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

arch/x86/Kconfig.debug

+12 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/mm/numa_64.c

+3 −0
Original line number Diff line number Diff line
@@ -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

include/asm-x86/topology.h

+7 −0
Original line number Diff line number Diff line
@@ -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