1 files changed, 46 insertions, 24 deletions

diff --git a/target/arm/tcg/translate.c b/target/arm/tcg/translate.c
index d8225b77c8..93772da39a 100644
--- a/target/arm/tcg/translate.c
+++ b/target/arm/tcg/translate.c
@@ -5003,10 +5003,49 @@ static bool op_store_rr(DisasContext *s, arg_ldst_rr *a,
     return true;
 }
 
-static bool trans_LDRD_rr(DisasContext *s, arg_ldst_rr *a)
+static void do_ldrd_load(DisasContext *s, TCGv_i32 addr, int rt, int rt2)
 {
+    /*
+     * LDRD is required to be an atomic 64-bit access if the
+     * address is 8-aligned, two atomic 32-bit accesses if
+     * it's only 4-aligned, and to give an alignment fault
+     * if it's not 4-aligned. This is MO_ALIGN_4 | MO_ATOM_SUBALIGN.
+     * Rt is always the word from the lower address, and Rt2 the
+     * data from the higher address, regardless of endianness.
+     * So (like gen_load_exclusive) we avoid gen_aa32_ld_i64()
+     * so we don't get its SCTLR_B check, and instead do a 64-bit access
+     * using MO_BE if appropriate and then split the two halves.
+     *
+     * For M-profile, and for A-profile before LPAE, the 64-bit
+     * atomicity is not required. We could model that using
+     * the looser MO_ATOM_IFALIGN_PAIR, but providing a higher
+     * level of atomicity than required is harmless (we would not
+     * currently generate better code for IFALIGN_PAIR here).
+     *
+     * This also gives us the correct behaviour of not updating
+     * rt if the load of rt2 faults; this is required for cases
+     * like "ldrd r2, r3, [r2]" where rt is also the base register.
+     */
     int mem_idx = get_mem_index(s);
-    TCGv_i32 addr, tmp;
+    MemOp opc = MO_64 | MO_ALIGN_4 | MO_ATOM_SUBALIGN | s->be_data;
+    TCGv taddr = gen_aa32_addr(s, addr, opc);
+    TCGv_i64 t64 = tcg_temp_new_i64();
+    TCGv_i32 tmp = tcg_temp_new_i32();
+    TCGv_i32 tmp2 = tcg_temp_new_i32();
+
+    tcg_gen_qemu_ld_i64(t64, taddr, mem_idx, opc);
+    if (s->be_data == MO_BE) {
+        tcg_gen_extr_i64_i32(tmp2, tmp, t64);
+    } else {
+        tcg_gen_extr_i64_i32(tmp, tmp2, t64);
+    }
+    store_reg(s, rt, tmp);
+    store_reg(s, rt2, tmp2);
+}
+
+static bool trans_LDRD_rr(DisasContext *s, arg_ldst_rr *a)
+{
+    TCGv_i32 addr;
 
     if (!ENABLE_ARCH_5TE) {
         return false;
@@ -5017,18 +5056,10 @@ static bool trans_LDRD_rr(DisasContext *s, arg_ldst_rr *a)
     }
     addr = op_addr_rr_pre(s, a);
 
-    tmp = tcg_temp_new_i32();
-    gen_aa32_ld_i32(s, tmp, addr, mem_idx, MO_UL | MO_ALIGN);
-    store_reg(s, a->rt, tmp);
-
-    tcg_gen_addi_i32(addr, addr, 4);
-
-    tmp = tcg_temp_new_i32();
-    gen_aa32_ld_i32(s, tmp, addr, mem_idx, MO_UL | MO_ALIGN);
-    store_reg(s, a->rt + 1, tmp);
+    do_ldrd_load(s, addr, a->rt, a->rt + 1);
 
     /* LDRD w/ base writeback is undefined if the registers overlap.  */
-    op_addr_rr_post(s, a, addr, -4);
+    op_addr_rr_post(s, a, addr, 0);
     return true;
 }
 
@@ -5152,23 +5183,14 @@ static bool op_store_ri(DisasContext *s, arg_ldst_ri *a,
 
 static bool op_ldrd_ri(DisasContext *s, arg_ldst_ri *a, int rt2)
 {
-    int mem_idx = get_mem_index(s);
-    TCGv_i32 addr, tmp;
+    TCGv_i32 addr;
 
     addr = op_addr_ri_pre(s, a);
 
-    tmp = tcg_temp_new_i32();
-    gen_aa32_ld_i32(s, tmp, addr, mem_idx, MO_UL | MO_ALIGN);
-    store_reg(s, a->rt, tmp);
-
-    tcg_gen_addi_i32(addr, addr, 4);
-
-    tmp = tcg_temp_new_i32();
-    gen_aa32_ld_i32(s, tmp, addr, mem_idx, MO_UL | MO_ALIGN);
-    store_reg(s, rt2, tmp);
+    do_ldrd_load(s, addr, a->rt, rt2);
 
     /* LDRD w/ base writeback is undefined if the registers overlap.  */
-    op_addr_ri_post(s, a, addr, -4);
+    op_addr_ri_post(s, a, addr, 0);
     return true;
 }