target/armv7m: prevent saving and restoring non existent regs

armv7m_start_algorithm() saves register values to arch_info->context.
armv7m_wait_algorithm() restores register values from arch_info->context.
Exclude registers with flag exist = false from both loops.

While on it refactor the register restore: introduce 'struct reg' pointer
and dereference it instead of numerous accesses by a full path
from armv7m pointer.

Change-Id: I1600084db84809ee13bcf8e7828b79f8c9ff9077
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reviewed-on: https://review.openocd.org/c/openocd/+/7276
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

diff --git a/src/target/armv7m.c b/src/target/armv7m.c
index d9d01923a25762b40b05d07dacb85ae83765ae07..d28702dd7bd59907b663a67adc5508af0979436c 100644 (file)
--- a/src/target/armv7m.c
+++ b/src/target/armv7m.c
@@ -529,6 +529,9 @@ 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->exist)
+                       continue;
+
                if (!reg->valid)
                        armv7m_get_core_reg(reg);
 
@@ -688,16 +691,19 @@ int armv7m_wait_algorithm(struct target *target,
        }
 
        for (int i = armv7m->arm.core_cache->num_regs - 1; i >= 0; i--) {
+               struct reg *reg = &armv7m->arm.core_cache->reg_list[i];
+               if (!reg->exist)
+                       continue;
+
                uint32_t regvalue;
-               regvalue = buf_get_u32(armv7m->arm.core_cache->reg_list[i].value, 0, 32);
+               regvalue = buf_get_u32(reg->value, 0, 32);
                if (regvalue != armv7m_algorithm_info->context[i]) {
                        LOG_DEBUG("restoring register %s with value 0x%8.8" PRIx32,
-                                       armv7m->arm.core_cache->reg_list[i].name,
-                               armv7m_algorithm_info->context[i]);
-                       buf_set_u32(armv7m->arm.core_cache->reg_list[i].value,
+                                         reg->name, armv7m_algorithm_info->context[i]);
+                       buf_set_u32(reg->value,
                                0, 32, armv7m_algorithm_info->context[i]);
-                       armv7m->arm.core_cache->reg_list[i].valid = true;
-                       armv7m->arm.core_cache->reg_list[i].dirty = true;
+                       reg->valid = true;
+                       reg->dirty = true;
                }
        }