[PATCH 06/17] ppc64: Clean register values in reginfo_init

[Richard Henderson]

Smash the stack and thread pointers to deadbeef, as is common
for the other architectures.  This allows us to drop these
special cases within reginfo_is_eq and reginfo_dump_mismatch.

Do not copy the unused special registers that are packed into gregs[].
Most of these are related to system instructions and thus are not
manipulable via the user-mode instructions targeted by RISU.  LNK and
CTR are not initialized by risugen, and since in general we cannot
test branches with risugen these can be ignored.  This leaves only
XER and CCR as the only special registers to be copied.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 risu_reginfo_ppc64.c | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/risu_reginfo_ppc64.c b/risu_reginfo_ppc64.c
index fc69805..67ea3ce 100644
--- a/risu_reginfo_ppc64.c
+++ b/risu_reginfo_ppc64.c
@@ -44,16 +44,16 @@ int reginfo_size(struct reginfo *ri)
 /* reginfo_init: initialize with a ucontext */
 void reginfo_init(struct reginfo *ri, ucontext_t *uc, void *siaddr)
 {
-    int i;
-
     memset(ri, 0, sizeof(*ri));
 
     ri->faulting_insn = *((uint32_t *) uc->uc_mcontext.regs->nip);
     ri->nip = uc->uc_mcontext.regs->nip - image_start_address;
 
-    for (i = 0; i < NGREG; i++) {
-        ri->gregs[i] = uc->uc_mcontext.gp_regs[i];
-    }
+    memcpy(ri->gregs, uc->uc_mcontext.gp_regs, 32 * sizeof(ri->gregs[0]));
+    ri->gregs[1] = 0xdeadbeefdeadbeef;   /* sp */
+    ri->gregs[13] = 0xdeadbeefdeadbeef;  /* tp */
+    ri->gregs[XER] = uc->uc_mcontext.gp_regs[XER];
+    ri->gregs[CCR] = uc->uc_mcontext.gp_regs[CCR];
 
     memcpy(ri->fpregs, uc->uc_mcontext.fp_regs, 32 * sizeof(double));
     ri->fpscr = uc->uc_mcontext.fp_regs[32];
@@ -69,10 +69,6 @@ int reginfo_is_eq(struct reginfo *m, struct reginfo *a)
 {
     int i;
     for (i = 0; i < 32; i++) {
-        if (i == 1 || i == 13) {
-            continue;
-        }
-
         if (m->gregs[i] != a->gregs[i]) {
             return 0;
         }
@@ -150,9 +146,6 @@ void reginfo_dump_mismatch(struct reginfo *m, struct 
reginfo *a, FILE *f)
     int i;
 
     for (i = 0; i < 32; i++) {
-        if (i == 1 || i == 13) {
-            continue;
-        }
         if (m->gregs[i] != a->gregs[i]) {
             fprintf(f, "%*s%d: %016lx vs %016lx\n",
                     6 - (1 < 10 ? 1 : 2), "r", i,
-- 
2.34.1