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linux/include/asm-ia64/kprobes.h
Rusty Lynch 9508dbfe39 [PATCH] Return probe redesign: ia64 specific implementation 
The following patch implements function return probes for ia64 using
the revised design.  With this new design we no longer need to do some
of the odd hacks previous required on the last ia64 return probe port
that I sent out for comments.

Note that this new implementation still does not resolve the problem noted
by Keith Owens where backtrace data is lost after a return probe is hit.

Changes include:
 * Addition of kretprobe_trampoline to act as a dummy function for instrumented
   functions to return to, and for the return probe infrastructure to place
   a kprobe on on, gaining control so that the return probe handler
   can be called, and so that the instruction pointer can be moved back
   to the original return address.
 * Addition of arch_init(), allowing a kprobe to be registered on
   kretprobe_trampoline
 * Addition of trampoline_probe_handler() which is used as the pre_handler
   for the kprobe inserted on kretprobe_implementation.  This is the function
   that handles the details for calling the return probe handler function
   and returning control back at the original return address
 * Addition of arch_prepare_kretprobe() which is setup as the pre_handler
   for a kprobe registered at the beginning of the target function by
   kernel/kprobes.c so that a return probe instance can be setup when
   a caller enters the target function.  (A return probe instance contains
   all the needed information for trampoline_probe_handler to do it's job.)
 * Hooks added to the exit path of a task so that we can cleanup any left-over
   return probe instances (i.e. if a task dies while inside a targeted function
   then the return probe instance was reserved at the beginning of the function
   but the function never returns so we need to mark the instance as unused.)

Signed-off-by: Rusty Lynch <rusty.lynch@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-27 15:23:53 -07:00

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#ifndef _ASM_KPROBES_H
#define _ASM_KPROBES_H
/*
* Kernel Probes (KProbes)
* include/asm-ia64/kprobes.h
*
* 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) IBM Corporation, 2002, 2004
* Copyright (C) Intel Corporation, 2005
*
* 2005-Apr Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
* <anil.s.keshavamurthy@intel.com> adapted from i386
*/
#include <linux/types.h>
#include <linux/ptrace.h>
#include <asm/break.h>
#define MAX_INSN_SIZE 16
#define BREAK_INST (long)(__IA64_BREAK_KPROBE << 6)
typedef union cmp_inst {
struct {
unsigned long long qp : 6;
unsigned long long p1 : 6;
unsigned long long c : 1;
unsigned long long r2 : 7;
unsigned long long r3 : 7;
unsigned long long p2 : 6;
unsigned long long ta : 1;
unsigned long long x2 : 2;
unsigned long long tb : 1;
unsigned long long opcode : 4;
unsigned long long reserved : 23;
}f;
unsigned long long l;
} cmp_inst_t;
struct kprobe;
typedef struct _bundle {
struct {
unsigned long long template : 5;
unsigned long long slot0 : 41;
unsigned long long slot1_p0 : 64-46;
} quad0;
struct {
unsigned long long slot1_p1 : 41 - (64-46);
unsigned long long slot2 : 41;
} quad1;
} __attribute__((__aligned__(16))) bundle_t;
#define JPROBE_ENTRY(pentry) (kprobe_opcode_t *)pentry
#define ARCH_SUPPORTS_KRETPROBES
#define SLOT0_OPCODE_SHIFT (37)
#define SLOT1_p1_OPCODE_SHIFT (37 - (64-46))
#define SLOT2_OPCODE_SHIFT (37)
#define INDIRECT_CALL_OPCODE (1)
#define IP_RELATIVE_CALL_OPCODE (5)
#define IP_RELATIVE_BRANCH_OPCODE (4)
#define IP_RELATIVE_PREDICT_OPCODE (7)
#define LONG_BRANCH_OPCODE (0xC)
#define LONG_CALL_OPCODE (0xD)
typedef struct kprobe_opcode {
bundle_t bundle;
} kprobe_opcode_t;
struct fnptr {
unsigned long ip;
unsigned long gp;
};
/* Architecture specific copy of original instruction*/
struct arch_specific_insn {
/* copy of the instruction to be emulated */
kprobe_opcode_t insn;
#define INST_FLAG_FIX_RELATIVE_IP_ADDR 1
#define INST_FLAG_FIX_BRANCH_REG 2
unsigned long inst_flag;
unsigned short target_br_reg;
};
/* ia64 does not need this */
static inline void arch_copy_kprobe(struct kprobe *p)
{
}
#ifdef CONFIG_KPROBES
extern int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data);
/* ia64 does not need this */
static inline void jprobe_return(void)
{
}
#else /* !CONFIG_KPROBES */
static inline int kprobe_exceptions_notify(struct notifier_block *self,
unsigned long val, void *data)
{
return 0;
}
#endif
#endif /* _ASM_KPROBES_H */
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