(2013/08/23 20:04), Heiko Carstens wrote:
> The current two insn slot caches both use module_alloc/module_free
> to allocate and free insn slot cache pages.
> For s390 this is not sufficient since there is the need to allocate
> insn slots that are either within the vmalloc module area or within
> dma memory.
> Therefore add a mechanism which allows to specify an own allocator
> for an own insn slot cache.
>
Acked-by: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Thank you!
> Signed-off-by: Heiko Carstens <heiko.carst...@de.ibm.com>
> ---
> include/linux/kprobes.h | 2 ++
> kernel/kprobes.c | 20 ++++++++++++++++++--
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
> index 077f653..925eaf2 100644
> --- a/include/linux/kprobes.h
> +++ b/include/linux/kprobes.h
> @@ -268,6 +268,8 @@ extern void kprobes_inc_nmissed_count(struct kprobe *p);
>
> struct kprobe_insn_cache {
> struct mutex mutex;
> + void *(*alloc)(void); /* allocate insn page */
> + void (*free)(void *); /* free insn page */
> struct list_head pages; /* list of kprobe_insn_page */
> size_t insn_size; /* size of instruction slot */
> int nr_garbage;
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index 9e4912d..a0d367a 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -112,6 +112,7 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
> struct kprobe_insn_page {
> struct list_head list;
> kprobe_opcode_t *insns; /* Page of instruction slots */
> + struct kprobe_insn_cache *cache;
> int nused;
> int ngarbage;
> char slot_used[];
> @@ -132,8 +133,20 @@ enum kprobe_slot_state {
> SLOT_USED = 2,
> };
>
> +static void *alloc_insn_page(void)
> +{
> + return module_alloc(PAGE_SIZE);
> +}
> +
> +static void free_insn_page(void *page)
> +{
> + module_free(NULL, page);
> +}
> +
> struct kprobe_insn_cache kprobe_insn_slots = {
> .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
> + .alloc = alloc_insn_page,
> + .free = free_insn_page,
> .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
> .insn_size = MAX_INSN_SIZE,
> .nr_garbage = 0,
> @@ -182,7 +195,7 @@ kprobe_opcode_t __kprobes *__get_insn_slot(struct
> kprobe_insn_cache *c)
> * kernel image and loaded module images reside. This is required
> * so x86_64 can correctly handle the %rip-relative fixups.
> */
> - kip->insns = module_alloc(PAGE_SIZE);
> + kip->insns = c->alloc();
> if (!kip->insns) {
> kfree(kip);
> goto out;
> @@ -192,6 +205,7 @@ kprobe_opcode_t __kprobes *__get_insn_slot(struct
> kprobe_insn_cache *c)
> kip->slot_used[0] = SLOT_USED;
> kip->nused = 1;
> kip->ngarbage = 0;
> + kip->cache = c;
> list_add(&kip->list, &c->pages);
> slot = kip->insns;
> out:
> @@ -213,7 +227,7 @@ static int __kprobes collect_one_slot(struct
> kprobe_insn_page *kip, int idx)
> */
> if (!list_is_singular(&kip->list)) {
> list_del(&kip->list);
> - module_free(NULL, kip->insns);
> + kip->cache->free(kip->insns);
> kfree(kip);
> }
> return 1;
> @@ -274,6 +288,8 @@ out:
> /* For optimized_kprobe buffer */
> struct kprobe_insn_cache kprobe_optinsn_slots = {
> .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
> + .alloc = alloc_insn_page,
> + .free = free_insn_page,
> .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
> /* .insn_size is initialized later */
> .nr_garbage = 0,
>
--
Masami HIRAMATSU
IT Management Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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