1 files changed, 551 insertions, 0 deletions

diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
new file mode 100644
index 000000000000..bebe03463461
--- /dev/null
+++ b/arch/x86/kernel/i387.c
@@ -0,0 +1,551 @@
+/*
+ *  Copyright (C) 1994 Linus Torvalds
+ *
+ *  Pentium III FXSR, SSE support
+ *  General FPU state handling cleanups
+ *      Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <asm/processor.h>
+#include <asm/i387.h>
+#include <asm/math_emu.h>
+#include <asm/sigcontext.h>
+#include <asm/user.h>
+#include <asm/ptrace.h>
+#include <asm/uaccess.h>
+
+#ifdef CONFIG_MATH_EMULATION
+#define HAVE_HWFP (boot_cpu_data.hard_math)
+#else
+#define HAVE_HWFP 1
+#endif
+
+static unsigned long mxcsr_feature_mask __read_mostly = 0xffffffff;
+
+void mxcsr_feature_mask_init(void)
+{
+        unsigned long mask = 0;
+        clts();
+        if (cpu_has_fxsr) {
+                memset(&current->thread.i387.fxsave, 0,
+                       sizeof(struct i387_fxsave_struct));
+                asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave));
+                mask = current->thread.i387.fxsave.mxcsr_mask;
+                if (mask == 0)
+                        mask = 0x0000ffbf;
+        }
+        mxcsr_feature_mask &= mask;
+        stts();
+}
+
+/*
+ * The _current_ task is using the FPU for the first time
+ * so initialize it and set the mxcsr to its default
+ * value at reset if we support XMM instructions and then
+ * remeber the current task has used the FPU.
+ */
+void init_fpu(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                memset(&tsk->thread.i387.fxsave, 0,
+                       sizeof(struct i387_fxsave_struct));
+                tsk->thread.i387.fxsave.cwd = 0x37f;
+                if (cpu_has_xmm)
+                        tsk->thread.i387.fxsave.mxcsr = 0x1f80;
+        } else {
+                memset(&tsk->thread.i387.fsave, 0,
+                       sizeof(struct i387_fsave_struct));
+                tsk->thread.i387.fsave.cwd = 0xffff037fu;
+                tsk->thread.i387.fsave.swd = 0xffff0000u;
+                tsk->thread.i387.fsave.twd = 0xffffffffu;
+                tsk->thread.i387.fsave.fos = 0xffff0000u;
+        }
+        /* only the device not available exception
+         * or ptrace can call init_fpu */
+        set_stopped_child_used_math(tsk);
+}
+
+/*
+ * FPU lazy state save handling.
+ */
+
+void kernel_fpu_begin(void)
+{
+        struct thread_info *thread = current_thread_info();
+
+        preempt_disable();
+        if (thread->status & TS_USEDFPU) {
+                __save_init_fpu(thread->task);
+                return;
+        }
+        clts();
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_begin);
+
+/*
+ * FPU tag word conversions.
+ */
+
+static inline unsigned short twd_i387_to_fxsr(unsigned short twd)
+{
+        unsigned int tmp; /* to avoid 16 bit prefixes in the code */
+
+        /* Transform each pair of bits into 01 (valid) or 00 (empty) */
+        tmp = ~twd;
+        tmp = (tmp | (tmp >> 1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
+        /* and move the valid bits to the lower byte. */
+        tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
+        tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
+        tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
+
+        return tmp;
+}
+
+static inline unsigned long twd_fxsr_to_i387(struct i387_fxsave_struct *fxsave)
+{
+        struct _fpxreg *st = NULL;
+        unsigned long tos = (fxsave->swd >> 11) & 7;
+        unsigned long twd = (unsigned long) fxsave->twd;
+        unsigned long tag;
+        unsigned long ret = 0xffff0000u;
+        int i;
+
+#define FPREG_ADDR(f, n)        ((void *)&(f)->st_space + (n) * 16);
+
+        for (i = 0; i < 8; i++) {
+                if (twd & 0x1) {
+                        st = FPREG_ADDR(fxsave, (i - tos) & 7);
+
+                        switch (st->exponent & 0x7fff) {
+                        case 0x7fff:
+                                tag = 2;                /* Special */
+                                break;
+                        case 0x0000:
+                                if (!st->significand[0] &&
+                                    !st->significand[1] &&
+                                    !st->significand[2] &&
+                                    !st->significand[3]) {
+                                        tag = 1;        /* Zero */
+                                } else {
+                                        tag = 2;        /* Special */
+                                }
+                                break;
+                        default:
+                                if (st->significand[3] & 0x8000) {
+                                        tag = 0;        /* Valid */
+                                } else {
+                                        tag = 2;        /* Special */
+                                }
+                                break;
+                        }
+                } else {
+                        tag = 3;                        /* Empty */
+                }
+                ret |= (tag << (2 * i));
+                twd = twd >> 1;
+        }
+        return ret;
+}
+
+/*
+ * FPU state interaction.
+ */
+
+unsigned short get_fpu_cwd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.i387.fxsave.cwd;
+        } else {
+                return (unsigned short)tsk->thread.i387.fsave.cwd;
+        }
+}
+
+unsigned short get_fpu_swd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.i387.fxsave.swd;
+        } else {
+                return (unsigned short)tsk->thread.i387.fsave.swd;
+        }
+}
+
+#if 0
+unsigned short get_fpu_twd(struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                return tsk->thread.i387.fxsave.twd;
+        } else {
+                return (unsigned short)tsk->thread.i387.fsave.twd;
+        }
+}
+#endif  /*  0  */
+
+unsigned short get_fpu_mxcsr(struct task_struct *tsk)
+{
+        if (cpu_has_xmm) {
+                return tsk->thread.i387.fxsave.mxcsr;
+        } else {
+                return 0x1f80;
+        }
+}
+
+#if 0
+
+void set_fpu_cwd(struct task_struct *tsk, unsigned short cwd)
+{
+        if (cpu_has_fxsr) {
+                tsk->thread.i387.fxsave.cwd = cwd;
+        } else {
+                tsk->thread.i387.fsave.cwd = ((long)cwd | 0xffff0000u);
+        }
+}
+
+void set_fpu_swd(struct task_struct *tsk, unsigned short swd)
+{
+        if (cpu_has_fxsr) {
+                tsk->thread.i387.fxsave.swd = swd;
+        } else {
+                tsk->thread.i387.fsave.swd = ((long)swd | 0xffff0000u);
+        }
+}
+
+void set_fpu_twd(struct task_struct *tsk, unsigned short twd)
+{
+        if (cpu_has_fxsr) {
+                tsk->thread.i387.fxsave.twd = twd_i387_to_fxsr(twd);
+        } else {
+                tsk->thread.i387.fsave.twd = ((long)twd | 0xffff0000u);
+        }
+}
+
+#endif  /*  0  */
+
+/*
+ * FXSR floating point environment conversions.
+ */
+
+static int convert_fxsr_to_user(struct _fpstate __user *buf,
+                                struct i387_fxsave_struct *fxsave)
+{
+        unsigned long env[7];
+        struct _fpreg __user *to;
+        struct _fpxreg *from;
+        int i;
+
+        env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
+        env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
+        env[2] = twd_fxsr_to_i387(fxsave);
+        env[3] = fxsave->fip;
+        env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
+        env[5] = fxsave->foo;
+        env[6] = fxsave->fos;
+
+        if (__copy_to_user(buf, env, 7 * sizeof(unsigned long)))
+                return 1;
+
+        to = &buf->_st[0];
+        from = (struct _fpxreg *) &fxsave->st_space[0];
+        for (i = 0; i < 8; i++, to++, from++) {
+                unsigned long __user *t = (unsigned long __user *)to;
+                unsigned long *f = (unsigned long *)from;
+
+                if (__put_user(*f, t) ||
+                    __put_user(*(f + 1), t + 1) ||
+                    __put_user(from->exponent, &to->exponent))
+                        return 1;
+        }
+        return 0;
+}
+
+static int convert_fxsr_from_user(struct i387_fxsave_struct *fxsave,
+                                  struct _fpstate __user *buf)
+{
+        unsigned long env[7];
+        struct _fpxreg *to;
+        struct _fpreg __user *from;
+        int i;
+
+        if (__copy_from_user(env, buf, 7 * sizeof(long)))
+                return 1;
+
+        fxsave->cwd = (unsigned short)(env[0] & 0xffff);
+        fxsave->swd = (unsigned short)(env[1] & 0xffff);
+        fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
+        fxsave->fip = env[3];
+        fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
+        fxsave->fcs = (env[4] & 0xffff);
+        fxsave->foo = env[5];
+        fxsave->fos = env[6];
+
+        to = (struct _fpxreg *) &fxsave->st_space[0];
+        from = &buf->_st[0];
+        for (i = 0; i < 8; i++, to++, from++) {
+                unsigned long *t = (unsigned long *)to;
+                unsigned long __user *f = (unsigned long __user *)from;
+
+                if (__get_user(*t, f) ||
+                    __get_user(*(t + 1), f + 1) ||
+                    __get_user(to->exponent, &from->exponent))
+                        return 1;
+        }
+        return 0;
+}
+
+/*
+ * Signal frame handlers.
+ */
+
+static inline int save_i387_fsave(struct _fpstate __user *buf)
+{
+        struct task_struct *tsk = current;
+
+        unlazy_fpu(tsk);
+        tsk->thread.i387.fsave.status = tsk->thread.i387.fsave.swd;
+        if (__copy_to_user(buf, &tsk->thread.i387.fsave,
+                           sizeof(struct i387_fsave_struct)))
+                return -1;
+        return 1;
+}
+
+static int save_i387_fxsave(struct _fpstate __user *buf)
+{
+        struct task_struct *tsk = current;
+        int err = 0;
+
+        unlazy_fpu(tsk);
+
+        if (convert_fxsr_to_user(buf, &tsk->thread.i387.fxsave))
+                return -1;
+
+        err |= __put_user(tsk->thread.i387.fxsave.swd, &buf->status);
+        err |= __put_user(X86_FXSR_MAGIC, &buf->magic);
+        if (err)
+                return -1;
+
+        if (__copy_to_user(&buf->_fxsr_env[0], &tsk->thread.i387.fxsave,
+                           sizeof(struct i387_fxsave_struct)))
+                return -1;
+        return 1;
+}
+
+int save_i387(struct _fpstate __user *buf)
+{
+        if (!used_math())
+                return 0;
+
+        /* This will cause a "finit" to be triggered by the next
+         * attempted FPU operation by the 'current' process.
+         */
+        clear_used_math();
+
+        if (HAVE_HWFP) {
+                if (cpu_has_fxsr) {
+                        return save_i387_fxsave(buf);
+                } else {
+                        return save_i387_fsave(buf);
+                }
+        } else {
+                return save_i387_soft(&current->thread.i387.soft, buf);
+        }
+}
+
+static inline int restore_i387_fsave(struct _fpstate __user *buf)
+{
+        struct task_struct *tsk = current;
+        clear_fpu(tsk);
+        return __copy_from_user(&tsk->thread.i387.fsave, buf,
+                                sizeof(struct i387_fsave_struct));
+}
+
+static int restore_i387_fxsave(struct _fpstate __user *buf)
+{
+        int err;
+        struct task_struct *tsk = current;
+        clear_fpu(tsk);
+        err = __copy_from_user(&tsk->thread.i387.fxsave, &buf->_fxsr_env[0],
+                               sizeof(struct i387_fxsave_struct));
+        /* mxcsr reserved bits must be masked to zero for security reasons */
+        tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
+        return err ? 1 : convert_fxsr_from_user(&tsk->thread.i387.fxsave, buf);
+}
+
+int restore_i387(struct _fpstate __user *buf)
+{
+        int err;
+
+        if (HAVE_HWFP) {
+                if (cpu_has_fxsr) {
+                        err = restore_i387_fxsave(buf);
+                } else {
+                        err = restore_i387_fsave(buf);
+                }
+        } else {
+                err = restore_i387_soft(&current->thread.i387.soft, buf);
+        }
+        set_used_math();
+        return err;
+}
+
+/*
+ * ptrace request handlers.
+ */
+
+static inline int get_fpregs_fsave(struct user_i387_struct __user *buf,
+                                   struct task_struct *tsk)
+{
+        return __copy_to_user(buf, &tsk->thread.i387.fsave,
+                              sizeof(struct user_i387_struct));
+}
+
+static inline int get_fpregs_fxsave(struct user_i387_struct __user *buf,
+                                    struct task_struct *tsk)
+{
+        return convert_fxsr_to_user((struct _fpstate __user *)buf,
+                                    &tsk->thread.i387.fxsave);
+}
+
+int get_fpregs(struct user_i387_struct __user *buf, struct task_struct *tsk)
+{
+        if (HAVE_HWFP) {
+                if (cpu_has_fxsr) {
+                        return get_fpregs_fxsave(buf, tsk);
+                } else {
+                        return get_fpregs_fsave(buf, tsk);
+                }
+        } else {
+                return save_i387_soft(&tsk->thread.i387.soft,
+                                      (struct _fpstate __user *)buf);
+        }
+}
+
+static inline int set_fpregs_fsave(struct task_struct *tsk,
+                                   struct user_i387_struct __user *buf)
+{
+        return __copy_from_user(&tsk->thread.i387.fsave, buf,
+                                sizeof(struct user_i387_struct));
+}
+
+static inline int set_fpregs_fxsave(struct task_struct *tsk,
+                                    struct user_i387_struct __user *buf)
+{
+        return convert_fxsr_from_user(&tsk->thread.i387.fxsave,
+                                      (struct _fpstate __user *)buf);
+}
+
+int set_fpregs(struct task_struct *tsk, struct user_i387_struct __user *buf)
+{
+        if (HAVE_HWFP) {
+                if (cpu_has_fxsr) {
+                        return set_fpregs_fxsave(tsk, buf);
+                } else {
+                        return set_fpregs_fsave(tsk, buf);
+                }
+        } else {
+                return restore_i387_soft(&tsk->thread.i387.soft,
+                                         (struct _fpstate __user *)buf);
+        }
+}
+
+int get_fpxregs(struct user_fxsr_struct __user *buf, struct task_struct *tsk)
+{
+        if (cpu_has_fxsr) {
+                if (__copy_to_user(buf, &tsk->thread.i387.fxsave,
+                                   sizeof(struct user_fxsr_struct)))
+                        return -EFAULT;
+                return 0;
+        } else {
+                return -EIO;
+        }
+}
+
+int set_fpxregs(struct task_struct *tsk, struct user_fxsr_struct __user *buf)
+{
+        int ret = 0;
+
+        if (cpu_has_fxsr) {
+                if (__copy_from_user(&tsk->thread.i387.fxsave, buf,
+                                     sizeof(struct user_fxsr_struct)))
+                        ret = -EFAULT;
+                /* mxcsr reserved bits must be masked to zero
+                 * for security reasons */
+                tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
+        } else {
+                ret = -EIO;
+        }
+        return ret;
+}
+
+/*
+ * FPU state for core dumps.
+ */
+
+static inline void copy_fpu_fsave(struct task_struct *tsk,
+                                  struct user_i387_struct *fpu)
+{
+        memcpy(fpu, &tsk->thread.i387.fsave,
+               sizeof(struct user_i387_struct));
+}
+
+static inline void copy_fpu_fxsave(struct task_struct *tsk,
+                                   struct user_i387_struct *fpu)
+{
+        unsigned short *to;
+        unsigned short *from;
+        int i;
+
+        memcpy(fpu, &tsk->thread.i387.fxsave, 7 * sizeof(long));
+
+        to = (unsigned short *)&fpu->st_space[0];
+        from = (unsigned short *)&tsk->thread.i387.fxsave.st_space[0];
+        for (i = 0; i < 8; i++, to += 5, from += 8)
+                memcpy(to, from, 5 * sizeof(unsigned short));
+}
+
+int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu)
+{
+        int fpvalid;
+        struct task_struct *tsk = current;
+
+        fpvalid = !!used_math();
+        if (fpvalid) {
+                unlazy_fpu(tsk);
+                if (cpu_has_fxsr) {
+                        copy_fpu_fxsave(tsk, fpu);
+                } else {
+                        copy_fpu_fsave(tsk, fpu);
+                }
+        }
+
+        return fpvalid;
+}
+EXPORT_SYMBOL(dump_fpu);
+
+int dump_task_fpu(struct task_struct *tsk, struct user_i387_struct *fpu)
+{
+        int fpvalid = !!tsk_used_math(tsk);
+
+        if (fpvalid) {
+                if (tsk == current)
+                        unlazy_fpu(tsk);
+                if (cpu_has_fxsr)
+                        copy_fpu_fxsave(tsk, fpu);
+                else
+                        copy_fpu_fsave(tsk, fpu);
+        }
+        return fpvalid;
+}
+
+int dump_task_extended_fpu(struct task_struct *tsk,
+                           struct user_fxsr_struct *fpu)
+{
+        int fpvalid = tsk_used_math(tsk) && cpu_has_fxsr;
+
+        if (fpvalid) {
+                if (tsk == current)
+                       unlazy_fpu(tsk);
+                memcpy(fpu, &tsk->thread.i387.fxsave, sizeof(*fpu));
+        }
+        return fpvalid;
+}