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>

target/arm/helper-a64.h

@@ -113,3 +113,6 @@ DEF_HELPER_FLAGS_2(stg_stub, TCG_CALL_NO_WG, void, env, i64)
 DEF_HELPER_FLAGS_3(st2g, TCG_CALL_NO_WG, void, env, i64, i64)
 DEF_HELPER_FLAGS_3(st2g_parallel, TCG_CALL_NO_WG, void, env, i64, i64)
 DEF_HELPER_FLAGS_2(st2g_stub, TCG_CALL_NO_WG, void, env, i64)
+DEF_HELPER_FLAGS_2(ldgm, TCG_CALL_NO_WG, i64, env, i64)
+DEF_HELPER_FLAGS_3(stgm, TCG_CALL_NO_WG, void, env, i64, i64)
+DEF_HELPER_FLAGS_3(stzgm_tags, TCG_CALL_NO_WG, void, env, i64, i64)

target/arm/mte_helper.c

@@ -274,3 +274,87 @@ void HELPER(st2g_stub)(CPUARMState *env, uint64_t ptr)
         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);
+    }
+}

target/arm/translate-a64.c

@@ -3736,7 +3736,7 @@ static void disas_ldst_tag(DisasContext *s, uint32_t insn)
     uint64_t offset = sextract64(insn, 12, 9) << LOG2_TAG_GRANULE;
     int op2 = extract32(insn, 10, 2);
     int op1 = extract32(insn, 22, 2);
-    bool is_load = false, is_pair = false, is_zero = false;
+    bool is_load = false, is_pair = false, is_zero = false, is_mult = false;
     int index = 0;
     TCGv_i64 addr, clean_addr, tcg_rt;
 
@@ -3756,9 +3756,14 @@ static void disas_ldst_tag(DisasContext *s, uint32_t insn)
         if (op2 != 0) {
             /* STG */
             index = op2 - 2;
-            break;
+        } else {
+            /* STZGM */
+            if (s->current_el == 0 || offset != 0) {
+                goto do_unallocated;
+            }
+            is_mult = is_zero = true;
         }
-        goto do_unallocated;
+        break;
     case 1:
         if (op2 != 0) {
             /* STZG */
@@ -3774,17 +3779,27 @@ static void disas_ldst_tag(DisasContext *s, uint32_t insn)
             /* ST2G */
             is_pair = true;
             index = op2 - 2;
-            break;
+        } else {
+            /* STGM */
+            if (s->current_el == 0 || offset != 0) {
+                goto do_unallocated;
+            }
+            is_mult = true;
         }
-        goto do_unallocated;
+        break;
     case 3:
         if (op2 != 0) {
             /* STZ2G */
             is_pair = is_zero = true;
             index = op2 - 2;
-            break;
+        } else {
+            /* LDGM */
+            if (s->current_el == 0 || offset != 0) {
+                goto do_unallocated;
+            }
+            is_mult = is_load = true;
         }
-        goto do_unallocated;
+        break;
 
     default:
     do_unallocated:
@@ -3792,7 +3807,9 @@ static void disas_ldst_tag(DisasContext *s, uint32_t insn)
         return;
     }
 
-    if (!dc_isar_feature(aa64_mte_insn_reg, s)) {
+    if (is_mult
+        ? !dc_isar_feature(aa64_mte, s)
+        : !dc_isar_feature(aa64_mte_insn_reg, s)) {
         goto do_unallocated;
     }
 
@@ -3806,6 +3823,44 @@ static void disas_ldst_tag(DisasContext *s, uint32_t insn)
         tcg_gen_addi_i64(addr, addr, offset);
     }
 
+    if (is_mult) {
+        tcg_rt = cpu_reg(s, rt);
+
+        if (is_zero) {
+            int size = 4 << s->dcz_blocksize;
+
+            if (s->ata) {
+                gen_helper_stzgm_tags(cpu_env, addr, tcg_rt);
+            }
+            /*
+             * The non-tags portion of STZGM is mostly like DC_ZVA,
+             * except the alignment happens before the access.
+             */
+            clean_addr = clean_data_tbi(s, addr);
+            tcg_gen_andi_i64(clean_addr, clean_addr, -size);
+            gen_helper_dc_zva(cpu_env, clean_addr);
+        } else if (s->ata) {
+            if (is_load) {
+                gen_helper_ldgm(tcg_rt, cpu_env, addr);
+            } else {
+                gen_helper_stgm(cpu_env, addr, tcg_rt);
+            }
+        } else {
+            MMUAccessType acc = is_load ? MMU_DATA_LOAD : MMU_DATA_STORE;
+            int size = 4 << GMID_EL1_BS;
+
+            clean_addr = clean_data_tbi(s, addr);
+            tcg_gen_andi_i64(clean_addr, clean_addr, -size);
+            gen_probe_access(s, clean_addr, acc, size);
+
+            if (is_load) {
+                /* The result tags are zeros.  */
+                tcg_gen_movi_i64(tcg_rt, 0);
+            }
+        }
+        return;
+    }
+
     if (is_load) {
         tcg_gen_andi_i64(addr, addr, -TAG_GRANULE);
         tcg_rt = cpu_reg(s, rt);
@@ -14472,6 +14527,7 @@ static void aarch64_tr_init_disas_context(DisasContextBase *dcbase,
     dc->vec_stride = 0;
     dc->cp_regs = arm_cpu->cp_regs;
     dc->features = env->features;
+    dc->dcz_blocksize = arm_cpu->dcz_blocksize;
 
     /* Single step state. The code-generation logic here is:
      *  SS_ACTIVE == 0:

target/arm/translate.h

@@ -91,6 +91,8 @@ typedef struct DisasContext {
      *  < 0, set by the current instruction.
      */
     int8_t btype;
+    /* A copy of cpu->dcz_blocksize. */
+    uint8_t dcz_blocksize;
     /* True if this page is guarded.  */
     bool guarded_page;
     /* Bottom two bits of XScale c15_cpar coprocessor access control reg */