Commit c49a4955 authored by travis@sgi.com's avatar travis@sgi.com Committed by Ingo Molnar
Browse files

x86: add debug of invalid per_cpu map accesses



Provide a means to trap usages of per_cpu map variables before
they are setup.  Define CONFIG_DEBUG_PER_CPU_MAPS to activate.
Signed-off-by: default avatarMike Travis <travis@sgi.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 602a54a8
......@@ -47,6 +47,18 @@ config DEBUG_PAGEALLOC
This results in a large slowdown, but helps to find certain types
of memory corruptions.
config DEBUG_PER_CPU_MAPS
bool "Debug access to per_cpu maps"
depends on DEBUG_KERNEL
depends on X86_64_SMP
default n
help
Say Y to verify that the per_cpu map being accessed has
been setup. Adds a fair amount of code to kernel memory
and decreases performance.
Say N if unsure.
config DEBUG_RODATA
bool "Write protect kernel read-only data structures"
depends on DEBUG_KERNEL
......
......@@ -37,6 +37,9 @@ u16 x86_cpu_to_node_map_init[NR_CPUS] = {
void *x86_cpu_to_node_map_early_ptr;
DEFINE_PER_CPU(u16, x86_cpu_to_node_map) = NUMA_NO_NODE;
EXPORT_PER_CPU_SYMBOL(x86_cpu_to_node_map);
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
EXPORT_SYMBOL(x86_cpu_to_node_map_early_ptr);
#endif
u16 apicid_to_node[MAX_LOCAL_APIC] __cpuinitdata = {
[0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE
......
......@@ -66,6 +66,13 @@ static inline int early_cpu_to_node(int cpu)
static inline int cpu_to_node(int cpu)
{
#ifdef CONFIG_DEBUG_PER_CPU_MAPS
if(x86_cpu_to_node_map_early_ptr) {
printk("KERN_NOTICE cpu_to_node(%d): usage too early!\n",
(int)cpu);
BUG();
}
#endif
if(per_cpu_offset(cpu))
return per_cpu(x86_cpu_to_node_map, cpu);
else
......
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