diff options
Diffstat (limited to 'contrib/syslinux-4.02/gpxe/src/arch/i386/core/gdbmach.c')
| -rw-r--r-- | contrib/syslinux-4.02/gpxe/src/arch/i386/core/gdbmach.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/gpxe/src/arch/i386/core/gdbmach.c b/contrib/syslinux-4.02/gpxe/src/arch/i386/core/gdbmach.c new file mode 100644 index 0000000..97827ec --- /dev/null +++ b/contrib/syslinux-4.02/gpxe/src/arch/i386/core/gdbmach.c @@ -0,0 +1,149 @@ +/* + * Copyright (C) 2008 Stefan Hajnoczi <stefanha@gmail.com>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <stddef.h> +#include <stdio.h> +#include <assert.h> +#include <gpxe/uaccess.h> +#include <gpxe/gdbstub.h> +#include <gdbmach.h> + +/** @file + * + * GDB architecture-specific bits for i386 + * + */ + +enum { + DR7_CLEAR = 0x00000400, /* disable hardware breakpoints */ + DR6_CLEAR = 0xffff0ff0, /* clear breakpoint status */ +}; + +/** Hardware breakpoint, fields stored in x86 bit pattern form */ +struct hwbp { + int type; /* type (1=write watchpoint, 3=access watchpoint) */ + unsigned long addr; /* linear address */ + size_t len; /* length (0=1-byte, 1=2-byte, 3=4-byte) */ + int enabled; +}; + +static struct hwbp hwbps [ 4 ]; +static gdbreg_t dr7 = DR7_CLEAR; + +static struct hwbp *gdbmach_find_hwbp ( int type, unsigned long addr, size_t len ) { + 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 ) { + 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 ) { + 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 ) { + /* Store and clear hardware breakpoints */ + __asm__ __volatile__ ( "movl %0, %%dr7\n" : : "r" ( DR7_CLEAR ) ); +} + +static void gdbmach_enable_hwbps ( void ) { + /* 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 ) { + gdbmach_disable_hwbps(); + gdbstub_handler ( signo, regs ); + gdbmach_enable_hwbps(); +} |