aboutsummaryrefslogtreecommitdiff
path: root/hw/ppc
diff options
context:
space:
mode:
authorRoman Kapl <rka@sysgo.com>2017-01-09 12:23:38 +0100
committerDavid Gibson <david@gibson.dropbear.id.au>2017-01-31 10:10:14 +1100
commit0dfe952dc5c2921488a1172407857d5bb81d17a4 (patch)
tree9f7f0dd45ef584991cd94e04135bae9e27e8eb81 /hw/ppc
parent2a084dadcbc207b27d3efc9d6c05cafb72fc83f0 (diff)
ppc: Prevent inifnite loop in decrementer auto-reload.
If the DECAR register is set to 0, QEMU tries to reload the decrementer with zero in an inifinite loop. According to PPC documentation, the decrementer is triggered on 1->0 transition, so avoid reloading the decrementer if if is already zero. The problem does not manifest under Linux, but it is valid to set DECAR to zero (and may make sense as part of decrementer initialization when interrupts are disabled). Signed-off-by: Roman Kapl <rka@sysgo.com> [dwg: Fixed style nit] Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'hw/ppc')
-rw-r--r--hw/ppc/ppc_booke.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/hw/ppc/ppc_booke.c b/hw/ppc/ppc_booke.c
index ab8d026c32..60baffaf1d 100644
--- a/hw/ppc/ppc_booke.c
+++ b/hw/ppc/ppc_booke.c
@@ -198,8 +198,12 @@ static void booke_decr_cb(void *opaque)
booke_update_irq(cpu);
if (env->spr[SPR_BOOKE_TCR] & TCR_ARE) {
- /* Auto Reload */
- cpu_ppc_store_decr(env, env->spr[SPR_BOOKE_DECAR]);
+ /* Do not reload 0, it is already there. It would just trigger
+ * the timer again and lead to infinite loop */
+ if (env->spr[SPR_BOOKE_DECAR] != 0) {
+ /* Auto Reload */
+ cpu_ppc_store_decr(env, env->spr[SPR_BOOKE_DECAR]);
+ }
}
}