diff --git a/include/linux/kmemcheck.h b/include/linux/kmemcheck.h index 093d23969b1b..47b39b7c7e84 100644 --- a/include/linux/kmemcheck.h +++ b/include/linux/kmemcheck.h @@ -33,6 +33,7 @@ void kmemcheck_mark_initialized_pages(struct page *p, unsigned int n); int kmemcheck_show_addr(unsigned long address); int kmemcheck_hide_addr(unsigned long address); + #else #define kmemcheck_enabled 0 @@ -100,4 +101,53 @@ static inline void kmemcheck_mark_initialized_pages(struct page *p, #endif /* CONFIG_KMEMCHECK */ +/* + * Bitfield annotations + * + * How to use: If you have a struct using bitfields, for example + * + * struct a { + * int x:8, y:8; + * }; + * + * then this should be rewritten as + * + * struct a { + * kmemcheck_bitfield_begin(flags); + * int x:8, y:8; + * kmemcheck_bitfield_end(flags); + * }; + * + * Now the "flags_begin" and "flags_end" members may be used to refer to the + * beginning and end, respectively, of the bitfield (and things like + * &x.flags_begin is allowed). As soon as the struct is allocated, the bit- + * fields should be annotated: + * + * struct a *a = kmalloc(sizeof(struct a), GFP_KERNEL); + * kmemcheck_annotate_bitfield(a, flags); + * + * Note: We provide the same definitions for both kmemcheck and non- + * kmemcheck kernels. This makes it harder to introduce accidental errors. It + * is also allowed to pass NULL pointers to kmemcheck_annotate_bitfield(). + */ +#define kmemcheck_bitfield_begin(name) \ + int name##_begin[0]; + +#define kmemcheck_bitfield_end(name) \ + int name##_end[0]; + +#define kmemcheck_annotate_bitfield(ptr, name) \ + do if (ptr) { \ + int _n = (long) &((ptr)->name##_end) \ + - (long) &((ptr)->name##_begin); \ + BUILD_BUG_ON(_n < 0); \ + \ + kmemcheck_mark_initialized(&((ptr)->name##_begin), _n); \ + } while (0) + +#define kmemcheck_annotate_variable(var) \ + do { \ + kmemcheck_mark_initialized(&(var), sizeof(var)); \ + } while (0) \ + #endif /* LINUX_KMEMCHECK_H */