git: 4beb385813c8 - main - gdb: allow setting/removing hardware watchpoints
Mitchell Horne
mhorne at FreeBSD.org
Tue Mar 30 14:37:05 UTC 2021
The branch main has been updated by mhorne:
URL: https://cgit.FreeBSD.org/src/commit/?id=4beb385813c8b1014f8250a31b07fdc09a059713
commit 4beb385813c8b1014f8250a31b07fdc09a059713
Author: Mitchell Horne <mhorne at FreeBSD.org>
AuthorDate: 2021-03-08 19:03:45 +0000
Commit: Mitchell Horne <mhorne at FreeBSD.org>
CommitDate: 2021-03-30 14:36:41 +0000
gdb: allow setting/removing hardware watchpoints
Handle the 'z' and 'Z' remote packets for manipulating hardware
watchpoints.
This could be expanded quite easily to support hardware or software
breakpoints as well.
https://sourceware.org/gdb/onlinedocs/gdb/Packets.html
Reviewed by: cem, markj
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
NetApp PR: 51
Differential Revision: https://reviews.freebsd.org/D29173
---
sys/arm64/arm64/debug_monitor.c | 5 +-
sys/conf/files.arm | 3 +-
sys/conf/files.x86 | 2 +-
sys/gdb/gdb_main.c | 102 ++++++++++++++++++++++++++++++++++++++++
sys/x86/x86/mp_x86.c | 3 +-
5 files changed, 110 insertions(+), 5 deletions(-)
diff --git a/sys/arm64/arm64/debug_monitor.c b/sys/arm64/arm64/debug_monitor.c
index 845784129b4c..c3dce1883e68 100644
--- a/sys/arm64/arm64/debug_monitor.c
+++ b/sys/arm64/arm64/debug_monitor.c
@@ -28,6 +28,7 @@
*/
#include "opt_ddb.h"
+#include "opt_gdb.h"
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
@@ -181,7 +182,7 @@ dbg_wb_write_reg(int reg, int n, uint64_t val)
isb();
}
-#ifdef DDB
+#if defined(DDB) || defined(GDB)
void
kdb_cpu_set_singlestep(void)
{
@@ -254,7 +255,9 @@ kdb_cpu_clr_watchpoint(vm_offset_t addr, vm_size_t size)
return (dbg_remove_watchpoint(NULL, addr, size));
}
+#endif /* DDB || GDB */
+#ifdef DDB
static const char *
dbg_watchtype_str(uint32_t type)
{
diff --git a/sys/conf/files.arm b/sys/conf/files.arm
index 69986585bdf6..a3b0d166f020 100644
--- a/sys/conf/files.arm
+++ b/sys/conf/files.arm
@@ -19,8 +19,7 @@ arm/arm/cpu_asm-v6.S standard
arm/arm/db_disasm.c optional ddb
arm/arm/db_interface.c optional ddb
arm/arm/db_trace.c optional ddb
-arm/arm/debug_monitor.c optional ddb armv6
-arm/arm/debug_monitor.c optional ddb armv7
+arm/arm/debug_monitor.c optional ddb | gdb
arm/arm/disassem.c optional ddb
arm/arm/dump_machdep.c standard
arm/arm/elf_machdep.c standard
diff --git a/sys/conf/files.x86 b/sys/conf/files.x86
index fd31d95fa162..0f83126e99a6 100644
--- a/sys/conf/files.x86
+++ b/sys/conf/files.x86
@@ -320,7 +320,7 @@ x86/x86/bus_machdep.c standard
x86/x86/busdma_bounce.c standard
x86/x86/busdma_machdep.c standard
x86/x86/cpu_machdep.c standard
-x86/x86/dbreg.c optional ddb
+x86/x86/dbreg.c optional ddb | gdb
x86/x86/dump_machdep.c standard
x86/x86/fdt_machdep.c optional fdt
x86/x86/identcpu.c standard
diff --git a/sys/gdb/gdb_main.c b/sys/gdb/gdb_main.c
index a9e935ebfbb5..a4469fdf4997 100644
--- a/sys/gdb/gdb_main.c
+++ b/sys/gdb/gdb_main.c
@@ -618,6 +618,100 @@ gdb_handle_detach(void)
#endif
}
+/*
+ * Handle a 'Z' packet: set a breakpoint or watchpoint.
+ *
+ * Currently, only watchpoints are supported.
+ */
+static void
+gdb_z_insert(void)
+{
+ intmax_t addr, length;
+ char ztype;
+ int error;
+
+ ztype = gdb_rx_char();
+ if (gdb_rx_char() != ',' || gdb_rx_varhex(&addr) ||
+ gdb_rx_char() != ',' || gdb_rx_varhex(&length)) {
+ error = EINVAL;
+ goto fail;
+ }
+
+ switch (ztype) {
+ case '2': /* write watchpoint */
+ error = kdb_cpu_set_watchpoint((vm_offset_t)addr,
+ (vm_size_t)length, KDB_DBG_ACCESS_W);
+ break;
+ case '3': /* read watchpoint */
+ error = kdb_cpu_set_watchpoint((vm_offset_t)addr,
+ (vm_size_t)length, KDB_DBG_ACCESS_R);
+ break;
+ case '4': /* access (RW) watchpoint */
+ error = kdb_cpu_set_watchpoint((vm_offset_t)addr,
+ (vm_size_t)length, KDB_DBG_ACCESS_RW);
+ break;
+ case '1': /* hardware breakpoint */
+ case '0': /* software breakpoint */
+ /* Not implemented. */
+ gdb_tx_empty();
+ return;
+ default:
+ error = EINVAL;
+ break;
+ }
+ if (error != 0)
+ goto fail;
+ gdb_tx_ok();
+ return;
+fail:
+ gdb_tx_err(error);
+ return;
+}
+
+/*
+ * Handle a 'z' packet; clear a breakpoint or watchpoint.
+ *
+ * Currently, only watchpoints are supported.
+ */
+static void
+gdb_z_remove(void)
+{
+ intmax_t addr, length;
+ char ztype;
+ int error;
+
+ ztype = gdb_rx_char();
+ if (gdb_rx_char() != ',' || gdb_rx_varhex(&addr) ||
+ gdb_rx_char() != ',' || gdb_rx_varhex(&length)) {
+ error = EINVAL;
+ goto fail;
+ }
+
+ switch (ztype) {
+ case '2': /* write watchpoint */
+ case '3': /* read watchpoint */
+ case '4': /* access (RW) watchpoint */
+ error = kdb_cpu_clr_watchpoint((vm_offset_t)addr,
+ (vm_size_t)length);
+ break;
+ case '1': /* hardware breakpoint */
+ case '0': /* software breakpoint */
+ /* Not implemented. */
+ gdb_tx_empty();
+ return;
+ default:
+ error = EINVAL;
+ break;
+ }
+ if (error != 0)
+ goto fail;
+ gdb_tx_ok();
+ return;
+fail:
+ gdb_tx_err(error);
+ return;
+}
+
static int
gdb_trap(int type, int code)
{
@@ -868,6 +962,14 @@ gdb_trap(int type, int code)
gdb_tx_err(ENOENT);
break;
}
+ case 'z': { /* Remove watchpoint. */
+ gdb_z_remove();
+ break;
+ }
+ case 'Z': { /* Set watchpoint. */
+ gdb_z_insert();
+ break;
+ }
case EOF:
/* Empty command. Treat as unknown command. */
/* FALLTHROUGH */
diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c
index 0f528f6567ee..2dcdf923c467 100644
--- a/sys/x86/x86/mp_x86.c
+++ b/sys/x86/x86/mp_x86.c
@@ -32,6 +32,7 @@ __FBSDID("$FreeBSD$");
#endif
#include "opt_cpu.h"
#include "opt_ddb.h"
+#include "opt_gdb.h"
#include "opt_kstack_pages.h"
#include "opt_pmap.h"
#include "opt_sched.h"
@@ -1520,7 +1521,7 @@ cpustop_handler_post(u_int cpu)
*/
invltlb_glob();
-#if defined(__amd64__) && defined(DDB)
+#if defined(__amd64__) && (defined(DDB) || defined(GDB))
amd64_db_resume_dbreg();
#endif
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