target/arm: Make FAULTMASK register banked for v8M

Make the FAULTMASK register banked if v8M security extensions are enabled.

Note that we do not yet implement the functionality of the new
AIRCR.PRIS bit (which allows the effect of the NS copy of FAULTMASK to
be restricted).

This patch includes the code to determine for v8M which copy
of FAULTMASK should be updated on exception exit; further
changes will be required to the exception exit code in general
to support v8M, so this is just a small piece of that.

The v8M ARM ARM introduces a notation where individual paragraphs
are labelled with R (for rule) or I (for information) followed
by a random group of subscript letters. In comments where we want
to refer to a particular part of the manual we use this convention,
which should be more stable across document revisions than using
section or page numbers.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 1503414539-28762-9-git-send-email-peter.maydell@linaro.org

1 files changed, 8 insertions, 1 deletions

diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index a6547929df..babdc3bae9 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -167,7 +167,7 @@ static inline int nvic_exec_prio(NVICState *s)
     CPUARMState *env = &s->cpu->env;
     int running;
 
-    if (env->v7m.faultmask) {
+    if (env->v7m.faultmask[env->v7m.secure]) {
         running = -1;
     } else if (env->v7m.primask[env->v7m.secure]) {
         running = 0;
@@ -187,6 +187,13 @@ bool armv7m_nvic_can_take_pending_exception(void *opaque)
     return nvic_exec_prio(s) > nvic_pending_prio(s);
 }
 
+int armv7m_nvic_raw_execution_priority(void *opaque)
+{
+    NVICState *s = opaque;
+
+    return s->exception_prio;
+}
+
 /* caller must call nvic_irq_update() after this */
 static void set_prio(NVICState *s, unsigned irq, uint8_t prio)
 {