diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/percpu-defs.h | 66 | ||||
| -rw-r--r-- | include/linux/percpu.h | 12 |
2 files changed, 66 insertions, 12 deletions
diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index 68438e18fff..aefc2f12b48 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 diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 26fd9d12f05..e5000343dd6 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -34,7 +34,7 @@ #ifdef CONFIG_SMP -#ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA +#ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA /* minimum unit size, also is the maximum supported allocation size */ #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10) @@ -80,7 +80,7 @@ extern ssize_t __init pcpu_embed_first_chunk( extern void *__alloc_reserved_percpu(size_t size, size_t align); -#else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ +#else /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */ struct percpu_data { void *ptrs[1]; @@ -99,11 +99,15 @@ struct percpu_data { (__typeof__(ptr))__p->ptrs[(cpu)]; \ }) -#endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ +#endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */ extern void *__alloc_percpu(size_t size, size_t align); extern void free_percpu(void *__pdata); +#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA +extern void __init setup_per_cpu_areas(void); +#endif + #else /* CONFIG_SMP */ #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) @@ -124,6 +128,8 @@ static inline void free_percpu(void *p) kfree(p); } +static inline void __init setup_per_cpu_areas(void) { } + #endif /* CONFIG_SMP */ #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \ |