2005-04-16 22:20:36 +00:00
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/*
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* Kernel Probes (KProbes)
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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; either version 2 of the License, or
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* (at your option) any later version.
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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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* Copyright (C) IBM Corporation, 2002, 2004
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*
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* 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
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* Probes initial implementation ( includes contributions from
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* Rusty Russell).
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* 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
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* interface to access function arguments.
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* 2004-Nov Ananth N Mavinakayanahalli <ananth@in.ibm.com> kprobes port
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* for PPC64
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*/
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#include <linux/kprobes.h>
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#include <linux/ptrace.h>
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#include <linux/preempt.h>
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2006-03-26 09:38:24 +00:00
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#include <linux/module.h>
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2007-05-08 07:27:03 +00:00
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#include <linux/kdebug.h>
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include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
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#include <linux/slab.h>
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2005-06-23 07:09:25 +00:00
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#include <asm/cacheflush.h>
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2005-04-16 22:20:36 +00:00
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#include <asm/sstep.h>
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2006-03-26 09:38:24 +00:00
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#include <asm/uaccess.h>
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2008-06-26 07:01:37 +00:00
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#include <asm/system.h>
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2010-02-08 11:50:57 +00:00
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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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2008-06-26 07:01:37 +00:00
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#define MSR_SINGLESTEP (MSR_DE)
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#else
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#define MSR_SINGLESTEP (MSR_SE)
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#endif
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2005-04-16 22:20:36 +00:00
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2005-11-07 09:00:10 +00:00
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DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
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DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
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2005-04-16 22:20:36 +00:00
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2007-10-16 08:27:49 +00:00
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struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
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2005-09-06 22:19:29 +00:00
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int __kprobes arch_prepare_kprobe(struct kprobe *p)
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2005-04-16 22:20:36 +00:00
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{
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2005-06-08 22:49:41 +00:00
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int ret = 0;
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2005-04-16 22:20:36 +00:00
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kprobe_opcode_t insn = *p->addr;
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2005-06-08 22:49:41 +00:00
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if ((unsigned long)p->addr & 0x03) {
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printk("Attempt to register kprobe at an unaligned address\n");
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ret = -EINVAL;
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2007-02-07 04:55:19 +00:00
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} else if (IS_MTMSRD(insn) || IS_RFID(insn) || IS_RFI(insn)) {
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printk("Cannot register a kprobe on rfi/rfid or mtmsr[d]\n");
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2005-06-08 22:49:41 +00:00
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ret = -EINVAL;
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}
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2005-06-27 22:17:01 +00:00
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2008-06-26 07:01:37 +00:00
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/* insn must be on a special executable page on ppc64. This is
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* not explicitly required on ppc32 (right now), but it doesn't hurt */
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2005-06-27 22:17:01 +00:00
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if (!ret) {
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2005-10-01 17:14:17 +00:00
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p->ainsn.insn = get_insn_slot();
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2005-06-27 22:17:01 +00:00
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if (!p->ainsn.insn)
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ret = -ENOMEM;
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}
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2005-04-16 22:20:36 +00:00
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2006-01-10 04:52:43 +00:00
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if (!ret) {
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2007-04-18 05:57:51 +00:00
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memcpy(p->ainsn.insn, p->addr,
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MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
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2006-01-10 04:52:43 +00:00
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p->opcode = *p->addr;
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[POWERPC] kprobes: Fix possible system crash during out-of-line single-stepping
- On archs that have no-exec support, we vmalloc() a executable scratch
area of PAGE_SIZE and divide it up into an array of slots of maximum
instruction size for that arch
- On a kprobe registration, the original instruction is copied to the
first available free slot, so if multiple kprobes are registered, chances
are, they get contiguous slots
- On POWER4, due to not having coherent icaches, we could hit a situation
where a probe that is registered on one processor, is hit immediately on
another. This second processor could have fetched the stream of text from
the out-of-line single-stepping area *before* the probe registration
completed, possibly due to an earlier (and a different) kprobe hit and
hence would see stale data at the slot.
Executing such an arbitrary instruction lead to a problem as reported
in LTC bugzilla 23555.
The correct solution is to call flush_icache_range() as soon as the
instruction is copied for out-of-line single-stepping, so the correct
instruction is seen on all processors.
Thanks to Will Schmidt who tracked this down.
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-08-11 11:31:34 +00:00
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flush_icache_range((unsigned long)p->ainsn.insn,
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(unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
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2006-01-10 04:52:43 +00:00
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}
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2007-04-18 05:57:51 +00:00
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p->ainsn.boostable = 0;
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2006-01-10 04:52:43 +00:00
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return ret;
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2005-04-16 22:20:36 +00:00
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}
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2005-09-06 22:19:29 +00:00
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void __kprobes arch_arm_kprobe(struct kprobe *p)
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2005-04-16 22:20:36 +00:00
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{
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2005-06-23 07:09:25 +00:00
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*p->addr = BREAKPOINT_INSTRUCTION;
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flush_icache_range((unsigned long) p->addr,
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(unsigned long) p->addr + sizeof(kprobe_opcode_t));
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2005-04-16 22:20:36 +00:00
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}
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2005-09-06 22:19:29 +00:00
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void __kprobes arch_disarm_kprobe(struct kprobe *p)
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2005-04-16 22:20:36 +00:00
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{
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*p->addr = p->opcode;
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2005-06-23 07:09:25 +00:00
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flush_icache_range((unsigned long) p->addr,
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(unsigned long) p->addr + sizeof(kprobe_opcode_t));
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}
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2006-01-10 04:52:46 +00:00
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void __kprobes arch_remove_kprobe(struct kprobe *p)
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2005-06-23 07:09:25 +00:00
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{
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2009-01-06 22:41:50 +00:00
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if (p->ainsn.insn) {
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free_insn_slot(p->ainsn.insn, 0);
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p->ainsn.insn = NULL;
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}
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2005-04-16 22:20:36 +00:00
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}
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2006-04-19 05:22:01 +00:00
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static void __kprobes prepare_singlestep(struct kprobe *p, struct pt_regs *regs)
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2005-04-16 22:20:36 +00:00
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{
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2008-06-26 06:57:58 +00:00
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/* We turn off async exceptions to ensure that the single step will
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* be for the instruction we have the kprobe on, if we dont its
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* possible we'd get the single step reported for an exception handler
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* like Decrementer or External Interrupt */
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regs->msr &= ~MSR_EE;
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2008-06-26 07:01:37 +00:00
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regs->msr |= MSR_SINGLESTEP;
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2010-02-08 11:50:57 +00:00
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#ifdef CONFIG_PPC_ADV_DEBUG_REGS
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2008-06-26 07:01:37 +00:00
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regs->msr &= ~MSR_CE;
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mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
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#endif
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2005-06-27 22:17:01 +00:00
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2006-04-28 12:08:42 +00:00
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/*
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* On powerpc we should single step on the original
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* instruction even if the probed insn is a trap
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* variant as values in regs could play a part in
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* if the trap is taken or not
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*/
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regs->nip = (unsigned long)p->ainsn.insn;
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2005-04-16 22:20:36 +00:00
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}
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2006-04-19 05:22:01 +00:00
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static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
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2005-11-07 09:00:10 +00:00
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{
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kcb->prev_kprobe.kp = kprobe_running();
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kcb->prev_kprobe.status = kcb->kprobe_status;
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kcb->prev_kprobe.saved_msr = kcb->kprobe_saved_msr;
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}
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2006-04-19 05:22:01 +00:00
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static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
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2005-06-23 07:09:38 +00:00
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{
|
2005-11-07 09:00:10 +00:00
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__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
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kcb->kprobe_status = kcb->prev_kprobe.status;
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kcb->kprobe_saved_msr = kcb->prev_kprobe.saved_msr;
|
2005-06-23 07:09:38 +00:00
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}
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|
2006-04-19 05:22:01 +00:00
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static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
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2005-11-07 09:00:10 +00:00
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struct kprobe_ctlblk *kcb)
|
2005-06-23 07:09:38 +00:00
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{
|
2005-11-07 09:00:10 +00:00
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__get_cpu_var(current_kprobe) = p;
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kcb->kprobe_saved_msr = regs->msr;
|
2005-06-23 07:09:38 +00:00
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}
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|
2007-05-08 07:34:14 +00:00
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void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri,
|
2005-09-06 22:19:29 +00:00
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struct pt_regs *regs)
|
2005-06-27 22:17:15 +00:00
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{
|
2007-05-08 07:34:14 +00:00
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ri->ret_addr = (kprobe_opcode_t *)regs->link;
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/* Replace the return addr with trampoline addr */
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regs->link = (unsigned long)kretprobe_trampoline;
|
2005-06-27 22:17:15 +00:00
|
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}
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|
2006-04-19 05:22:01 +00:00
|
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static int __kprobes kprobe_handler(struct pt_regs *regs)
|
2005-04-16 22:20:36 +00:00
|
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{
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struct kprobe *p;
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int ret = 0;
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unsigned int *addr = (unsigned int *)regs->nip;
|
2005-11-07 09:00:14 +00:00
|
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struct kprobe_ctlblk *kcb;
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|
|
|
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|
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/*
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* We don't want to be preempted for the entire
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* duration of kprobe processing
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*/
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preempt_disable();
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kcb = get_kprobe_ctlblk();
|
2005-04-16 22:20:36 +00:00
|
|
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/* Check we're not actually recursing */
|
|
|
|
if (kprobe_running()) {
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p = get_kprobe(addr);
|
|
|
|
if (p) {
|
2005-09-06 22:19:35 +00:00
|
|
|
kprobe_opcode_t insn = *p->ainsn.insn;
|
2005-11-07 09:00:10 +00:00
|
|
|
if (kcb->kprobe_status == KPROBE_HIT_SS &&
|
2005-09-06 22:19:35 +00:00
|
|
|
is_trap(insn)) {
|
2008-06-26 07:01:37 +00:00
|
|
|
/* Turn off 'trace' bits */
|
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|
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regs->msr &= ~MSR_SINGLESTEP;
|
2005-11-07 09:00:10 +00:00
|
|
|
regs->msr |= kcb->kprobe_saved_msr;
|
2005-04-16 22:20:36 +00:00
|
|
|
goto no_kprobe;
|
|
|
|
}
|
2005-06-23 07:09:38 +00:00
|
|
|
/* We have reentered the kprobe_handler(), since
|
|
|
|
* another probe was hit while within the handler.
|
|
|
|
* We here save the original kprobes variables and
|
|
|
|
* just single step on the instruction of the new probe
|
|
|
|
* without calling any user handlers.
|
|
|
|
*/
|
2005-11-07 09:00:10 +00:00
|
|
|
save_previous_kprobe(kcb);
|
|
|
|
set_current_kprobe(p, regs, kcb);
|
|
|
|
kcb->kprobe_saved_msr = regs->msr;
|
2005-12-12 08:37:34 +00:00
|
|
|
kprobes_inc_nmissed_count(p);
|
2005-06-23 07:09:38 +00:00
|
|
|
prepare_singlestep(p, regs);
|
2005-11-07 09:00:10 +00:00
|
|
|
kcb->kprobe_status = KPROBE_REENTER;
|
2005-06-23 07:09:38 +00:00
|
|
|
return 1;
|
2005-04-16 22:20:36 +00:00
|
|
|
} else {
|
2006-01-11 20:17:42 +00:00
|
|
|
if (*addr != BREAKPOINT_INSTRUCTION) {
|
|
|
|
/* If trap variant, then it belongs not to us */
|
|
|
|
kprobe_opcode_t cur_insn = *addr;
|
|
|
|
if (is_trap(cur_insn))
|
|
|
|
goto no_kprobe;
|
|
|
|
/* The breakpoint instruction was removed by
|
|
|
|
* another cpu right after we hit, no further
|
|
|
|
* handling of this interrupt is appropriate
|
|
|
|
*/
|
|
|
|
ret = 1;
|
|
|
|
goto no_kprobe;
|
|
|
|
}
|
2005-11-07 09:00:10 +00:00
|
|
|
p = __get_cpu_var(current_kprobe);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (p->break_handler && p->break_handler(p, regs)) {
|
|
|
|
goto ss_probe;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
goto no_kprobe;
|
|
|
|
}
|
|
|
|
|
|
|
|
p = get_kprobe(addr);
|
|
|
|
if (!p) {
|
|
|
|
if (*addr != BREAKPOINT_INSTRUCTION) {
|
|
|
|
/*
|
|
|
|
* PowerPC has multiple variants of the "trap"
|
|
|
|
* instruction. If the current instruction is a
|
|
|
|
* trap variant, it could belong to someone else
|
|
|
|
*/
|
|
|
|
kprobe_opcode_t cur_insn = *addr;
|
2005-09-06 22:19:35 +00:00
|
|
|
if (is_trap(cur_insn))
|
2005-04-16 22:20:36 +00:00
|
|
|
goto no_kprobe;
|
|
|
|
/*
|
|
|
|
* The breakpoint instruction was removed right
|
|
|
|
* after we hit it. Another cpu has removed
|
|
|
|
* either a probepoint or a debugger breakpoint
|
|
|
|
* at this address. In either case, no further
|
|
|
|
* handling of this interrupt is appropriate.
|
|
|
|
*/
|
|
|
|
ret = 1;
|
|
|
|
}
|
|
|
|
/* Not one of ours: let kernel handle it */
|
|
|
|
goto no_kprobe;
|
|
|
|
}
|
|
|
|
|
2005-11-07 09:00:10 +00:00
|
|
|
kcb->kprobe_status = KPROBE_HIT_ACTIVE;
|
|
|
|
set_current_kprobe(p, regs, kcb);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (p->pre_handler && p->pre_handler(p, regs))
|
|
|
|
/* handler has already set things up, so skip ss setup */
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
ss_probe:
|
2007-04-18 05:57:51 +00:00
|
|
|
if (p->ainsn.boostable >= 0) {
|
|
|
|
unsigned int insn = *p->ainsn.insn;
|
|
|
|
|
|
|
|
/* regs->nip is also adjusted if emulate_step returns 1 */
|
|
|
|
ret = emulate_step(regs, insn);
|
|
|
|
if (ret > 0) {
|
|
|
|
/*
|
|
|
|
* Once this instruction has been boosted
|
|
|
|
* successfully, set the boostable flag
|
|
|
|
*/
|
|
|
|
if (unlikely(p->ainsn.boostable == 0))
|
|
|
|
p->ainsn.boostable = 1;
|
|
|
|
|
|
|
|
if (p->post_handler)
|
|
|
|
p->post_handler(p, regs, 0);
|
|
|
|
|
|
|
|
kcb->kprobe_status = KPROBE_HIT_SSDONE;
|
|
|
|
reset_current_kprobe();
|
|
|
|
preempt_enable_no_resched();
|
|
|
|
return 1;
|
|
|
|
} else if (ret < 0) {
|
|
|
|
/*
|
|
|
|
* We don't allow kprobes on mtmsr(d)/rfi(d), etc.
|
|
|
|
* So, we should never get here... but, its still
|
|
|
|
* good to catch them, just in case...
|
|
|
|
*/
|
|
|
|
printk("Can't step on instruction %x\n", insn);
|
|
|
|
BUG();
|
|
|
|
} else if (ret == 0)
|
|
|
|
/* This instruction can't be boosted */
|
|
|
|
p->ainsn.boostable = -1;
|
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
prepare_singlestep(p, regs);
|
2005-11-07 09:00:10 +00:00
|
|
|
kcb->kprobe_status = KPROBE_HIT_SS;
|
2005-04-16 22:20:36 +00:00
|
|
|
return 1;
|
|
|
|
|
|
|
|
no_kprobe:
|
2005-11-07 09:00:14 +00:00
|
|
|
preempt_enable_no_resched();
|
2005-04-16 22:20:36 +00:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2005-06-27 22:17:15 +00:00
|
|
|
/*
|
|
|
|
* Function return probe trampoline:
|
|
|
|
* - init_kprobes() establishes a probepoint here
|
|
|
|
* - When the probed function returns, this probe
|
|
|
|
* causes the handlers to fire
|
|
|
|
*/
|
2008-02-15 10:59:17 +00:00
|
|
|
static void __used kretprobe_trampoline_holder(void)
|
2005-06-27 22:17:15 +00:00
|
|
|
{
|
|
|
|
asm volatile(".global kretprobe_trampoline\n"
|
|
|
|
"kretprobe_trampoline:\n"
|
|
|
|
"nop\n");
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Called when the probe at kretprobe trampoline is hit
|
|
|
|
*/
|
2008-02-15 10:59:17 +00:00
|
|
|
static int __kprobes trampoline_probe_handler(struct kprobe *p,
|
|
|
|
struct pt_regs *regs)
|
2005-06-27 22:17:15 +00:00
|
|
|
{
|
2006-10-02 09:17:33 +00:00
|
|
|
struct kretprobe_instance *ri = NULL;
|
2006-10-02 09:17:35 +00:00
|
|
|
struct hlist_head *head, empty_rp;
|
2006-10-02 09:17:33 +00:00
|
|
|
struct hlist_node *node, *tmp;
|
2005-11-07 09:00:14 +00:00
|
|
|
unsigned long flags, orig_ret_address = 0;
|
2005-06-27 22:17:15 +00:00
|
|
|
unsigned long trampoline_address =(unsigned long)&kretprobe_trampoline;
|
|
|
|
|
2006-10-02 09:17:35 +00:00
|
|
|
INIT_HLIST_HEAD(&empty_rp);
|
2008-07-25 08:46:04 +00:00
|
|
|
kretprobe_hash_lock(current, &head, &flags);
|
2005-06-27 22:17:15 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* It is possible to have multiple instances associated with a given
|
|
|
|
* task either because an multiple functions in the call path
|
2008-10-16 17:02:37 +00:00
|
|
|
* have a return probe installed on them, and/or more than one return
|
2005-06-27 22:17:15 +00:00
|
|
|
* return probe was registered for a target function.
|
|
|
|
*
|
|
|
|
* We can handle this because:
|
|
|
|
* - instances are always inserted at the head of the list
|
|
|
|
* - when multiple return probes are registered for the same
|
2006-10-02 09:17:33 +00:00
|
|
|
* function, the first instance's ret_addr will point to the
|
2005-06-27 22:17:15 +00:00
|
|
|
* real return address, and all the rest will point to
|
|
|
|
* kretprobe_trampoline
|
|
|
|
*/
|
|
|
|
hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
|
2006-10-02 09:17:33 +00:00
|
|
|
if (ri->task != current)
|
2005-06-27 22:17:15 +00:00
|
|
|
/* another task is sharing our hash bucket */
|
2006-10-02 09:17:33 +00:00
|
|
|
continue;
|
2005-06-27 22:17:15 +00:00
|
|
|
|
|
|
|
if (ri->rp && ri->rp->handler)
|
|
|
|
ri->rp->handler(ri, regs);
|
|
|
|
|
|
|
|
orig_ret_address = (unsigned long)ri->ret_addr;
|
2006-10-02 09:17:35 +00:00
|
|
|
recycle_rp_inst(ri, &empty_rp);
|
2005-06-27 22:17:15 +00:00
|
|
|
|
|
|
|
if (orig_ret_address != trampoline_address)
|
|
|
|
/*
|
|
|
|
* This is the real return address. Any other
|
|
|
|
* instances associated with this task are for
|
|
|
|
* other calls deeper on the call stack
|
|
|
|
*/
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
2007-05-08 07:28:27 +00:00
|
|
|
kretprobe_assert(ri, orig_ret_address, trampoline_address);
|
2005-06-27 22:17:15 +00:00
|
|
|
regs->nip = orig_ret_address;
|
|
|
|
|
2005-11-07 09:00:10 +00:00
|
|
|
reset_current_kprobe();
|
2008-07-25 08:46:04 +00:00
|
|
|
kretprobe_hash_unlock(current, &flags);
|
2005-11-07 09:00:07 +00:00
|
|
|
preempt_enable_no_resched();
|
2005-06-27 22:17:15 +00:00
|
|
|
|
2006-10-02 09:17:35 +00:00
|
|
|
hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
|
|
|
|
hlist_del(&ri->hlist);
|
|
|
|
kfree(ri);
|
|
|
|
}
|
2006-10-02 09:17:33 +00:00
|
|
|
/*
|
|
|
|
* By returning a non-zero value, we are telling
|
|
|
|
* kprobe_handler() that we don't want the post_handler
|
|
|
|
* to run (and have re-enabled preemption)
|
|
|
|
*/
|
|
|
|
return 1;
|
2005-06-27 22:17:15 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* Called after single-stepping. p->addr is the address of the
|
|
|
|
* instruction whose first byte has been replaced by the "breakpoint"
|
|
|
|
* instruction. To avoid the SMP problems that can occur when we
|
|
|
|
* temporarily put back the original opcode to single-step, we
|
|
|
|
* single-stepped a copy of the instruction. The address of this
|
|
|
|
* copy is p->ainsn.insn.
|
|
|
|
*/
|
2005-09-06 22:19:29 +00:00
|
|
|
static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
int ret;
|
2005-06-27 22:17:01 +00:00
|
|
|
unsigned int insn = *p->ainsn.insn;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
regs->nip = (unsigned long)p->addr;
|
2005-06-27 22:17:01 +00:00
|
|
|
ret = emulate_step(regs, insn);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (ret == 0)
|
|
|
|
regs->nip = (unsigned long)p->addr + 4;
|
|
|
|
}
|
|
|
|
|
2006-04-19 05:22:01 +00:00
|
|
|
static int __kprobes post_kprobe_handler(struct pt_regs *regs)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2005-11-07 09:00:10 +00:00
|
|
|
struct kprobe *cur = kprobe_running();
|
|
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
|
|
|
|
|
|
if (!cur)
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
|
2008-06-26 06:57:58 +00:00
|
|
|
/* make sure we got here for instruction we have a kprobe on */
|
|
|
|
if (((unsigned long)cur->ainsn.insn + 4) != regs->nip)
|
|
|
|
return 0;
|
|
|
|
|
2005-11-07 09:00:10 +00:00
|
|
|
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
|
|
|
|
kcb->kprobe_status = KPROBE_HIT_SSDONE;
|
|
|
|
cur->post_handler(cur, regs, 0);
|
2005-06-23 07:09:38 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-07 09:00:10 +00:00
|
|
|
resume_execution(cur, regs);
|
|
|
|
regs->msr |= kcb->kprobe_saved_msr;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-06-23 07:09:38 +00:00
|
|
|
/*Restore back the original saved kprobes variables and continue. */
|
2005-11-07 09:00:10 +00:00
|
|
|
if (kcb->kprobe_status == KPROBE_REENTER) {
|
|
|
|
restore_previous_kprobe(kcb);
|
2005-06-23 07:09:38 +00:00
|
|
|
goto out;
|
|
|
|
}
|
2005-11-07 09:00:10 +00:00
|
|
|
reset_current_kprobe();
|
2005-06-23 07:09:38 +00:00
|
|
|
out:
|
2005-04-16 22:20:36 +00:00
|
|
|
preempt_enable_no_resched();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* if somebody else is singlestepping across a probe point, msr
|
2008-06-26 07:01:37 +00:00
|
|
|
* will have DE/SE set, in which case, continue the remaining processing
|
2005-04-16 22:20:36 +00:00
|
|
|
* of do_debug, as if this is not a probe hit.
|
|
|
|
*/
|
2008-06-26 07:01:37 +00:00
|
|
|
if (regs->msr & MSR_SINGLESTEP)
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
2007-04-30 10:56:46 +00:00
|
|
|
int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2005-11-07 09:00:10 +00:00
|
|
|
struct kprobe *cur = kprobe_running();
|
|
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
2006-03-26 09:38:24 +00:00
|
|
|
const struct exception_table_entry *entry;
|
|
|
|
|
|
|
|
switch(kcb->kprobe_status) {
|
|
|
|
case KPROBE_HIT_SS:
|
|
|
|
case KPROBE_REENTER:
|
|
|
|
/*
|
|
|
|
* We are here because the instruction being single
|
|
|
|
* stepped caused a page fault. We reset the current
|
|
|
|
* kprobe and the nip points back to the probe address
|
|
|
|
* and allow the page fault handler to continue as a
|
|
|
|
* normal page fault.
|
|
|
|
*/
|
|
|
|
regs->nip = (unsigned long)cur->addr;
|
2008-06-26 07:01:37 +00:00
|
|
|
regs->msr &= ~MSR_SINGLESTEP; /* Turn off 'trace' bits */
|
2005-11-07 09:00:10 +00:00
|
|
|
regs->msr |= kcb->kprobe_saved_msr;
|
2006-03-26 09:38:24 +00:00
|
|
|
if (kcb->kprobe_status == KPROBE_REENTER)
|
|
|
|
restore_previous_kprobe(kcb);
|
|
|
|
else
|
|
|
|
reset_current_kprobe();
|
2005-04-16 22:20:36 +00:00
|
|
|
preempt_enable_no_resched();
|
2006-03-26 09:38:24 +00:00
|
|
|
break;
|
|
|
|
case KPROBE_HIT_ACTIVE:
|
|
|
|
case KPROBE_HIT_SSDONE:
|
|
|
|
/*
|
|
|
|
* We increment the nmissed count for accounting,
|
|
|
|
* we can also use npre/npostfault count for accouting
|
|
|
|
* these specific fault cases.
|
|
|
|
*/
|
|
|
|
kprobes_inc_nmissed_count(cur);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We come here because instructions in the pre/post
|
|
|
|
* handler caused the page_fault, this could happen
|
|
|
|
* if handler tries to access user space by
|
|
|
|
* copy_from_user(), get_user() etc. Let the
|
|
|
|
* user-specified handler try to fix it first.
|
|
|
|
*/
|
|
|
|
if (cur->fault_handler && cur->fault_handler(cur, regs, trapnr))
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* In case the user-specified fault handler returned
|
|
|
|
* zero, try to fix up.
|
|
|
|
*/
|
|
|
|
if ((entry = search_exception_tables(regs->nip)) != NULL) {
|
|
|
|
regs->nip = entry->fixup;
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* fixup_exception() could not handle it,
|
|
|
|
* Let do_page_fault() fix it.
|
|
|
|
*/
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Wrapper routine to for handling exceptions.
|
|
|
|
*/
|
2005-09-06 22:19:29 +00:00
|
|
|
int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
|
|
|
|
unsigned long val, void *data)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct die_args *args = (struct die_args *)data;
|
|
|
|
int ret = NOTIFY_DONE;
|
|
|
|
|
2006-03-26 09:38:21 +00:00
|
|
|
if (args->regs && user_mode(args->regs))
|
|
|
|
return ret;
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
switch (val) {
|
|
|
|
case DIE_BPT:
|
|
|
|
if (kprobe_handler(args->regs))
|
|
|
|
ret = NOTIFY_STOP;
|
|
|
|
break;
|
|
|
|
case DIE_SSTEP:
|
|
|
|
if (post_kprobe_handler(args->regs))
|
|
|
|
ret = NOTIFY_STOP;
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2007-07-19 08:48:11 +00:00
|
|
|
#ifdef CONFIG_PPC64
|
|
|
|
unsigned long arch_deref_entry_point(void *entry)
|
|
|
|
{
|
2008-05-23 04:22:21 +00:00
|
|
|
return ((func_descr_t *)entry)->entry;
|
2007-07-19 08:48:11 +00:00
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
2005-09-06 22:19:29 +00:00
|
|
|
int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
struct jprobe *jp = container_of(p, struct jprobe, kp);
|
2005-11-07 09:00:10 +00:00
|
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-11-07 09:00:10 +00:00
|
|
|
memcpy(&kcb->jprobe_saved_regs, regs, sizeof(struct pt_regs));
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/* setup return addr to the jprobe handler routine */
|
2007-07-19 08:48:11 +00:00
|
|
|
regs->nip = arch_deref_entry_point(jp->entry);
|
2007-02-07 04:55:19 +00:00
|
|
|
#ifdef CONFIG_PPC64
|
2005-04-16 22:20:36 +00:00
|
|
|
regs->gpr[2] = (unsigned long)(((func_descr_t *)jp->entry)->toc);
|
2007-02-07 04:55:19 +00:00
|
|
|
#endif
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
2008-02-15 10:59:17 +00:00
|
|
|
void __used __kprobes jprobe_return(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
asm volatile("trap" ::: "memory");
|
|
|
|
}
|
|
|
|
|
2008-02-15 10:59:17 +00:00
|
|
|
static void __used __kprobes jprobe_return_end(void)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
};
|
|
|
|
|
2005-09-06 22:19:29 +00:00
|
|
|
int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2005-11-07 09:00:10 +00:00
|
|
|
struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* FIXME - we should ideally be validating that we got here 'cos
|
|
|
|
* of the "trap" in jprobe_return() above, before restoring the
|
|
|
|
* saved regs...
|
|
|
|
*/
|
2005-11-07 09:00:10 +00:00
|
|
|
memcpy(regs, &kcb->jprobe_saved_regs, sizeof(struct pt_regs));
|
2005-11-07 09:00:14 +00:00
|
|
|
preempt_enable_no_resched();
|
2005-04-16 22:20:36 +00:00
|
|
|
return 1;
|
|
|
|
}
|
2005-06-27 22:17:15 +00:00
|
|
|
|
|
|
|
static struct kprobe trampoline_p = {
|
|
|
|
.addr = (kprobe_opcode_t *) &kretprobe_trampoline,
|
|
|
|
.pre_handler = trampoline_probe_handler
|
|
|
|
};
|
|
|
|
|
2005-07-06 01:54:50 +00:00
|
|
|
int __init arch_init_kprobes(void)
|
2005-06-27 22:17:15 +00:00
|
|
|
{
|
|
|
|
return register_kprobe(&trampoline_p);
|
|
|
|
}
|
2007-05-08 07:34:16 +00:00
|
|
|
|
|
|
|
int __kprobes arch_trampoline_kprobe(struct kprobe *p)
|
|
|
|
{
|
|
|
|
if (p->addr == (kprobe_opcode_t *)&kretprobe_trampoline)
|
|
|
|
return 1;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|