Eric Lee / linux-smarc-t335x-v3.2

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Commit 129415607845d4daea11ddcba706005c69dcb942

Authored by Masami Hiramatsu
Committed by Linus Torvalds
1 parent a06f6211ef
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

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>

Showing 7 changed files with 38 additions and 19 deletions Side-by-side Diff

arch/arm/kernel/kprobes.c
Diff comments   View file @ 1294156
... ... @@ -92,9 +92,7 @@
92 92 void __kprobes arch_remove_kprobe(struct kprobe *p)
93 93 {
94 94 if (p->ainsn.insn) {
95   - mutex_lock(&kprobe_mutex);
96 95 free_insn_slot(p->ainsn.insn, 0);
97   - mutex_unlock(&kprobe_mutex);
98 96 p->ainsn.insn = NULL;
99 97 }
100 98 }
arch/ia64/kernel/kprobes.c
Diff comments   View file @ 1294156
... ... @@ -670,9 +670,11 @@
670 670  
671 671 void __kprobes arch_remove_kprobe(struct kprobe *p)
672 672 {
673   - mutex_lock(&kprobe_mutex);
674   - free_insn_slot(p->ainsn.insn, p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
675   - mutex_unlock(&kprobe_mutex);
  673 + if (p->ainsn.insn) {
  674 + free_insn_slot(p->ainsn.insn,
  675 + p->ainsn.inst_flag & INST_FLAG_BOOSTABLE);
  676 + p->ainsn.insn = NULL;
  677 + }
676 678 }
677 679 /*
678 680 * We are resuming execution after a single step fault, so the pt_regs
arch/powerpc/kernel/kprobes.c
Diff comments   View file @ 1294156
... ... @@ -96,9 +96,10 @@
96 96  
97 97 void __kprobes arch_remove_kprobe(struct kprobe *p)
98 98 {
99   - mutex_lock(&kprobe_mutex);
100   - free_insn_slot(p->ainsn.insn, 0);
101   - mutex_unlock(&kprobe_mutex);
  99 + if (p->ainsn.insn) {
  100 + free_insn_slot(p->ainsn.insn, 0);
  101 + p->ainsn.insn = NULL;
  102 + }
102 103 }
103 104  
104 105 static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
arch/s390/kernel/kprobes.c
Diff comments   View file @ 1294156
... ... @@ -218,9 +218,10 @@
218 218  
219 219 void __kprobes arch_remove_kprobe(struct kprobe *p)
220 220 {
221   - mutex_lock(&kprobe_mutex);
222   - free_insn_slot(p->ainsn.insn, 0);
223   - mutex_unlock(&kprobe_mutex);
  221 + if (p->ainsn.insn) {
  222 + free_insn_slot(p->ainsn.insn, 0);
  223 + p->ainsn.insn = NULL;
  224 + }
224 225 }
225 226  
226 227 static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
arch/x86/kernel/kprobes.c
Diff comments   View file @ 1294156
... ... @@ -376,9 +376,10 @@
376 376  
377 377 void __kprobes arch_remove_kprobe(struct kprobe *p)
378 378 {
379   - mutex_lock(&kprobe_mutex);
380   - free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
381   - mutex_unlock(&kprobe_mutex);
  379 + if (p->ainsn.insn) {
  380 + free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
  381 + p->ainsn.insn = NULL;
  382 + }
382 383 }
383 384  
384 385 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
include/linux/kprobes.h
Diff comments   View file @ 1294156
... ... @@ -201,7 +201,6 @@
201 201 }
202 202 #endif /* CONFIG_KPROBES_SANITY_TEST */
203 203  
204   -extern struct mutex kprobe_mutex;
205 204 extern int arch_prepare_kprobe(struct kprobe *p);
206 205 extern void arch_arm_kprobe(struct kprobe *p);
207 206 extern void arch_disarm_kprobe(struct kprobe *p);
... ... @@ -69,7 +69,7 @@
69 69 /* NOTE: change this value only with kprobe_mutex held */
70 70 static bool kprobe_enabled;
71 71  
72   -DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
  72 +static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
73 73 static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
74 74 static struct {
75 75 spinlock_t lock ____cacheline_aligned_in_smp;
... ... @@ -115,6 +115,7 @@
115 115 SLOT_USED = 2,
116 116 };
117 117  
  118 +static DEFINE_MUTEX(kprobe_insn_mutex); /* Protects kprobe_insn_pages */
118 119 static struct hlist_head kprobe_insn_pages;
119 120 static int kprobe_garbage_slots;
120 121 static int collect_garbage_slots(void);
121 122  
... ... @@ -144,10 +145,10 @@
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.
148 149 * We allocate an executable page if there's no room on existing ones.
149 150 */
150   -kprobe_opcode_t __kprobes *get_insn_slot(void)
  151 +static kprobe_opcode_t __kprobes *__get_insn_slot(void)
151 152 {
152 153 struct kprobe_insn_page *kip;
153 154 struct hlist_node *pos;
... ... @@ -196,6 +197,15 @@
196 197 return kip->insns;
197 198 }
198 199  
  200 +kprobe_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 +
199 209 /* Return 1 if all garbages are collected, otherwise 0. */
200 210 static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
201 211 {
202 212  
... ... @@ -226,9 +236,13 @@
226 236 {
227 237 struct kprobe_insn_page *kip;
228 238 struct hlist_node *pos, *next;
  239 + int safety;
229 240  
230 241 /* 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)
232 246 return -EAGAIN;
233 247  
234 248 hlist_for_each_entry_safe(kip, pos, next, &kprobe_insn_pages, hlist) {
... ... @@ -251,6 +265,7 @@
251 265 struct kprobe_insn_page *kip;
252 266 struct hlist_node *pos;
253 267  
  268 + mutex_lock(&kprobe_insn_mutex);
254 269 hlist_for_each_entry(kip, pos, &kprobe_insn_pages, hlist) {
255 270 if (kip->insns <= slot &&
256 271 slot < kip->insns + (INSNS_PER_PAGE * MAX_INSN_SIZE)) {
... ... @@ -267,6 +282,8 @@
267 282  
268 283 if (dirty && ++kprobe_garbage_slots > INSNS_PER_PAGE)
269 284 collect_garbage_slots();
  285 +
  286 + mutex_unlock(&kprobe_insn_mutex);
270 287 }
271 288 #endif
272 289