[PATCH v7 10/42] target/arm: Implement the ADDG, SUBG instructions

[Richard Henderson]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
v2: Shift offset in translate; use extract32.
v6: Implement inline for !ATA.
---
 target/arm/helper-a64.h    |  1 +
 target/arm/internals.h     |  9 +++++++++
 target/arm/mte_helper.c    | 10 ++++++++++
 target/arm/translate-a64.c | 36 ++++++++++++++++++++++++++++++++++--
 4 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/target/arm/helper-a64.h b/target/arm/helper-a64.h
index 587ccbe42f..6c116481e8 100644
--- a/target/arm/helper-a64.h
+++ b/target/arm/helper-a64.h
@@ -105,3 +105,4 @@ DEF_HELPER_FLAGS_2(xpaci, TCG_CALL_NO_RWG_SE, i64, env, i64)
 DEF_HELPER_FLAGS_2(xpacd, TCG_CALL_NO_RWG_SE, i64, env, i64)
 
 DEF_HELPER_FLAGS_3(irg, TCG_CALL_NO_RWG, i64, env, i64, i64)
+DEF_HELPER_FLAGS_4(addsubg, TCG_CALL_NO_RWG_SE, i64, env, i64, s32, i32)
diff --git a/target/arm/internals.h b/target/arm/internals.h
index ae611a6ff5..5c69d4e5a5 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -1261,6 +1261,15 @@ void arm_log_exception(int idx);
  */
 #define GMID_EL1_BS  6
 
+/* We associate one allocation tag per 16 bytes, the minimum.  */
+#define LOG2_TAG_GRANULE 4
+#define TAG_GRANULE      (1 << LOG2_TAG_GRANULE)
+
+static inline int allocation_tag_from_addr(uint64_t ptr)
+{
+    return extract64(ptr, 56, 4);
+}
+
 static inline uint64_t address_with_allocation_tag(uint64_t ptr, int rtag)
 {
     return deposit64(ptr, 56, 4, rtag);
diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 539a04de84..9ab9ed749d 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -70,3 +70,13 @@ uint64_t HELPER(irg)(CPUARMState *env, uint64_t rn, uint64_t 
rm)
 
     return address_with_allocation_tag(rn, rtag);
 }
+
+uint64_t HELPER(addsubg)(CPUARMState *env, uint64_t ptr,
+                         int32_t offset, uint32_t tag_offset)
+{
+    int start_tag = allocation_tag_from_addr(ptr);
+    uint16_t exclude = extract32(env->cp15.gcr_el1, 0, 16);
+    int rtag = choose_nonexcluded_tag(start_tag, tag_offset, exclude);
+
+    return address_with_allocation_tag(ptr + offset, rtag);
+}
diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c
index 2481561925..a18d71ad98 100644
--- a/target/arm/translate-a64.c
+++ b/target/arm/translate-a64.c
@@ -3753,17 +3753,20 @@ static void disas_pc_rel_adr(DisasContext *s, uint32_t 
insn)
  *    sf: 0 -> 32bit, 1 -> 64bit
  *    op: 0 -> add  , 1 -> sub
  *     S: 1 -> set flags
- * shift: 00 -> LSL imm by 0, 01 -> LSL imm by 12
+ * shift: 00 -> LSL imm by 0,
+ *        01 -> LSL imm by 12
+ *        10 -> ADDG, SUBG
  */
 static void disas_add_sub_imm(DisasContext *s, uint32_t insn)
 {
     int rd = extract32(insn, 0, 5);
     int rn = extract32(insn, 5, 5);
-    uint64_t imm = extract32(insn, 10, 12);
+    int imm = extract32(insn, 10, 12);
     int shift = extract32(insn, 22, 2);
     bool setflags = extract32(insn, 29, 1);
     bool sub_op = extract32(insn, 30, 1);
     bool is_64bit = extract32(insn, 31, 1);
+    bool is_tag = false;
 
     TCGv_i64 tcg_rn = cpu_reg_sp(s, rn);
     TCGv_i64 tcg_rd = setflags ? cpu_reg(s, rd) : cpu_reg_sp(s, rd);
@@ -3775,11 +3778,40 @@ static void disas_add_sub_imm(DisasContext *s, uint32_t 
insn)
     case 0x1:
         imm <<= 12;
         break;
+    case 0x2:
+        /* ADDG, SUBG */
+        if (!is_64bit || setflags || (imm & 0x30) ||
+            !dc_isar_feature(aa64_mte_insn_reg, s)) {
+            goto do_unallocated;
+        }
+        is_tag = true;
+        break;
     default:
+    do_unallocated:
         unallocated_encoding(s);
         return;
     }
 
+    if (is_tag) {
+        imm = (imm >> 6) << LOG2_TAG_GRANULE;
+        if (sub_op) {
+            imm = -imm;
+        }
+
+        if (s->ata) {
+            TCGv_i32 tag_offset = tcg_const_i32(imm & 15);
+            TCGv_i32 offset = tcg_const_i32(imm);
+
+            gen_helper_addsubg(tcg_rd, cpu_env, tcg_rn, offset, tag_offset);
+            tcg_temp_free_i32(tag_offset);
+            tcg_temp_free_i32(offset);
+        } else {
+            tcg_gen_addi_i64(tcg_rd, tcg_rn, imm);
+            gen_address_with_allocation_tag0(tcg_rd, tcg_rd);
+        }
+        return;
+    }
+
     tcg_result = tcg_temp_new_i64();
     if (!setflags) {
         if (sub_op) {
-- 
2.25.1