[tip:x86/bsp-hotplug] x86, hotplug: The first online processor saves the MTRR state

[tip-bot for Fenghua Yu]

Commit-ID:  8e5e52c7922c212067326850b794618f3e26aa63
Gitweb:     http://git.kernel.org/tip/8e5e52c7922c212067326850b794618f3e26aa63
Author:     Fenghua Yu <fenghua.yu@xxxxxxxxx>
AuthorDate: Sat, 25 Aug 2012 10:41:26 -0700
Committer:  H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Sat, 25 Aug 2012 19:26:35 -0700

x86, hotplug: The first online processor saves the MTRR state

Ask the first online CPU to save mtrr instead of asking BSP. BSP could be
offline when mtrr_save_state() is called.

Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1345916488-8355-11-git-send-email-fenghua.yu@xxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/mtrr/main.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c
index 6b96110..e4c1a41 100644
--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -695,11 +695,16 @@ void mtrr_ap_init(void)
 }
 
 /**
- * Save current fixed-range MTRR state of the BSP
+ * Save current fixed-range MTRR state of the first cpu in cpu_online_mask.
  */
 void mtrr_save_state(void)
 {
-	smp_call_function_single(0, mtrr_save_fixed_ranges, NULL, 1);
+	int first_cpu;
+
+	get_online_cpus();
+	first_cpu = cpumask_first(cpu_online_mask);
+	smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);
+	put_online_cpus();
 }
 
 void set_mtrr_aps_delayed_init(void)
--
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