target/armv7m: prevent storing invalid register

armv7m_start_algorithm() stored all non-debug execution
registers from register cache without checking validity.

Check if the register cache is valid.
Try to read from CPU if not valid.
Issue a warning if register read fails.

Change-Id: I365f86d65243230cf521b13909575e5986a87a50
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/7240
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Jonathan Bell <jonathan@raspberrypi.com>

diff --git a/src/target/armv7m.c b/src/target/armv7m.c
index 2db2ce2dd58796a4aeedb7a2b8967d15df053041..6f6a170b701be8c02c822fe2fe8c5a2bb9566b8b 100644 (file)
--- a/src/target/armv7m.c
+++ b/src/target/armv7m.c
@@ -528,11 +528,14 @@ int armv7m_start_algorithm(struct target *target,
 
        /* Store all non-debug execution registers to armv7m_algorithm_info context */
        for (unsigned i = 0; i < armv7m->arm.core_cache->num_regs; i++) {
+               struct reg *reg = &armv7m->arm.core_cache->reg_list[i];
+               if (!reg->valid)
+                       armv7m_get_core_reg(reg);
 
-               armv7m_algorithm_info->context[i] = buf_get_u32(
-                               armv7m->arm.core_cache->reg_list[i].value,
-                               0,
-                               32);
+               if (!reg->valid)
+                       LOG_TARGET_WARNING(target, "Storing invalid register %s", reg->name);
+
+               armv7m_algorithm_info->context[i] = buf_get_u32(reg->value, 0, 32);
        }
 
        for (int i = 0; i < num_mem_params; i++) {