Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20150902' into staging

queued tcg patches

# gpg: Signature made Wed 02 Sep 2015 22:35:37 BST using RSA key ID 4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"

* remotes/rth/tags/pull-tcg-20150902:
  tcg/i386: omit a few REXW prefixes in softmmu code
  tcg/aarch64: Fix tcg_out_qemu_{ld, st} for guest_base == 0

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 29 insertions, 13 deletions

diff --git a/tcg/aarch64/tcg-target.c b/tcg/aarch64/tcg-target.c
index 01ae610cd7..0ed10a9741 100644
--- a/tcg/aarch64/tcg-target.c
+++ b/tcg/aarch64/tcg-target.c
@@ -56,6 +56,11 @@ static const int tcg_target_call_oarg_regs[1] = {
 #define TCG_REG_TMP TCG_REG_X30
 
 #ifndef CONFIG_SOFTMMU
+/* Note that XZR cannot be encoded in the address base register slot,
+   as that actaully encodes SP.  So if we need to zero-extend the guest
+   address, via the address index register slot, we need to load even
+   a zero guest base into a register.  */
+#define USE_GUEST_BASE     (guest_base != 0 || TARGET_LONG_BITS == 32)
 #define TCG_REG_GUEST_BASE TCG_REG_X28
 #endif
 
@@ -1224,9 +1229,13 @@ static void tcg_out_qemu_ld(TCGContext *s, TCGReg data_reg, TCGReg addr_reg,
     add_qemu_ldst_label(s, true, oi, ext, data_reg, addr_reg,
                         s->code_ptr, label_ptr);
 #else /* !CONFIG_SOFTMMU */
-    tcg_out_qemu_ld_direct(s, memop, ext, data_reg,
-                           guest_base ? TCG_REG_GUEST_BASE : TCG_REG_XZR,
-                           otype, addr_reg);
+    if (USE_GUEST_BASE) {
+        tcg_out_qemu_ld_direct(s, memop, ext, data_reg,
+                               TCG_REG_GUEST_BASE, otype, addr_reg);
+    } else {
+        tcg_out_qemu_ld_direct(s, memop, ext, data_reg,
+                               addr_reg, TCG_TYPE_I64, TCG_REG_XZR);
+    }
 #endif /* CONFIG_SOFTMMU */
 }
 
@@ -1245,9 +1254,13 @@ static void tcg_out_qemu_st(TCGContext *s, TCGReg data_reg, TCGReg addr_reg,
     add_qemu_ldst_label(s, false, oi, (memop & MO_SIZE)== MO_64,
                         data_reg, addr_reg, s->code_ptr, label_ptr);
 #else /* !CONFIG_SOFTMMU */
-    tcg_out_qemu_st_direct(s, memop, data_reg,
-                           guest_base ? TCG_REG_GUEST_BASE : TCG_REG_XZR,
-                           otype, addr_reg);
+    if (USE_GUEST_BASE) {
+        tcg_out_qemu_st_direct(s, memop, data_reg,
+                               TCG_REG_GUEST_BASE, otype, addr_reg);
+    } else {
+        tcg_out_qemu_st_direct(s, memop, data_reg,
+                               addr_reg, TCG_TYPE_I64, TCG_REG_XZR);
+    }
 #endif /* CONFIG_SOFTMMU */
 }
 
@@ -1806,7 +1819,7 @@ static void tcg_target_qemu_prologue(TCGContext *s)
                   CPU_TEMP_BUF_NLONGS * sizeof(long));
 
 #if !defined(CONFIG_SOFTMMU)
-    if (guest_base) {
+    if (USE_GUEST_BASE) {
         tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_GUEST_BASE, guest_base);
         tcg_regset_set_reg(s->reserved_regs, TCG_REG_GUEST_BASE);
     }
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index d2adbc4d17..9187d34caf 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -1178,8 +1178,8 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
     const TCGReg r0 = TCG_REG_L0;
     const TCGReg r1 = TCG_REG_L1;
     TCGType ttype = TCG_TYPE_I32;
-    TCGType htype = TCG_TYPE_I32;
-    int trexw = 0, hrexw = 0;
+    TCGType tlbtype = TCG_TYPE_I32;
+    int trexw = 0, hrexw = 0, tlbrexw = 0;
     int s_mask = (1 << (opc & MO_SIZE)) - 1;
     bool aligned = (opc & MO_AMASK) == MO_ALIGN || s_mask == 0;
 
@@ -1189,12 +1189,15 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
             trexw = P_REXW;
         }
         if (TCG_TYPE_PTR == TCG_TYPE_I64) {
-            htype = TCG_TYPE_I64;
             hrexw = P_REXW;
+            if (TARGET_PAGE_BITS + CPU_TLB_BITS > 32) {
+                tlbtype = TCG_TYPE_I64;
+                tlbrexw = P_REXW;
+            }
         }
     }
 
-    tcg_out_mov(s, htype, r0, addrlo);
+    tcg_out_mov(s, tlbtype, r0, addrlo);
     if (aligned) {
         tcg_out_mov(s, ttype, r1, addrlo);
     } else {
@@ -1203,12 +1206,12 @@ static inline void tcg_out_tlb_load(TCGContext *s, TCGReg addrlo, TCGReg addrhi,
         tcg_out_modrm_offset(s, OPC_LEA + trexw, r1, addrlo, s_mask);
     }
 
-    tcg_out_shifti(s, SHIFT_SHR + hrexw, r0,
+    tcg_out_shifti(s, SHIFT_SHR + tlbrexw, r0,
                    TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS);
 
     tgen_arithi(s, ARITH_AND + trexw, r1,
                 TARGET_PAGE_MASK | (aligned ? s_mask : 0), 0);
-    tgen_arithi(s, ARITH_AND + hrexw, r0,
+    tgen_arithi(s, ARITH_AND + tlbrexw, r0,
                 (CPU_TLB_SIZE - 1) << CPU_TLB_ENTRY_BITS, 0);
 
     tcg_out_modrm_sib_offset(s, OPC_LEA + hrexw, r0, TCG_AREG0, r0, 0,