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x86: add debug of invalid per_cpu map accesses

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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: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
travis@sgi.com 2008-01-30 13:33:22 +01:00 committed by Ingo Molnar
parent 602a54a8ca
commit c49a4955ea
3 changed files with 22 additions and 0 deletions
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12
arch/x86/Kconfig.debug
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@ -47,6 +47,18 @@ config DEBUG_PAGEALLOC
This results in a large slowdown, but helps to find certain types This results in a large slowdown, but helps to find certain types
of memory corruptions. 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 config DEBUG_RODATA
bool "Write protect kernel read-only data structures" bool "Write protect kernel read-only data structures"
depends on DEBUG_KERNEL depends on DEBUG_KERNEL

3
arch/x86/mm/numa_64.c
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@ -37,6 +37,9 @@ u16 x86_cpu_to_node_map_init[NR_CPUS] = {
void *x86_cpu_to_node_map_early_ptr; void *x86_cpu_to_node_map_early_ptr;
DEFINE_PER_CPU(u16, x86_cpu_to_node_map) = NUMA_NO_NODE; DEFINE_PER_CPU(u16, x86_cpu_to_node_map) = NUMA_NO_NODE;
EXPORT_PER_CPU_SYMBOL(x86_cpu_to_node_map); 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 = { u16 apicid_to_node[MAX_LOCAL_APIC] __cpuinitdata = {
[0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE [0 ... MAX_LOCAL_APIC-1] = NUMA_NO_NODE

7
include/asm-x86/topology.h
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@ -66,6 +66,13 @@ static inline int early_cpu_to_node(int cpu)
static inline int 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)) if(per_cpu_offset(cpu))
return per_cpu(x86_cpu_to_node_map, cpu); return per_cpu(x86_cpu_to_node_map, cpu);
else else