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Message-Id: <1377255854-30163-2-git-send-email-heiko.carstens@de.ibm.com>
Date: Fri, 23 Aug 2013 13:04:12 +0200
From: Heiko Carstens <heiko.carstens@...ibm.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Ananth N Mavinakayanahalli <ananth@...ibm.com>,
Ingo Molnar <mingo@...nel.org>,
Martin Schwidefsky <schwidefsky@...ibm.com>
Cc: linux-kernel@...r.kernel.org,
Heiko Carstens <heiko.carstens@...ibm.com>
Subject: [Patch v2 1/3] kprobes: unify insn caches
The two insn caches (insn, and optinsn) each have an own mutex and
alloc/free functions (get_[opt]insn_slot() / free_[opt]insn_slot()).
Since there is the need for yet another insn cache which satifies
dma allocations on s390, unify and simplify the current implementation:
- Move the per insn cache mutex into struct kprobe_insn_cache.
- Move the alloc/free functions to kprobe.h so they are simply
wrappers for the generic __get_insn_slot/__free_insn_slot functions.
The implementation is done with a DEFINE_INSN_CACHE_OPS() macro
which provides the alloc/free functions for each cache if needed.
- move the struct kprobe_insn_cache to kprobe.h which allows to generate
architecture specific insn slot caches outside of the core kprobes
code.
Signed-off-by: Heiko Carstens <heiko.carstens@...ibm.com>
---
include/linux/kprobes.h | 32 +++++++++++++++++---
kernel/kprobes.c | 75 +++++++++++++----------------------------------
2 files changed, 49 insertions(+), 58 deletions(-)
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index ca1d27a..077f653 100644
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -264,10 +264,34 @@ extern void arch_arm_kprobe(struct kprobe *p);
extern void arch_disarm_kprobe(struct kprobe *p);
extern int arch_init_kprobes(void);
extern void show_registers(struct pt_regs *regs);
-extern kprobe_opcode_t *get_insn_slot(void);
-extern void free_insn_slot(kprobe_opcode_t *slot, int dirty);
extern void kprobes_inc_nmissed_count(struct kprobe *p);
+struct kprobe_insn_cache {
+ struct mutex mutex;
+ struct list_head pages; /* list of kprobe_insn_page */
+ size_t insn_size; /* size of instruction slot */
+ int nr_garbage;
+};
+
+extern kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c);
+extern void __free_insn_slot(struct kprobe_insn_cache *c,
+ kprobe_opcode_t *slot, int dirty);
+
+#define DEFINE_INSN_CACHE_OPS(__name) \
+extern struct kprobe_insn_cache kprobe_##__name##_slots; \
+ \
+static inline kprobe_opcode_t *get_##__name##_slot(void) \
+{ \
+ return __get_insn_slot(&kprobe_##__name##_slots); \
+} \
+ \
+static inline void free_##__name##_slot(kprobe_opcode_t *slot, int dirty)\
+{ \
+ __free_insn_slot(&kprobe_##__name##_slots, slot, dirty); \
+} \
+
+DEFINE_INSN_CACHE_OPS(insn);
+
#ifdef CONFIG_OPTPROBES
/*
* Internal structure for direct jump optimized probe
@@ -287,13 +311,13 @@ extern void arch_optimize_kprobes(struct list_head *oplist);
extern void arch_unoptimize_kprobes(struct list_head *oplist,
struct list_head *done_list);
extern void arch_unoptimize_kprobe(struct optimized_kprobe *op);
-extern kprobe_opcode_t *get_optinsn_slot(void);
-extern void free_optinsn_slot(kprobe_opcode_t *slot, int dirty);
extern int arch_within_optimized_kprobe(struct optimized_kprobe *op,
unsigned long addr);
extern void opt_pre_handler(struct kprobe *p, struct pt_regs *regs);
+DEFINE_INSN_CACHE_OPS(optinsn);
+
#ifdef CONFIG_SYSCTL
extern int sysctl_kprobes_optimization;
extern int proc_kprobes_optimization_handler(struct ctl_table *table,
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 6e33498..9e4912d 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -121,12 +121,6 @@ struct kprobe_insn_page {
(offsetof(struct kprobe_insn_page, slot_used) + \
(sizeof(char) * (slots)))
-struct kprobe_insn_cache {
- struct list_head pages; /* list of kprobe_insn_page */
- size_t insn_size; /* size of instruction slot */
- int nr_garbage;
-};
-
static int slots_per_page(struct kprobe_insn_cache *c)
{
return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
@@ -138,8 +132,8 @@ enum kprobe_slot_state {
SLOT_USED = 2,
};
-static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
-static struct kprobe_insn_cache kprobe_insn_slots = {
+struct kprobe_insn_cache kprobe_insn_slots = {
+ .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
.insn_size = MAX_INSN_SIZE,
.nr_garbage = 0,
@@ -150,10 +144,12 @@ static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
* __get_insn_slot() - Find a slot on an executable page for an instruction.
* We allocate an executable page if there's no room on existing ones.
*/
-static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
+kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
{
struct kprobe_insn_page *kip;
+ kprobe_opcode_t *slot = NULL;
+ mutex_lock(&c->mutex);
retry:
list_for_each_entry(kip, &c->pages, list) {
if (kip->nused < slots_per_page(c)) {
@@ -162,7 +158,8 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
if (kip->slot_used[i] == SLOT_CLEAN) {
kip->slot_used[i] = SLOT_USED;
kip->nused++;
- return kip->insns + (i * c->insn_size);
+ slot = kip->insns + (i * c->insn_size);
+ goto out;
}
}
/* kip->nused is broken. Fix it. */
@@ -178,7 +175,7 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
/* All out of space. Need to allocate a new page. */
kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
if (!kip)
- return NULL;
+ goto out;
/*
* Use module_alloc so this page is within +/- 2GB of where the
@@ -188,7 +185,7 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
kip->insns = module_alloc(PAGE_SIZE);
if (!kip->insns) {
kfree(kip);
- return NULL;
+ goto out;
}
INIT_LIST_HEAD(&kip->list);
memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
@@ -196,19 +193,10 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
kip->nused = 1;
kip->ngarbage = 0;
list_add(&kip->list, &c->pages);
- return kip->insns;
-}
-
-
-kprobe_opcode_t __kprobes *get_insn_slot(void)
-{
- kprobe_opcode_t *ret = NULL;
-
- mutex_lock(&kprobe_insn_mutex);
- ret = __get_insn_slot(&kprobe_insn_slots);
- mutex_unlock(&kprobe_insn_mutex);
-
- return ret;
+ slot = kip->insns;
+out:
+ mutex_unlock(&c->mutex);
+ return slot;
}
/* Return 1 if all garbages are collected, otherwise 0. */
@@ -255,11 +243,12 @@ static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
return 0;
}
-static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
- kprobe_opcode_t *slot, int dirty)
+void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
+ kprobe_opcode_t *slot, int dirty)
{
struct kprobe_insn_page *kip;
+ mutex_lock(&c->mutex);
list_for_each_entry(kip, &c->pages, list) {
long idx = ((long)slot - (long)kip->insns) /
(c->insn_size * sizeof(kprobe_opcode_t));
@@ -272,45 +261,23 @@ static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
collect_garbage_slots(c);
} else
collect_one_slot(kip, idx);
- return;
+ goto out;
}
}
/* Could not free this slot. */
WARN_ON(1);
+out:
+ mutex_unlock(&c->mutex);
}
-void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
-{
- mutex_lock(&kprobe_insn_mutex);
- __free_insn_slot(&kprobe_insn_slots, slot, dirty);
- mutex_unlock(&kprobe_insn_mutex);
-}
#ifdef CONFIG_OPTPROBES
/* For optimized_kprobe buffer */
-static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
-static struct kprobe_insn_cache kprobe_optinsn_slots = {
+struct kprobe_insn_cache kprobe_optinsn_slots = {
+ .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
/* .insn_size is initialized later */
.nr_garbage = 0,
};
-/* Get a slot for optimized_kprobe buffer */
-kprobe_opcode_t __kprobes *get_optinsn_slot(void)
-{
- kprobe_opcode_t *ret = NULL;
-
- mutex_lock(&kprobe_optinsn_mutex);
- ret = __get_insn_slot(&kprobe_optinsn_slots);
- mutex_unlock(&kprobe_optinsn_mutex);
-
- return ret;
-}
-
-void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
-{
- mutex_lock(&kprobe_optinsn_mutex);
- __free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
- mutex_unlock(&kprobe_optinsn_mutex);
-}
#endif
#endif
--
1.7.10.4
--
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