From: Masami Hiramatsu <mhiramat@redhat.com>
To: Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@elte.hu>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
lkml<linux-kernel@vger.kernel.org>
Cc: systemtap<systemtap@sources.redhat.com>,
DLE<dle-develop@lists.sourceforge.net>,
Masami Hiramatsu <mhiramat@redhat.com>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Ingo Molnar <mingo@elte.hu>,
Jim Keniston <jkenisto@us.ibm.com>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Christoph Hellwig <hch@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Anders Kaseorg <andersk@ksplice.com>,
Tim Abbott <tabbott@ksplice.com>,
Andi Kleen <andi@firstfloor.org>,
Jason Baron <jbaron@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: [PATCH -tip v5 02/10] kprobes: Introduce generic insn_slot framework
Date: Mon, 23 Nov 2009 23:18:00 -0000 [thread overview]
Message-ID: <20091123232133.22071.78982.stgit@dhcp-100-2-132.bos.redhat.com> (raw)
In-Reply-To: <20091123232115.22071.71558.stgit@dhcp-100-2-132.bos.redhat.com>
Make insn_slot framework support various size slots.
Current insn_slot just supports one-size instruction buffer slot. However,
kprobes jump optimization needs larger size buffers.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Anders Kaseorg <andersk@ksplice.com>
Cc: Tim Abbott <tabbott@ksplice.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
---
kernel/kprobes.c | 102 +++++++++++++++++++++++++++++++++---------------------
1 files changed, 63 insertions(+), 39 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index e5342a3..10d2ed5 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -103,26 +103,42 @@ static struct kprobe_blackpoint kprobe_blacklist[] = {
* stepping on the instruction on a vmalloced/kmalloced/data page
* is a recipe for disaster
*/
-#define INSNS_PER_PAGE (PAGE_SIZE/(MAX_INSN_SIZE * sizeof(kprobe_opcode_t)))
-
struct kprobe_insn_page {
struct list_head list;
kprobe_opcode_t *insns; /* Page of instruction slots */
- char slot_used[INSNS_PER_PAGE];
int nused;
int ngarbage;
+ char slot_used[];
};
+#define KPROBE_INSN_PAGE_SIZE(slots) \
+ (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));
+}
+
enum kprobe_slot_state {
SLOT_CLEAN = 0,
SLOT_DIRTY = 1,
SLOT_USED = 2,
};
-static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */
-static LIST_HEAD(kprobe_insn_pages);
-static int kprobe_garbage_slots;
-static int collect_garbage_slots(void);
+static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_slots */
+static struct kprobe_insn_cache kprobe_insn_slots = {
+ .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
+ .insn_size = MAX_INSN_SIZE,
+ .nr_garbage = 0,
+};
+static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
static int __kprobes check_safety(void)
{
@@ -152,32 +168,33 @@ loop_end:
* __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(void)
+static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
{
struct kprobe_insn_page *kip;
retry:
- list_for_each_entry(kip, &kprobe_insn_pages, list) {
- if (kip->nused < INSNS_PER_PAGE) {
+ list_for_each_entry(kip, &c->pages, list) {
+ if (kip->nused < slots_per_page(c)) {
int i;
- for (i = 0; i < INSNS_PER_PAGE; i++) {
+ for (i = 0; i < slots_per_page(c); i++) {
if (kip->slot_used[i] == SLOT_CLEAN) {
kip->slot_used[i] = SLOT_USED;
kip->nused++;
- return kip->insns + (i * MAX_INSN_SIZE);
+ return kip->insns + (i * c->insn_size);
}
}
- /* Surprise! No unused slots. Fix kip->nused. */
- kip->nused = INSNS_PER_PAGE;
+ /* kip->nused is broken. Fix it. */
+ kip->nused = slots_per_page(c);
+ WARN_ON(1);
}
}
/* If there are any garbage slots, collect it and try again. */
- if (kprobe_garbage_slots && collect_garbage_slots() == 0) {
+ if (c->nr_garbage && collect_garbage_slots(c) == 0)
goto retry;
- }
- /* All out of space. Need to allocate a new page. Use slot 0. */
- kip = kmalloc(sizeof(struct kprobe_insn_page), GFP_KERNEL);
+
+ /* 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;
@@ -192,19 +209,20 @@ static kprobe_opcode_t __kprobes *__get_insn_slot(void)
return NULL;
}
INIT_LIST_HEAD(&kip->list);
- list_add(&kip->list, &kprobe_insn_pages);
- memset(kip->slot_used, SLOT_CLEAN, INSNS_PER_PAGE);
+ memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
kip->slot_used[0] = SLOT_USED;
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;
+ kprobe_opcode_t *ret = NULL;
mutex_lock(&kprobe_insn_mutex);
- ret = __get_insn_slot();
+ ret = __get_insn_slot(&kprobe_insn_slots);
mutex_unlock(&kprobe_insn_mutex);
return ret;
}
@@ -221,7 +239,7 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
* so as not to have to set it up again the
* next time somebody inserts a probe.
*/
- if (!list_is_singular(&kprobe_insn_pages)) {
+ if (!list_is_singular(&kip->list)) {
list_del(&kip->list);
module_free(NULL, kip->insns);
kfree(kip);
@@ -231,7 +249,7 @@ static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
return 0;
}
-static int __kprobes collect_garbage_slots(void)
+static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
{
struct kprobe_insn_page *kip, *next;
@@ -239,42 +257,48 @@ static int __kprobes collect_garbage_slots(void)
if (check_safety())
return -EAGAIN;
- list_for_each_entry_safe(kip, next, &kprobe_insn_pages, list) {
+ list_for_each_entry_safe(kip, next, &c->pages, list) {
int i;
if (kip->ngarbage == 0)
continue;
kip->ngarbage = 0; /* we will collect all garbages */
- for (i = 0; i < INSNS_PER_PAGE; i++) {
+ for (i = 0; i < slots_per_page(c); i++) {
if (kip->slot_used[i] == SLOT_DIRTY &&
collect_one_slot(kip, i))
break;
}
}
- kprobe_garbage_slots = 0;
+ c->nr_garbage = 0;
return 0;
}
-void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
+static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
+ kprobe_opcode_t *slot, int dirty)
{
struct kprobe_insn_page *kip;
- mutex_lock(&kprobe_insn_mutex);
- list_for_each_entry(kip, &kprobe_insn_pages, list) {
- if (kip->insns <= slot &&
- slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
- int i = (slot - kip->insns) / MAX_INSN_SIZE;
+ list_for_each_entry(kip, &c->pages, list) {
+ long idx = ((long)slot - (long)kip->insns) / c->insn_size;
+ if (idx >= 0 && idx < slots_per_page(c)) {
+ WARN_ON(kip->slot_used[idx] != SLOT_USED);
if (dirty) {
- kip->slot_used[i] = SLOT_DIRTY;
+ kip->slot_used[idx] = SLOT_DIRTY;
kip->ngarbage++;
+ if (++c->nr_garbage > slots_per_page(c))
+ collect_garbage_slots(c);
} else
- collect_one_slot(kip, i);
- break;
+ collect_one_slot(kip, idx);
+ return;
}
}
+ /* Could not free this slot. */
+ WARN_ON(1);
+}
- if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
- collect_garbage_slots();
-
+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);
}
#endif
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
next prev parent reply other threads:[~2009-11-23 23:18 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-23 23:18 [PATCH -tip v5 00/10] kprobes: Kprobes jump optimization support Masami Hiramatsu
2009-11-23 23:18 ` Masami Hiramatsu [this message]
2009-11-23 23:18 ` [PATCH -tip v5 01/10] kprobes/x86: Cleanup RELATIVEJUMP_INSTRUCTION to RELATIVEJUMP_OPCODE Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 04/10] kprobes: Jump optimization sysctl interface Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 03/10] kprobes: Introduce kprobes jump optimization Masami Hiramatsu
2009-11-24 2:44 ` Frederic Weisbecker
2009-11-24 3:31 ` Frederic Weisbecker
2009-11-24 15:32 ` Masami Hiramatsu
2009-11-24 20:14 ` Frederic Weisbecker
2009-11-24 20:59 ` Masami Hiramatsu
2009-11-25 21:09 ` Steven Rostedt
2009-11-25 21:30 ` Masami Hiramatsu
2009-11-24 21:12 ` H. Peter Anvin
2009-11-24 15:31 ` Masami Hiramatsu
2009-11-24 19:45 ` Frederic Weisbecker
2009-11-24 21:15 ` Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 07/10] kprobes/x86: Support kprobes jump optimization on x86 Masami Hiramatsu
2009-11-24 3:15 ` Frederic Weisbecker
2009-11-24 16:27 ` Jason Baron
2009-11-24 17:46 ` Masami Hiramatsu
2009-11-25 16:12 ` Masami Hiramatsu
2009-11-24 16:42 ` H. Peter Anvin
2009-11-24 17:01 ` Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 05/10] kprobes/x86: Boost probes when reentering Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 06/10] kprobes/x86: Cleanup save/restore registers Masami Hiramatsu
2009-11-24 2:51 ` Frederic Weisbecker
2009-11-24 15:36 ` Masami Hiramatsu
2009-11-24 20:19 ` Frederic Weisbecker
2009-11-24 15:40 ` Frank Ch. Eigler
2009-11-24 20:20 ` Frederic Weisbecker
2009-11-23 23:19 ` [PATCH -tip v5 10/10] [RFC] kprobes/x86: Use text_poke_fixup() for jump optimization Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 08/10] kprobes: Add documents of " Masami Hiramatsu
2009-11-23 23:19 ` [PATCH -tip v5 09/10] [RFC] x86: Introduce generic jump patching without stop_machine Masami Hiramatsu
2009-11-24 2:03 ` [PATCH -tip v5 00/10] kprobes: Kprobes jump optimization support Frederic Weisbecker
2009-11-24 3:20 ` Frederic Weisbecker
2009-11-24 7:53 ` Ingo Molnar
2009-11-24 16:03 ` Masami Hiramatsu
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