powerpc/le: Ensure that the 'stop-self' RTAS token is handled correctly

Currently we're storing a host endian RTAS token in
rtas_stop_self_args.token.  We then pass that directly to rtas.  This is
fine on big endian however on little endian the token is not what we
expect.

This will typically result in hitting:
	panic("Alas, I survived.\n");

To fix this we always use the stop-self token in host order and always
convert it to be32 before passing this to rtas.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 82789e79e53985cf2b6c856f313628ff1eb0ca3e..0ea99e3d4815733a74b8098864f3594839ed97eb 100644 (file)
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -35,12 +35,7 @@
 #include "offline_states.h"
 
 /* This version can't take the spinlock, because it never returns */
-static struct rtas_args rtas_stop_self_args = {
-       .token = RTAS_UNKNOWN_SERVICE,
-       .nargs = 0,
-       .nret = 1,
-       .rets = &rtas_stop_self_args.args[0],
-};
+static int rtas_stop_self_token = RTAS_UNKNOWN_SERVICE;
 
 static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) =
                                                        CPU_STATE_OFFLINE;
@@ -93,15 +88,20 @@ void set_default_offline_state(int cpu)
 
 static void rtas_stop_self(void)
 {
-       struct rtas_args *args = &rtas_stop_self_args;
+       struct rtas_args args = {
+               .token = cpu_to_be32(rtas_stop_self_token),
+               .nargs = 0,
+               .nret = 1,
+               .rets = &args.args[0],
+       };
 
        local_irq_disable();
 
-       BUG_ON(args->token == RTAS_UNKNOWN_SERVICE);
+       BUG_ON(rtas_stop_self_token == RTAS_UNKNOWN_SERVICE);
 
        printk("cpu %u (hwid %u) Ready to die...\n",
               smp_processor_id(), hard_smp_processor_id());
-       enter_rtas(__pa(args));
+       enter_rtas(__pa(&args));
 
        panic("Alas, I survived.\n");
 }
@@ -392,10 +392,10 @@ static int __init pseries_cpu_hotplug_init(void)
                }
        }
 
-       rtas_stop_self_args.token = rtas_token("stop-self");
+       rtas_stop_self_token = rtas_token("stop-self");
        qcss_tok = rtas_token("query-cpu-stopped-state");
 
-       if (rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE ||
+       if (rtas_stop_self_token == RTAS_UNKNOWN_SERVICE ||
                        qcss_tok == RTAS_UNKNOWN_SERVICE) {
                printk(KERN_INFO "CPU Hotplug not supported by firmware "
                                "- disabling.\n");