x86: fix cpu_mask_to_apicid_and to include cpu_online_mask

Impact: fix potential APIC crash

In determining the destination apicid, there are usually three cpumasks
that are considered: the incoming cpumask arg, cfg->domain and the
cpu_online_mask.  Since we are just introducing the cpu_mask_to_apicid_and
function, make sure it includes the cpu_online_mask in it's evaluation.
[Added with this patch.]

There are two io_apic.c functions that did not previously use the
cpu_online_mask:  setup_IO_APIC_irq and msi_compose_msg.  Both of these
simply used cpu_mask_to_apicid(cfg->domain & TARGET_CPUS), and all but
one arch (NUMAQ[*]) returns only online cpus in the TARGET_CPUS mask,
so the behavior is identical for all cases.

[*: NUMAQ bug?]

Note that alloc_cpumask_var is only used for the 32-bit cases where
it's highly likely that the cpumask set size will be small and therefore
CPUMASK_OFFSTACK=n.  But if that's not the case, failing the allocate
will cause the same return value as the default.

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 17 insertions, 13 deletions

diff --git a/arch/x86/include/asm/summit/apic.h b/arch/x86/include/asm/summit/apic.h
index 651a938..99327d1 100644
--- a/arch/x86/include/asm/summit/apic.h
+++ b/arch/x86/include/asm/summit/apic.h
@@ -170,35 +170,37 @@ static inline unsigned int cpu_mask_to_apicid(const cpumask_t *cpumask)
 	return apicid;
 }
 
-static inline unsigned int cpu_mask_to_apicid_and(const struct cpumask *cpumask,
+static inline unsigned int cpu_mask_to_apicid_and(const struct cpumask *inmask,
 						  const struct cpumask *andmask)
 {
 	int num_bits_set;
-	int num_bits_set2;
 	int cpus_found = 0;
 	int cpu;
-	int apicid = 0;
+	int apicid = 0xFF;
+	cpumask_var_t cpumask;
+
+	if (!alloc_cpumask_var(&cpumask, GFP_ATOMIC))
+		return (int) 0xFF;
+
+	cpumask_and(cpumask, inmask, andmask);
+	cpumask_and(cpumask, cpumask, cpu_online_mask);
 
 	num_bits_set = cpumask_weight(cpumask);
-	num_bits_set2 = cpumask_weight(andmask);
-	num_bits_set = min(num_bits_set, num_bits_set2);
 	/* Return id to all */
-	if (num_bits_set >= nr_cpu_ids)
-		return 0xFF;
+	if (num_bits_set == nr_cpu_ids)
+		goto exit;
 	/*
 	 * The cpus in the mask must all be on the apic cluster.  If are not
 	 * on the same apicid cluster return default value of TARGET_CPUS.
 	 */
-	cpu = cpumask_first_and(cpumask, andmask);
+	cpu = cpumask_first(cpumask);
 	apicid = cpu_to_logical_apicid(cpu);
 	while (cpus_found < num_bits_set) {
-		if (cpumask_test_cpu(cpu, cpumask)
-		    && cpumask_test_cpu(cpu, andmask)) {
+		if (cpumask_test_cpu(cpu, cpumask)) {
 			int new_apicid = cpu_to_logical_apicid(cpu);
 			if (apicid_cluster(apicid) !=
-					apicid_cluster(new_apicid)) {
-				printk(KERN_WARNING
-					"%s: Not a valid mask!\n", __func__);
+					apicid_cluster(new_apicid)){
+				printk ("%s: Not a valid mask!\n", __func__);
 				return 0xFF;
 			}
 			apicid = apicid | new_apicid;
@@ -206,6 +208,8 @@ static inline unsigned int cpu_mask_to_apicid_and(const struct cpumask *cpumask,
 		}
 		cpu++;
 	}
+exit:
+	free_cpumask_var(cpumask);
 	return apicid;
 }