patch-2.1.80 linux/arch/arm/kernel/ioport.c

• Lines: 99
• Date: Tue Jan 20 16:39:41 1998
• Orig file: v2.1.79/linux/arch/arm/kernel/ioport.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.79/linux/arch/arm/kernel/ioport.c linux/arch/arm/kernel/ioport.c
@@ -0,0 +1,98 @@
+/*
+ * linux/arch/arm/kernel/ioport.c
+ *
+ * This contains the io-permission bitmap code - written by obz, with changes
+ * by Linus.
+ *
+ * Modifications for ARM processor Copyright (C) 1995, 1996 Russell King
+ */
+
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/ioport.h>
+
+/* Set EXTENT bits starting at BASE in BITMAP to value TURN_ON. */
+asmlinkage void set_bitmap(unsigned long *bitmap, short base, short extent, int new_value)
+{
+	int mask;
+	unsigned long *bitmap_base = bitmap + (base >> 5);
+	unsigned short low_index = base & 0x1f;
+	int length = low_index + extent;
+
+	if (low_index != 0) {
+		mask = (~0 << low_index);
+		if (length < 32)
+				mask &= ~(~0 << length);
+		if (new_value)
+			*bitmap_base++ |= mask;
+		else
+			*bitmap_base++ &= ~mask;
+		length -= 32;
+	}
+
+	mask = (new_value ? ~0 : 0);
+	while (length >= 32) {
+		*bitmap_base++ = mask;
+		length -= 32;
+	}
+
+	if (length > 0) {
+		mask = ~(~0 << length);
+		if (new_value)
+			*bitmap_base++ |= mask;
+		else
+			*bitmap_base++ &= ~mask;
+	}
+}
+
+/*
+ * this changes the io permissions bitmap in the current task.
+ */
+asmlinkage int sys_ioperm(unsigned long from, unsigned long num, int turn_on)
+{
+	if (from + num <= from)
+		return -EINVAL;
+#ifndef __arm__
+	if (from + num > IO_BITMAP_SIZE*32)
+		return -EINVAL;
+#endif
+	if (!suser())
+		return -EPERM;
+
+#ifdef IODEBUG
+	printk("io: from=%d num=%d %s\n", from, num, (turn_on ? "on" : "off"));
+#endif
+#ifndef __arm__
+	set_bitmap((unsigned long *)current->tss.io_bitmap, from, num, !turn_on);
+#endif
+	return 0;
+}
+
+unsigned int *stack;
+
+/*
+ * sys_iopl has to be used when you want to access the IO ports
+ * beyond the 0x3ff range: to get the full 65536 ports bitmapped
+ * you'd need 8kB of bitmaps/process, which is a bit excessive.
+ *
+ * Here we just change the eflags value on the stack: we allow
+ * only the super-user to do it. This depends on the stack-layout
+ * on system-call entry - see also fork() and the signal handling
+ * code.
+ */
+asmlinkage int sys_iopl(long ebx,long ecx,long edx,
+	     long esi, long edi, long ebp, long eax, long ds,
+	     long es, long fs, long gs, long orig_eax,
+	     long eip,long cs,long eflags,long esp,long ss)
+{
+	unsigned int level = ebx;
+
+	if (level > 3)
+		return -EINVAL;
+	if (!suser())
+		return -EPERM;
+	*(&eflags) = (eflags & 0xffffcfff) | (level << 12);
+	return 0;
+}