target-xtensa: implement ATOMCTL SR

ATOMCTL SR controls s32c1i opcode behavior depending on targeted memory
type. See ISA, 4.3.12.4 for details.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/target-xtensa/op_helper.c b/target-xtensa/op_helper.c
index ae0c09977b..0e0f21d1a2 100644
--- a/target-xtensa/op_helper.c
+++ b/target-xtensa/op_helper.c
@@ -415,6 +415,63 @@ void HELPER(check_interrupts)(CPUXtensaState *env)
     check_interrupts(env);
 }
 
+/*!
+ * Check vaddr accessibility/cache attributes and raise an exception if
+ * specified by the ATOMCTL SR.
+ *
+ * Note: local memory exclusion is not implemented
+ */
+void HELPER(check_atomctl)(CPUXtensaState *env, uint32_t pc, uint32_t vaddr)
+{
+    uint32_t paddr, page_size, access;
+    uint32_t atomctl = env->sregs[ATOMCTL];
+    int rc = xtensa_get_physical_addr(env, true, vaddr, 1,
+            xtensa_get_cring(env), &paddr, &page_size, &access);
+
+    /*
+     * s32c1i never causes LOAD_PROHIBITED_CAUSE exceptions,
+     * see opcode description in the ISA
+     */
+    if (rc == 0 &&
+            (access & (PAGE_READ | PAGE_WRITE)) != (PAGE_READ | PAGE_WRITE)) {
+        rc = STORE_PROHIBITED_CAUSE;
+    }
+
+    if (rc) {
+        HELPER(exception_cause_vaddr)(env, pc, rc, vaddr);
+    }
+
+    /*
+     * When data cache is not configured use ATOMCTL bypass field.
+     * See ISA, 4.3.12.4 The Atomic Operation Control Register (ATOMCTL)
+     * under the Conditional Store Option.
+     */
+    if (!xtensa_option_enabled(env->config, XTENSA_OPTION_DCACHE)) {
+        access = PAGE_CACHE_BYPASS;
+    }
+
+    switch (access & PAGE_CACHE_MASK) {
+    case PAGE_CACHE_WB:
+        atomctl >>= 2;
+    case PAGE_CACHE_WT:
+        atomctl >>= 2;
+    case PAGE_CACHE_BYPASS:
+        if ((atomctl & 0x3) == 0) {
+            HELPER(exception_cause_vaddr)(env, pc,
+                    LOAD_STORE_ERROR_CAUSE, vaddr);
+        }
+        break;
+
+    case PAGE_CACHE_ISOLATE:
+        HELPER(exception_cause_vaddr)(env, pc,
+                LOAD_STORE_ERROR_CAUSE, vaddr);
+        break;
+
+    default:
+        break;
+    }
+}
+
 void HELPER(wsr_rasid)(CPUXtensaState *env, uint32_t v)
 {
     v = (v & 0xffffff00) | 0x1;