tcg/arm: Adjust constraints on qemu_ld/st

Always reserve r3 for tlb softmmu lookup.  Fix a bug in user-only
ALL_QLDST_REGS, in that r14 is clobbered by the BLNE that leads
to the misaligned trap.  Remove r0+r1 from user-only ALL_QLDST_REGS;
I believe these had been reserved for bswap, which we no longer
perform during qemu_st.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/arm/tcg-target-con-set.h

@@ -12,19 +12,19 @@
 C_O0_I1(r)
 C_O0_I2(r, r)
 C_O0_I2(r, rIN)
-C_O0_I2(s, s)
+C_O0_I2(q, q)
 C_O0_I2(w, r)
-C_O0_I3(s, s, s)
-C_O0_I3(S, p, s)
+C_O0_I3(q, q, q)
+C_O0_I3(Q, p, q)
 C_O0_I4(r, r, rI, rI)
-C_O0_I4(S, p, s, s)
-C_O1_I1(r, l)
+C_O0_I4(Q, p, q, q)
+C_O1_I1(r, q)
 C_O1_I1(r, r)
 C_O1_I1(w, r)
 C_O1_I1(w, w)
 C_O1_I1(w, wr)
 C_O1_I2(r, 0, rZ)
-C_O1_I2(r, l, l)
+C_O1_I2(r, q, q)
 C_O1_I2(r, r, r)
 C_O1_I2(r, r, rI)
 C_O1_I2(r, r, rIK)
@@ -39,8 +39,8 @@ C_O1_I2(w, w, wZ)
 C_O1_I3(w, w, w, w)
 C_O1_I4(r, r, r, rI, rI)
 C_O1_I4(r, r, rIN, rIK, 0)
-C_O2_I1(e, p, l)
-C_O2_I2(e, p, l, l)
+C_O2_I1(e, p, q)
+C_O2_I2(e, p, q, q)
 C_O2_I2(r, r, r, r)
 C_O2_I4(r, r, r, r, rIN, rIK)
 C_O2_I4(r, r, rI, rI, rIN, rIK)

tcg/arm/tcg-target-con-str.h

@@ -10,9 +10,8 @@
  */
 REGS('e', ALL_GENERAL_REGS & 0x5555) /* even regs */
 REGS('r', ALL_GENERAL_REGS)
-REGS('l', ALL_QLOAD_REGS)
-REGS('s', ALL_QSTORE_REGS)
-REGS('S', ALL_QSTORE_REGS & 0x5555)  /* even qstore */
+REGS('q', ALL_QLDST_REGS)
+REGS('Q', ALL_QLDST_REGS & 0x5555)   /* even qldst */
 REGS('w', ALL_VECTOR_REGS)
 
 /*

tcg/arm/tcg-target.c.inc

@@ -353,23 +353,16 @@ static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
 #define ALL_VECTOR_REGS   0xffff0000u
 
 /*
- * r0-r2 will be overwritten when reading the tlb entry (softmmu only)
- * and r0-r1 doing the byte swapping, so don't use these.
- * r3 is removed for softmmu to avoid clashes with helper arguments.
+ * r0-r3 will be overwritten when reading the tlb entry (softmmu only);
+ * r14 will be overwritten by the BLNE branching to the slow path.
  */
 #ifdef CONFIG_SOFTMMU
-#define ALL_QLOAD_REGS \
+#define ALL_QLDST_REGS \
     (ALL_GENERAL_REGS & ~((1 << TCG_REG_R0) | (1 << TCG_REG_R1) | \
                           (1 << TCG_REG_R2) | (1 << TCG_REG_R3) | \
                           (1 << TCG_REG_R14)))
-#define ALL_QSTORE_REGS \
-    (ALL_GENERAL_REGS & ~((1 << TCG_REG_R0) | (1 << TCG_REG_R1) | \
-                          (1 << TCG_REG_R2) | (1 << TCG_REG_R14) | \
-                          ((TARGET_LONG_BITS == 64) << TCG_REG_R3)))
 #else
-#define ALL_QLOAD_REGS   ALL_GENERAL_REGS
-#define ALL_QSTORE_REGS \
-    (ALL_GENERAL_REGS & ~((1 << TCG_REG_R0) | (1 << TCG_REG_R1)))
+#define ALL_QLDST_REGS   (ALL_GENERAL_REGS & ~(1 << TCG_REG_R14))
 #endif
 
 /*
@@ -2203,13 +2196,13 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
         return C_O1_I4(r, r, r, rI, rI);
 
     case INDEX_op_qemu_ld_i32:
-        return TARGET_LONG_BITS == 32 ? C_O1_I1(r, l) : C_O1_I2(r, l, l);
+        return TARGET_LONG_BITS == 32 ? C_O1_I1(r, q) : C_O1_I2(r, q, q);
     case INDEX_op_qemu_ld_i64:
-        return TARGET_LONG_BITS == 32 ? C_O2_I1(e, p, l) : C_O2_I2(e, p, l, l);
+        return TARGET_LONG_BITS == 32 ? C_O2_I1(e, p, q) : C_O2_I2(e, p, q, q);
     case INDEX_op_qemu_st_i32:
-        return TARGET_LONG_BITS == 32 ? C_O0_I2(s, s) : C_O0_I3(s, s, s);
+        return TARGET_LONG_BITS == 32 ? C_O0_I2(q, q) : C_O0_I3(q, q, q);
     case INDEX_op_qemu_st_i64:
-        return TARGET_LONG_BITS == 32 ? C_O0_I3(S, p, s) : C_O0_I4(S, p, s, s);
+        return TARGET_LONG_BITS == 32 ? C_O0_I3(Q, p, q) : C_O0_I4(Q, p, q, q);
 
     case INDEX_op_st_vec:
         return C_O0_I2(w, r);