From dd17c8f72993f9461e9c19250e3f155d6d99df22 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 29 Oct 2009 22:34:15 +0900 Subject: percpu: remove per_cpu__ prefix. Now that the return from alloc_percpu is compatible with the address of per-cpu vars, it makes sense to hand around the address of per-cpu variables. To make this sane, we remove the per_cpu__ prefix we used created to stop people accidentally using these vars directly. Now we have sparse, we can use that (next patch). tj: * Updated to convert stuff which were missed by or added after the original patch. * Kill per_cpu_var() macro. Signed-off-by: Rusty Russell Signed-off-by: Tejun Heo Reviewed-by: Christoph Lameter --- include/linux/percpu.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 522f421ec213..e12410e55e05 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -182,7 +182,7 @@ static inline void *pcpu_lpage_remapped(void *kaddr) #ifndef percpu_read # define percpu_read(var) \ ({ \ - typeof(per_cpu_var(var)) __tmp_var__; \ + typeof(var) __tmp_var__; \ __tmp_var__ = get_cpu_var(var); \ put_cpu_var(var); \ __tmp_var__; \ @@ -253,8 +253,7 @@ do { \ /* * Optimized manipulation for memory allocated through the per cpu - * allocator or for addresses of per cpu variables (can be determined - * using per_cpu_var(xx). + * allocator or for addresses of per cpu variables. * * These operation guarantee exclusivity of access for other operations * on the *same* processor. The assumption is that per cpu data is only -- cgit v1.2.3 From f7b64fe806029e0a0454df132eec3c5ab576102c Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 29 Oct 2009 22:34:15 +0900 Subject: percpu: make access macros universal Now that per_cpu__ prefix is gone, there's no distinction between static and dynamic percpu variables. Make get_cpu_var() take dynamic percpu variables and ensure that all macros have parentheses around the parameter evaluation and evaluate the variable parameter only once such that any expression which evaluates to percpu address can be used safely. Signed-off-by: Tejun Heo --- include/linux/percpu.h | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/include/linux/percpu.h b/include/linux/percpu.h index e12410e55e05..f965f833a643 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -27,10 +27,13 @@ * we force a syntax error here if it isn't. */ #define get_cpu_var(var) (*({ \ - extern int simple_identifier_##var(void); \ preempt_disable(); \ &__get_cpu_var(var); })) -#define put_cpu_var(var) preempt_enable() + +#define put_cpu_var(var) do { \ + (void)(var); \ + preempt_enable(); \ +} while (0) #ifdef CONFIG_SMP @@ -182,17 +185,19 @@ static inline void *pcpu_lpage_remapped(void *kaddr) #ifndef percpu_read # define percpu_read(var) \ ({ \ - typeof(var) __tmp_var__; \ - __tmp_var__ = get_cpu_var(var); \ - put_cpu_var(var); \ - __tmp_var__; \ + typeof(var) *pr_ptr__ = &(var); \ + typeof(var) pr_ret__; \ + pr_ret__ = get_cpu_var(*pr_ptr__); \ + put_cpu_var(*pr_ptr__); \ + pr_ret__; \ }) #endif #define __percpu_generic_to_op(var, val, op) \ do { \ - get_cpu_var(var) op val; \ - put_cpu_var(var); \ + typeof(var) *pgto_ptr__ = &(var); \ + get_cpu_var(*pgto_ptr__) op val; \ + put_cpu_var(*pgto_ptr__); \ } while (0) #ifndef percpu_write @@ -304,7 +309,7 @@ do { \ #define _this_cpu_generic_to_op(pcp, val, op) \ do { \ preempt_disable(); \ - *__this_cpu_ptr(&pcp) op val; \ + *__this_cpu_ptr(&(pcp)) op val; \ preempt_enable(); \ } while (0) -- cgit v1.2.3 From e0fdb0e050eae331046385643618f12452aa7e73 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 29 Oct 2009 22:34:15 +0900 Subject: percpu: add __percpu for sparse. We have to make __kernel "__attribute__((address_space(0)))" so we can cast to it. tj: * put_cpu_var() update. * Annotations added to dynamic allocator interface. Signed-off-by: Rusty Russell Cc: Al Viro Signed-off-by: Tejun Heo --- include/asm-generic/percpu.h | 4 +++- include/linux/compiler.h | 4 +++- include/linux/percpu-defs.h | 2 +- include/linux/percpu.h | 18 +++++++++++------- 4 files changed, 18 insertions(+), 10 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h index ca6f0491412b..fded453fd25c 100644 --- a/include/asm-generic/percpu.h +++ b/include/asm-generic/percpu.h @@ -41,7 +41,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS]; * Only S390 provides its own means of moving the pointer. */ #ifndef SHIFT_PERCPU_PTR -#define SHIFT_PERCPU_PTR(__p, __offset) RELOC_HIDE((__p), (__offset)) +/* Weird cast keeps both GCC and sparse happy. */ +#define SHIFT_PERCPU_PTR(__p, __offset) \ + RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) #endif /* diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 04fb5135b4e1..abba8045c6ef 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -5,7 +5,7 @@ #ifdef __CHECKER__ # define __user __attribute__((noderef, address_space(1))) -# define __kernel /* default address space */ +# define __kernel __attribute__((address_space(0))) # define __safe __attribute__((safe)) # define __force __attribute__((force)) # define __nocast __attribute__((nocast)) @@ -15,6 +15,7 @@ # define __acquire(x) __context__(x,1) # define __release(x) __context__(x,-1) # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0) +# define __percpu __attribute__((noderef, address_space(3))) extern void __chk_user_ptr(const volatile void __user *); extern void __chk_io_ptr(const volatile void __iomem *); #else @@ -32,6 +33,7 @@ extern void __chk_io_ptr(const volatile void __iomem *); # define __acquire(x) (void)0 # define __release(x) (void)0 # define __cond_lock(x,c) (c) +# define __percpu #endif #ifdef __KERNEL__ diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index ee99f6c2cdcd..0fa0cb524250 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -12,7 +12,7 @@ * that section. */ #define __PCPU_ATTRS(sec) \ - __attribute__((section(PER_CPU_BASE_SECTION sec))) \ + __percpu __attribute__((section(PER_CPU_BASE_SECTION sec))) \ PER_CPU_ATTRIBUTES #define __PCPU_DUMMY_ATTRS \ diff --git a/include/linux/percpu.h b/include/linux/percpu.h index f965f833a643..2c0d31a3f6b6 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -30,8 +30,12 @@ preempt_disable(); \ &__get_cpu_var(var); })) +/* + * The weird & is necessary because sparse considers (void)(var) to be + * a direct dereference of percpu variable (var). + */ #define put_cpu_var(var) do { \ - (void)(var); \ + (void)&(var); \ preempt_enable(); \ } while (0) @@ -130,9 +134,9 @@ extern int __init pcpu_page_first_chunk(size_t reserved_size, */ #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))) -extern void *__alloc_reserved_percpu(size_t size, size_t align); -extern void *__alloc_percpu(size_t size, size_t align); -extern void free_percpu(void *__pdata); +extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align); +extern void __percpu *__alloc_percpu(size_t size, size_t align); +extern void free_percpu(void __percpu *__pdata); #ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA extern void __init setup_per_cpu_areas(void); @@ -142,7 +146,7 @@ extern void __init setup_per_cpu_areas(void); #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) -static inline void *__alloc_percpu(size_t size, size_t align) +static inline void __percpu *__alloc_percpu(size_t size, size_t align) { /* * Can't easily make larger alignment work with kmalloc. WARN @@ -153,7 +157,7 @@ static inline void *__alloc_percpu(size_t size, size_t align) return kzalloc(size, GFP_KERNEL); } -static inline void free_percpu(void *p) +static inline void free_percpu(void __percpu *p) { kfree(p); } @@ -168,7 +172,7 @@ static inline void *pcpu_lpage_remapped(void *kaddr) #endif /* CONFIG_SMP */ #define alloc_percpu(type) \ - (typeof(type) *)__alloc_percpu(sizeof(type), __alignof__(type)) + (typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type)) /* * Optional methods for optimized non-lvalue per-cpu variable access. -- cgit v1.2.3 From 545695fb41da117928ab946067a42d9e15fd009d Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 29 Oct 2009 22:34:15 +0900 Subject: percpu: make accessors check for percpu pointer in sparse The previous patch made sparse warn about percpu variables being used directly without going through percpu accessors. This patch implements the other half - checking whether non percpu variable is passed into percpu accessors. Signed-off-by: Tejun Heo Cc: Rusty Russell Cc: Al Viro --- include/asm-generic/percpu.h | 6 ++++-- include/linux/percpu-defs.h | 20 ++++++++++++++++++-- include/linux/percpu.h | 2 ++ 3 files changed, 24 insertions(+), 4 deletions(-) (limited to 'include/linux/percpu.h') diff --git a/include/asm-generic/percpu.h b/include/asm-generic/percpu.h index fded453fd25c..04f91c2d3f7b 100644 --- a/include/asm-generic/percpu.h +++ b/include/asm-generic/percpu.h @@ -42,8 +42,10 @@ extern unsigned long __per_cpu_offset[NR_CPUS]; */ #ifndef SHIFT_PERCPU_PTR /* Weird cast keeps both GCC and sparse happy. */ -#define SHIFT_PERCPU_PTR(__p, __offset) \ - RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)) +#define SHIFT_PERCPU_PTR(__p, __offset) ({ \ + __verify_pcpu_ptr((__p)); \ + RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \ +}) #endif /* diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index 0fa0cb524250..1fa36eb54b6a 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -18,6 +18,16 @@ #define __PCPU_DUMMY_ATTRS \ __attribute__((section(".discard"), unused)) +/* + * Macro which verifies @ptr is a percpu pointer without evaluating + * @ptr. This is to be used in percpu accessors to verify that the + * input parameter is a percpu pointer. + */ +#define __verify_pcpu_ptr(ptr) do { \ + void __percpu *__vpp_verify = (typeof(ptr))NULL; \ + (void)__vpp_verify; \ +} while (0) + /* * s390 and alpha modules require percpu variables to be defined as * weak to force the compiler to generate GOT based external @@ -129,10 +139,16 @@ __aligned(PAGE_SIZE) /* - * Intermodule exports for per-CPU variables. + * Intermodule exports for per-CPU variables. sparse forgets about + * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to + * noop if __CHECKER__. */ +#ifndef __CHECKER__ #define EXPORT_PER_CPU_SYMBOL(var) EXPORT_SYMBOL(var) #define EXPORT_PER_CPU_SYMBOL_GPL(var) EXPORT_SYMBOL_GPL(var) - +#else +#define EXPORT_PER_CPU_SYMBOL(var) +#define EXPORT_PER_CPU_SYMBOL_GPL(var) +#endif #endif /* _LINUX_PERCPU_DEFS_H */ diff --git a/include/linux/percpu.h b/include/linux/percpu.h index 2c0d31a3f6b6..42878f0cd0e2 100644 --- a/include/linux/percpu.h +++ b/include/linux/percpu.h @@ -237,6 +237,7 @@ extern void __bad_size_call_parameter(void); #define __pcpu_size_call_return(stem, variable) \ ({ typeof(variable) pscr_ret__; \ + __verify_pcpu_ptr(&(variable)); \ switch(sizeof(variable)) { \ case 1: pscr_ret__ = stem##1(variable);break; \ case 2: pscr_ret__ = stem##2(variable);break; \ @@ -250,6 +251,7 @@ extern void __bad_size_call_parameter(void); #define __pcpu_size_call(stem, variable, ...) \ do { \ + __verify_pcpu_ptr(&(variable)); \ switch(sizeof(variable)) { \ case 1: stem##1(variable, __VA_ARGS__);break; \ case 2: stem##2(variable, __VA_ARGS__);break; \ -- cgit v1.2.3