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Merge branch 'topic/kprobes' into next
Although most of these kprobes patches are powerpc specific, there's a couple that touch generic code (with Acks). At the moment there's one conflict with acme's tree, but it's not too bad. Still just in case some other conflicts show up, we've put these in a topic branch so another tree could merge some or all of it if necessary.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,104 @@ | ||
| /* | ||
| * 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 | ||
| * Copyright 2016 Naveen N. Rao <[email protected]> | ||
| * IBM Corporation | ||
| */ | ||
| #include <linux/kprobes.h> | ||
| #include <linux/ptrace.h> | ||
| #include <linux/hardirq.h> | ||
| #include <linux/preempt.h> | ||
| #include <linux/ftrace.h> | ||
|
|
||
| static nokprobe_inline | ||
| int __skip_singlestep(struct kprobe *p, struct pt_regs *regs, | ||
| struct kprobe_ctlblk *kcb, unsigned long orig_nip) | ||
| { | ||
| /* | ||
| * Emulate singlestep (and also recover regs->nip) | ||
| * as if there is a nop | ||
| */ | ||
| regs->nip = (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); | ||
| if (orig_nip) | ||
| regs->nip = orig_nip; | ||
| return 1; | ||
| } | ||
|
|
||
| int skip_singlestep(struct kprobe *p, struct pt_regs *regs, | ||
| struct kprobe_ctlblk *kcb) | ||
| { | ||
| if (kprobe_ftrace(p)) | ||
| return __skip_singlestep(p, regs, kcb, 0); | ||
| else | ||
| return 0; | ||
| } | ||
| NOKPROBE_SYMBOL(skip_singlestep); | ||
|
|
||
| /* Ftrace callback handler for kprobes */ | ||
| void kprobe_ftrace_handler(unsigned long nip, unsigned long parent_nip, | ||
| 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); | ||
| hard_irq_disable(); | ||
|
|
||
| p = get_kprobe((kprobe_opcode_t *)nip); | ||
| if (unlikely(!p) || kprobe_disabled(p)) | ||
| goto end; | ||
|
|
||
| kcb = get_kprobe_ctlblk(); | ||
| if (kprobe_running()) { | ||
| kprobes_inc_nmissed_count(p); | ||
| } else { | ||
| unsigned long orig_nip = regs->nip; | ||
|
|
||
| /* | ||
| * On powerpc, NIP is *before* this instruction for the | ||
| * pre handler | ||
| */ | ||
| regs->nip -= MCOUNT_INSN_SIZE; | ||
|
|
||
| __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, orig_nip); | ||
| /* | ||
| * If pre_handler returns !0, it sets regs->nip and | ||
| * resets current kprobe. | ||
| */ | ||
| } | ||
| end: | ||
| local_irq_restore(flags); | ||
| } | ||
| NOKPROBE_SYMBOL(kprobe_ftrace_handler); | ||
|
|
||
| int arch_prepare_kprobe_ftrace(struct kprobe *p) | ||
| { | ||
| p->ainsn.insn = NULL; | ||
| p->ainsn.boostable = -1; | ||
| return 0; | ||
| } |
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