arm7_9_common: fix host endianness bug in arm7_9_full_context()

The original code passes to ->read_core_regs() and to
->read_xpsr() the pointer to the little-endian buffer reg.value.
This is incorrect because the two functions above require a
pointer to uint32_t, since they already run the conversion with
arm_le_to_h_u32() in the jtag callback.
This causes a mismatch on big-endian host and the registers get
read with the incorrect endianness.

Use an intermediate buffer to read the registers as uint32_t and
to track the destination reg.value pointer, then copy the value in
reg.value after the call to jtag_execute_queue().

Tested with qemu-armeb and an OpenOCD built through buildroot
configured for cortex-a7 big-endian.

Note that if jtag_execute_queue() fails, the openocd register
cache is not updated, so the already modified flags 'valid' and
'dirty' are incorrect. This part should be moved after the call to
jtag_execute_queue() too.

Change-Id: Iba70d964ffbb74bf0860bfd9d299f218e3bc65bf
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5943
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

1 files changed, 20 insertions, 4 deletions

diff --git a/src/target/arm7_9_common.c b/src/target/arm7_9_common.c
index d70d273..d992aa7 100644
--- a/src/target/arm7_9_common.c
+++ b/src/target/arm7_9_common.c
@@ -1391,6 +1391,11 @@ static int arm7_9_full_context(struct target *target)
 	int retval;
 	struct arm7_9_common *arm7_9 = target_to_arm7_9(target);
 	struct arm *arm = &arm7_9->arm;
+	struct {
+		uint32_t value;
+		void *reg_p;
+	} read_cache[6 * (16 + 1)];
+	int read_cache_idx = 0;
 
 	LOG_DEBUG("-");
 
@@ -1433,10 +1438,12 @@ static int arm7_9_full_context(struct target *target)
 			for (j = 0; j < 15; j++) {
 				if (!ARMV4_5_CORE_REG_MODE(arm->core_cache,
 						armv4_5_number_to_mode(i), j).valid) {
-					reg_p[j] = (uint32_t *)ARMV4_5_CORE_REG_MODE(
+					read_cache[read_cache_idx].reg_p = ARMV4_5_CORE_REG_MODE(
 							arm->core_cache,
 							armv4_5_number_to_mode(i),
 							j).value;
+					reg_p[j] = &read_cache[read_cache_idx].value;
+					read_cache_idx++;
 					mask |= 1 << j;
 					ARMV4_5_CORE_REG_MODE(arm->core_cache,
 						armv4_5_number_to_mode(i),
@@ -1454,9 +1461,10 @@ static int arm7_9_full_context(struct target *target)
 			/* check if the PSR has to be read */
 			if (!ARMV4_5_CORE_REG_MODE(arm->core_cache, armv4_5_number_to_mode(i),
 					16).valid) {
-				arm7_9->read_xpsr(target,
-					(uint32_t *)ARMV4_5_CORE_REG_MODE(arm->core_cache,
-						armv4_5_number_to_mode(i), 16).value, 1);
+				read_cache[read_cache_idx].reg_p = ARMV4_5_CORE_REG_MODE(arm->core_cache,
+					armv4_5_number_to_mode(i), 16).value;
+				arm7_9->read_xpsr(target, &read_cache[read_cache_idx].value, 1);
+				read_cache_idx++;
 				ARMV4_5_CORE_REG_MODE(arm->core_cache, armv4_5_number_to_mode(i),
 					16).valid = true;
 				ARMV4_5_CORE_REG_MODE(arm->core_cache, armv4_5_number_to_mode(i),
@@ -1472,6 +1480,14 @@ static int arm7_9_full_context(struct target *target)
 	retval = jtag_execute_queue();
 	if (retval != ERROR_OK)
 		return retval;
+	/*
+	 * FIXME: regs in cache should be tagged as 'valid' only now,
+	 * not before the jtag_execute_queue()
+	 */
+	while (read_cache_idx) {
+		read_cache_idx--;
+		buf_set_u32(read_cache[read_cache_idx].reg_p, 0, 32, read_cache[read_cache_idx].value);
+	}
 	return ERROR_OK;
 }