x86: cleanup early setup_percpu references

[ Based on original patch from Christoph Lameter and Mike Travis. ]

  * Ruggedize some calls in setup_percpu.c to prevent mishaps
    in early calls, particularly for non-critical functions.

  * Cleanup DEBUG_PER_CPU_MAPS usages and some comments.

Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 40 insertions, 16 deletions

diff --git a/arch/x86/kernel/setup_percpu.c b/arch/x86/kernel/setup_percpu.c
index bf63de72b643..56c63ac62b10 100644
--- a/arch/x86/kernel/setup_percpu.c
+++ b/arch/x86/kernel/setup_percpu.c
@@ -15,6 +15,12 @@
 #include <asm/highmem.h>
 #include <asm/cpumask.h>
 
+#ifdef CONFIG_DEBUG_PER_CPU_MAPS
+# define DBG(x...) printk(KERN_DEBUG x)
+#else
+# define DBG(x...)
+#endif
+
 #ifdef CONFIG_X86_LOCAL_APIC
 unsigned int num_processors;
 unsigned disabled_cpus __cpuinitdata;
@@ -27,31 +33,39 @@ unsigned int max_physical_apicid;
 physid_mask_t phys_cpu_present_map;
 #endif
 
-/* map cpu index to physical APIC ID */
+/*
+ * Map cpu index to physical APIC ID
+ */
 DEFINE_EARLY_PER_CPU(u16, x86_cpu_to_apicid, BAD_APICID);
 DEFINE_EARLY_PER_CPU(u16, x86_bios_cpu_apicid, BAD_APICID);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_bios_cpu_apicid);
 
 #if defined(CONFIG_NUMA) && defined(CONFIG_X86_64)
-#define X86_64_NUMA     1
+#define X86_64_NUMA     1       /* (used later) */
 
-/* map cpu index to node index */
+/*
+ * Map cpu index to node index
+ */
 DEFINE_EARLY_PER_CPU(int, x86_cpu_to_node_map, NUMA_NO_NODE);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_node_map);
 
-/* which logical CPUs are on which nodes */
+/*
+ * Which logical CPUs are on which nodes
+ */
 cpumask_t *node_to_cpumask_map;
 EXPORT_SYMBOL(node_to_cpumask_map);
 
-/* setup node_to_cpumask_map */
+/*
+ * Setup node_to_cpumask_map
+ */
 static void __init setup_node_to_cpumask_map(void);
 
 #else
 static inline void setup_node_to_cpumask_map(void) { }
 #endif
 
-#if defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) && defined(CONFIG_X86_SMP)
+#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA
 /*
  * Copy data used in early init routines from the initial arrays to the
  * per cpu data areas.  These arrays then become expendable and the
@@ -200,6 +214,8 @@ void __init setup_per_cpu_areas(void)
 #endif
                 per_cpu_offset(cpu) = ptr - __per_cpu_start;
                 memcpy(ptr, __per_cpu_start, __per_cpu_end - __per_cpu_start);
+
+                DBG("PERCPU: cpu %4d %p\n", cpu, ptr);
         }
 
         /* Setup percpu data maps */
@@ -221,6 +237,7 @@ void __init setup_per_cpu_areas(void)
  * Requires node_possible_map to be valid.
  *
  * Note: node_to_cpumask() is not valid until after this is done.
+ * (Use CONFIG_DEBUG_PER_CPU_MAPS to check this.)
  */
 static void __init setup_node_to_cpumask_map(void)
 {
@@ -236,6 +253,7 @@ static void __init setup_node_to_cpumask_map(void)
 
         /* allocate the map */
         map = alloc_bootmem_low(nr_node_ids * sizeof(cpumask_t));
+        DBG("node_to_cpumask_map at %p for %d nodes\n", map, nr_node_ids);
 
         pr_debug("Node to cpumask map at %p for %d nodes\n",
                  map, nr_node_ids);
@@ -248,17 +266,23 @@ void __cpuinit numa_set_node(int cpu, int node)
 {
         int *cpu_to_node_map = early_per_cpu_ptr(x86_cpu_to_node_map);
 
-        if (cpu_pda(cpu) && node != NUMA_NO_NODE)
-                cpu_pda(cpu)->nodenumber = node;
-
-        if (cpu_to_node_map)
+        /* early setting, no percpu area yet */
+        if (cpu_to_node_map) {
                 cpu_to_node_map[cpu] = node;
+                return;
+        }
 
-        else if (per_cpu_offset(cpu))
-                per_cpu(x86_cpu_to_node_map, cpu) = node;
+#ifdef CONFIG_DEBUG_PER_CPU_MAPS
+        if (cpu >= nr_cpu_ids || !per_cpu_offset(cpu)) {
+                printk(KERN_ERR "numa_set_node: invalid cpu# (%d)\n", cpu);
+                dump_stack();
+                return;
+        }
+#endif
+        per_cpu(x86_cpu_to_node_map, cpu) = node;
 
-        else
-                pr_debug("Setting node for non-present cpu %d\n", cpu);
+        if (node != NUMA_NO_NODE)
+                cpu_pda(cpu)->nodenumber = node;
 }
 
 void __cpuinit numa_clear_node(int cpu)
@@ -275,7 +299,7 @@ void __cpuinit numa_add_cpu(int cpu)
 
 void __cpuinit numa_remove_cpu(int cpu)
 {
-        cpu_clear(cpu, node_to_cpumask_map[cpu_to_node(cpu)]);
+        cpu_clear(cpu, node_to_cpumask_map[early_cpu_to_node(cpu)]);
 }
 
 #else /* CONFIG_DEBUG_PER_CPU_MAPS */
@@ -285,7 +309,7 @@ void __cpuinit numa_remove_cpu(int cpu)
  */
 static void __cpuinit numa_set_cpumask(int cpu, int enable)
 {
-        int node = cpu_to_node(cpu);
+        int node = early_cpu_to_node(cpu);
         cpumask_t *mask;
         char buf[64];