x86/fpu: Remove struct fpu::fpregs_active

The previous changes paved the way for the removal of the
fpu::fpregs_active state flag - we now only have the
fpu::fpstate_active and fpu::last_cpu fields left.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-21-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 42a6016..629e7ab 100644 (file)
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -526,14 +526,12 @@ static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu)
  */
 static inline void fpregs_deactivate(struct fpu *fpu)
 {
-       fpu->fpregs_active = 0;
        this_cpu_write(fpu_fpregs_owner_ctx, NULL);
        trace_x86_fpu_regs_deactivated(fpu);
 }
 
 static inline void fpregs_activate(struct fpu *fpu)
 {
-       fpu->fpregs_active = 1;
        this_cpu_write(fpu_fpregs_owner_ctx, fpu);
        trace_x86_fpu_regs_activated(fpu);
 }
@@ -552,8 +550,6 @@ static inline void fpregs_activate(struct fpu *fpu)
 static inline void
 switch_fpu_prepare(struct fpu *old_fpu, int cpu)
 {
-       WARN_ON_FPU(old_fpu->fpregs_active != old_fpu->fpstate_active);
-
        if (old_fpu->fpstate_active) {
                if (!copy_fpregs_to_fpstate(old_fpu))
                        old_fpu->last_cpu = -1;
@@ -561,7 +557,6 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu)
                        old_fpu->last_cpu = cpu;
 
                /* But leave fpu_fpregs_owner_ctx! */
-               old_fpu->fpregs_active = 0;
                trace_x86_fpu_regs_deactivated(old_fpu);
        } else
                old_fpu->last_cpu = -1;

diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 3c80f5b..0c314a3 100644 (file)
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -299,29 +299,6 @@ struct fpu {
        unsigned char                   fpstate_active;
 
        /*
-        * @fpregs_active:
-        *
-        * This flag determines whether a given context is actively
-        * loaded into the FPU's registers and that those registers
-        * represent the task's current FPU state.
-        *
-        * Note the interaction with fpstate_active:
-        *
-        *   # task does not use the FPU:
-        *   fpstate_active == 0
-        *
-        *   # task uses the FPU and regs are active:
-        *   fpstate_active == 1 && fpregs_active == 1
-        *
-        *   # the regs are inactive but still match fpstate:
-        *   fpstate_active == 1 && fpregs_active == 0 && fpregs_owner == fpu
-        *
-        * The third state is what we use for the lazy restore optimization
-        * on lazy-switching CPUs.
-        */
-       unsigned char                   fpregs_active;
-
-       /*
         * @state:
         *
         * In-memory copy of all FPU registers that we save/restore

diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h
index 342e597..da565aa 100644 (file)
--- a/arch/x86/include/asm/trace/fpu.h
+++ b/arch/x86/include/asm/trace/fpu.h
@@ -12,7 +12,6 @@ DECLARE_EVENT_CLASS(x86_fpu,
 
        TP_STRUCT__entry(
                __field(struct fpu *, fpu)
-               __field(bool, fpregs_active)
                __field(bool, fpstate_active)
                __field(u64, xfeatures)
                __field(u64, xcomp_bv)
@@ -20,16 +19,14 @@ DECLARE_EVENT_CLASS(x86_fpu,
 
        TP_fast_assign(
                __entry->fpu            = fpu;
-               __entry->fpregs_active  = fpu->fpregs_active;
                __entry->fpstate_active = fpu->fpstate_active;
                if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
                        __entry->xfeatures = fpu->state.xsave.header.xfeatures;
                        __entry->xcomp_bv  = fpu->state.xsave.header.xcomp_bv;
                }
        ),
-       TP_printk("x86/fpu: %p fpregs_active: %d fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
+       TP_printk("x86/fpu: %p fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
                        __entry->fpu,
-                       __entry->fpregs_active,
                        __entry->fpstate_active,
                        __entry->xfeatures,
                        __entry->xcomp_bv

diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 01a47e9..93103a9 100644 (file)
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -147,8 +147,6 @@ void fpu__save(struct fpu *fpu)
        WARN_ON_FPU(fpu != &current->thread.fpu);
 
        preempt_disable();
-       WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
-
        trace_x86_fpu_before_save(fpu);
        if (fpu->fpstate_active) {
                if (!copy_fpregs_to_fpstate(fpu)) {
@@ -191,7 +189,6 @@ EXPORT_SYMBOL_GPL(fpstate_init);
 
 int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
 {
-       dst_fpu->fpregs_active = 0;
        dst_fpu->last_cpu = -1;
 
        if (!src_fpu->fpstate_active || !static_cpu_has(X86_FEATURE_FPU))
@@ -264,7 +261,6 @@ EXPORT_SYMBOL_GPL(fpu__activate_curr);
  */
 void fpu__activate_fpstate_read(struct fpu *fpu)
 {
-       WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
        /*
         * If fpregs are active (in the current CPU), then
         * copy them to the fpstate:
@@ -365,7 +361,6 @@ void fpu__current_fpstate_write_end(void)
 {
        struct fpu *fpu = &current->thread.fpu;
 
-       WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
        /*
         * 'fpu' now has an updated copy of the state, but the
         * registers may still be out of date.  Update them with
@@ -419,8 +414,6 @@ void fpu__drop(struct fpu *fpu)
        preempt_disable();
 
        if (fpu == &current->thread.fpu) {
-               WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
-
                if (fpu->fpstate_active) {
                        /* Ignore delayed exceptions from user space */
                        asm volatile("1: fwait\n"
@@ -428,8 +421,6 @@ void fpu__drop(struct fpu *fpu)
                                     _ASM_EXTABLE(1b, 2b));
                        fpregs_deactivate(fpu);
                }
-       } else {
-               WARN_ON_FPU(fpu->fpregs_active);
        }
 
        fpu->fpstate_active = 0;

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index a88083b..629106e 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -171,8 +171,6 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
                        sizeof(struct user_i387_ia32_struct), NULL,
                        (struct _fpstate_32 __user *) buf) ? -1 : 1;
 
-       WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
-
        if (fpu->fpstate_active || using_compacted_format()) {
                /* Save the live register state to the user directly. */
                if (copy_fpregs_to_sigframe(buf_fx))