patch-2.1.113 linux/include/asm-i386/debugreg.h

• Lines: 65
• Date: Fri Jul 31 12:53:37 1998
• Orig file: v2.1.112/linux/include/asm-i386/debugreg.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.112/linux/include/asm-i386/debugreg.h linux/include/asm-i386/debugreg.h
@@ -0,0 +1,64 @@
+#ifndef _I386_DEBUGREG_H
+#define _I386_DEBUGREG_H
+
+
+/* Indicate the register numbers for a number of the specific
+   debug registers.  Registers 0-3 contain the addresses we wish to trap on */
+#define DR_FIRSTADDR 0        /* u_debugreg[DR_FIRSTADDR] */
+#define DR_LASTADDR 3         /* u_debugreg[DR_LASTADDR]  */
+
+#define DR_STATUS 6           /* u_debugreg[DR_STATUS]     */
+#define DR_CONTROL 7          /* u_debugreg[DR_CONTROL] */
+
+/* Define a few things for the status register.  We can use this to determine
+   which debugging register was responsible for the trap.  The other bits
+   are either reserved or not of interest to us. */
+
+#define DR_TRAP0	(0x1)		/* db0 */
+#define DR_TRAP1	(0x2)		/* db1 */
+#define DR_TRAP2	(0x4)		/* db2 */
+#define DR_TRAP3	(0x8)		/* db3 */
+
+#define DR_STEP		(0x4000)	/* single-step */
+#define DR_SWITCH	(0x8000)	/* task switch */
+
+/* Now define a bunch of things for manipulating the control register.
+   The top two bytes of the control register consist of 4 fields of 4
+   bits - each field corresponds to one of the four debug registers,
+   and indicates what types of access we trap on, and how large the data
+   field is that we are looking at */
+
+#define DR_CONTROL_SHIFT 16 /* Skip this many bits in ctl register */
+#define DR_CONTROL_SIZE 4   /* 4 control bits per register */
+
+#define DR_RW_EXECUTE (0x0)   /* Settings for the access types to trap on */
+#define DR_RW_WRITE (0x1)
+#define DR_RW_READ (0x3)
+
+#define DR_LEN_1 (0x0) /* Settings for data length to trap on */
+#define DR_LEN_2 (0x4)
+#define DR_LEN_4 (0xC)
+
+/* The low byte to the control register determine which registers are
+   enabled.  There are 4 fields of two bits.  One bit is "local", meaning
+   that the processor will reset the bit after a task switch and the other
+   is global meaning that we have to explicitly reset the bit.  With linux,
+   you can use either one, since we explicitly zero the register when we enter
+   kernel mode. */
+
+#define DR_LOCAL_ENABLE_SHIFT 0    /* Extra shift to the local enable bit */
+#define DR_GLOBAL_ENABLE_SHIFT 1   /* Extra shift to the global enable bit */
+#define DR_ENABLE_SIZE 2           /* 2 enable bits per register */
+
+#define DR_LOCAL_ENABLE_MASK (0x55)  /* Set  local bits for all 4 regs */
+#define DR_GLOBAL_ENABLE_MASK (0xAA) /* Set global bits for all 4 regs */
+
+/* The second byte to the control register has a few special things.
+   We can slow the instruction pipeline for instructions coming via the
+   gdt or the ldt if we want to.  I am not sure why this is an advantage */
+
+#define DR_CONTROL_RESERVED (0xFC00) /* Reserved by Intel */
+#define DR_LOCAL_SLOWDOWN (0x100)   /* Local slow the pipeline */
+#define DR_GLOBAL_SLOWDOWN (0x200)  /* Global slow the pipeline */
+
+#endif