|
|
@@ -0,0 +1,93 @@
|
|
|
+/*
|
|
|
+ * Dynamic Ftrace based Kprobes Optimization
|
|
|
+ *
|
|
|
+ * This program is free software; you can redistribute it and/or modify
|
|
|
+ * it under the terms of the GNU General Public License as published by
|
|
|
+ * the Free Software Foundation; either version 2 of the License, or
|
|
|
+ * (at your option) any later version.
|
|
|
+ *
|
|
|
+ * This program is distributed in the hope that it will be useful,
|
|
|
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
+ * GNU General Public License for more details.
|
|
|
+ *
|
|
|
+ * You should have received a copy of the GNU General Public License
|
|
|
+ * along with this program; if not, write to the Free Software
|
|
|
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
|
+ *
|
|
|
+ * Copyright (C) Hitachi Ltd., 2012
|
|
|
+ */
|
|
|
+#include <linux/kprobes.h>
|
|
|
+#include <linux/ptrace.h>
|
|
|
+#include <linux/hardirq.h>
|
|
|
+#include <linux/preempt.h>
|
|
|
+#include <linux/ftrace.h>
|
|
|
+
|
|
|
+#include "kprobes-common.h"
|
|
|
+
|
|
|
+static int __skip_singlestep(struct kprobe *p, struct pt_regs *regs,
|
|
|
+ struct kprobe_ctlblk *kcb)
|
|
|
+{
|
|
|
+ /*
|
|
|
+ * Emulate singlestep (and also recover regs->ip)
|
|
|
+ * as if there is a 5byte nop
|
|
|
+ */
|
|
|
+ regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
|
|
|
+ if (unlikely(p->post_handler)) {
|
|
|
+ kcb->kprobe_status = KPROBE_HIT_SSDONE;
|
|
|
+ p->post_handler(p, regs, 0);
|
|
|
+ }
|
|
|
+ __this_cpu_write(current_kprobe, NULL);
|
|
|
+ return 1;
|
|
|
+}
|
|
|
+
|
|
|
+int __kprobes skip_singlestep(struct kprobe *p, struct pt_regs *regs,
|
|
|
+ struct kprobe_ctlblk *kcb)
|
|
|
+{
|
|
|
+ if (kprobe_ftrace(p))
|
|
|
+ return __skip_singlestep(p, regs, kcb);
|
|
|
+ else
|
|
|
+ return 0;
|
|
|
+}
|
|
|
+
|
|
|
+/* Ftrace callback handler for kprobes */
|
|
|
+void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
|
|
|
+ struct ftrace_ops *ops, struct pt_regs *regs)
|
|
|
+{
|
|
|
+ struct kprobe *p;
|
|
|
+ struct kprobe_ctlblk *kcb;
|
|
|
+ unsigned long flags;
|
|
|
+
|
|
|
+ /* Disable irq for emulating a breakpoint and avoiding preempt */
|
|
|
+ local_irq_save(flags);
|
|
|
+
|
|
|
+ p = get_kprobe((kprobe_opcode_t *)ip);
|
|
|
+ if (unlikely(!p) || kprobe_disabled(p))
|
|
|
+ goto end;
|
|
|
+
|
|
|
+ kcb = get_kprobe_ctlblk();
|
|
|
+ if (kprobe_running()) {
|
|
|
+ kprobes_inc_nmissed_count(p);
|
|
|
+ } else {
|
|
|
+ /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
|
|
|
+ regs->ip = ip + sizeof(kprobe_opcode_t);
|
|
|
+
|
|
|
+ __this_cpu_write(current_kprobe, p);
|
|
|
+ kcb->kprobe_status = KPROBE_HIT_ACTIVE;
|
|
|
+ if (!p->pre_handler || !p->pre_handler(p, regs))
|
|
|
+ __skip_singlestep(p, regs, kcb);
|
|
|
+ /*
|
|
|
+ * If pre_handler returns !0, it sets regs->ip and
|
|
|
+ * resets current kprobe.
|
|
|
+ */
|
|
|
+ }
|
|
|
+end:
|
|
|
+ local_irq_restore(flags);
|
|
|
+}
|
|
|
+
|
|
|
+int __kprobes arch_prepare_kprobe_ftrace(struct kprobe *p)
|
|
|
+{
|
|
|
+ p->ainsn.insn = NULL;
|
|
|
+ p->ainsn.boostable = -1;
|
|
|
+ return 0;
|
|
|
+}
|
Masami Hiramatsu