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[IA64] Remove getting break_num by decoding instruction 

break.b always sets cr.iim to 0 and the current code tries to
get the break_num by decoding instruction. However, their
seems to be a race condition while reading the regs->cr_iip,
as on other cpu the break.b at regs->cr_iip might have been
replaced with the original instruction as a result of
unregister_kprobe() and hence decoding instruction to
obtain break_num will result in wrong value in this case.

Also includes changes to kprobes.c which now has to handle
break number zero.

Signed-off-by: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Keshavamurthy Anil S 2005-11-22 14:15:49 -08:00 committed by Tony Luck
parent b77dae5293
commit 5a94bcfd2a
2 changed files with 1 additions and 19 deletions
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2
arch/ia64/kernel/kprobes.c
View File

@ -740,7 +740,7 @@ int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
switch(val) {
case DIE_BREAK:
/* err is break number from ia64_bad_break() */
if (args->err == 0x80200 || args->err == 0x80300)
if (args->err == 0x80200 || args->err == 0x80300 || args->err == 0)
if (pre_kprobes_handler(args))
ret = NOTIFY_STOP;
break;

18
arch/ia64/kernel/traps.c
View File

@ -132,24 +132,6 @@ __kprobes ia64_bad_break (unsigned long break_num, struct pt_regs *regs)
siginfo_t siginfo;
int sig, code;
/* break.b always sets cr.iim to 0, which causes problems for
* debuggers. Get the real break number from the original instruction,
* but only for kernel code. User space break.b is left alone, to
* preserve the existing behaviour. All break codings have the same
* format, so there is no need to check the slot type.
*/
if (break_num == 0 && !user_mode(regs)) {
struct ia64_psr *ipsr = ia64_psr(regs);
unsigned long *bundle = (unsigned long *)regs->cr_iip;
unsigned long slot;
switch (ipsr->ri) {
case 0: slot = (bundle[0] >> 5); break;
case 1: slot = (bundle[0] >> 46) | (bundle[1] << 18); break;
default: slot = (bundle[1] >> 23); break;
}
break_num = ((slot >> 36 & 1) << 20) | (slot >> 6 & 0xfffff);
}
/* SIGILL, SIGFPE, SIGSEGV, and SIGBUS want these field initialized: */
siginfo.si_addr = (void __user *) (regs->cr_iip + ia64_psr(regs)->ri);
siginfo.si_imm = break_num;