Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

Pull x86 fpu updates from Ingo Molnar:
 "Three changes:

   - preparatory patch for AVX state tracking that computing-cluster
     folks would like to use for user-space batching - but we are not
     happy about the related ABI yet so this is only the kernel tracking
     side

   - a cleanup for CR0 handling in do_device_not_available()

   - plus we removed a workaround for an ancient binutils version"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu: Track AVX-512 usage of tasks
  x86/fpu: Get rid of CONFIG_AS_FXSAVEQ
  x86/traps: Have read_cr0() only once in the #NM handler

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index f55420a..2d8b9d8 100644 (file)
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -187,7 +187,6 @@ cfi-sigframe := $(call as-instr,.cfi_startproc\n.cfi_signal_frame\n.cfi_endproc,
 cfi-sections := $(call as-instr,.cfi_sections .debug_frame,-DCONFIG_AS_CFI_SECTIONS=1)
 
 # does binutils support specific instructions?
-asinstr := $(call as-instr,fxsaveq (%rax),-DCONFIG_AS_FXSAVEQ=1)
 asinstr += $(call as-instr,pshufb %xmm0$(comma)%xmm0,-DCONFIG_AS_SSSE3=1)
 avx_instr := $(call as-instr,vxorps %ymm0$(comma)%ymm1$(comma)%ymm2,-DCONFIG_AS_AVX=1)
 avx2_instr :=$(call as-instr,vpbroadcastb %xmm0$(comma)%ymm1,-DCONFIG_AS_AVX2=1)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index fa2c93c..fb04a3d 100644 (file)
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -137,37 +137,25 @@ static inline int copy_fxregs_to_user(struct fxregs_state __user *fx)
 {
        if (IS_ENABLED(CONFIG_X86_32))
                return user_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx));
-       else if (IS_ENABLED(CONFIG_AS_FXSAVEQ))
+       else
                return user_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx));
 
-       /* See comment in copy_fxregs_to_kernel() below. */
-       return user_insn(rex64/fxsave (%[fx]), "=m" (*fx), [fx] "R" (fx));
 }
 
 static inline void copy_kernel_to_fxregs(struct fxregs_state *fx)
 {
-       if (IS_ENABLED(CONFIG_X86_32)) {
+       if (IS_ENABLED(CONFIG_X86_32))
                kernel_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
-       } else {
-               if (IS_ENABLED(CONFIG_AS_FXSAVEQ)) {
-                       kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
-               } else {
-                       /* See comment in copy_fxregs_to_kernel() below. */
-                       kernel_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), "m" (*fx));
-               }
-       }
+       else
+               kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
 }
 
 static inline int copy_user_to_fxregs(struct fxregs_state __user *fx)
 {
        if (IS_ENABLED(CONFIG_X86_32))
                return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx));
-       else if (IS_ENABLED(CONFIG_AS_FXSAVEQ))
+       else
                return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx));
-
-       /* See comment in copy_fxregs_to_kernel() below. */
-       return user_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx),
-                         "m" (*fx));
 }
 
 static inline void copy_kernel_to_fregs(struct fregs_state *fx)
@@ -184,34 +172,8 @@ static inline void copy_fxregs_to_kernel(struct fpu *fpu)
 {
        if (IS_ENABLED(CONFIG_X86_32))
                asm volatile( "fxsave %[fx]" : [fx] "=m" (fpu->state.fxsave));
-       else if (IS_ENABLED(CONFIG_AS_FXSAVEQ))
+       else
                asm volatile("fxsaveq %[fx]" : [fx] "=m" (fpu->state.fxsave));
-       else {
-               /* Using "rex64; fxsave %0" is broken because, if the memory
-                * operand uses any extended registers for addressing, a second
-                * REX prefix will be generated (to the assembler, rex64
-                * followed by semicolon is a separate instruction), and hence
-                * the 64-bitness is lost.
-                *
-                * Using "fxsaveq %0" would be the ideal choice, but is only
-                * supported starting with gas 2.16.
-                *
-                * Using, as a workaround, the properly prefixed form below
-                * isn't accepted by any binutils version so far released,
-                * complaining that the same type of prefix is used twice if
-                * an extended register is needed for addressing (fix submitted
-                * to mainline 2005-11-21).
-                *
-                *  asm volatile("rex64/fxsave %0" : "=m" (fpu->state.fxsave));
-                *
-                * This, however, we can work around by forcing the compiler to
-                * select an addressing mode that doesn't require extended
-                * registers.
-                */
-               asm volatile( "rex64/fxsave (%[fx])"
-                            : "=m" (fpu->state.fxsave)
-                            : [fx] "R" (&fpu->state.fxsave));
-       }
 }
 
 /* These macros all use (%edi)/(%rdi) as the single memory argument. */
@@ -414,6 +376,13 @@ static inline int copy_fpregs_to_fpstate(struct fpu *fpu)
 {
        if (likely(use_xsave())) {
                copy_xregs_to_kernel(&fpu->state.xsave);
+
+               /*
+                * AVX512 state is tracked here because its use is
+                * known to slow the max clock speed of the core.
+                */
+               if (fpu->state.xsave.header.xfeatures & XFEATURE_MASK_AVX512)
+                       fpu->avx512_timestamp = jiffies;
                return 1;
        }
 

diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 202c539..2e32e17 100644 (file)
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -302,6 +302,13 @@ struct fpu {
         */
        unsigned char                   initialized;
 
+       /*
+        * @avx512_timestamp:
+        *
+        * Records the timestamp of AVX512 use during last context switch.
+        */
+       unsigned long                   avx512_timestamp;
+
        /*
         * @state:
         *

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index e289ce1..d26f9e9 100644 (file)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -881,12 +881,12 @@ do_spurious_interrupt_bug(struct pt_regs *regs, long error_code)
 dotraplinkage void
 do_device_not_available(struct pt_regs *regs, long error_code)
 {
-       unsigned long cr0;
+       unsigned long cr0 = read_cr0();
 
        RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
 
 #ifdef CONFIG_MATH_EMULATION
-       if (!boot_cpu_has(X86_FEATURE_FPU) && (read_cr0() & X86_CR0_EM)) {
+       if (!boot_cpu_has(X86_FEATURE_FPU) && (cr0 & X86_CR0_EM)) {
                struct math_emu_info info = { };
 
                cond_local_irq_enable(regs);
@@ -898,7 +898,6 @@ do_device_not_available(struct pt_regs *regs, long error_code)
 #endif
 
        /* This should not happen. */
-       cr0 = read_cr0();
        if (WARN(cr0 & X86_CR0_TS, "CR0.TS was set")) {
                /* Try to fix it up and carry on. */
                write_cr0(cr0 & ~X86_CR0_TS);