[Qemu-devel] [PATCH] PPC: Fix for the gdb single step problem on an rfi instruction

[Sebastian Bauer <mail@sebastianbauer.info>]

When using gdb to single step a ppc interrupt routine, the execution 
flow passes
the rfi instruction without actually returning from the interrupt. The 
patch
fixes this by avoiding to update the nip when the debug exception is 
raised
and a previous POWERPC_EXCP_SYNC was set. The latter is the case only, 
if code for
rfi or a related instruction was generated.

Signed-off-by: Sebastian Bauer <mail@sebastianbauer.info>
---
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index fd7c208..42b91fd 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -287,7 +287,7 @@ static inline void gen_debug_exception(DisasContext 
*ctx)
  {
      TCGv_i32 t0;

-    if (ctx->exception != POWERPC_EXCP_BRANCH)
+    if (ctx->exception != POWERPC_EXCP_BRANCH && ctx->exception != 
POWERPC_EXCP_SYNC)
          gen_update_nip(ctx, ctx->nip);
      t0 = tcg_const_i32(EXCP_DEBUG);
      gen_helper_raise_exception(t0);