1 files changed, 555 insertions, 0 deletions

diff --git a/arch/i386/kernel/i387.c b/arch/i386/kernel/i387.c
new file mode 100644
index 000000000000..c55e037f08f7
--- /dev/null
+++ b/arch/i386/kernel/i387.c
@@ -0,0 +1,555 @@
+/*
+ *  linux/arch/i386/kernel/i387.c
+ *
+ *  Copyright (C) 1994 Linus Torvalds
+ *
+ *  Pentium III FXSR, SSE support
+ *  General FPU state handling cleanups
+ *      Gareth Hughes <gareth@valinux.com>, May 2000
+ */
+
+#include <linux/config.h>
+#include <linux/sched.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 = 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();
+}
+
+void restore_fpu( struct task_struct *tsk )
+{
+        if ( cpu_has_fxsr ) {
+                asm volatile( "fxrstor %0"
+                              : : "m" (tsk->thread.i387.fxsave) );
+        } else {
+                asm volatile( "frstor %0"
+                              : : "m" (tsk->thread.i387.fsave) );
+        }
+}
+
+/*
+ * 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;
+}
+
+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;
+}