target/arm: Implement the LDGM, STGM, STZGM instructions
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200626033144.790098-20-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 7ec7930..27d4b45 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -274,3 +274,87 @@
probe_write(env, ptr + TAG_GRANULE, TAG_GRANULE, mmu_idx, ra);
}
}
+
+#define LDGM_STGM_SIZE (4 << GMID_EL1_BS)
+
+uint64_t HELPER(ldgm)(CPUARMState *env, uint64_t ptr)
+{
+ int mmu_idx = cpu_mmu_index(env, false);
+ uintptr_t ra = GETPC();
+ void *tag_mem;
+
+ ptr = QEMU_ALIGN_DOWN(ptr, LDGM_STGM_SIZE);
+
+ /* Trap if accessing an invalid page. */
+ tag_mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_LOAD,
+ LDGM_STGM_SIZE, MMU_DATA_LOAD,
+ LDGM_STGM_SIZE / (2 * TAG_GRANULE), ra);
+
+ /* The tag is squashed to zero if the page does not support tags. */
+ if (!tag_mem) {
+ return 0;
+ }
+
+ QEMU_BUILD_BUG_ON(GMID_EL1_BS != 6);
+ /*
+ * We are loading 64-bits worth of tags. The ordering of elements
+ * within the word corresponds to a 64-bit little-endian operation.
+ */
+ return ldq_le_p(tag_mem);
+}
+
+void HELPER(stgm)(CPUARMState *env, uint64_t ptr, uint64_t val)
+{
+ int mmu_idx = cpu_mmu_index(env, false);
+ uintptr_t ra = GETPC();
+ void *tag_mem;
+
+ ptr = QEMU_ALIGN_DOWN(ptr, LDGM_STGM_SIZE);
+
+ /* Trap if accessing an invalid page. */
+ tag_mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE,
+ LDGM_STGM_SIZE, MMU_DATA_LOAD,
+ LDGM_STGM_SIZE / (2 * TAG_GRANULE), ra);
+
+ /*
+ * Tag store only happens if the page support tags,
+ * and if the OS has enabled access to the tags.
+ */
+ if (!tag_mem) {
+ return;
+ }
+
+ QEMU_BUILD_BUG_ON(GMID_EL1_BS != 6);
+ /*
+ * We are storing 64-bits worth of tags. The ordering of elements
+ * within the word corresponds to a 64-bit little-endian operation.
+ */
+ stq_le_p(tag_mem, val);
+}
+
+void HELPER(stzgm_tags)(CPUARMState *env, uint64_t ptr, uint64_t val)
+{
+ uintptr_t ra = GETPC();
+ int mmu_idx = cpu_mmu_index(env, false);
+ int log2_dcz_bytes, log2_tag_bytes;
+ intptr_t dcz_bytes, tag_bytes;
+ uint8_t *mem;
+
+ /*
+ * In arm_cpu_realizefn, we assert that dcz > LOG2_TAG_GRANULE+1,
+ * i.e. 32 bytes, which is an unreasonably small dcz anyway,
+ * to make sure that we can access one complete tag byte here.
+ */
+ log2_dcz_bytes = env_archcpu(env)->dcz_blocksize + 2;
+ log2_tag_bytes = log2_dcz_bytes - (LOG2_TAG_GRANULE + 1);
+ dcz_bytes = (intptr_t)1 << log2_dcz_bytes;
+ tag_bytes = (intptr_t)1 << log2_tag_bytes;
+ ptr &= -dcz_bytes;
+
+ mem = allocation_tag_mem(env, mmu_idx, ptr, MMU_DATA_STORE, dcz_bytes,
+ MMU_DATA_STORE, tag_bytes, ra);
+ if (mem) {
+ int tag_pair = (val & 0xf) * 0x11;
+ memset(mem, tag_pair, tag_bytes);
+ }
+}
