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-rw-r--r--arch/i386/kernel/i387.c555
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;
+}
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