--- /dev/null
+/*
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stddef.h>
+#include <stdio.h>
+#include <assert.h>
+#include <ipxe/uaccess.h>
+#include <ipxe/gdbstub.h>
+#include <librm.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();
+}
+
+static void * gdbmach_interrupt_vectors[] = {
+ gdbmach_nocode_sigfpe, /* Divide by zero */
+ gdbmach_nocode_sigtrap, /* Debug trap */
+ NULL, /* Non-maskable interrupt */
+ gdbmach_nocode_sigtrap, /* Breakpoint */
+ gdbmach_nocode_sigstkflt, /* Overflow */
+ gdbmach_nocode_sigstkflt, /* Bound range exceeded */
+ gdbmach_nocode_sigill, /* Invalid opcode */
+ NULL, /* Device not available */
+ gdbmach_withcode_sigbus, /* Double fault */
+ NULL, /* Coprocessor segment overrun */
+ gdbmach_withcode_sigsegv, /* Invalid TSS */
+ gdbmach_withcode_sigsegv, /* Segment not present */
+ gdbmach_withcode_sigsegv, /* Stack segment fault */
+ gdbmach_withcode_sigsegv, /* General protection fault */
+ gdbmach_withcode_sigsegv, /* Page fault */
+};
+
+void gdbmach_init ( void ) {
+ unsigned int i;
+
+ for ( i = 0 ; i < ( sizeof ( gdbmach_interrupt_vectors ) /
+ sizeof ( gdbmach_interrupt_vectors[0] ) ) ; i++ ) {
+ set_interrupt_vector ( i, gdbmach_interrupt_vectors[i] );
+ }
+}
Code Review / kvmfornfv.git / blobdiff