commit 7caee782e996988d5d178ed0838e73781f608ae1
author Greg Kurz <groug@kaod.org> Thu May 14 00:57:00 2020 +0200
committer David Gibson <david@gibson.dropbear.id.au> Wed May 27 15:29:36 2020 +1000
tree ac349b5c93455a784ffe239ba052431d34a55ee5
parent 1830422611806abba07694605e933a566d634eec

target/ppc: Don't initialize some local variables in ppc_radix64_xlate()

It is the job of the ppc_radix64_get_fully_qualified_addr() function
which is called at the beginning of ppc_radix64_xlate() to set both
lpid *and* pid. It doesn't buy us anything to initialize them first.

Worse, a bug in ppc_radix64_get_fully_qualified_addr(), eg. failing to
set either lpid or pid, would be undetectable by static analysis tools
like coverity.

Some recent versions of gcc (eg. gcc-9.3.1-2.fc30) may still think
that lpid or pid is used uninitialized though, so this also adds
default cases in the switch statements to make it clear this cannot
happen.

Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <158941062048.240484.9693581559252337111.stgit@bahia.lan>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

target/ppc/mmu-radix64.c

diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
index c76879f..07f956c 100644
--- a/target/ppc/mmu-radix64.c
+++ b/target/ppc/mmu-radix64.c
@@ -50,6 +50,8 @@
             *lpid = 0;
             *pid = 0;
             break;
+        default:
+            g_assert_not_reached();
         }
     } else {  /* !MSR[HV] -> Guest */
         switch (eaddr & R_EADDR_QUADRANT) {
@@ -64,6 +66,8 @@
             *lpid = env->spr[SPR_LPIDR];
             *pid = 0; /* pid set to 0 -> addresses guest operating system */
             break;
+        default:
+            g_assert_not_reached();
         }
     }
 
@@ -433,7 +437,7 @@
                              bool cause_excp)
 {
     CPUPPCState *env = &cpu->env;
-    uint64_t lpid = 0, pid = 0;
+    uint64_t lpid, pid;
     ppc_v3_pate_t pate;
     int psize, prot;
     hwaddr g_raddr;