![Linus Torvalds](/assets/img/avatar_default.png)
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
185 lines
4.6 KiB
C
185 lines
4.6 KiB
C
/*
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* Copyright 2002 Andi Kleen, SuSE Labs.
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* FXSAVE<->i387 conversion support. Based on code by Gareth Hughes.
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* This is used for ptrace, signals and coredumps in 32bit emulation.
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* $Id: fpu32.c,v 1.1 2002/03/21 14:16:32 ak Exp $
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*/
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#include <linux/sched.h>
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#include <asm/sigcontext32.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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#include <asm/i387.h>
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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 = 0xffff0000;
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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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static inline int convert_fxsr_from_user(struct i387_fxsave_struct *fxsave,
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struct _fpstate_ia32 __user *buf)
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{
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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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u32 v;
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int err = 0;
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#define G(num,val) err |= __get_user(val, num + (u32 __user *)buf)
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G(0, fxsave->cwd);
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G(1, fxsave->swd);
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G(2, fxsave->twd);
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fxsave->twd = twd_i387_to_fxsr(fxsave->twd);
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G(3, fxsave->rip);
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G(4, v);
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fxsave->fop = v>>16; /* cs ignored */
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G(5, fxsave->rdp);
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/* 6: ds ignored */
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#undef G
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if (err)
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return -1;
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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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if (__copy_from_user(to, from, sizeof(*from)))
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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 inline int convert_fxsr_to_user(struct _fpstate_ia32 __user *buf,
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struct i387_fxsave_struct *fxsave,
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struct pt_regs *regs,
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struct task_struct *tsk)
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{
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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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u16 cs,ds;
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int err = 0;
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if (tsk == current) {
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/* should be actually ds/cs at fpu exception time,
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but that information is not available in 64bit mode. */
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asm("movw %%ds,%0 " : "=r" (ds));
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asm("movw %%cs,%0 " : "=r" (cs));
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} else { /* ptrace. task has stopped. */
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ds = tsk->thread.ds;
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cs = regs->cs;
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}
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#define P(num,val) err |= __put_user(val, num + (u32 __user *)buf)
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P(0, (u32)fxsave->cwd | 0xffff0000);
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P(1, (u32)fxsave->swd | 0xffff0000);
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P(2, twd_fxsr_to_i387(fxsave));
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P(3, (u32)fxsave->rip);
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P(4, cs | ((u32)fxsave->fop) << 16);
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P(5, fxsave->rdp);
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P(6, 0xffff0000 | ds);
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#undef P
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if (err)
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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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if (__copy_to_user(to, from, sizeof(*to)))
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return -1;
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}
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return 0;
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}
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int restore_i387_ia32(struct task_struct *tsk, struct _fpstate_ia32 __user *buf, int fsave)
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{
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clear_fpu(tsk);
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if (!fsave) {
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if (__copy_from_user(&tsk->thread.i387.fxsave,
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&buf->_fxsr_env[0],
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sizeof(struct i387_fxsave_struct)))
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return -1;
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tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask;
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set_stopped_child_used_math(tsk);
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}
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return convert_fxsr_from_user(&tsk->thread.i387.fxsave, buf);
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}
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int save_i387_ia32(struct task_struct *tsk,
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struct _fpstate_ia32 __user *buf,
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struct pt_regs *regs,
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int fsave)
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{
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int err = 0;
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init_fpu(tsk);
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if (convert_fxsr_to_user(buf, &tsk->thread.i387.fxsave, regs, tsk))
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return -1;
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if (fsave)
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return 0;
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err |= __put_user(tsk->thread.i387.fxsave.swd, &buf->status);
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if (fsave)
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return err ? -1 : 1;
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err |= __put_user(X86_FXSR_MAGIC, &buf->magic);
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err |= __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 err ? -1 : 1;
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}
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