6457a396bb
This patch provides support for kprobes on branch instructions. The branch instruction at the probed address is actually emulated and not executed out-of-line like other normal instructions. Instead the delay-slot instruction is copied and single stepped out of line. At the time of probe hit, the original branch instruction is evaluated and the target cp0_epc is computed similar to compute_retrun_epc(). It is also checked if the delay slot instruction can be skipped, which is true if there is a NOP in delay slot or branch is taken in case of branch likely instructions. Once the delay slot instruction is single stepped the normal execution resume with the cp0_epc updated the earlier computed cp0_epc as per the branch instructions. Signed-off-by: Maneesh Soni <manesoni@cisco.com> Signed-off-by: Victor Kamensky <kamensky@cisco.com> Cc: David Daney <david.daney@cavium.com> Cc: ananth@in.ibm.com Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/2914/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
97 lines
2.6 KiB
C
97 lines
2.6 KiB
C
/*
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* Kernel Probes (KProbes)
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* include/asm-mips/kprobes.h
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*
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* Copyright 2006 Sony Corp.
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* Copyright 2010 Cavium Networks
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _ASM_KPROBES_H
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#define _ASM_KPROBES_H
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#include <linux/ptrace.h>
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#include <linux/types.h>
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#include <asm/cacheflush.h>
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#include <asm/kdebug.h>
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#include <asm/inst.h>
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#define __ARCH_WANT_KPROBES_INSN_SLOT
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struct kprobe;
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struct pt_regs;
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typedef union mips_instruction kprobe_opcode_t;
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#define MAX_INSN_SIZE 2
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#define flush_insn_slot(p) \
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do { \
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flush_icache_range((unsigned long)p->addr, \
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(unsigned long)p->addr + \
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(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \
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} while (0)
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#define kretprobe_blacklist_size 0
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void arch_remove_kprobe(struct kprobe *p);
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/* Architecture specific copy of original instruction*/
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struct arch_specific_insn {
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/* copy of the original instruction */
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kprobe_opcode_t *insn;
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};
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struct prev_kprobe {
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struct kprobe *kp;
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unsigned long status;
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unsigned long old_SR;
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unsigned long saved_SR;
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unsigned long saved_epc;
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};
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#define MAX_JPROBES_STACK_SIZE 128
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#define MAX_JPROBES_STACK_ADDR \
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(((unsigned long)current_thread_info()) + THREAD_SIZE - 32 - sizeof(struct pt_regs))
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#define MIN_JPROBES_STACK_SIZE(ADDR) \
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((((ADDR) + MAX_JPROBES_STACK_SIZE) > MAX_JPROBES_STACK_ADDR) \
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? MAX_JPROBES_STACK_ADDR - (ADDR) \
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: MAX_JPROBES_STACK_SIZE)
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#define SKIP_DELAYSLOT 0x0001
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/* per-cpu kprobe control block */
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struct kprobe_ctlblk {
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unsigned long kprobe_status;
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unsigned long kprobe_old_SR;
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unsigned long kprobe_saved_SR;
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unsigned long kprobe_saved_epc;
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unsigned long jprobe_saved_sp;
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struct pt_regs jprobe_saved_regs;
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/* Per-thread fields, used while emulating branches */
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unsigned long flags;
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unsigned long target_epc;
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u8 jprobes_stack[MAX_JPROBES_STACK_SIZE];
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struct prev_kprobe prev_kprobe;
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};
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extern int kprobe_exceptions_notify(struct notifier_block *self,
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unsigned long val, void *data);
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#endif /* _ASM_KPROBES_H */
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