target-arm: Add exception target el infrastructure

Add a CPU state exception target EL field that will be used for communicating
the EL to which an exception should be routed.

Add a disassembly context field for tracking the EL3 architecture needed for
determining the target exception EL.

Add a target EL argument to the generic exception helper for callers to specify
the EL to which the exception should be routed.  Extended the helper to set
the newly added CPU state exception target el.

Added a function for setting the target exception EL and updated calls to helpers
to call it.

Signed-off-by: Greg Bellows <greg.bellows@linaro.org>
Acked-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1429722561-12651-2-git-send-email-greg.bellows@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/target-arm/translate.h b/target-arm/translate.h
index 9829576..2eadcb7 100644
--- a/target-arm/translate.h
+++ b/target-arm/translate.h
@@ -23,6 +23,7 @@ typedef struct DisasContext {
     ARMMMUIdx mmu_idx; /* MMU index to use for normal loads/stores */
     bool ns;        /* Use non-secure CPREG bank on access */
     bool cpacr_fpen; /* FP enabled via CPACR.FPEN */
+    bool el3_is_aa64;  /* Flag indicating whether EL3 is AArch64 or not */
     bool vfp_enabled; /* FP enabled via FPSCR.EN */
     int vec_len;
     int vec_stride;
@@ -73,6 +74,20 @@ static inline int get_mem_index(DisasContext *s)
     return s->mmu_idx;
 }
 
+/* Function used to determine the target exception EL when otherwise not known
+ * or default.
+ */
+static inline int default_exception_el(DisasContext *s)
+{
+    /* If we are coming from secure EL0 in a system with a 32-bit EL3, then
+     * there is no secure EL1, so we route exceptions to EL3.  Otherwise,
+     * exceptions can only be routed to ELs above 1, so we target the higher of
+     * 1 or the current EL.
+     */
+    return (s->mmu_idx == ARMMMUIdx_S1SE0 && !s->el3_is_aa64)
+            ? 3 : MAX(1, s->current_el);
+}
+
 /* target-specific extra values for is_jmp */
 /* These instructions trap after executing, so the A32/T32 decoder must
  * defer them until after the conditional execution state has been updated.