memory: Single byte swap along the I/O path

Now that MemOp has been pushed down into the memory API, and
callers are encoding endianness, we can collapse byte swaps
along the I/O path into the accelerator and target independent
adjust_endianness.

Collapsing byte swaps along the I/O path enables additional endian
inversion logic, e.g. SPARC64 Invert Endian TTE bit, with redundant
byte swaps cancelling out.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Tony Nguyen <tony.nguyen@bt.com>
Message-Id: <911ff31af11922a9afba9b7ce128af8b8b80f316.1566466906.git.tony.nguyen@bt.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 3 insertions, 39 deletions

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 5c12eef292..3c9e634d99 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1200,38 +1200,6 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
     cpu_loop_exit_atomic(env_cpu(env), retaddr);
 }
 
-#ifdef TARGET_WORDS_BIGENDIAN
-#define NEED_BE_BSWAP 0
-#define NEED_LE_BSWAP 1
-#else
-#define NEED_BE_BSWAP 1
-#define NEED_LE_BSWAP 0
-#endif
-
-/*
- * Byte Swap Helper
- *
- * This should all dead code away depending on the build host and
- * access type.
- */
-
-static inline uint64_t handle_bswap(uint64_t val, MemOp op)
-{
-    if ((memop_big_endian(op) && NEED_BE_BSWAP) ||
-        (!memop_big_endian(op) && NEED_LE_BSWAP)) {
-        switch (op & MO_SIZE) {
-        case MO_8: return val;
-        case MO_16: return bswap16(val);
-        case MO_32: return bswap32(val);
-        case MO_64: return bswap64(val);
-        default:
-            g_assert_not_reached();
-        }
-    } else {
-        return val;
-    }
-}
-
 /*
  * Load Helpers
  *
@@ -1306,10 +1274,8 @@ load_helper(CPUArchState *env, target_ulong addr, TCGMemOpIdx oi,
             }
         }
 
-        /* TODO: Merge bswap into io_readx -> memory_region_dispatch_read.  */
-        res = io_readx(env, &env_tlb(env)->d[mmu_idx].iotlb[index],
-                       mmu_idx, addr, retaddr, access_type, op);
-        return handle_bswap(res, op);
+        return io_readx(env, &env_tlb(env)->d[mmu_idx].iotlb[index],
+                        mmu_idx, addr, retaddr, access_type, op);
     }
 
     /* Handle slow unaligned access (it spans two pages or IO).  */
@@ -1552,10 +1518,8 @@ store_helper(CPUArchState *env, target_ulong addr, uint64_t val,
             }
         }
 
-        /* TODO: Merge bswap into io_writex -> memory_region_dispatch_write.  */
         io_writex(env, &env_tlb(env)->d[mmu_idx].iotlb[index], mmu_idx,
-                  handle_bswap(val, op),
-                  addr, retaddr, op);
+                  val, addr, retaddr, op);
         return;
     }