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-rw-r--r--arch/x86/ia32/fpu32.c183
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 00000000000..2c8209a3605
--- /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;
+}