linux/arch/mips/include/asm/kprobes.h
Maneesh Soni 6457a396bb MIPS Kprobes: Support branch instructions probing
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>
2011-12-07 22:04:03 +00:00

98 lines
2.6 KiB
C

/*
* Kernel Probes (KProbes)
* include/asm-mips/kprobes.h
*
* Copyright 2006 Sony Corp.
* Copyright 2010 Cavium Networks
*
* 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; version 2 of the License.
*
* 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
*/
#ifndef _ASM_KPROBES_H
#define _ASM_KPROBES_H
#include <linux/ptrace.h>
#include <linux/types.h>
#include <asm/cacheflush.h>
#include <asm/kdebug.h>
#include <asm/inst.h>
#define __ARCH_WANT_KPROBES_INSN_SLOT
struct kprobe;
struct pt_regs;
typedef union mips_instruction kprobe_opcode_t;
#define MAX_INSN_SIZE 2
#define flush_insn_slot(p) \
do { \
flush_icache_range((unsigned long)p->addr, \
(unsigned long)p->addr + \
(MAX_INSN_SIZE * sizeof(kprobe_opcode_t))); \
} while (0)
#define kretprobe_blacklist_size 0
void arch_remove_kprobe(struct kprobe *p);
/* Architecture specific copy of original instruction*/
struct arch_specific_insn {
/* copy of the original instruction */
kprobe_opcode_t *insn;
};
struct prev_kprobe {
struct kprobe *kp;
unsigned long status;
unsigned long old_SR;
unsigned long saved_SR;
unsigned long saved_epc;
};
#define MAX_JPROBES_STACK_SIZE 128
#define MAX_JPROBES_STACK_ADDR \
(((unsigned long)current_thread_info()) + THREAD_SIZE - 32 - sizeof(struct pt_regs))
#define MIN_JPROBES_STACK_SIZE(ADDR) \
((((ADDR) + MAX_JPROBES_STACK_SIZE) > MAX_JPROBES_STACK_ADDR) \
? MAX_JPROBES_STACK_ADDR - (ADDR) \
: MAX_JPROBES_STACK_SIZE)
#define SKIP_DELAYSLOT 0x0001
/* per-cpu kprobe control block */
struct kprobe_ctlblk {
unsigned long kprobe_status;
unsigned long kprobe_old_SR;
unsigned long kprobe_saved_SR;
unsigned long kprobe_saved_epc;
unsigned long jprobe_saved_sp;
struct pt_regs jprobe_saved_regs;
/* Per-thread fields, used while emulating branches */
unsigned long flags;
unsigned long target_epc;
u8 jprobes_stack[MAX_JPROBES_STACK_SIZE];
struct prev_kprobe prev_kprobe;
};
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
#endif /* _ASM_KPROBES_H */