Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

Pull powerpc fixes from Ben Herrenschmidt:
 "Here are a few things for -rc2, this time it's all written by me so it
  can only be perfect .... right ? :)

  So we have the fix to call irq_enter/exit on the irq stack we've been
  discussing, plus a cleanup on top to remove an unused (and broken)
  stack limit tracking feature (well, make it 32-bit only in fact where
  it is used and works properly).

  Then we have two things that I wrote over the last couple of days and
  made the executive decision to include just because I can (and I'm
  sure you won't object .... right ?).

  They fix a couple of annoying and long standing "issues":

   - We had separate zImages for when booting via Open Firmware vs.
     booting via a flat device-tree, while it's trivial to make one that
     deals with both

   - We wasted a ton of cycles spinning secondary CPUs uselessly at boot
     instead of starting them when needed on pseries, thus contributing
     significantly to global warming"

* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
  powerpc/pseries: Do not start secondaries in Open Firmware
  powerpc/zImage: make the "OF" wrapper support ePAPR boot
  powerpc: Remove ksp_limit on ppc64
  powerpc/irq: Run softirqs off the top of the irq stack

1 files changed, 16 insertions, 10 deletions

diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 1c1771a40250..24f58cb0a543 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -233,18 +233,24 @@ static void __init smp_init_pseries(void)
 
 	alloc_bootmem_cpumask_var(&of_spin_mask);
 
-	/* Mark threads which are still spinning in hold loops. */
-	if (cpu_has_feature(CPU_FTR_SMT)) {
-		for_each_present_cpu(i) { 
-			if (cpu_thread_in_core(i) == 0)
-				cpumask_set_cpu(i, of_spin_mask);
-		}
-	} else {
-		cpumask_copy(of_spin_mask, cpu_present_mask);
+	/*
+	 * Mark threads which are still spinning in hold loops
+	 *
+	 * We know prom_init will not have started them if RTAS supports
+	 * query-cpu-stopped-state.
+	 */
+	if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) {
+		if (cpu_has_feature(CPU_FTR_SMT)) {
+			for_each_present_cpu(i) {
+				if (cpu_thread_in_core(i) == 0)
+					cpumask_set_cpu(i, of_spin_mask);
+			}
+		} else
+			cpumask_copy(of_spin_mask, cpu_present_mask);
+
+		cpumask_clear_cpu(boot_cpuid, of_spin_mask);
 	}
 
-	cpumask_clear_cpu(boot_cpuid, of_spin_mask);
-
 	/* Non-lpar has additional take/give timebase */
 	if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
 		smp_ops->give_timebase = rtas_give_timebase;