git: 7446b0888d92 - main - gdb: report specific stop reason for watchpoints
Mitchell Horne
mhorne at FreeBSD.org
Tue Mar 30 14:37:12 UTC 2021
The branch main has been updated by mhorne:
URL: https://cgit.FreeBSD.org/src/commit/?id=7446b0888d920124516284eaa32714d63353e2c9
commit 7446b0888d920124516284eaa32714d63353e2c9
Author: Mitchell Horne <mhorne at FreeBSD.org>
AuthorDate: 2021-03-08 19:04:51 +0000
Commit: Mitchell Horne <mhorne at FreeBSD.org>
CommitDate: 2021-03-30 14:36:41 +0000
gdb: report specific stop reason for watchpoints
The remote protocol allows for implementations to report more specific
reasons for the break in execution back to the client [1]. This is
entirely optional, so it is only implemented for amd64, arm64, and i386
at the moment.
[1] https://sourceware.org/gdb/current/onlinedocs/gdb/Stop-Reply-Packets.html
Reviewed by: jhb
MFC after: 3 weeks
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
NetApp PR: 51
Differential Revision: https://reviews.freebsd.org/D29174
---
sys/amd64/amd64/gdb_machdep.c | 35 ++++++++++++++++++++++++++++++++++
sys/amd64/include/gdb_machdep.h | 1 +
sys/arm/include/gdb_machdep.h | 6 ++++++
sys/arm64/arm64/gdb_machdep.c | 12 ++++++++++++
sys/arm64/include/gdb_machdep.h | 1 +
sys/gdb/gdb_main.c | 3 ++-
sys/i386/i386/gdb_machdep.c | 40 +++++++++++++++++++++++++++++++++++++--
sys/i386/include/gdb_machdep.h | 1 +
sys/mips/include/gdb_machdep.h | 6 ++++++
sys/powerpc/include/gdb_machdep.h | 6 ++++++
10 files changed, 108 insertions(+), 3 deletions(-)
diff --git a/sys/amd64/amd64/gdb_machdep.c b/sys/amd64/amd64/gdb_machdep.c
index 610096e1355d..176c770a3731 100644
--- a/sys/amd64/amd64/gdb_machdep.c
+++ b/sys/amd64/amd64/gdb_machdep.c
@@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$");
#include <machine/endian.h>
#include <gdb/gdb.h>
+#include <gdb/gdb_int.h>
void *
gdb_cpu_getreg(int regnum, size_t *regsz)
@@ -152,6 +153,40 @@ gdb_cpu_signal(int type, int code)
return (SIGEMT);
}
+void
+gdb_cpu_stop_reason(int type, int code)
+{
+ uintmax_t val;
+
+ val = 0;
+ if (type == T_TRCTRAP) {
+ /* NB: 'code' contains the value of dr6 at the trap. */
+ if ((code & DBREG_DR6_B(0)) != 0) {
+ val = rdr0();
+ }
+ if ((code & DBREG_DR6_B(1)) != 0) {
+ val = rdr1();
+ }
+ if ((code & DBREG_DR6_B(2)) != 0) {
+ val = rdr2();
+ }
+ if ((code & DBREG_DR6_B(3)) != 0) {
+ val = rdr3();
+ }
+
+ /*
+ * TODO: validate the bits in DR7 to differentiate between a
+ * watchpoint trap and a hardware breakpoint trap (currently
+ * unsupported).
+ */
+ if (val != 0) {
+ gdb_tx_str("watch:");
+ gdb_tx_varhex(val);
+ gdb_tx_char(';');
+ }
+ }
+}
+
void *
gdb_begin_write(void)
{
diff --git a/sys/amd64/include/gdb_machdep.h b/sys/amd64/include/gdb_machdep.h
index 459d4f17e9d1..4379b8a74709 100644
--- a/sys/amd64/include/gdb_machdep.h
+++ b/sys/amd64/include/gdb_machdep.h
@@ -72,5 +72,6 @@ void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
void gdb_end_write(void *);
+void gdb_cpu_stop_reason(int, int);
#endif /* !_MACHINE_GDB_MACHDEP_H_ */
diff --git a/sys/arm/include/gdb_machdep.h b/sys/arm/include/gdb_machdep.h
index 017025253bd5..5190c2a4097e 100644
--- a/sys/arm/include/gdb_machdep.h
+++ b/sys/arm/include/gdb_machdep.h
@@ -66,6 +66,12 @@ gdb_end_write(void *arg __unused)
}
+static __inline void
+gdb_cpu_stop_reason(int type __unused, int code __unused)
+{
+
+}
+
void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
diff --git a/sys/arm64/arm64/gdb_machdep.c b/sys/arm64/arm64/gdb_machdep.c
index dc0a7eeba692..b27e1edb3d7f 100644
--- a/sys/arm64/arm64/gdb_machdep.c
+++ b/sys/arm64/arm64/gdb_machdep.c
@@ -41,6 +41,7 @@
#include <machine/pcb.h>
#include <gdb/gdb.h>
+#include <gdb/gdb_int.h>
void *
gdb_cpu_getreg(int regnum, size_t *regsz)
@@ -110,3 +111,14 @@ gdb_cpu_signal(int type, int code __unused)
}
return (SIGEMT);
}
+
+void
+gdb_cpu_stop_reason(int type, int code __unused)
+{
+
+ if (type == EXCP_WATCHPT_EL1) {
+ gdb_tx_str("watch:");
+ gdb_tx_varhex((uintmax_t)READ_SPECIALREG(far_el1));
+ gdb_tx_char(';');
+ }
+}
diff --git a/sys/arm64/include/gdb_machdep.h b/sys/arm64/include/gdb_machdep.h
index 755c5d1657c0..17b46edd1a27 100644
--- a/sys/arm64/include/gdb_machdep.h
+++ b/sys/arm64/include/gdb_machdep.h
@@ -77,5 +77,6 @@ gdb_end_write(void *arg __unused)
void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
+void gdb_cpu_stop_reason(int, int);
#endif /* !_MACHINE_GDB_MACHDEP_H_ */
diff --git a/sys/gdb/gdb_main.c b/sys/gdb/gdb_main.c
index a4469fdf4997..c5e4ba608f29 100644
--- a/sys/gdb/gdb_main.c
+++ b/sys/gdb/gdb_main.c
@@ -741,8 +741,9 @@ gdb_trap(int type, int code)
gdb_tx_char(':');
gdb_tx_reg(GDB_REG_PC);
gdb_tx_char(';');
+ gdb_cpu_stop_reason(type, code);
gdb_tx_str("thread:");
- gdb_tx_varhex((long)kdb_thread->td_tid);
+ gdb_tx_varhex((uintmax_t)kdb_thread->td_tid);
gdb_tx_char(';');
gdb_tx_end(); /* XXX check error condition. */
diff --git a/sys/i386/i386/gdb_machdep.c b/sys/i386/i386/gdb_machdep.c
index fd522309dbb2..549c6de7ba1b 100644
--- a/sys/i386/i386/gdb_machdep.c
+++ b/sys/i386/i386/gdb_machdep.c
@@ -36,13 +36,15 @@ __FBSDID("$FreeBSD$");
#include <sys/proc.h>
#include <sys/signal.h>
+#include <machine/endian.h>
+#include <machine/frame.h>
#include <machine/gdb_machdep.h>
#include <machine/pcb.h>
+#include <machine/reg.h>
#include <machine/trap.h>
-#include <machine/frame.h>
-#include <machine/endian.h>
#include <gdb/gdb.h>
+#include <gdb/gdb_int.h>
void *
gdb_cpu_getreg(int regnum, size_t *regsz)
@@ -114,3 +116,37 @@ gdb_cpu_signal(int type, int code)
}
return (SIGEMT);
}
+
+void
+gdb_cpu_stop_reason(int type, int code)
+{
+ uintmax_t val;
+
+ val = 0;
+ if (type == T_TRCTRAP) {
+ /* NB: 'code' contains the value of dr6 at the trap. */
+ if ((code & DBREG_DR6_B(0)) != 0) {
+ val = rdr0();
+ }
+ if ((code & DBREG_DR6_B(1)) != 0) {
+ val = rdr1();
+ }
+ if ((code & DBREG_DR6_B(2)) != 0) {
+ val = rdr2();
+ }
+ if ((code & DBREG_DR6_B(3)) != 0) {
+ val = rdr3();
+ }
+
+ /*
+ * TODO: validate the bits in DR7 to differentiate between a
+ * watchpoint trap and a hardware breakpoint trap (currently
+ * unsupported).
+ */
+ if (val != 0) {
+ gdb_tx_str("watch:");
+ gdb_tx_varhex(val);
+ gdb_tx_char(';');
+ }
+ }
+}
diff --git a/sys/i386/include/gdb_machdep.h b/sys/i386/include/gdb_machdep.h
index ef9500160be1..77eb70e2fb28 100644
--- a/sys/i386/include/gdb_machdep.h
+++ b/sys/i386/include/gdb_machdep.h
@@ -63,5 +63,6 @@ gdb_end_write(void *arg __unused)
void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
+void gdb_cpu_stop_reason(int, int);
#endif /* !_MACHINE_GDB_MACHDEP_H_ */
diff --git a/sys/mips/include/gdb_machdep.h b/sys/mips/include/gdb_machdep.h
index 03378b760024..e8ff620edc88 100644
--- a/sys/mips/include/gdb_machdep.h
+++ b/sys/mips/include/gdb_machdep.h
@@ -64,6 +64,12 @@ gdb_end_write(void *arg __unused)
}
+static __inline void
+gdb_cpu_stop_reason(int type __unused, int code __unused)
+{
+
+}
+
void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
diff --git a/sys/powerpc/include/gdb_machdep.h b/sys/powerpc/include/gdb_machdep.h
index 41a9ab1f4fa7..5edf4d96cb7c 100644
--- a/sys/powerpc/include/gdb_machdep.h
+++ b/sys/powerpc/include/gdb_machdep.h
@@ -128,6 +128,12 @@ gdb_end_write(void *arg __unused)
}
+static __inline void
+gdb_cpu_stop_reason(int type __unused, int code __unused)
+{
+
+}
+
void *gdb_cpu_getreg(int, size_t *);
void gdb_cpu_setreg(int, void *);
int gdb_cpu_signal(int, int);
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