target/arm: Implement MTE tag-checking functions for FEAT_MOPS

The FEAT_MOPS instructions need a couple of helper routines that
check for MTE tag failures:
 * mte_mops_probe() checks whether there is going to be a tag
   error in the next up-to-a-page worth of data
 * mte_check_fail() is an existing function to record the fact
   of a tag failure, which we need to make global so we can
   call it from helper-a64.c

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230912140434.1333369-7-peter.maydell@linaro.org

1 files changed, 28 insertions, 0 deletions

diff --git a/target/arm/internals.h b/target/arm/internals.h
index 5f5393b25c..a70a7fd50f 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1272,6 +1272,34 @@ FIELD(MTEDESC, SIZEM1, 12, SIMD_DATA_BITS - 12)  /* size - 1 */
 bool mte_probe(CPUARMState *env, uint32_t desc, uint64_t ptr);
 uint64_t mte_check(CPUARMState *env, uint32_t desc, uint64_t ptr, uintptr_t ra);
 
+/**
+ * mte_mops_probe: Check where the next MTE failure is for a FEAT_MOPS operation
+ * @env: CPU env
+ * @ptr: start address of memory region (dirty pointer)
+ * @size: length of region (guaranteed not to cross a page boundary)
+ * @desc: MTEDESC descriptor word (0 means no MTE checks)
+ * Returns: the size of the region that can be copied without hitting
+ *          an MTE tag failure
+ *
+ * Note that we assume that the caller has already checked the TBI
+ * and TCMA bits with mte_checks_needed() and an MTE check is definitely
+ * required.
+ */
+uint64_t mte_mops_probe(CPUARMState *env, uint64_t ptr, uint64_t size,
+                        uint32_t desc);
+
+/**
+ * mte_check_fail: Record an MTE tag check failure
+ * @env: CPU env
+ * @desc: MTEDESC descriptor word
+ * @dirty_ptr: Failing dirty address
+ * @ra: TCG retaddr
+ *
+ * This may never return (if the MTE tag checks are configured to fault).
+ */
+void mte_check_fail(CPUARMState *env, uint32_t desc,
+                    uint64_t dirty_ptr, uintptr_t ra);
+
 static inline int allocation_tag_from_addr(uint64_t ptr)
 {
     return extract64(ptr, 56, 4);