patch-2.4.20 linux-2.4.20/arch/x86_64/ia32/fpu32.c

• Lines: 173
• Date: Thu Nov 28 15:53:12 2002
• Orig file: linux-2.4.19/arch/x86_64/ia32/fpu32.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/arch/x86_64/ia32/fpu32.c linux-2.4.20/arch/x86_64/ia32/fpu32.c
@@ -0,0 +1,172 @@
+/* 
+ * 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 twd = (unsigned long) fxsave->twd;
+	unsigned long tag;
+	unsigned long ret = 0xffff0000;
+	int i;
+
+#define FPREG_ADDR(f, n)	((char *)&(f)->st_space + (n) * 16);
+
+	for (i = 0 ; i < 8 ; i++) {
+		if (twd & 0x1) {
+			st = (struct _fpxreg *) FPREG_ADDR( fxsave, i );
+
+			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 *buf)
+{
+	struct _fpxreg *to;
+	struct _fpreg *from;
+	int i;
+	int err; 
+	__u32 v;
+
+	err = __get_user(fxsave->cwd, (u16 *)&buf->cw); 
+	err |= __get_user(fxsave->swd, (u16 *)&buf->sw);
+	err |= __get_user(fxsave->twd, (u16 *)&buf->tag);
+	fxsave->twd = twd_i387_to_fxsr(fxsave->twd);
+	err |= __get_user(fxsave->rip, &buf->ipoff); 
+	err |= __get_user(fxsave->rdp, &buf->dataoff); 
+	err |= __get_user(v, &buf->cssel); 
+	fxsave->fop = v >> 16;
+	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 *buf,
+				       struct i387_fxsave_struct *fxsave,
+				       struct pt_regs *regs,
+				       struct task_struct *tsk)
+{
+	struct _fpreg *to;
+	struct _fpxreg *from;
+	int i;
+	u32 ds; 
+	int err; 
+
+	err = __put_user((unsigned long)fxsave->cwd | 0xffff0000, &buf->cw);
+	err |= __put_user((unsigned long)fxsave->swd | 0xffff0000, &buf->sw);
+	err |= __put_user((u32)fxsave->rip, &buf->ipoff); 
+	err |= __put_user((u32)(regs->cs | ((u32)fxsave->fop << 16)), 
+			  &buf->cssel); 
+	err |= __put_user((u32)twd_fxsr_to_i387(fxsave), &buf->tag); 
+	err |= __put_user((u32)fxsave->rdp, &buf->dataoff); 
+	if (tsk == current) 
+		asm("movl %%ds,%0 " : "=r" (ds)); 
+	else /* ptrace. task has stopped. */
+		ds = tsk->thread.ds;
+	err |= __put_user(ds, &buf->datasel); 
+	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 *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 &= 0xffbf;
+	return convert_fxsr_from_user(&tsk->thread.i387.fxsave, buf);
+}  
+
+int save_i387_ia32(struct task_struct *tsk, 
+		   struct _fpstate_ia32 *buf, 
+		   struct pt_regs *regs,
+		   int fsave)
+{
+	int err = 0;
+
+	if (!tsk->used_math) 
+		return 0;
+	tsk->used_math = 0; 
+	unlazy_fpu(tsk);
+	if (convert_fxsr_to_user(buf, &tsk->thread.i387.fxsave, regs, tsk))
+		return -1;
+	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;
+}