gdbmach.c File Reference

GDB architecture-specific bits for i386. More...

#include <stddef.h>
#include <stdio.h>
#include <assert.h>
#include <gpxe/uaccess.h>
#include <gpxe/gdbstub.h>
#include <gdbmach.h>

Go to the source code of this file.

Data Structures
struct	hwbp
	Hardware breakpoint, fields stored in x86 bit pattern form. More...
Enumerations
enum	{ DR7_CLEAR = 0x00000400, DR6_CLEAR = 0xffff0ff0 }
Functions
static struct hwbp *	gdbmach_find_hwbp (int type, unsigned long addr, size_t len)
static void	gdbmach_commit_hwbp (struct hwbp *bp)
int	gdbmach_set_breakpoint (int type, unsigned long addr, size_t len, int enable)
static void	gdbmach_disable_hwbps (void)
static void	gdbmach_enable_hwbps (void)
__asmcall void	gdbmach_handler (int signo, gdbreg_t *regs)
Variables
static struct hwbp	hwbps [4]
static gdbreg_t	dr7 = DR7_CLEAR

---

Detailed Description

GDB architecture-specific bits for i386.

Definition in file gdbmach.c.

---

Enumeration Type Documentation

anonymous enum

Enumerator:

DR7_CLEAR
DR6_CLEAR

Definition at line 32 of file gdbmach.c.

     {
        DR7_CLEAR = 0x00000400,    /* disable hardware breakpoints */
        DR6_CLEAR = 0xffff0ff0,    /* clear breakpoint status */
};

---

Function Documentation

static struct hwbp* gdbmach_find_hwbp	(	int	type,
		unsigned long	addr,
		size_t	len
	)			[static, read]

Definition at line 48 of file gdbmach.c.

References hwbp::enabled, hwbps, and NULL.

Referenced by gdbmach_set_breakpoint().

                                                                                   {
        struct hwbp *available = NULL;
        unsigned int i;
        for ( i = 0; i < sizeof hwbps / sizeof hwbps [ 0 ]; i++ ) {
                if ( hwbps [ i ].type == type && hwbps [ i ].addr == addr && hwbps [ i ].len == len ) {
                        return &hwbps [ i ];
                }
                if ( !hwbps [ i ].enabled ) {
                        available = &hwbps [ i ];
                }
        }
        return available;
}

static void gdbmach_commit_hwbp

(

struct hwbp *

bp

)

[static]

Definition at line 62 of file gdbmach.c.

References __asm__(), hwbp::addr, assert, dr7, hwbp::enabled, hwbps, hwbp::len, and hwbp::type.

Referenced by gdbmach_set_breakpoint().

                                                    {
        unsigned int regnum = bp - hwbps;

        /* Set breakpoint address */
        assert ( regnum < ( sizeof hwbps / sizeof hwbps [ 0 ] ) );
        switch ( regnum ) {
                case 0:
                        __asm__ __volatile__ ( "movl %0, %%dr0\n" : : "r" ( bp->addr ) );
                        break;
                case 1:
                        __asm__ __volatile__ ( "movl %0, %%dr1\n" : : "r" ( bp->addr ) );
                        break;
                case 2:
                        __asm__ __volatile__ ( "movl %0, %%dr2\n" : : "r" ( bp->addr ) );
                        break;
                case 3:
                        __asm__ __volatile__ ( "movl %0, %%dr3\n" : : "r" ( bp->addr ) );
                        break;
        }

        /* Set type */
        dr7 &= ~( 0x3 << ( 16 + 4 * regnum ) );
        dr7 |= bp->type << ( 16 + 4 * regnum );

        /* Set length */
        dr7 &= ~( 0x3 << ( 18 + 4 * regnum ) );
        dr7 |= bp->len << ( 18 + 4 * regnum );

        /* Set/clear local enable bit */
        dr7 &= ~( 0x3 << 2 * regnum );
        dr7 |= bp->enabled << 2 * regnum;
}

int gdbmach_set_breakpoint	(	int	type,
		unsigned long	addr,
		size_t	len,
		int	enable
	)

Definition at line 95 of file gdbmach.c.

References hwbp::addr, hwbp::enabled, GDBMACH_AWATCH, gdbmach_commit_hwbp(), gdbmach_find_hwbp(), GDBMACH_WATCH, hwbp::len, hwbp::type, and virt_offset.

Referenced by gdbstub_breakpoint().

                                                                                    {
        struct hwbp *bp;
        
        /* Check and convert breakpoint type to x86 type */
        switch ( type ) {
                case GDBMACH_WATCH:
                        type = 0x1;
                        break;
                case GDBMACH_AWATCH:
                        type = 0x3;
                        break;
                default:
                        return 0; /* unsupported breakpoint type */
        }

        /* Only lengths 1, 2, and 4 are supported */
        if ( len != 2 && len != 4 ) {
                len = 1;
        }
        len--; /* convert to x86 breakpoint length bit pattern */

        /* Calculate linear address by adding segment base */
        addr += virt_offset;

        /* Set up the breakpoint */
        bp = gdbmach_find_hwbp ( type, addr, len );
        if ( !bp ) {
                return 0; /* ran out of hardware breakpoints */
        }
        bp->type = type;
        bp->addr = addr;
        bp->len = len;
        bp->enabled = enable;
        gdbmach_commit_hwbp ( bp );
        return 1;
}

static void gdbmach_disable_hwbps

(

void

)

[static]

Definition at line 132 of file gdbmach.c.

References __asm__(), and DR7_CLEAR.

Referenced by gdbmach_handler().

                                           {
        /* Store and clear hardware breakpoints */
        __asm__ __volatile__ ( "movl %0, %%dr7\n" : : "r" ( DR7_CLEAR ) );
}

static void gdbmach_enable_hwbps

(

void

)

[static]

Definition at line 137 of file gdbmach.c.

References __asm__(), DR6_CLEAR, and dr7.

Referenced by gdbmach_handler().

                                          {
        /* Clear breakpoint status register */
        __asm__ __volatile__ ( "movl %0, %%dr6\n" : : "r" ( DR6_CLEAR ) );

        /* Restore hardware breakpoints */
        __asm__ __volatile__ ( "movl %0, %%dr7\n" : : "r" ( dr7 ) );
}

__asmcall void gdbmach_handler	(	int	signo,
		gdbreg_t *	regs
	)

Definition at line 145 of file gdbmach.c.

References gdbmach_disable_hwbps(), gdbmach_enable_hwbps(), and gdbstub_handler().

                                                             {
        gdbmach_disable_hwbps();
        gdbstub_handler ( signo, regs );
        gdbmach_enable_hwbps();
}

---

Variable Documentation

struct hwbp hwbps[4] [static]

Definition at line 45 of file gdbmach.c.

Referenced by gdbmach_commit_hwbp(), and gdbmach_find_hwbp().

gdbreg_t dr7 = DR7_CLEAR [static]

Definition at line 46 of file gdbmach.c.

Referenced by gdbmach_commit_hwbp(), and gdbmach_enable_hwbps().