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From:   ebiederm@xmission.com (Eric W. Biederman)
To:     Vincent Chen <deanbo422@gmail.com>
Cc:     linux-arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Greentime Hu <green.hu@gmail.com>
References: <87604mhrnb.fsf@xmission.com>
        <20180420143811.9994-9-ebiederm@xmission.com>
        <CAJsyPhy_GbfnzCNa_rJDMSRrUfVKOJKCVqrkWkDUmH6jPDGPhw@mail.gmail.com>
Date:   Wed, 25 Apr 2018 10:57:22 -0500
In-Reply-To: <CAJsyPhy_GbfnzCNa_rJDMSRrUfVKOJKCVqrkWkDUmH6jPDGPhw@mail.gmail.com>
        (Vincent Chen's message of "Wed, 25 Apr 2018 19:29:34 +0800")
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Subject: Re: [REVIEW][PATCH 09/22] signal/nds32: Use force_sig_fault where appropriate
Sender: linux-kernel-owner@vger.kernel.org
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Vincent Chen <deanbo422@gmail.com> writes:

> 2018-04-20 22:37 GMT+08:00 Eric W. Biederman <ebiederm@xmission.com>:
>> Filling in struct siginfo before calling force_sig_info a tedious and
>> error prone process, where once in a great while the wrong fields
>> are filled out, and siginfo has been inconsistently cleared.
>>
>> Simplify this process by using the helper force_sig_fault.  Which
>> takes as a parameters all of the information it needs, ensures
>> all of the fiddly bits of filling in struct siginfo are done properly
>> and then calls force_sig_info.
>>
>> In short about a 5 line reduction in code for every time force_sig_info
>> is called, which makes the calling function clearer.
>>
>> Cc: Greentime Hu <green.hu@gmail.com>
>> Cc: Vincent Chen <deanbo422@gmail.com>
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>>  arch/nds32/kernel/traps.c | 20 ++++----------------
>>  arch/nds32/mm/fault.c     | 19 +++++--------------
>>  2 files changed, 9 insertions(+), 30 deletions(-)
>>
>> diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
>> index 46911768f4b5..636d1c7aa895 100644
>> --- a/arch/nds32/kernel/traps.c
>> +++ b/arch/nds32/kernel/traps.c
>> @@ -222,20 +222,13 @@ void die_if_kernel(const char *str, struct pt_regs *regs, int err)
>>
>>  int bad_syscall(int n, struct pt_regs *regs)
>>  {
>> -       siginfo_t info;
>> -
>>         if (current->personality != PER_LINUX) {
>>                 send_sig(SIGSEGV, current, 1);
>>                 return regs->uregs[0];
>>         }
>>
>> -       clear_siginfo(&info);
>> -       info.si_signo = SIGILL;
>> -       info.si_errno = 0;
>> -       info.si_code = ILL_ILLTRP;
>> -       info.si_addr = (void __user *)instruction_pointer(regs) - 4;
>> -
>> -       force_sig_info(SIGILL, &info, current);
>> +       force_sig_fault(SIGILL, ILL_ILLTRP,
>> +                       (void __user *)instruction_pointer(regs) - 4, current);
>>         die_if_kernel("Oops - bad syscall", regs, n);
>>         return regs->uregs[0];
>>  }
>> @@ -288,16 +281,11 @@ void __init early_trap_init(void)
>>  void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs,
>>                   int error_code, int si_code)
>>  {
>> -       struct siginfo info;
>> -
>>         tsk->thread.trap_no = ENTRY_DEBUG_RELATED;
>>         tsk->thread.error_code = error_code;
>>
>> -       clear_siginfo(&info);
>> -       info.si_signo = SIGTRAP;
>> -       info.si_code = si_code;
>> -       info.si_addr = (void __user *)instruction_pointer(regs);
>> -       force_sig_info(SIGTRAP, &info, tsk);
>> +       force_sig_fault(SIGTRAP, si_code
>> +                       (void __user *)instruction_pointer(regs), tsk);
>>  }
>>
>
> I found a comma is missing after argument si_code.

Good catch.  Fixed.

Unfortunately the only compiler I have for nds32 is my eyeballs so
this slipped through.  Grr.


> Except the missing comma in send_sigtrap(), I think this patch for nds32 is OK.
>

I have corrected the change as you suggested and have added your Acked
by.

Eric