summaryrefslogtreecommitdiffstats
path: root/src
diff options
context:
space:
mode:
Diffstat (limited to 'src')
-rw-r--r--src/arch/i386/core/gdbidt.S2
-rw-r--r--src/arch/i386/core/gdbmach.c126
-rw-r--r--src/arch/i386/include/gdbmach.h13
-rw-r--r--src/core/gdbstub.c22
-rw-r--r--src/include/gpxe/gdbstub.h9
-rw-r--r--src/tests/gdbstub_test.S21
-rwxr-xr-xsrc/tests/gdbstub_test.gdb30
7 files changed, 221 insertions, 2 deletions
diff --git a/src/arch/i386/core/gdbidt.S b/src/arch/i386/core/gdbidt.S
index 45d079f6..a4949232 100644
--- a/src/arch/i386/core/gdbidt.S
+++ b/src/arch/i386/core/gdbidt.S
@@ -184,7 +184,7 @@ do_interrupt:
/* Call GDB stub exception handler */
pushl %esp
pushl (IH_OFFSET_SIGNO + 4)(%esp)
- call gdbstub_handler
+ call gdbmach_handler
addl $8, %esp
/* Restore CPU state from GDB register snapshot */
diff --git a/src/arch/i386/core/gdbmach.c b/src/arch/i386/core/gdbmach.c
new file mode 100644
index 00000000..7cffc9e7
--- /dev/null
+++ b/src/arch/i386/core/gdbmach.c
@@ -0,0 +1,126 @@
+#include <stddef.h>
+#include <stdio.h>
+#include <assert.h>
+#include <virtaddr.h>
+#include <gpxe/gdbstub.h>
+#include <gdbmach.h>
+
+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 gdbreg_t dr6;
+
+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 ) {
+ int regnum = bp - hwbps;
+
+ /* Set breakpoint address */
+ assert ( regnum >= 0 && 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 breakpoint status register */
+ __asm__ __volatile__ ( "movl %%dr6, %0\n" "movl %1, %%dr6\n" : "=r" ( dr6 ) : "r" ( DR6_CLEAR ) );
+
+ /* Store and clear hardware breakpoints */
+ __asm__ __volatile__ ( "movl %0, %%dr7\n" : : "r" ( DR7_CLEAR ) );
+}
+
+static void gdbmach_enable_hwbps ( void ) {
+ /* Restore hardware breakpoints */
+ __asm__ __volatile__ ( "movl %0, %%dr7\n" : : "r" ( dr7 ) );
+}
+
+__cdecl void gdbmach_handler ( int signo, gdbreg_t *regs ) {
+ gdbmach_disable_hwbps();
+ gdbstub_handler ( signo, regs );
+ gdbmach_enable_hwbps();
+}
diff --git a/src/arch/i386/include/gdbmach.h b/src/arch/i386/include/gdbmach.h
index 9f6dc8f0..1a38ccd1 100644
--- a/src/arch/i386/include/gdbmach.h
+++ b/src/arch/i386/include/gdbmach.h
@@ -10,6 +10,8 @@
*
*/
+#include <stdint.h>
+
typedef uint32_t gdbreg_t;
/* The register snapshot, this must be in sync with interrupt handler and the
@@ -35,6 +37,15 @@ enum {
GDBMACH_SIZEOF_REGS = GDBMACH_NREGS * sizeof ( gdbreg_t )
};
+/* Breakpoint types */
+enum {
+ GDBMACH_BPMEM,
+ GDBMACH_BPHW,
+ GDBMACH_WATCH,
+ GDBMACH_RWATCH,
+ GDBMACH_AWATCH,
+};
+
static inline void gdbmach_set_pc ( gdbreg_t *regs, gdbreg_t pc ) {
regs [ GDBMACH_EIP ] = pc;
}
@@ -48,4 +59,6 @@ static inline void gdbmach_breakpoint ( void ) {
__asm__ __volatile__ ( "int $3\n" );
}
+extern int gdbmach_set_breakpoint ( int type, unsigned long addr, size_t len, int enable );
+
#endif /* GDBMACH_H */
diff --git a/src/core/gdbstub.c b/src/core/gdbstub.c
index c331b85b..8e338775 100644
--- a/src/core/gdbstub.c
+++ b/src/core/gdbstub.c
@@ -249,6 +249,22 @@ static void gdbstub_continue ( struct gdbstub *stub, int single_step ) {
/* Reply will be sent when we hit the next breakpoint or interrupt */
}
+static void gdbstub_breakpoint ( struct gdbstub *stub ) {
+ unsigned long args [ 3 ];
+ int enable = stub->payload [ 0 ] == 'Z' ? 1 : 0;
+ if ( !gdbstub_get_packet_args ( stub, args, sizeof args / sizeof args [ 0 ], NULL ) ) {
+ gdbstub_send_errno ( stub, POSIX_EINVAL );
+ return;
+ }
+ if ( gdbmach_set_breakpoint ( args [ 0 ], args [ 1 ], args [ 2 ], enable ) ) {
+ gdbstub_send_ok ( stub );
+ } else {
+ /* Not supported */
+ stub->len = 0;
+ gdbstub_tx_packet ( stub );
+ }
+}
+
static void gdbstub_rx_packet ( struct gdbstub *stub ) {
switch ( stub->payload [ 0 ] ) {
case '?':
@@ -275,6 +291,10 @@ static void gdbstub_rx_packet ( struct gdbstub *stub ) {
gdbstub_send_ok ( stub );
}
break;
+ case 'Z': /* Insert breakpoint */
+ case 'z': /* Remove breakpoint */
+ gdbstub_breakpoint ( stub );
+ break;
default:
stub->len = 0;
gdbstub_tx_packet ( stub );
@@ -341,7 +361,7 @@ static struct gdbstub stub = {
.parse = gdbstub_state_new
};
-__cdecl void gdbstub_handler ( int signo, gdbreg_t *regs ) {
+void gdbstub_handler ( int signo, gdbreg_t *regs ) {
char packet [ SIZEOF_PAYLOAD + 4 ];
size_t len, i;
diff --git a/src/include/gpxe/gdbstub.h b/src/include/gpxe/gdbstub.h
index adc7e382..bf5d24d2 100644
--- a/src/include/gpxe/gdbstub.h
+++ b/src/include/gpxe/gdbstub.h
@@ -9,6 +9,7 @@
#include <stdint.h>
#include <gpxe/tables.h>
+#include <gdbmach.h>
/**
* A transport mechanism for the GDB protocol
@@ -61,4 +62,12 @@ extern struct gdb_transport *find_gdb_transport ( const char *name );
*/
extern void gdbstub_start ( struct gdb_transport *trans );
+/**
+ * Interrupt handler
+ *
+ * @signo POSIX signal number
+ * @regs CPU register snapshot
+ **/
+extern void gdbstub_handler ( int signo, gdbreg_t *regs );
+
#endif /* _GPXE_GDBSTUB_H */
diff --git a/src/tests/gdbstub_test.S b/src/tests/gdbstub_test.S
index 64783089..bd293836 100644
--- a/src/tests/gdbstub_test.S
+++ b/src/tests/gdbstub_test.S
@@ -1,4 +1,9 @@
.arch i386
+
+ .section ".data"
+watch_me:
+ .long 0xfeedbeef
+
.section ".text"
.code32
gdbstub_test:
@@ -29,5 +34,21 @@ gdbstub_test:
int $3
nop
+ /* 6. Access watch test */
+ movl $0x600d0000, %ecx
+ movl watch_me, %eax
+ movl $0xbad00000, %ecx
+ int $3
+ movl $0x600d0001, %ecx
+ movl %eax, watch_me
+ movl $0xbad00001, %ecx
+ int $3
+
+ /* 7. Write watch test */
+ movl $0x600d0002, %ecx
+ movl %eax, watch_me
+ movl $0xbad00002, %ecx
+ int $3
+
1:
jmp 1b
diff --git a/src/tests/gdbstub_test.gdb b/src/tests/gdbstub_test.gdb
index c86d4f2a..191799af 100755
--- a/src/tests/gdbstub_test.gdb
+++ b/src/tests/gdbstub_test.gdb
@@ -77,6 +77,34 @@ define gpxe_test_step
gpxe_assert ({char}($eip-1)) (char)0x90 "gpxe_test_step" # nop = 0x90
end
+define gpxe_test_awatch
+ awatch watch_me
+
+ c
+ gpxe_assert $ecx 0x600d0000 "gpxe_test_awatch"
+ if $ecx == 0x600d0000
+ c
+ end
+
+ c
+ gpxe_assert $ecx 0x600d0001 "gpxe_test_awatch"
+ if $ecx == 0x600d0001
+ c
+ end
+
+ delete
+end
+
+define gpxe_test_watch
+ watch watch_me
+ c
+ gpxe_assert $ecx 0x600d0002 "gpxe_test_watch"
+ if $ecx == 0x600d0002
+ c
+ end
+ delete
+end
+
gpxe_load_symbols
gpxe_start_tests
gpxe_test_regs_read
@@ -84,3 +112,5 @@ gpxe_test_regs_write
gpxe_test_mem_read
gpxe_test_mem_write
gpxe_test_step
+gpxe_test_awatch
+gpxe_test_watch
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-07-02 00:50:23 +0200