Re: [PATCH 4/9] MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'

From: Ralf Baechle <ralf@linux-mips.org>
To: "Maciej W. Rozycki" <macro@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>,
	linux-mips@linux-mips.org, stable@vger.kernel.org
Subject: Re: [PATCH 4/9] MIPS: Send SIGILL for BPOSGE32 in `__compute_return_epc_for_insn'
Date: Thu, 8 Jun 2017 15:11:41 +0200	[thread overview]
Message-ID: <20170608131141.GB8108@linux-mips.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1706050258410.10864@tp.orcam.me.uk>

On Tue, Jun 06, 2017 at 12:17:05AM +0100, Maciej W. Rozycki wrote:

> Fix commit e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.") and 
> send SIGILL rather than SIGBUS whenever an unimplemented BPOSGE32 DSP 
> ASE instruction has been encountered in `__compute_return_epc_for_insn' 
> as our Reserved Instruction exception handler would in response to an 
> attempt to actually execute the instruction.  Sending SIGBUS only makes 
> sense for the unaligned PC case, since moved to `__compute_return_epc'.  
> Adjust function documentation accordingly, correct formatting and use
> `pr_info' rather than `printk' as the other exit path already does.
> 
> Cc: stable@vger.kernel.org # 2.6.14+
> Fixes: e50c0a8fa60d ("Support the MIPS32 / MIPS64 DSP ASE.")
> Signed-off-by: Maciej W. Rozycki <macro@imgtec.com>
> ---
>  I hope folding the formatting fix and `pr_info' update with the base 
> change is fine given that they all apply to the same code line.

Ok, but ...

>  sigill_dsp:
> -	printk("%s: DSP branch but not DSP ASE - sending SIGBUS.\n", current->comm);
> -	force_sig(SIGBUS, current);
> +	pr_info("%s: DSP branch but not DSP ASE - sending SIGILL.\n",
> +		current->comm);

Shouldn't this then maybe be a pr_debug then?  With pr_info the right
kind of program can produce lots of useless clutter.

  Ralf