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SubjectRe: [RFC PATCH 07/11] kprobes: introduces macros for allocing early kprobe resources.
On 2015/1/7 15:35, Wang Nan wrote:
> Introduces macros to genearte common early kprobe related resource
> allocator.
>
> All early kprobe related resources are statically allocated during
> linking for each early kprobe slot. For each type of resource, a bitmap
> is used to track allocation. __DEFINE_EKPROBE_ALLOC_OPS defines alloc
> and free handler for them. The range of the resource and the bitmap
> should be provided for allocaing and freeing. DEFINE_EKPROBE_ALLOC_OPS
> defines bitmap and the array used by it.
>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> ---
> include/linux/kprobes.h | 69 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 69 insertions(+)
>
> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index b0265f9..9a18188 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -270,6 +270,75 @@ extern void show_registers(struct pt_regs *regs);
> extern void kprobes_inc_nmissed_count(struct kprobe *p);
> extern bool arch_within_kprobe_blacklist(unsigned long addr);
>
> +#ifdef CONFIG_EARLY_KPROBES
> +
> +#define NR_EARLY_KPROBES_SLOTS CONFIG_NR_EARLY_KPROBES_SLOTS
> +#define ALIGN_UP(v, a) (((v) + ((a) - 1)) & ~((a) - 1))
> +#define EARLY_KPROBES_BITMAP_SZ ALIGN_UP(NR_EARLY_KPROBES_SLOTS, BITS_PER_LONG)
> +
> +#define __ek_in_range(v, s, e) (((v) >= (s)) && ((v) < (e)))
> +#define __ek_buf_sz(s, e) ((void *)(e) - (void *)(s))
> +#define __ek_elem_sz_b(s, e) (__ek_buf_sz(s, e) / NR_EARLY_KPROBES_SLOTS)
> +#define __ek_elem_sz(s, e) (__ek_elem_sz_b(s, e) / sizeof(s[0]))
> +#define __ek_elem_idx(v, s, e) (__ek_buf_sz(s, v) / __ek_elem_sz_b(s, e))
> +#define __ek_get_elem(i, s, e) (&((s)[__ek_elem_sz(s, e) * (i)]))
> +#define __DEFINE_EKPROBE_ALLOC_OPS(__t, __name) \
> +static inline __t *__ek_alloc_##__name(__t *__s, __t *__e, unsigned long *__b)\
> +{ \
> + int __i = find_next_zero_bit(__b, NR_EARLY_KPROBES_SLOTS, 0); \
> + if (__i >= NR_EARLY_KPROBES_SLOTS) \
> + return NULL; \
> + set_bit(__i, __b); \
> + return __ek_get_elem(__i, __s, __e); \
> +} \
> +static inline int __ek_free_##__name(__t *__v, __t *__s, __t *__e, unsigned long *__b) \
> +{ \
> + if (!__ek_in_range(__v, __s, __e)) \
> + return 0; \
> + clear_bit(__ek_elem_idx(__v, __s, __e), __b); \
> + return 1; \
> +}
> +
> +#define DEFINE_EKPROBE_ALLOC_OPS(__t, __name, __static) \
> +__static __t __ek_##__name##_slots[NR_EARLY_KPROBES_SLOTS]; \
> +__static unsigned long __ek_##__name##_bitmap[EARLY_KPROBES_BITMAP_SZ]; \
> +__DEFINE_EKPROBE_ALLOC_OPS(__t, __name) \
> +static inline __t *ek_alloc_##__name(void) \
> +{ \
> + return __ek_alloc_##__name(&((__ek_##__name##_slots)[0]), \
> + &((__ek_##__name##_slots)[NR_EARLY_KPROBES_SLOTS]),\
> + (__ek_##__name##_bitmap)); \
> +} \
> +static inline int ek_free_##__name(__t *__s) \
> +{ \
> + return __ek_free_##__name(__s, &((__ek_##__name##_slots)[0]), \
> + &((__ek_##__name##_slots)[NR_EARLY_KPROBES_SLOTS]),\
> + (__ek_##__name##_bitmap)); \
> +}
> +
> +
> +#else
> +#define __DEFINE_EKPROBE_ALLOC_OPS(__t, __name) \
> +static inline __t *__ek_alloc_##__name(__t *__s, __t *__e, unsigned long *__b)\
> +{ \
> + return NULL; \
> +} \
> +static inline int __ek_free_##__name(__t *__v, __t *__s, __t *__e, unsigned long *__b)\
> +{ \
> + return 0; \
> +}
> +
> +#define DEFINE_EKPROBE_ALLOC_OPS(__t, __name, __static) \
> +static inline __t *ek_alloc_##__name(void) \
> +{ \
> + return NULL; \
> +} \
> +static inline void ek_free_##__name(__t *__s) \
> +{ \
> +}
> +

Sorry, here is a small problem. Should be:
static inline int ek_free_##__name(__t *__s) \
{ \
return 0; \
}

> +#endif
> +
> struct kprobe_insn_cache {
> struct mutex mutex;
> void *(*alloc)(void); /* allocate insn page */
>




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