patch-2.0.33 linux/arch/i386/mm/fault.c

• Lines: 159
• Date: Tue Dec 2 13:58:53 1997
• Orig file: v2.0.32/linux/arch/i386/mm/fault.c
• Orig date: Tue Dec 2 13:52:31 1997

diff -u --recursive --new-file v2.0.32/linux/arch/i386/mm/fault.c linux/arch/i386/mm/fault.c
@@ -21,128 +21,10 @@
 
 extern void die_if_kernel(const char *,struct pt_regs *,long);
 
-asmlinkage void do_divide_error (struct pt_regs *, unsigned long);
-asmlinkage void do_debug (struct pt_regs *, unsigned long);
-asmlinkage void do_nmi (struct pt_regs *, unsigned long);
-asmlinkage void do_int3 (struct pt_regs *, unsigned long);
-asmlinkage void do_overflow (struct pt_regs *, unsigned long);
-asmlinkage void do_bounds (struct pt_regs *, unsigned long);
 asmlinkage void do_invalid_op (struct pt_regs *, unsigned long);
-asmlinkage void do_general_protection (struct pt_regs *, unsigned long);
 
 extern int pentium_f00f_bug;
 
-static int handle_intx_eip_adjust(struct pt_regs *regs)
-{
-	unsigned char *addr, *csp = 0;
-	int wrap = 0;
-	int count = 8; /* only check for reasonable number of bytes
-			 * else we do it the save 'simple way' */
-	unsigned long _eip;
-#define XX_WRAP(x) (wrap ? *((unsigned short *)&x) : x)
-
-	/* We rely on being able to access the memory pointed to by cs:eip
-	 * and the bytes behind it up to the faulting instruction,
-	 * because we just got an exception for this instruction and
-	 * hence the memory should just be successfully accessed.
-	 * In case of crossing a page boundary or when accessing kernel space
-	 * we just do the simple fix (increase eip by one).
-	 * This assumption also obsoletes checking of segment limit.
-	 * ( should be veryfied, however, if this assumption is true )
-	 */
-
-	if (regs->cs == KERNEL_CS) {
-		/* not what we expect */
-		regs->eip++;
-		return 0;
-	}
-
-	if (regs->eflags & VM_MASK) {
-		/* we have real mode type selector */
-		wrap = 1;
-		csp = (unsigned char *)((unsigned long)regs->cs << 4);
-	}
-	else if (regs->cs & 4) {
-		/* we have a LDT selector */
-		struct desc_struct *p, *ldt = current->ldt;
-		if (!ldt)
-			ldt = (struct desc_struct*) &default_ldt;
-		p = ldt + (regs->cs >> 3);
-		csp = (unsigned char *)((p->a >> 16) | ((p->b & 0xff) << 16) | (p->b & 0xFF000000));
-		if (!(p->b & 0x400000))
-			wrap = 1;	/* 16-bit segment */
-	}
-
-	_eip = regs->eip;
-	addr = csp+XX_WRAP(_eip);
-	while (count-- > 0) {
-		if ((unsigned long)addr >= TASK_SIZE) {
-			/* accessing kernel space, do the simple case */
-			regs->eip++;
-			return 0;
-		}
-		switch (get_user(addr)) {
-
-			case 0xCC:	/* single byte INT3 */
-				XX_WRAP(_eip)++;
-				regs->eip = _eip;
-				return 0;
-
-			case 0xCD:	/* two byte INT 3 */
-				XX_WRAP(_eip)++;
-				/* fall through */
-			case 0xCE:	/* INTO, single byte */
-				XX_WRAP(_eip)++;
-				if ( (regs->eflags & VM_MASK)
-					&& ((regs->eflags & IOPL_MASK) != IOPL_MASK)) {
-					/* not allowed, do GP0 fault */
-					do_general_protection(regs, 0);
-					return -1;
-				}
-				regs->eip = _eip;
-				return 0;
-
-					/* the prefixes from the Intel patch */
-			case 0xF2 ... 0xF3:
-			case 0x2E:
-			case 0x36:
-			case 0x3E:
-			case 0x26:
-			case 0x64 ... 0x67:
-				break;	/* just skipping them */
-
-			default:
-				/* not what we handle here,
-				 * just doing the simple fix
-				 */
-				regs->eip++;
-				return 0;
-		}
-
-		if ( !(++XX_WRAP(_eip)) ) {
-			/* we wrapped around */
-			regs->eip++;
-			return 0;
-		}
-
-		addr = csp+XX_WRAP(_eip);
-		if ( !((unsigned long)addr & ~(PAGE_SIZE -1)) ) {
-			/* we would cross page boundary, not good,
-			 * doing the simple fix
-			 */
-			regs->eip++;
-			return 0;
-		}
-	}
-
-	/* if we come here something weird happened,
-	 * just doing the simple fix
-	 */
-	regs->eip++;
-	return 0;
-}
-
-
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
@@ -245,22 +127,15 @@
 	 */
 	if ( pentium_f00f_bug ) {
 		unsigned long nr;
+		extern struct {
+			unsigned short limit;
+			unsigned long addr __attribute__((packed));
+		} idt_descriptor;
 
-		nr = (address - TASK_SIZE - (unsigned long) idt) >> 3;
+		nr = (address - idt_descriptor.addr) >> 3;
 
-		if (nr < 7) {
-			static void (*handler[])(struct pt_regs *, unsigned long) = {
-				do_divide_error,	/* 0 - divide overflow */
-				do_debug,		/* 1 - debug trap */
-				do_nmi,			/* 2 - NMI */
-				do_int3,		/* 3 - int 3 */
-				do_overflow,		/* 4 - overflow */
-				do_bounds,		/* 5 - bound range */
-				do_invalid_op };	/* 6 - invalid opcode */
-			if ((nr == 3) || (nr == 4))
-				if (handle_intx_eip_adjust(regs))
-					return;
-			handler[nr](regs, error_code);
+		if (nr == 6) {
+			do_invalid_op(regs, 0);
 			return;
 		}
 	}