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authorMasami Hiramatsu <mhiramat@redhat.com>2009-01-06 17:41:50 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-06 18:59:20 -0500
commit129415607845d4daea11ddcba706005c69dcb942 (patch)
tree9046ea79a0b81c8823b9d42f00fd7c158861ed5c /kernel
parenta06f6211ef9b1785922f9d0e8766d63ac4e66de1 (diff)
kprobes: add kprobe_insn_mutex and cleanup arch_remove_kprobe()
Add kprobe_insn_mutex for protecting kprobe_insn_pages hlist, and remove kprobe_mutex from architecture dependent code. This allows us to call arch_remove_kprobe() (and free_insn_slot) while holding kprobe_mutex. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c25
1 files changed, 21 insertions, 4 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 3afd354c46f1..29e87921437d 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -69,7 +69,7 @@ static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
69/* NOTE: change this value only with kprobe_mutex held */ 69/* NOTE: change this value only with kprobe_mutex held */
70static bool kprobe_enabled; 70static bool kprobe_enabled;
71 71
72DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ 72static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
73static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; 73static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
74static struct { 74static struct {
75 spinlock_t lock ____cacheline_aligned_in_smp; 75 spinlock_t lock ____cacheline_aligned_in_smp;
@@ -115,6 +115,7 @@ enum kprobe_slot_state {
115 SLOT_USED = 2, 115 SLOT_USED = 2,
116}; 116};
117 117
118static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */
118static struct hlist_head kprobe_insn_pages; 119static struct hlist_head kprobe_insn_pages;
119static int kprobe_garbage_slots; 120static int kprobe_garbage_slots;
120static int collect_garbage_slots(void); 121static int collect_garbage_slots(void);
@@ -144,10 +145,10 @@ loop_end:
144} 145}
145 146
146/** 147/**
147 * get_insn_slot() - Find a slot on an executable page for an instruction. 148 * __get_insn_slot() - Find a slot on an executable page for an instruction.
148 * We allocate an executable page if there's no room on existing ones. 149 * We allocate an executable page if there's no room on existing ones.
149 */ 150 */
150kprobe_opcode_t __kprobes *get_insn_slot(void) 151static kprobe_opcode_t __kprobes *__get_insn_slot(void)
151{ 152{
152 struct kprobe_insn_page *kip; 153 struct kprobe_insn_page *kip;
153 struct hlist_node *pos; 154 struct hlist_node *pos;
@@ -196,6 +197,15 @@ kprobe_opcode_t __kprobes *get_insn_slot(void)
196 return kip->insns; 197 return kip->insns;
197} 198}
198 199
200kprobe_opcode_t __kprobes *get_insn_slot(void)
201{
202 kprobe_opcode_t *ret;
203 mutex_lock(&kprobe_insn_mutex);
204 ret = __get_insn_slot();
205 mutex_unlock(&kprobe_insn_mutex);
206 return ret;
207}
208
199/* Return 1 if all garbages are collected, otherwise 0. */ 209/* Return 1 if all garbages are collected, otherwise 0. */
200static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx) 210static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
201{ 211{
@@ -226,9 +236,13 @@ static int __kprobes collect_garbage_slots(void)
226{ 236{
227 struct kprobe_insn_page *kip; 237 struct kprobe_insn_page *kip;
228 struct hlist_node *pos, *next; 238 struct hlist_node *pos, *next;
239 int safety;
229 240
230 /* Ensure no-one is preepmted on the garbages */ 241 /* Ensure no-one is preepmted on the garbages */
231 if (check_safety() != 0) 242 mutex_unlock(&kprobe_insn_mutex);
243 safety = check_safety();
244 mutex_lock(&kprobe_insn_mutex);
245 if (safety != 0)
232 return -EAGAIN; 246 return -EAGAIN;
233 247
234 hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) { 248 hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
@@ -251,6 +265,7 @@ void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
251 struct kprobe_insn_page *kip; 265 struct kprobe_insn_page *kip;
252 struct hlist_node *pos; 266 struct hlist_node *pos;
253 267
268 mutex_lock(&kprobe_insn_mutex);
254 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) { 269 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
255 if (kip->insns <= slot && 270 if (kip->insns <= slot &&
256 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) { 271 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
@@ -267,6 +282,8 @@ void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
267 282
268 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE) 283 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
269 collect_garbage_slots(); 284 collect_garbage_slots();
285
286 mutex_unlock(&kprobe_insn_mutex);
270} 287}
271#endif 288#endif
272 289