/* * Copyright 2002 Andi Kleen, SuSE Labs. * FXSAVE<->i387 conversion support. Based on code by Gareth Hughes. * This is used for ptrace, signals and coredumps in 32bit emulation. * $Id: fpu32.c,v 1.1 2002/03/21 14:16:32 ak Exp $ */ #include <linux/sched.h> #include <asm/sigcontext32.h> #include <asm/processor.h> #include <asm/uaccess.h> #include <asm/i387.h> 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 = 0xffff0000; 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; } static inline int convert_fxsr_from_user(struct i387_fxsave_struct *fxsave, struct _fpstate_ia32 __user *buf) { struct _fpxreg *to; struct _fpreg __user *from; int i; u32 v; int err = 0; #define G(num,val) err |= __get_user(val, num + (u32 __user *)buf) G(0, fxsave->cwd); G(1, fxsave->swd); G(2, fxsave->twd); fxsave->twd = twd_i387_to_fxsr(fxsave->twd); G(3, fxsave->rip); G(4, v); fxsave->fop = v>>16; /* cs ignored */ G(5, fxsave->rdp); /* 6: ds ignored */ #undef G if (err) return -1; to = (struct _fpxreg *)&fxsave->st_space[0]; from = &buf->_st[0]; for (i = 0 ; i < 8 ; i++, to++, from++) { if (__copy_from_user(to, from, sizeof(*from))) return -1; } return 0; } static inline int convert_fxsr_to_user(struct _fpstate_ia32 __user *buf, struct i387_fxsave_struct *fxsave, struct pt_regs *regs, struct task_struct *tsk) { struct _fpreg __user *to; struct _fpxreg *from; int i; u16 cs,ds; int err = 0; if (tsk == current) { /* should be actually ds/cs at fpu exception time, but that information is not available in 64bit mode. */ asm("movw %%ds,%0 " : "=r" (ds)); asm("movw %%cs,%0 " : "=r" (cs)); } else { /* ptrace. task has stopped. */ ds = tsk->thread.ds; cs = regs->cs; } #define P(num,val) err |= __put_user(val, num + (u32 __user *)buf) P(0, (u32)fxsave->cwd | 0xffff0000); P(1, (u32)fxsave->swd | 0xffff0000); P(2, twd_fxsr_to_i387(fxsave)); P(3, (u32)fxsave->rip); P(4, cs | ((u32)fxsave->fop) << 16); P(5, fxsave->rdp); P(6, 0xffff0000 | ds); #undef P if (err) return -1; to = &buf->_st[0]; from = (struct _fpxreg *) &fxsave->st_space[0]; for ( i = 0 ; i < 8 ; i++, to++, from++ ) { if (__copy_to_user(to, from, sizeof(*to))) return -1; } return 0; } int restore_i387_ia32(struct task_struct *tsk, struct _fpstate_ia32 __user *buf, int fsave) { clear_fpu(tsk); if (!fsave) { if (__copy_from_user(&tsk->thread.i387.fxsave, &buf->_fxsr_env[0], sizeof(struct i387_fxsave_struct))) return -1; tsk->thread.i387.fxsave.mxcsr &= mxcsr_feature_mask; set_stopped_child_used_math(tsk); } return convert_fxsr_from_user(&tsk->thread.i387.fxsave, buf); } int save_i387_ia32(struct task_struct *tsk, struct _fpstate_ia32 __user *buf, struct pt_regs *regs, int fsave) { int err = 0; init_fpu(tsk); if (convert_fxsr_to_user(buf, &tsk->thread.i387.fxsave, regs, tsk)) return -1; if (fsave) return 0; err |= __put_user(tsk->thread.i387.fxsave.swd, &buf->status); if (fsave) return err ? -1 : 1; err |= __put_user(X86_FXSR_MAGIC, &buf->magic); err |= __copy_to_user(&buf->_fxsr_env[0], &tsk->thread.i387.fxsave, sizeof(struct i387_fxsave_struct)); return err ? -1 : 1; }