Ram Pai <linuxram@xxxxxxxxxx> writes:
> On Tue, Jan 23, 2018 at 03:07:15PM -0600, Eric W. Biederman wrote:
>> The helpers added are:
>> send_sig_mceerr
>> force_sig_mceerr
>> force_sig_bnderr
>> force_sig_pkuerr
>>
>> Filling out siginfo properly can ge tricky. Especially for these
>> specialized cases where the temptation is to share code with other
>> cases which use a different subset of siginfo fields. Unfortunately
>> that code sharing frequently results in bugs with the wrong siginfo
>> fields filled in, and makes it harder to verify that the siginfo
>> structure was properly initialized.
>>
>> Provide these helpers instead that get all of the details right, and
>> guarantee that siginfo is properly initialized.
>>
>> send_sig_mceerr and force_sig_mceer are a little special as two si
>> codes BUS_MCEERR_AO and BUS_MCEER_AR both use the same extended
>> signinfo layout.
>
> nice. i can make use of these helpers in the memory-key implementation.
>
> One small nit-pick below though...
>
>>
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
>> ---
>> include/linux/sched/signal.h | 6 +++++
>> kernel/signal.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 67 insertions(+)
>>
>> diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
>
> ...snip..
>
>> +
>> +#ifdef SEGV_PKUERR
>
> Should this really be under SEGV_PKUERR ? that macro is defined
> unconditionally anyway.
Unless you are running my unified siginfo.h (from an earlier patchset
which I build upon). It turns out that ia64 has a conflict for that
number. So ia64 really can't use the define and this infrastructure.
We might decide to sort that out and always have SEGV_PKUERR always
defined. Sadly for the moment the #ifdef is necessary.
>> +int force_sig_pkuerr(void __user *addr, u32 pkey)
>> +{
>> + struct siginfo info;
>> +
>> + clear_siginfo(&info);
>> + info.si_signo = SIGSEGV;
>> + info.si_errno = 0;
>> + info.si_code = SEGV_PKUERR;
>> + info.si_addr = addr;
>> + info.si_pkey = pkey;
>> + return force_sig_info(info.si_signo, &info, current);
>> +}
>> +#endif
Eric
