powerpc: Properly handshake CPUs going out of boot spin loop
We need to wait a bit for them to have done their CPU setup
or we might end up with translation and EE on with different
LPCR values between threads
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 5a0401f..91a5cc5 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -72,6 +72,7 @@
#endif
int boot_cpuid = 0;
+int __initdata boot_cpu_count;
u64 ppc64_pft_size;
/* Pick defaults since we might want to patch instructions
@@ -233,6 +234,7 @@
void smp_release_cpus(void)
{
unsigned long *ptr;
+ int i;
DBG(" -> smp_release_cpus()\n");
@@ -245,7 +247,16 @@
ptr = (unsigned long *)((unsigned long)&__secondary_hold_spinloop
- PHYSICAL_START);
*ptr = __pa(generic_secondary_smp_init);
- mb();
+
+ /* And wait a bit for them to catch up */
+ for (i = 0; i < 100000; i++) {
+ mb();
+ HMT_low();
+ if (boot_cpu_count == 0)
+ break;
+ udelay(1);
+ }
+ DBG("boot_cpu_count = %d\n", boot_cpu_count);
DBG(" <- smp_release_cpus()\n");
}