1 files changed, 520 insertions, 0 deletions

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
new file mode 100644
index 000000000000..4fa88154e4de
--- /dev/null
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -0,0 +1,520 @@
+/*
+ * Copyright (C) 1994 Linus Torvalds
+ *
+ * Pentium III FXSR, SSE support
+ * General FPU state handling cleanups
+ *      Gareth Hughes <gareth@valinux.com>, May 2000
+ * x86-64 work by Andi Kleen 2002
+ */
+
+#ifndef _FPU_INTERNAL_H
+#define _FPU_INTERNAL_H
+
+#include <linux/kernel_stat.h>
+#include <linux/regset.h>
+#include <linux/slab.h>
+#include <asm/asm.h>
+#include <asm/cpufeature.h>
+#include <asm/processor.h>
+#include <asm/sigcontext.h>
+#include <asm/user.h>
+#include <asm/uaccess.h>
+#include <asm/xsave.h>
+
+extern unsigned int sig_xstate_size;
+extern void fpu_init(void);
+
+DECLARE_PER_CPU(struct task_struct *, fpu_owner_task);
+
+extern user_regset_active_fn fpregs_active, xfpregs_active;
+extern user_regset_get_fn fpregs_get, xfpregs_get, fpregs_soft_get,
+                                xstateregs_get;
+extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set,
+                                 xstateregs_set;
+
+
+/*
+ * xstateregs_active == fpregs_active. Please refer to the comment
+ * at the definition of fpregs_active.
+ */
+#define xstateregs_active       fpregs_active
+
+extern struct _fpx_sw_bytes fx_sw_reserved;
+#ifdef CONFIG_IA32_EMULATION
+extern unsigned int sig_xstate_ia32_size;
+extern struct _fpx_sw_bytes fx_sw_reserved_ia32;
+struct _fpstate_ia32;
+struct _xstate_ia32;
+extern int save_i387_xstate_ia32(void __user *buf);
+extern int restore_i387_xstate_ia32(void __user *buf);
+#endif
+
+#ifdef CONFIG_MATH_EMULATION
+extern void finit_soft_fpu(struct i387_soft_struct *soft);
+#else
+static inline void finit_soft_fpu(struct i387_soft_struct *soft) {}
+#endif
+
+#define X87_FSW_ES (1 << 7)     /* Exception Summary */
+
+static __always_inline __pure bool use_xsaveopt(void)
+{
+        return static_cpu_has(X86_FEATURE_XSAVEOPT);
+}
+
+static __always_inline __pure bool use_xsave(void)
+{
+        return static_cpu_has(X86_FEATURE_XSAVE);
+}
+
+static __always_inline __pure bool use_fxsr(void)
+{
+        return static_cpu_has(X86_FEATURE_FXSR);
+}
+
+extern void __sanitize_i387_state(struct task_struct *);
+
+static inline void sanitize_i387_state(struct task_struct *tsk)
+{
+        if (!use_xsaveopt())
+                return;
+        __sanitize_i387_state(tsk);
+}
+
+#ifdef CONFIG_X86_64
+static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
+{
+        int err;
+
+        /* See comment in fxsave() below. */
+#ifdef CONFIG_AS_FXSAVEQ
+        asm volatile("1:  fxrstorq %[fx]\n\t"
+                     "2:\n"
+                     ".section .fixup,\"ax\"\n"
+                     "3:  movl $-1,%[err]\n"
+                     "    jmp  2b\n"
+                     ".previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : [err] "=r" (err)
+                     : [fx] "m" (*fx), "0" (0));
+#else
+        asm volatile("1:  rex64/fxrstor (%[fx])\n\t"
+                     "2:\n"
+                     ".section .fixup,\"ax\"\n"
+                     "3:  movl $-1,%[err]\n"
+                     "    jmp  2b\n"
+                     ".previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : [err] "=r" (err)
+                     : [fx] "R" (fx), "m" (*fx), "0" (0));
+#endif
+        return err;
+}
+
+static inline int fxsave_user(struct i387_fxsave_struct __user *fx)
+{
+        int err;
+
+        /*
+         * Clear the bytes not touched by the fxsave and reserved
+         * for the SW usage.
+         */
+        err = __clear_user(&fx->sw_reserved,
+                           sizeof(struct _fpx_sw_bytes));
+        if (unlikely(err))
+                return -EFAULT;
+
+        /* See comment in fxsave() below. */
+#ifdef CONFIG_AS_FXSAVEQ
+        asm volatile("1:  fxsaveq %[fx]\n\t"
+                     "2:\n"
+                     ".section .fixup,\"ax\"\n"
+                     "3:  movl $-1,%[err]\n"
+                     "    jmp  2b\n"
+                     ".previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : [err] "=r" (err), [fx] "=m" (*fx)
+                     : "0" (0));
+#else
+        asm volatile("1:  rex64/fxsave (%[fx])\n\t"
+                     "2:\n"
+                     ".section .fixup,\"ax\"\n"
+                     "3:  movl $-1,%[err]\n"
+                     "    jmp  2b\n"
+                     ".previous\n"
+                     _ASM_EXTABLE(1b, 3b)
+                     : [err] "=r" (err), "=m" (*fx)
+                     : [fx] "R" (fx), "0" (0));
+#endif
+        if (unlikely(err) &&
+            __clear_user(fx, sizeof(struct i387_fxsave_struct)))
+                err = -EFAULT;
+        /* No need to clear here because the caller clears USED_MATH */
+        return err;
+}
+
+static inline void fpu_fxsave(struct fpu *fpu)
+{
+        /* 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. */
+
+#ifdef CONFIG_AS_FXSAVEQ
+        /* Using "fxsaveq %0" would be the ideal choice, but is only supported
+           starting with gas 2.16. */
+        __asm__ __volatile__("fxsaveq %0"
+                             : "=m" (fpu->state->fxsave));
+#else
+        /* 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));
+#endif
+}
+
+#else  /* CONFIG_X86_32 */
+
+/* perform fxrstor iff the processor has extended states, otherwise frstor */
+static inline int fxrstor_checking(struct i387_fxsave_struct *fx)
+{
+        /*
+         * The "nop" is needed to make the instructions the same
+         * length.
+         */
+        alternative_input(
+                "nop ; frstor %1",
+                "fxrstor %1",
+                X86_FEATURE_FXSR,
+                "m" (*fx));
+
+        return 0;
+}
+
+static inline void fpu_fxsave(struct fpu *fpu)
+{
+        asm volatile("fxsave %[fx]"
+                     : [fx] "=m" (fpu->state->fxsave));
+}
+
+#endif  /* CONFIG_X86_64 */
+
+/*
+ * These must be called with preempt disabled. Returns
+ * 'true' if the FPU state is still intact.
+ */
+static inline int fpu_save_init(struct fpu *fpu)
+{
+        if (use_xsave()) {
+                fpu_xsave(fpu);
+
+                /*
+                 * xsave header may indicate the init state of the FP.
+                 */
+                if (!(fpu->state->xsave.xsave_hdr.xstate_bv & XSTATE_FP))
+                        return 1;
+        } else if (use_fxsr()) {
+                fpu_fxsave(fpu);
+        } else {
+                asm volatile("fnsave %[fx]; fwait"
+                             : [fx] "=m" (fpu->state->fsave));
+                return 0;
+        }
+
+        /*
+         * If exceptions are pending, we need to clear them so
+         * that we don't randomly get exceptions later.
+         *
+         * FIXME! Is this perhaps only true for the old-style
+         * irq13 case? Maybe we could leave the x87 state
+         * intact otherwise?
+         */
+        if (unlikely(fpu->state->fxsave.swd & X87_FSW_ES)) {
+                asm volatile("fnclex");
+                return 0;
+        }
+        return 1;
+}
+
+static inline int __save_init_fpu(struct task_struct *tsk)
+{
+        return fpu_save_init(&tsk->thread.fpu);
+}
+
+static inline int fpu_fxrstor_checking(struct fpu *fpu)
+{
+        return fxrstor_checking(&fpu->state->fxsave);
+}
+
+static inline int fpu_restore_checking(struct fpu *fpu)
+{
+        if (use_xsave())
+                return fpu_xrstor_checking(fpu);
+        else
+                return fpu_fxrstor_checking(fpu);
+}
+
+static inline int restore_fpu_checking(struct task_struct *tsk)
+{
+        /* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
+           is pending.  Clear the x87 state here by setting it to fixed
+           values. "m" is a random variable that should be in L1 */
+        alternative_input(
+                ASM_NOP8 ASM_NOP2,
+                "emms\n\t"              /* clear stack tags */
+                "fildl %P[addr]",       /* set F?P to defined value */
+                X86_FEATURE_FXSAVE_LEAK,
+                [addr] "m" (tsk->thread.fpu.has_fpu));
+
+        return fpu_restore_checking(&tsk->thread.fpu);
+}
+
+/*
+ * Software FPU state helpers. Careful: these need to
+ * be preemption protection *and* they need to be
+ * properly paired with the CR0.TS changes!
+ */
+static inline int __thread_has_fpu(struct task_struct *tsk)
+{
+        return tsk->thread.fpu.has_fpu;
+}
+
+/* Must be paired with an 'stts' after! */
+static inline void __thread_clear_has_fpu(struct task_struct *tsk)
+{
+        tsk->thread.fpu.has_fpu = 0;
+        percpu_write(fpu_owner_task, NULL);
+}
+
+/* Must be paired with a 'clts' before! */
+static inline void __thread_set_has_fpu(struct task_struct *tsk)
+{
+        tsk->thread.fpu.has_fpu = 1;
+        percpu_write(fpu_owner_task, tsk);
+}
+
+/*
+ * Encapsulate the CR0.TS handling together with the
+ * software flag.
+ *
+ * These generally need preemption protection to work,
+ * do try to avoid using these on their own.
+ */
+static inline void __thread_fpu_end(struct task_struct *tsk)
+{
+        __thread_clear_has_fpu(tsk);
+        stts();
+}
+
+static inline void __thread_fpu_begin(struct task_struct *tsk)
+{
+        clts();
+        __thread_set_has_fpu(tsk);
+}
+
+/*
+ * FPU state switching for scheduling.
+ *
+ * This is a two-stage process:
+ *
+ *  - switch_fpu_prepare() saves the old state and
+ *    sets the new state of the CR0.TS bit. This is
+ *    done within the context of the old process.
+ *
+ *  - switch_fpu_finish() restores the new state as
+ *    necessary.
+ */
+typedef struct { int preload; } fpu_switch_t;
+
+/*
+ * FIXME! We could do a totally lazy restore, but we need to
+ * add a per-cpu "this was the task that last touched the FPU
+ * on this CPU" variable, and the task needs to have a "I last
+ * touched the FPU on this CPU" and check them.
+ *
+ * We don't do that yet, so "fpu_lazy_restore()" always returns
+ * false, but some day..
+ */
+static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu)
+{
+        return new == percpu_read_stable(fpu_owner_task) &&
+                cpu == new->thread.fpu.last_cpu;
+}
+
+static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct task_struct *new, int cpu)
+{
+        fpu_switch_t fpu;
+
+        fpu.preload = tsk_used_math(new) && new->fpu_counter > 5;
+        if (__thread_has_fpu(old)) {
+                if (!__save_init_fpu(old))
+                        cpu = ~0;
+                old->thread.fpu.last_cpu = cpu;
+                old->thread.fpu.has_fpu = 0;    /* But leave fpu_owner_task! */
+
+                /* Don't change CR0.TS if we just switch! */
+                if (fpu.preload) {
+                        new->fpu_counter++;
+                        __thread_set_has_fpu(new);
+                        prefetch(new->thread.fpu.state);
+                } else
+                        stts();
+        } else {
+                old->fpu_counter = 0;
+                old->thread.fpu.last_cpu = ~0;
+                if (fpu.preload) {
+                        new->fpu_counter++;
+                        if (fpu_lazy_restore(new, cpu))
+                                fpu.preload = 0;
+                        else
+                                prefetch(new->thread.fpu.state);
+                        __thread_fpu_begin(new);
+                }
+        }
+        return fpu;
+}
+
+/*
+ * By the time this gets called, we've already cleared CR0.TS and
+ * given the process the FPU if we are going to preload the FPU
+ * state - all we need to do is to conditionally restore the register
+ * state itself.
+ */
+static inline void switch_fpu_finish(struct task_struct *new, fpu_switch_t fpu)
+{
+        if (fpu.preload) {
+                if (unlikely(restore_fpu_checking(new)))
+                        __thread_fpu_end(new);
+        }
+}
+
+/*
+ * Signal frame handlers...
+ */
+extern int save_i387_xstate(void __user *buf);
+extern int restore_i387_xstate(void __user *buf);
+
+static inline void __clear_fpu(struct task_struct *tsk)
+{
+        if (__thread_has_fpu(tsk)) {
+                /* Ignore delayed exceptions from user space */
+                asm volatile("1: fwait\n"
+                             "2:\n"
+                             _ASM_EXTABLE(1b, 2b));
+                __thread_fpu_end(tsk);
+        }
+}
+
+/*
+ * The actual user_fpu_begin/end() functions
+ * need to be preemption-safe.
+ *
+ * NOTE! user_fpu_end() must be used only after you
+ * have saved the FP state, and user_fpu_begin() must
+ * be used only immediately before restoring it.
+ * These functions do not do any save/restore on
+ * their own.
+ */
+static inline void user_fpu_end(void)
+{
+        preempt_disable();
+        __thread_fpu_end(current);
+        preempt_enable();
+}
+
+static inline void user_fpu_begin(void)
+{
+        preempt_disable();
+        if (!user_has_fpu())
+                __thread_fpu_begin(current);
+        preempt_enable();
+}
+
+/*
+ * These disable preemption on their own and are safe
+ */
+static inline void save_init_fpu(struct task_struct *tsk)
+{
+        WARN_ON_ONCE(!__thread_has_fpu(tsk));
+        preempt_disable();
+        __save_init_fpu(tsk);
+        __thread_fpu_end(tsk);
+        preempt_enable();
+}
+
+static inline void clear_fpu(struct task_struct *tsk)
+{
+        preempt_disable();
+        __clear_fpu(tsk);
+        preempt_enable();
+}
+
+/*
+ * i387 state interaction
+ */
+static inline unsigned short get_fpu_cwd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.fpu.state->fxsave.cwd;
+        } else {
+                return (unsigned short)tsk->thread.fpu.state->fsave.cwd;
+        }
+}
+
+static inline unsigned short get_fpu_swd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.fpu.state->fxsave.swd;
+        } else {
+                return (unsigned short)tsk->thread.fpu.state->fsave.swd;
+        }
+}
+
+static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk)
+{
+        if (cpu_has_xmm) {
+                return tsk->thread.fpu.state->fxsave.mxcsr;
+        } else {
+                return MXCSR_DEFAULT;
+        }
+}
+
+static bool fpu_allocated(struct fpu *fpu)
+{
+        return fpu->state != NULL;
+}
+
+static inline int fpu_alloc(struct fpu *fpu)
+{
+        if (fpu_allocated(fpu))
+                return 0;
+        fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
+        if (!fpu->state)
+                return -ENOMEM;
+        WARN_ON((unsigned long)fpu->state & 15);
+        return 0;
+}
+
+static inline void fpu_free(struct fpu *fpu)
+{
+        if (fpu->state) {
+                kmem_cache_free(task_xstate_cachep, fpu->state);
+                fpu->state = NULL;
+        }
+}
+
+static inline void fpu_copy(struct fpu *dst, struct fpu *src)
+{
+        memcpy(dst->state, src->state, xstate_size);
+}
+
+extern void fpu_finit(struct fpu *fpu);
+
+#endif