kprobe_opcode_t opcode;
kprobe_opcode_t *orig_opcodes = opcodes;
+ if (search_exception_tables((unsigned long)opcodes))
+ return 0; /* Page fault may occur on this address. */
+
retry:
if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
return 0;
void __kprobes arch_remove_kprobe(struct kprobe *p)
{
- mutex_lock(&kprobe_mutex);
- free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
- mutex_unlock(&kprobe_mutex);
+ if (p->ainsn.insn) {
+ free_insn_slot(p->ainsn.insn, (p->ainsn.boostable == 1));
+ p->ainsn.insn = NULL;
+ }
}
static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
static void __kprobes clear_btf(void)
{
if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsr(MSR_IA32_DEBUGCTLMSR, 0, 0);
+ update_debugctlmsr(0);
}
static void __kprobes restore_btf(void)
{
if (test_thread_flag(TIF_DEBUGCTLMSR))
- wrmsr(MSR_IA32_DEBUGCTLMSR, current->thread.debugctlmsr, 0);
+ update_debugctlmsr(current->thread.debugctlmsr);
}
static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
regs->ip = (unsigned long)p->ainsn.insn;
}
-/* Called with kretprobe_lock held */
void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
struct pt_regs *regs)
{
/* Replace the return addr with trampoline addr */
*sara = (unsigned long) &kretprobe_trampoline;
}
+
+static void __kprobes setup_singlestep(struct kprobe *p, struct pt_regs *regs,
+ struct kprobe_ctlblk *kcb)
+{
+#if !defined(CONFIG_PREEMPT) || defined(CONFIG_FREEZER)
+ if (p->ainsn.boostable == 1 && !p->post_handler) {
+ /* Boost up -- we can execute copied instructions directly */
+ reset_current_kprobe();
+ regs->ip = (unsigned long)p->ainsn.insn;
+ preempt_enable_no_resched();
+ return;
+ }
+#endif
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_HIT_SS;
+}
+
/*
* We have reentered the kprobe_handler(), since another probe was hit while
* within the handler. We save the original kprobes variables and just single
static int __kprobes reenter_kprobe(struct kprobe *p, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
- if (kcb->kprobe_status == KPROBE_HIT_SS &&
- *p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
- regs->flags &= ~X86_EFLAGS_TF;
- regs->flags |= kcb->kprobe_saved_flags;
- return 0;
+ switch (kcb->kprobe_status) {
+ case KPROBE_HIT_SSDONE:
#ifdef CONFIG_X86_64
- } else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
/* TODO: Provide re-entrancy from post_kprobes_handler() and
* avoid exception stack corruption while single-stepping on
* the instruction of the new probe.
arch_disarm_kprobe(p);
regs->ip = (unsigned long)p->addr;
reset_current_kprobe();
- return 1;
+ preempt_enable_no_resched();
+ break;
#endif
+ case KPROBE_HIT_ACTIVE:
+ save_previous_kprobe(kcb);
+ set_current_kprobe(p, regs, kcb);
+ kprobes_inc_nmissed_count(p);
+ prepare_singlestep(p, regs);
+ kcb->kprobe_status = KPROBE_REENTER;
+ break;
+ case KPROBE_HIT_SS:
+ if (p == kprobe_running()) {
+ regs->flags &= ~X86_EFLAGS_TF;
+ regs->flags |= kcb->kprobe_saved_flags;
+ return 0;
+ } else {
+ /* A probe has been hit in the codepath leading up
+ * to, or just after, single-stepping of a probed
+ * instruction. This entire codepath should strictly
+ * reside in .kprobes.text section. Raise a warning
+ * to highlight this peculiar case.
+ */
+ }
+ default:
+ /* impossible cases */
+ WARN_ON(1);
+ return 0;
}
- save_previous_kprobe(kcb);
- set_current_kprobe(p, regs, kcb);
- kprobes_inc_nmissed_count(p);
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_REENTER;
+
return 1;
}
*/
static int __kprobes kprobe_handler(struct pt_regs *regs)
{
- struct kprobe *p;
- int ret = 0;
kprobe_opcode_t *addr;
+ struct kprobe *p;
struct kprobe_ctlblk *kcb;
addr = (kprobe_opcode_t *)(regs->ip - sizeof(kprobe_opcode_t));
+ if (*addr != BREAKPOINT_INSTRUCTION) {
+ /*
+ * The breakpoint instruction was removed right
+ * after we hit it. Another cpu has removed
+ * either a probepoint or a debugger breakpoint
+ * at this address. In either case, no further
+ * handling of this interrupt is appropriate.
+ * Back up over the (now missing) int3 and run
+ * the original instruction.
+ */
+ regs->ip = (unsigned long)addr;
+ return 1;
+ }
/*
* We don't want to be preempted for the entire
- * duration of kprobe processing
+ * duration of kprobe processing. We conditionally
+ * re-enable preemption at the end of this function,
+ * and also in reenter_kprobe() and setup_singlestep().
*/
preempt_disable();
- kcb = get_kprobe_ctlblk();
+ kcb = get_kprobe_ctlblk();
p = get_kprobe(addr);
+
if (p) {
- /* Check we're not actually recursing */
if (kprobe_running()) {
- ret = reenter_kprobe(p, regs, kcb);
- if (kcb->kprobe_status == KPROBE_REENTER)
- {
- ret = 1;
- goto out;
- }
- goto preempt_out;
+ if (reenter_kprobe(p, regs, kcb))
+ return 1;
} else {
set_current_kprobe(p, regs, kcb);
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
- if (p->pre_handler && p->pre_handler(p, regs))
- {
- /* handler set things up, skip ss setup */
- ret = 1;
- goto out;
- }
- }
- } else {
- if (*addr != BREAKPOINT_INSTRUCTION) {
+
/*
- * The breakpoint instruction was removed right
- * after we hit it. Another cpu has removed
- * either a probepoint or a debugger breakpoint
- * at this address. In either case, no further
- * handling of this interrupt is appropriate.
- * Back up over the (now missing) int3 and run
- * the original instruction.
+ * If we have no pre-handler or it returned 0, we
+ * continue with normal processing. If we have a
+ * pre-handler and it returned non-zero, it prepped
+ * for calling the break_handler below on re-entry
+ * for jprobe processing, so get out doing nothing
+ * more here.
*/
- regs->ip = (unsigned long)addr;
- ret = 1;
- goto preempt_out;
+ if (!p->pre_handler || !p->pre_handler(p, regs))
+ setup_singlestep(p, regs, kcb);
+ return 1;
}
- if (kprobe_running()) {
- p = __get_cpu_var(current_kprobe);
- if (p->break_handler && p->break_handler(p, regs))
- goto ss_probe;
+ } else if (kprobe_running()) {
+ p = __get_cpu_var(current_kprobe);
+ if (p->break_handler && p->break_handler(p, regs)) {
+ setup_singlestep(p, regs, kcb);
+ return 1;
}
- /* Not one of ours: let kernel handle it */
- goto preempt_out;
- }
+ } /* else: not a kprobe fault; let the kernel handle it */
-ss_probe:
- ret = 1;
-#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PM)
- if (p->ainsn.boostable == 1 && !p->post_handler) {
- /* Boost up -- we can execute copied instructions directly */
- reset_current_kprobe();
- regs->ip = (unsigned long)p->ainsn.insn;
- goto preempt_out;
- }
-#endif
- prepare_singlestep(p, regs);
- kcb->kprobe_status = KPROBE_HIT_SS;
- goto out;
-
-preempt_out:
preempt_enable_no_resched();
-out:
- return ret;
+ return 0;
}
/*
* When a retprobed function returns, this code saves registers and
* calls trampoline_handler() runs, which calls the kretprobe's handler.
*/
- void __kprobes kretprobe_trampoline_holder(void)
- {
+static void __used __kprobes kretprobe_trampoline_holder(void)
+{
asm volatile (
".global kretprobe_trampoline\n"
"kretprobe_trampoline: \n"
#else
" pushf\n"
/*
- * Skip cs, ip, orig_ax.
+ * Skip cs, ip, orig_ax and gs.
* trampoline_handler() will plug in these values
*/
- " subl $12, %esp\n"
+ " subl $16, %esp\n"
" pushl %fs\n"
- " pushl %ds\n"
" pushl %es\n"
+ " pushl %ds\n"
" pushl %eax\n"
" pushl %ebp\n"
" pushl %edi\n"
" movl %esp, %eax\n"
" call trampoline_handler\n"
/* Move flags to cs */
- " movl 52(%esp), %edx\n"
- " movl %edx, 48(%esp)\n"
+ " movl 56(%esp), %edx\n"
+ " movl %edx, 52(%esp)\n"
/* Replace saved flags with true return address. */
- " movl %eax, 52(%esp)\n"
+ " movl %eax, 56(%esp)\n"
" popl %ebx\n"
" popl %ecx\n"
" popl %edx\n"
" popl %edi\n"
" popl %ebp\n"
" popl %eax\n"
- /* Skip ip, orig_ax, es, ds, fs */
- " addl $20, %esp\n"
+ /* Skip ds, es, fs, gs, orig_ax and ip */
+ " addl $24, %esp\n"
" popf\n"
#endif
" ret\n");
- }
+}
/*
* Called from kretprobe_trampoline
*/
-void * __kprobes trampoline_handler(struct pt_regs *regs)
+static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
{
struct kretprobe_instance *ri = NULL;
struct hlist_head *head, empty_rp;
unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;
INIT_HLIST_HEAD(&empty_rp);
- spin_lock_irqsave(&kretprobe_lock, flags);
- head = kretprobe_inst_table_head(current);
+ kretprobe_hash_lock(current, &head, &flags);
/* fixup registers */
#ifdef CONFIG_X86_64
regs->cs = __KERNEL_CS;
#else
regs->cs = __KERNEL_CS | get_kernel_rpl();
+ regs->gs = 0;
#endif
regs->ip = trampoline_address;
regs->orig_ax = ~0UL;
/*
* It is possible to have multiple instances associated with a given
* task either because multiple functions in the call path have
- * return probes installed on them, and/or more then one
+ * return probes installed on them, and/or more than one
* return probe was registered for a target function.
*
* We can handle this because:
kretprobe_assert(ri, orig_ret_address, trampoline_address);
- spin_unlock_irqrestore(&kretprobe_lock, flags);
+ kretprobe_hash_unlock(current, &flags);
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
hlist_del(&ri->hlist);
if (!cur)
return 0;
+ resume_execution(cur, regs, kcb);
+ regs->flags |= kcb->kprobe_saved_flags;
+
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
- resume_execution(cur, regs, kcb);
- regs->flags |= kcb->kprobe_saved_flags;
- trace_hardirqs_fixup_flags(regs->flags);
-
/* Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER) {
restore_previous_kprobe(kcb);
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
- struct die_args *args = (struct die_args *)data;
+ struct die_args *args = data;
int ret = NOTIFY_DONE;
if (args->regs && user_mode_vm(args->regs))
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff