8ed1383fb7
It's really just a single instruction, conditional on whether the CPU supports FXSR or not, so implement it as such instead of making it a function that queries FXSR dynamically. This means that the instruction just gets automatically rewritten to the correct one at boot-time.
547 lines
13 KiB
C
547 lines
13 KiB
C
/*
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* linux/arch/i386/kernel/i387.c
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*
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* Copyright (C) 1994 Linus Torvalds
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*
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* Pentium III FXSR, SSE support
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* General FPU state handling cleanups
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* Gareth Hughes <gareth@valinux.com>, May 2000
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*/
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#include <linux/config.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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#include <asm/processor.h>
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#include <asm/i387.h>
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#include <asm/math_emu.h>
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#include <asm/sigcontext.h>
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#include <asm/user.h>
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#include <asm/ptrace.h>
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#include <asm/uaccess.h>
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#ifdef CONFIG_MATH_EMULATION
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#define HAVE_HWFP (boot_cpu_data.hard_math)
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#else
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#define HAVE_HWFP 1
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#endif
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static unsigned long mxcsr_feature_mask = 0xffffffff;
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void mxcsr_feature_mask_init(void)
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{
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unsigned long mask = 0;
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clts();
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if (cpu_has_fxsr) {
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memset(¤t->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
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asm volatile("fxsave %0" : : "m" (current->thread.i387.fxsave));
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mask = current->thread.i387.fxsave.mxcsr_mask;
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if (mask == 0) mask = 0x0000ffbf;
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}
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mxcsr_feature_mask &= mask;
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stts();
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}
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/*
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* The _current_ task is using the FPU for the first time
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* so initialize it and set the mxcsr to its default
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* value at reset if we support XMM instructions and then
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* remeber the current task has used the FPU.
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*/
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void init_fpu(struct task_struct *tsk)
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{
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if (cpu_has_fxsr) {
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memset(&tsk->thread.i387.fxsave, 0, sizeof(struct i387_fxsave_struct));
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tsk->thread.i387.fxsave.cwd = 0x37f;
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if (cpu_has_xmm)
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tsk->thread.i387.fxsave.mxcsr = 0x1f80;
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} else {
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memset(&tsk->thread.i387.fsave, 0, sizeof(struct i387_fsave_struct));
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tsk->thread.i387.fsave.cwd = 0xffff037fu;
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tsk->thread.i387.fsave.swd = 0xffff0000u;
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tsk->thread.i387.fsave.twd = 0xffffffffu;
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tsk->thread.i387.fsave.fos = 0xffff0000u;
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}
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/* only the device not available exception or ptrace can call init_fpu */
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set_stopped_child_used_math(tsk);
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}
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/*
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* FPU lazy state save handling.
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*/
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void kernel_fpu_begin(void)
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{
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struct thread_info *thread = current_thread_info();
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preempt_disable();
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if (thread->status & TS_USEDFPU) {
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__save_init_fpu(thread->task);
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return;
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}
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clts();
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}
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EXPORT_SYMBOL_GPL(kernel_fpu_begin);
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/*
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* FPU tag word conversions.
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*/
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static inline unsigned short twd_i387_to_fxsr( unsigned short twd )
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{
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unsigned int tmp; /* to avoid 16 bit prefixes in the code */
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/* Transform each pair of bits into 01 (valid) or 00 (empty) */
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tmp = ~twd;
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tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */
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/* and move the valid bits to the lower byte. */
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tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */
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tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */
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tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */
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return tmp;
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}
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static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave )
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{
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struct _fpxreg *st = NULL;
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unsigned long tos = (fxsave->swd >> 11) & 7;
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unsigned long twd = (unsigned long) fxsave->twd;
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unsigned long tag;
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unsigned long ret = 0xffff0000u;
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int i;
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#define FPREG_ADDR(f, n) ((void *)&(f)->st_space + (n) * 16);
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for ( i = 0 ; i < 8 ; i++ ) {
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if ( twd & 0x1 ) {
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st = FPREG_ADDR( fxsave, (i - tos) & 7 );
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switch ( st->exponent & 0x7fff ) {
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case 0x7fff:
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tag = 2; /* Special */
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break;
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case 0x0000:
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if ( !st->significand[0] &&
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!st->significand[1] &&
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!st->significand[2] &&
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!st->significand[3] ) {
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tag = 1; /* Zero */
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} else {
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tag = 2; /* Special */
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}
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break;
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default:
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if ( st->significand[3] & 0x8000 ) {
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tag = 0; /* Valid */
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} else {
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tag = 2; /* Special */
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}
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break;
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}
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} else {
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tag = 3; /* Empty */
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}
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ret |= (tag << (2 * i));
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twd = twd >> 1;
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}
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return ret;
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}
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/*
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* FPU state interaction.
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*/
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unsigned short get_fpu_cwd( struct task_struct *tsk )
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{
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if ( cpu_has_fxsr ) {
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return tsk->thread.i387.fxsave.cwd;
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} else {
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return (unsigned short)tsk->thread.i387.fsave.cwd;
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}
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}
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unsigned short get_fpu_swd( struct task_struct *tsk )
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{
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if ( cpu_has_fxsr ) {
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return tsk->thread.i387.fxsave.swd;
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} else {
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return (unsigned short)tsk->thread.i387.fsave.swd;
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}
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}
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#if 0
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unsigned short get_fpu_twd( struct task_struct *tsk )
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{
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if ( cpu_has_fxsr ) {
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return tsk->thread.i387.fxsave.twd;
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} else {
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return (unsigned short)tsk->thread.i387.fsave.twd;
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}
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}
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#endif /* 0 */
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unsigned short get_fpu_mxcsr( struct task_struct *tsk )
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{
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if ( cpu_has_xmm ) {
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return tsk->thread.i387.fxsave.mxcsr;
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} else {
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return 0x1f80;
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}
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}
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#if 0
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void set_fpu_cwd( struct task_struct *tsk, unsigned short cwd )
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{
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if ( cpu_has_fxsr ) {
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tsk->thread.i387.fxsave.cwd = cwd;
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} else {
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tsk->thread.i387.fsave.cwd = ((long)cwd | 0xffff0000u);
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}
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}
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void set_fpu_swd( struct task_struct *tsk, unsigned short swd )
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{
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if ( cpu_has_fxsr ) {
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tsk->thread.i387.fxsave.swd = swd;
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} else {
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tsk->thread.i387.fsave.swd = ((long)swd | 0xffff0000u);
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}
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}
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void set_fpu_twd( struct task_struct *tsk, unsigned short twd )
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{
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if ( cpu_has_fxsr ) {
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tsk->thread.i387.fxsave.twd = twd_i387_to_fxsr(twd);
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} else {
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tsk->thread.i387.fsave.twd = ((long)twd | 0xffff0000u);
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}
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}
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#endif /* 0 */
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/*
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* FXSR floating point environment conversions.
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*/
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static int convert_fxsr_to_user( struct _fpstate __user *buf,
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struct i387_fxsave_struct *fxsave )
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{
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unsigned long env[7];
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struct _fpreg __user *to;
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struct _fpxreg *from;
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int i;
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env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul;
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env[1] = (unsigned long)fxsave->swd | 0xffff0000ul;
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env[2] = twd_fxsr_to_i387(fxsave);
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env[3] = fxsave->fip;
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env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
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env[5] = fxsave->foo;
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env[6] = fxsave->fos;
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if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) )
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return 1;
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to = &buf->_st[0];
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from = (struct _fpxreg *) &fxsave->st_space[0];
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for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
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unsigned long __user *t = (unsigned long __user *)to;
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unsigned long *f = (unsigned long *)from;
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if (__put_user(*f, t) ||
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__put_user(*(f + 1), t + 1) ||
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__put_user(from->exponent, &to->exponent))
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return 1;
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}
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return 0;
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}
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static int convert_fxsr_from_user( struct i387_fxsave_struct *fxsave,
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struct _fpstate __user *buf )
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{
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unsigned long env[7];
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struct _fpxreg *to;
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struct _fpreg __user *from;
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int i;
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if ( __copy_from_user( env, buf, 7 * sizeof(long) ) )
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return 1;
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fxsave->cwd = (unsigned short)(env[0] & 0xffff);
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fxsave->swd = (unsigned short)(env[1] & 0xffff);
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fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
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fxsave->fip = env[3];
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fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16);
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fxsave->fcs = (env[4] & 0xffff);
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fxsave->foo = env[5];
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fxsave->fos = env[6];
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to = (struct _fpxreg *) &fxsave->st_space[0];
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from = &buf->_st[0];
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for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
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unsigned long *t = (unsigned long *)to;
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unsigned long __user *f = (unsigned long __user *)from;
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if (__get_user(*t, f) ||
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__get_user(*(t + 1), f + 1) ||
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__get_user(to->exponent, &from->exponent))
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return 1;
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}
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return 0;
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}
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/*
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* Signal frame handlers.
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*/
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static inline int save_i387_fsave( struct _fpstate __user *buf )
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{
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struct task_struct *tsk = current;
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unlazy_fpu( tsk );
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tsk->thread.i387.fsave.status = tsk->thread.i387.fsave.swd;
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if ( __copy_to_user( buf, &tsk->thread.i387.fsave,
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sizeof(struct i387_fsave_struct) ) )
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return -1;
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return 1;
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}
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static int save_i387_fxsave( struct _fpstate __user *buf )
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{
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struct task_struct *tsk = current;
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int err = 0;
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unlazy_fpu( tsk );
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if ( convert_fxsr_to_user( buf, &tsk->thread.i387.fxsave ) )
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return -1;
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err |= __put_user( tsk->thread.i387.fxsave.swd, &buf->status );
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err |= __put_user( X86_FXSR_MAGIC, &buf->magic );
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if ( err )
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return -1;
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if ( __copy_to_user( &buf->_fxsr_env[0], &tsk->thread.i387.fxsave,
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sizeof(struct i387_fxsave_struct) ) )
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return -1;
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return 1;
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}
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int save_i387( struct _fpstate __user *buf )
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{
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if ( !used_math() )
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return 0;
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/* This will cause a "finit" to be triggered by the next
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* attempted FPU operation by the 'current' process.
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*/
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clear_used_math();
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if ( HAVE_HWFP ) {
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if ( cpu_has_fxsr ) {
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return save_i387_fxsave( buf );
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} else {
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return save_i387_fsave( buf );
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}
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} else {
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return save_i387_soft( ¤t->thread.i387.soft, buf );
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}
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}
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static inline int restore_i387_fsave( struct _fpstate __user *buf )
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{
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struct task_struct *tsk = current;
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clear_fpu( tsk );
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return __copy_from_user( &tsk->thread.i387.fsave, buf,
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sizeof(struct i387_fsave_struct) );
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}
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static int restore_i387_fxsave( struct _fpstate __user *buf )
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{
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int err;
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struct task_struct *tsk = current;
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clear_fpu( tsk );
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err = __copy_from_user( &tsk->thread.i387.fxsave, &buf->_fxsr_env[0],
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sizeof(struct i387_fxsave_struct) );
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/* mxcsr reserved bits must be masked to zero for security reasons */
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tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
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return err ? 1 : convert_fxsr_from_user( &tsk->thread.i387.fxsave, buf );
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}
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int restore_i387( struct _fpstate __user *buf )
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{
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int err;
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if ( HAVE_HWFP ) {
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if ( cpu_has_fxsr ) {
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err = restore_i387_fxsave( buf );
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} else {
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err = restore_i387_fsave( buf );
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}
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} else {
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err = restore_i387_soft( ¤t->thread.i387.soft, buf );
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}
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set_used_math();
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return err;
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}
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/*
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* ptrace request handlers.
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*/
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static inline int get_fpregs_fsave( struct user_i387_struct __user *buf,
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struct task_struct *tsk )
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{
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return __copy_to_user( buf, &tsk->thread.i387.fsave,
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sizeof(struct user_i387_struct) );
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}
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static inline int get_fpregs_fxsave( struct user_i387_struct __user *buf,
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struct task_struct *tsk )
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{
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return convert_fxsr_to_user( (struct _fpstate __user *)buf,
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&tsk->thread.i387.fxsave );
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}
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int get_fpregs( struct user_i387_struct __user *buf, struct task_struct *tsk )
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{
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if ( HAVE_HWFP ) {
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if ( cpu_has_fxsr ) {
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return get_fpregs_fxsave( buf, tsk );
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} else {
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return get_fpregs_fsave( buf, tsk );
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}
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} else {
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return save_i387_soft( &tsk->thread.i387.soft,
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(struct _fpstate __user *)buf );
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}
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}
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static inline int set_fpregs_fsave( struct task_struct *tsk,
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struct user_i387_struct __user *buf )
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{
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return __copy_from_user( &tsk->thread.i387.fsave, buf,
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sizeof(struct user_i387_struct) );
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}
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static inline int set_fpregs_fxsave( struct task_struct *tsk,
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struct user_i387_struct __user *buf )
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{
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return convert_fxsr_from_user( &tsk->thread.i387.fxsave,
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(struct _fpstate __user *)buf );
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}
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int set_fpregs( struct task_struct *tsk, struct user_i387_struct __user *buf )
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{
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if ( HAVE_HWFP ) {
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if ( cpu_has_fxsr ) {
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return set_fpregs_fxsave( tsk, buf );
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} else {
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return set_fpregs_fsave( tsk, buf );
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}
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} else {
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return restore_i387_soft( &tsk->thread.i387.soft,
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(struct _fpstate __user *)buf );
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}
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}
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int get_fpxregs( struct user_fxsr_struct __user *buf, struct task_struct *tsk )
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{
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if ( cpu_has_fxsr ) {
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if (__copy_to_user( buf, &tsk->thread.i387.fxsave,
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sizeof(struct user_fxsr_struct) ))
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return -EFAULT;
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return 0;
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} else {
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return -EIO;
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}
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}
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int set_fpxregs( struct task_struct *tsk, struct user_fxsr_struct __user *buf )
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{
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int ret = 0;
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if ( cpu_has_fxsr ) {
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if (__copy_from_user( &tsk->thread.i387.fxsave, buf,
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sizeof(struct user_fxsr_struct) ))
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ret = -EFAULT;
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/* mxcsr reserved bits must be masked to zero for security reasons */
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tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
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} else {
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ret = -EIO;
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}
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return ret;
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}
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/*
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* FPU state for core dumps.
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*/
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static inline void copy_fpu_fsave( struct task_struct *tsk,
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struct user_i387_struct *fpu )
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{
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memcpy( fpu, &tsk->thread.i387.fsave,
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sizeof(struct user_i387_struct) );
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}
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static inline void copy_fpu_fxsave( struct task_struct *tsk,
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struct user_i387_struct *fpu )
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{
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unsigned short *to;
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unsigned short *from;
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int i;
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memcpy( fpu, &tsk->thread.i387.fxsave, 7 * sizeof(long) );
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to = (unsigned short *)&fpu->st_space[0];
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from = (unsigned short *)&tsk->thread.i387.fxsave.st_space[0];
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for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) {
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memcpy( to, from, 5 * sizeof(unsigned short) );
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}
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}
|
|
|
|
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;
|
|
}
|