diff options
Diffstat (limited to 'arch/x86/ia32/fpu32.c')
| -rw-r--r-- | arch/x86/ia32/fpu32.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/arch/x86/ia32/fpu32.c b/arch/x86/ia32/fpu32.c new file mode 100644 index 000000000000..2c8209a3605a --- /dev/null +++ b/arch/x86/ia32/fpu32.c @@ -0,0 +1,183 @@ +/* + * 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. + */ + +#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; +} |