linux-kernel - Re: [PATCH v6 3/4] riscv: Decouple emulated unaligned accesses from access speed

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Date: Wed, 6 Mar 2024 10:25:05 -0800
From: Charlie Jenkins <charlie@...osinc.com>
To: Conor Dooley <conor.dooley@...rochip.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>,
	Palmer Dabbelt <palmer@...belt.com>,
	Albert Ou <aou@...s.berkeley.edu>,
	Jisheng Zhang <jszhang@...nel.org>, Evan Green <evan@...osinc.com>,
	Clément Léger <cleger@...osinc.com>,
	Eric Biggers <ebiggers@...nel.org>,
	Elliot Berman <quic_eberman@...cinc.com>,
	Charles Lohr <lohr85@...il.com>, linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 3/4] riscv: Decouple emulated unaligned accesses from
 access speed

On Wed, Mar 06, 2024 at 01:19:37PM +0000, Conor Dooley wrote:
> On Fri, Mar 01, 2024 at 05:45:34PM -0800, Charlie Jenkins wrote:
> 
> > -void unaligned_emulation_finish(void)
> > +bool check_unaligned_access_emulated_all_cpus(void)
> >  {
> >  	int cpu;
> >  
> > -	/*
> > -	 * We can only support PR_UNALIGN controls if all CPUs have misaligned
> > -	 * accesses emulated since tasks requesting such control can run on any
> > -	 * CPU.
> > -	 */
> 
> Why was this comment removed? This patch doesn't change the situations
> in which PR_UNALIGN is allowed, right?

I'll add it back, that was unintentional. Thank you.

- Charlie

> 
> > -	for_each_online_cpu(cpu) {
> > -		if (per_cpu(misaligned_access_speed, cpu) !=
> > -					RISCV_HWPROBE_MISALIGNED_EMULATED) {
> > -			return;
> > -		}
> > -	}
> > +	for_each_online_cpu(cpu)
> > +		if (check_unaligned_access_emulated(cpu))
> > +			return false;
> > +
> >  	unaligned_ctl = true;
> > +	return true;
> >  }
>