gdb server: new feature, add stop reason in stop reply packet for gdb

In GDB remote serial protocol, the stop reply packet could contain more
detail stop reason. The currently defined stop reasons are listed below.

* watch
* rwatch
* awatch
* library
* replaylog

This commit adds stop reason, watch/rwatch/awatch, in stop reply packet for
just hit watchpoint. As manual indicates, at most one stop reason should be present.

The function needs target to implement new hook, hit_watchpoint. The hook will fill
the hit watchpoint in second parameter. The information will assist gdb to locate
the watchpoint. If no such information, gdb needs to scan all watchpoints by itself.

Refer to GDB Manual, D.3 Stop Reply Packets

Change-Id: I1f70a1a9cc772e88e641b6171f1a009629a43bd1
Signed-off-by: Hsiangkai Wang <hsiangkai@gmail.com>
Reviewed-on: http://openocd.zylin.com/1092
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>

1 files changed, 37 insertions, 0 deletions

diff --git a/src/target/nds32_v2.c b/src/target/nds32_v2.c
index 90961d7d..3f5f636f 100644
--- a/src/target/nds32_v2.c
+++ b/src/target/nds32_v2.c
@@ -534,6 +534,42 @@ static int nds32_v2_get_exception_address(struct nds32 *nds32,
 	return ERROR_OK;
 }
 
+/**
+ * find out which watchpoint hits
+ * get exception address and compare the address to watchpoints
+ */
+static int nds32_v2_hit_watchpoint(struct target *target,
+		struct watchpoint **hit_watchpoint)
+{
+	uint32_t exception_address;
+	struct watchpoint *wp;
+	static struct watchpoint scan_all_watchpoint;
+	struct nds32 *nds32 = target_to_nds32(target);
+
+	scan_all_watchpoint.address = 0;
+	scan_all_watchpoint.rw = WPT_WRITE;
+	scan_all_watchpoint.next = 0;
+	scan_all_watchpoint.unique_id = 0x5CA8;
+
+	exception_address = nds32->watched_address;
+
+	if (exception_address == 0) {
+		/* send watch:0 to tell GDB to do software scan for hitting multiple watchpoints */
+		*hit_watchpoint = &scan_all_watchpoint;
+		return ERROR_OK;
+	}
+
+	for (wp = target->watchpoints; wp; wp = wp->next) {
+		if (((exception_address ^ wp->address) & (~wp->mask)) == 0) {
+			/* TODO: dispel false match */
+			*hit_watchpoint = wp;
+			return ERROR_OK;
+		}
+	}
+
+	return ERROR_FAIL;
+}
+
 static int nds32_v2_run_algorithm(struct target *target,
 		int num_mem_params,
 		struct mem_param *mem_params,
@@ -747,6 +783,7 @@ struct target_type nds32_v2_target = {
 	.remove_breakpoint = nds32_v2_remove_breakpoint,
 	.add_watchpoint = nds32_v2_add_watchpoint,
 	.remove_watchpoint = nds32_v2_remove_watchpoint,
+	.hit_watchpoint = nds32_v2_hit_watchpoint,
 
 	/* MMU */
 	.mmu = nds32_mmu,