ARMv7-M: start using "struct arm"

This sets up a few of the core "struct arm" data structures so they
can be used with ARMv7-M cores.  Specifically, it:

 - defines new ARM core_modes to match the microcontroller modes
   (e.g. HANDLER not IRQ, and two types of thread mode);

 - Establishes a new microcontroller "core_type", which can be
   used to make sure v7-M (and v6-M) cores are handled right;

 - adds "struct arm" to "struct armv7m" and arranges for the
   target_to_armv7m() converter to use it;

 - sets up the arm.core_cache and arm.cpsr values

 - makes the Cortex-M3 code maintain arm.map and arm.core_mode.

This is currently set up as a parallel data structure, primarily to
minimize special cases for the semihosting support with microcontroller
profile cores.

Later patches can rip out the duplicative ARMv7-M support and start
reusing core ARM code.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/target/armv4_5.c b/src/target/armv4_5.c
index c7b73676..8d3a8917 100644
--- a/src/target/armv4_5.c
+++ b/src/target/armv4_5.c
@@ -1426,10 +1426,12 @@ int arm_init_arch_info(struct target *target, struct arm *armv4_5)
 	armv4_5->target = target;
 
 	armv4_5->common_magic = ARM_COMMON_MAGIC;
-	arm_set_cpsr(armv4_5, ARM_MODE_USR);
 
 	/* core_type may be overridden by subtype logic */
-	armv4_5->core_type = ARM_MODE_ANY;
+	if (armv4_5->core_type != ARM_MODE_THREAD) {
+		armv4_5->core_type = ARM_MODE_ANY;
+		arm_set_cpsr(armv4_5, ARM_MODE_USR);
+	}
 
 	/* default full_context() has no core-specific optimizations */
 	if (!armv4_5->full_context && armv4_5->read_core_reg)