# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1275385206 -3600
# Node ID 2f765c9825b22c4f6d335d6ab126a69b94222f02
# Parent 458589ad3793ca68be1a067683e6b22d918a4ceb
x86 mtrr: Fix set_mtrr() race against cpu_online_map changes.
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/cpu/mtrr/main.c | 25 ++++++++++++++-----------
1 files changed, 14 insertions(+), 11 deletions(-)
diff -r 458589ad3793 -r 2f765c9825b2 xen/arch/x86/cpu/mtrr/main.c
--- a/xen/arch/x86/cpu/mtrr/main.c Tue Jun 01 07:06:50 2010 +0100
+++ b/xen/arch/x86/cpu/mtrr/main.c Tue Jun 01 10:40:06 2010 +0100
@@ -229,29 +229,32 @@ static void set_mtrr(unsigned int reg, u
static void set_mtrr(unsigned int reg, unsigned long base,
unsigned long size, mtrr_type type)
{
+ cpumask_t allbutself;
+ unsigned int nr_cpus;
struct set_mtrr_data data;
unsigned long flags;
+
+ allbutself = cpu_online_map;
+ cpu_clear(smp_processor_id(), allbutself);
+ nr_cpus = cpus_weight(allbutself);
data.smp_reg = reg;
data.smp_base = base;
data.smp_size = size;
data.smp_type = type;
- atomic_set(&data.count, num_online_cpus() - 1);
- /* make sure data.count is visible before unleashing other CPUs */
- smp_wmb();
+ atomic_set(&data.count, nr_cpus);
atomic_set(&data.gate,0);
- /* Start the ball rolling on other CPUs */
- if (smp_call_function(ipi_handler, &data, 0) != 0)
- panic("mtrr: timed out waiting for other CPUs\n");
+ /* Start the ball rolling on other CPUs */
+ on_selected_cpus(&allbutself, ipi_handler, &data, 0);
local_irq_save(flags);
- while(atomic_read(&data.count))
+ while (atomic_read(&data.count))
cpu_relax();
/* ok, reset count and toggle gate */
- atomic_set(&data.count, num_online_cpus() - 1);
+ atomic_set(&data.count, nr_cpus);
smp_wmb();
atomic_set(&data.gate,1);
@@ -271,10 +274,10 @@ static void set_mtrr(unsigned int reg, u
mtrr_if->set(reg,base,size,type);
/* wait for the others */
- while(atomic_read(&data.count))
+ while (atomic_read(&data.count))
cpu_relax();
- atomic_set(&data.count, num_online_cpus() - 1);
+ atomic_set(&data.count, nr_cpus);
smp_wmb();
atomic_set(&data.gate,0);
@@ -282,7 +285,7 @@ static void set_mtrr(unsigned int reg, u
* Wait here for everyone to have seen the gate change
* So we're the last ones to touch 'data'
*/
- while(atomic_read(&data.count))
+ while (atomic_read(&data.count))
cpu_relax();
local_irq_restore(flags);
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