91 lines
2.9 KiB
ArmAsm
91 lines
2.9 KiB
ArmAsm
/*
|
|
* Jprobe specific operations
|
|
*
|
|
* 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) Intel Corporation, 2005
|
|
*
|
|
* 2005-May Rusty Lynch <rusty.lynch@intel.com> and Anil S Keshavamurthy
|
|
* <anil.s.keshavamurthy@intel.com> initial implementation
|
|
*
|
|
* Jprobes (a.k.a. "jump probes" which is built on-top of kprobes) allow a
|
|
* probe to be inserted into the beginning of a function call. The fundamental
|
|
* difference between a jprobe and a kprobe is the jprobe handler is executed
|
|
* in the same context as the target function, while the kprobe handlers
|
|
* are executed in interrupt context.
|
|
*
|
|
* For jprobes we initially gain control by placing a break point in the
|
|
* first instruction of the targeted function. When we catch that specific
|
|
* break, we:
|
|
* * set the return address to our jprobe_inst_return() function
|
|
* * jump to the jprobe handler function
|
|
*
|
|
* Since we fixed up the return address, the jprobe handler will return to our
|
|
* jprobe_inst_return() function, giving us control again. At this point we
|
|
* are back in the parents frame marker, so we do yet another call to our
|
|
* jprobe_break() function to fix up the frame marker as it would normally
|
|
* exist in the target function.
|
|
*
|
|
* Our jprobe_return function then transfers control back to kprobes.c by
|
|
* executing a break instruction using one of our reserved numbers. When we
|
|
* catch that break in kprobes.c, we continue like we do for a normal kprobe
|
|
* by single stepping the emulated instruction, and then returning execution
|
|
* to the correct location.
|
|
*/
|
|
#include <asm/asmmacro.h>
|
|
#include <asm/break.h>
|
|
|
|
/*
|
|
* void jprobe_break(void)
|
|
*/
|
|
.section .kprobes.text, "ax"
|
|
ENTRY(jprobe_break)
|
|
break.m __IA64_BREAK_JPROBE
|
|
END(jprobe_break)
|
|
|
|
/*
|
|
* void jprobe_inst_return(void)
|
|
*/
|
|
GLOBAL_ENTRY(jprobe_inst_return)
|
|
br.call.sptk.many b0=jprobe_break
|
|
END(jprobe_inst_return)
|
|
|
|
GLOBAL_ENTRY(invalidate_stacked_regs)
|
|
movl r16=invalidate_restore_cfm
|
|
;;
|
|
mov b6=r16
|
|
;;
|
|
br.ret.sptk.many b6
|
|
;;
|
|
invalidate_restore_cfm:
|
|
mov r16=ar.rsc
|
|
;;
|
|
mov ar.rsc=r0
|
|
;;
|
|
loadrs
|
|
;;
|
|
mov ar.rsc=r16
|
|
;;
|
|
br.cond.sptk.many rp
|
|
END(invalidate_stacked_regs)
|
|
|
|
GLOBAL_ENTRY(flush_register_stack)
|
|
// flush dirty regs to backing store (must be first in insn group)
|
|
flushrs
|
|
;;
|
|
br.ret.sptk.many rp
|
|
END(flush_register_stack)
|
|
|