tcg/ppc: Fix CONFIG_TCG_PASS_AREG0 mode

Adjust the tcg_out_qemu_{ld,st}() slow paths to pass AREG0 in r3,
based on patches by malc.

Also adjust the registers clobbered, based on patch by Alex.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Alexander Graf <agraf@suse.de>
[AF: Do not hardcode r3 for AREG0, requested by Alex]
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/tcg/ppc/tcg-target.c b/tcg/ppc/tcg-target.c
index 20888e2..4cde48d 100644
--- a/tcg/ppc/tcg-target.c
+++ b/tcg/ppc/tcg-target.c
@@ -244,9 +244,19 @@
         tcg_regset_set32(ct->u.regs, 0, 0xffffffff);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R3);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R4);
+#ifdef CONFIG_TCG_PASS_AREG0
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
+#if TARGET_LONG_BITS == 64
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
+#ifdef TCG_TARGET_CALL_ALIGN_ARGS
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R7);
+#endif
+#endif
+#else /* !AREG0 */
 #if TARGET_LONG_BITS == 64
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
 #endif
+#endif
         break;
     case 'K':                   /* qemu_st[8..32] constraint */
         ct->ct |= TCG_CT_REG;
@@ -254,9 +264,19 @@
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R3);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R4);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
+#ifdef CONFIG_TCG_PASS_AREG0
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
+#if TARGET_LONG_BITS == 64
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R7);
+#ifdef TCG_TARGET_CALL_ALIGN_ARGS
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R8);
+#endif
+#endif
+#else /* !AREG0 */
 #if TARGET_LONG_BITS == 64
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
 #endif
+#endif
         break;
     case 'M':                   /* qemu_st64 constraint */
         ct->ct |= TCG_CT_REG;
@@ -266,6 +286,12 @@
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R5);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R6);
         tcg_regset_reset_reg(ct->u.regs, TCG_REG_R7);
+#if defined(CONFIG_TCG_PASS_AREG0)
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R8);
+#ifdef TCG_TARGET_CALL_ALIGN_ARGS
+        tcg_regset_reset_reg(ct->u.regs, TCG_REG_R9);
+#endif
+#endif
         break;
 #else
     case 'L':
@@ -512,7 +538,6 @@
 #include "../../softmmu_defs.h"
 
 #ifdef CONFIG_TCG_PASS_AREG0
-#error CONFIG_TCG_PASS_AREG0 is not supported
 /* helper signature: helper_ld_mmu(CPUState *env, target_ulong addr,
    int mmu_idx) */
 static const void * const qemu_ld_helpers[4] = {
@@ -618,6 +643,9 @@
 
     /* slow path */
     ir = 3;
+#ifdef CONFIG_TCG_PASS_AREG0
+    tcg_out_mov (s, TCG_TYPE_I32, ir++, TCG_AREG0);
+#endif
 #if TARGET_LONG_BITS == 32
     tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
 #else
@@ -817,6 +845,9 @@
 
     /* slow path */
     ir = 3;
+#ifdef CONFIG_TCG_PASS_AREG0
+    tcg_out_mov (s, TCG_TYPE_I32, ir++, TCG_AREG0);
+#endif
 #if TARGET_LONG_BITS == 32
     tcg_out_mov (s, TCG_TYPE_I32, ir++, addr_reg);
 #else