x86_32. This patch gets rid of the explicit paravirt_enabled check by introducing X86_BUG_ESPFIX on 32-bit systems and using an ALTERNATIVE to skip espfix on paravirt systems where iret != native_iret. This is also messy, but it's at least in line with other things we do. This improves espfix performance by removing a branch, but no one cares. More importantly, it removes a paravirt_enabled user, which is good because paravirt_enabled is ill-defined and is going away. Signed-off-by: Andy Lutomirski <luto@kernel.org> Reviewed-by: Borislav Petkov <bp@suse.de> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: boris.ostrovsky@oracle.com Cc: david.vrabel@citrix.com Cc: konrad.wilk@oracle.com Cc: lguest@lists.ozlabs.org Cc: xen-devel@lists.xensource.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-01 07:50:19 +08:00
#ifdef CONFIG_X86_32
/*
* 64-bit kernels don't use X86_BUG_ESPFIX. Make the define conditional
* to avoid confusion.
*/
#define X86_BUG_ESPFIX X86_BUG(9) /* "" IRET to 16-bit SS corrupts ESP/RSP high bits */
#endif
#endif /* _ASM_X86_CPUFEATURES_H */