target/arm: Implement helper_mte_check1

Fill out the stub that was added earlier.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200626033144.790098-26-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 131 insertions, 1 deletions

diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 907a12b366..c8a5e7c0ed 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -359,12 +359,142 @@ void HELPER(stzgm_tags)(CPUARMState *env, uint64_t ptr, uint64_t val)
     }
 }
 
+/* Record a tag check failure.  */
+static void mte_check_fail(CPUARMState *env, int mmu_idx,
+                           uint64_t dirty_ptr, uintptr_t ra)
+{
+    ARMMMUIdx arm_mmu_idx = core_to_aa64_mmu_idx(mmu_idx);
+    int el, reg_el, tcf, select;
+    uint64_t sctlr;
+
+    reg_el = regime_el(env, arm_mmu_idx);
+    sctlr = env->cp15.sctlr_el[reg_el];
+
+    switch (arm_mmu_idx) {
+    case ARMMMUIdx_E10_0:
+    case ARMMMUIdx_E20_0:
+        el = 0;
+        tcf = extract64(sctlr, 38, 2);
+        break;
+    default:
+        el = reg_el;
+        tcf = extract64(sctlr, 40, 2);
+    }
+
+    switch (tcf) {
+    case 1:
+        /*
+         * Tag check fail causes a synchronous exception.
+         *
+         * In restore_state_to_opc, we set the exception syndrome
+         * for the load or store operation.  Unwind first so we
+         * may overwrite that with the syndrome for the tag check.
+         */
+        cpu_restore_state(env_cpu(env), ra, true);
+        env->exception.vaddress = dirty_ptr;
+        raise_exception(env, EXCP_DATA_ABORT,
+                        syn_data_abort_no_iss(el != 0, 0, 0, 0, 0, 0, 0x11),
+                        exception_target_el(env));
+        /* noreturn, but fall through to the assert anyway */
+
+    case 0:
+        /*
+         * Tag check fail does not affect the PE.
+         * We eliminate this case by not setting MTE_ACTIVE
+         * in tb_flags, so that we never make this runtime call.
+         */
+        g_assert_not_reached();
+
+    case 2:
+        /* Tag check fail causes asynchronous flag set.  */
+        mmu_idx = arm_mmu_idx_el(env, el);
+        if (regime_has_2_ranges(mmu_idx)) {
+            select = extract64(dirty_ptr, 55, 1);
+        } else {
+            select = 0;
+        }
+        env->cp15.tfsr_el[el] |= 1 << select;
+        break;
+
+    default:
+        /* Case 3: Reserved. */
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "Tag check failure with SCTLR_EL%d.TCF%s "
+                      "set to reserved value %d\n",
+                      reg_el, el ? "" : "0", tcf);
+        break;
+    }
+}
+
 /*
  * Perform an MTE checked access for a single logical or atomic access.
  */
+static bool mte_probe1_int(CPUARMState *env, uint32_t desc, uint64_t ptr,
+                           uintptr_t ra, int bit55)
+{
+    int mem_tag, mmu_idx, ptr_tag, size;
+    MMUAccessType type;
+    uint8_t *mem;
+
+    ptr_tag = allocation_tag_from_addr(ptr);
+
+    if (tcma_check(desc, bit55, ptr_tag)) {
+        return true;
+    }
+
+    mmu_idx = FIELD_EX32(desc, MTEDESC, MIDX);
+    type = FIELD_EX32(desc, MTEDESC, WRITE) ? MMU_DATA_STORE : MMU_DATA_LOAD;
+    size = FIELD_EX32(desc, MTEDESC, ESIZE);
+
+    mem = allocation_tag_mem(env, mmu_idx, ptr, type, size,
+                             MMU_DATA_LOAD, 1, ra);
+    if (!mem) {
+        return true;
+    }
+
+    mem_tag = load_tag1(ptr, mem);
+    return ptr_tag == mem_tag;
+}
+
+/*
+ * No-fault version of mte_check1, to be used by SVE for MemSingleNF.
+ * Returns false if the access is Checked and the check failed.  This
+ * is only intended to probe the tag -- the validity of the page must
+ * be checked beforehand.
+ */
+bool mte_probe1(CPUARMState *env, uint32_t desc, uint64_t ptr)
+{
+    int bit55 = extract64(ptr, 55, 1);
+
+    /* If TBI is disabled, the access is unchecked. */
+    if (unlikely(!tbi_check(desc, bit55))) {
+        return true;
+    }
+
+    return mte_probe1_int(env, desc, ptr, 0, bit55);
+}
+
+uint64_t mte_check1(CPUARMState *env, uint32_t desc,
+                    uint64_t ptr, uintptr_t ra)
+{
+    int bit55 = extract64(ptr, 55, 1);
+
+    /* If TBI is disabled, the access is unchecked, and ptr is not dirty. */
+    if (unlikely(!tbi_check(desc, bit55))) {
+        return ptr;
+    }
+
+    if (unlikely(!mte_probe1_int(env, desc, ptr, ra, bit55))) {
+        int mmu_idx = FIELD_EX32(desc, MTEDESC, MIDX);
+        mte_check_fail(env, mmu_idx, ptr, ra);
+    }
+
+    return useronly_clean_ptr(ptr);
+}
+
 uint64_t HELPER(mte_check1)(CPUARMState *env, uint32_t desc, uint64_t ptr)
 {
-    return ptr;
+    return mte_check1(env, desc, ptr, GETPC());
 }
 
 /*