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author | Tejun Heo <tj@kernel.org> | 2009-09-15 09:57:19 +0900 |
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committer | Tejun Heo <tj@kernel.org> | 2009-09-15 09:57:19 +0900 |
commit | 5579fd7e6aed8860ea0c8e3f11897493153b10ad (patch) | |
tree | 8f797ccd0f1a2c88f1605ae9e90b3ac17485de27 /include/linux/percpu-defs.h | |
parent | 04a13c7c632e1fe04a5f6e6c83565d2559e37598 (diff) | |
parent | c2a7e818019f20a5cf7fb26a6eb59e212e6c0cd8 (diff) | |
download | linux-stable-5579fd7e6aed8860ea0c8e3f11897493153b10ad.tar.gz linux-stable-5579fd7e6aed8860ea0c8e3f11897493153b10ad.tar.bz2 linux-stable-5579fd7e6aed8860ea0c8e3f11897493153b10ad.zip |
Merge branch 'for-next' into for-linus
* pcpu_chunk_page_occupied() doesn't exist in for-next.
* pcpu_chunk_addr_search() updated to use raw_smp_processor_id().
Conflicts:
mm/percpu.c
Diffstat (limited to 'include/linux/percpu-defs.h')
-rw-r--r-- | include/linux/percpu-defs.h | 66 |
1 files changed, 57 insertions, 9 deletions
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index 68438e18fff4..aefc2f12b48c 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -10,22 +10,70 @@ /* * Base implementations of per-CPU variable declarations and definitions, where * the section in which the variable is to be placed is provided by the - * 'section' argument. This may be used to affect the parameters governing the + * 'sec' argument. This may be used to affect the parameters governing the * variable's storage. * * NOTE! The sections for the DECLARE and for the DEFINE must match, lest * linkage errors occur due the compiler generating the wrong code to access * that section. */ -#define DECLARE_PER_CPU_SECTION(type, name, section) \ - extern \ - __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ - PER_CPU_ATTRIBUTES __typeof__(type) per_cpu__##name - -#define DEFINE_PER_CPU_SECTION(type, name, section) \ - __attribute__((__section__(PER_CPU_BASE_SECTION section))) \ - PER_CPU_ATTRIBUTES PER_CPU_DEF_ATTRIBUTES \ +#define __PCPU_ATTRS(sec) \ + __attribute__((section(PER_CPU_BASE_SECTION sec))) \ + PER_CPU_ATTRIBUTES + +#define __PCPU_DUMMY_ATTRS \ + __attribute__((section(".discard"), unused)) + +/* + * s390 and alpha modules require percpu variables to be defined as + * weak to force the compiler to generate GOT based external + * references for them. This is necessary because percpu sections + * will be located outside of the usually addressable area. + * + * This definition puts the following two extra restrictions when + * defining percpu variables. + * + * 1. The symbol must be globally unique, even the static ones. + * 2. Static percpu variables cannot be defined inside a function. + * + * Archs which need weak percpu definitions should define + * ARCH_NEEDS_WEAK_PER_CPU in asm/percpu.h when necessary. + * + * To ensure that the generic code observes the above two + * restrictions, if CONFIG_DEBUG_FORCE_WEAK_PER_CPU is set weak + * definition is used for all cases. + */ +#if defined(ARCH_NEEDS_WEAK_PER_CPU) || defined(CONFIG_DEBUG_FORCE_WEAK_PER_CPU) +/* + * __pcpu_scope_* dummy variable is used to enforce scope. It + * receives the static modifier when it's used in front of + * DEFINE_PER_CPU() and will trigger build failure if + * DECLARE_PER_CPU() is used for the same variable. + * + * __pcpu_unique_* dummy variable is used to enforce symbol uniqueness + * such that hidden weak symbol collision, which will cause unrelated + * variables to share the same address, can be detected during build. + */ +#define DECLARE_PER_CPU_SECTION(type, name, sec) \ + extern __PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \ + extern __PCPU_ATTRS(sec) __typeof__(type) per_cpu__##name + +#define DEFINE_PER_CPU_SECTION(type, name, sec) \ + __PCPU_DUMMY_ATTRS char __pcpu_scope_##name; \ + __PCPU_DUMMY_ATTRS char __pcpu_unique_##name; \ + __PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES __weak \ + __typeof__(type) per_cpu__##name +#else +/* + * Normal declaration and definition macros. + */ +#define DECLARE_PER_CPU_SECTION(type, name, sec) \ + extern __PCPU_ATTRS(sec) __typeof__(type) per_cpu__##name + +#define DEFINE_PER_CPU_SECTION(type, name, sec) \ + __PCPU_ATTRS(sec) PER_CPU_DEF_ATTRIBUTES \ __typeof__(type) per_cpu__##name +#endif /* * Variant on the per-CPU variable declaration/definition theme used for |