From: Dave Martin <Dave.Martin@arm.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: marc.zyngier@arm.com, catalin.marinas@arm.com,
will.deacon@arm.com, linux-kernel@vger.kernel.org,
linux@dominikbrodowski.net, james.morse@arm.com,
viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 06/18] arm64: move sve_user_{enable, disable} to <asm/fpsimd.h>
Date: Fri, 1 Jun 2018 11:42:14 +0100 [thread overview]
Message-ID: <20180601104214.GE22983@e103592.cambridge.arm.com> (raw)
In-Reply-To: <20180601102913.ougz2vshzzttvuaj@lakrids.cambridge.arm.com>
On Fri, Jun 01, 2018 at 11:29:13AM +0100, Mark Rutland wrote:
> On Wed, May 16, 2018 at 10:01:32AM +0100, Dave Martin wrote:
> > On Tue, May 15, 2018 at 05:33:52PM +0100, Mark Rutland wrote:
> > > On Tue, May 15, 2018 at 01:19:26PM +0100, Dave Martin wrote:
> > > > On Tue, May 15, 2018 at 11:39:36AM +0100, Mark Rutland wrote:
> > > > > Earlier I'd put BUILD_BUG() in the body for the !CONFIG_ARM64_SVE case,
> > > > > to catch that kind of thing -- I could restore that.
> > > >
> > > > IIUC:
> > > >
> > > > if (0) {
> > > > BUILD_BUG_ON(1);
> > > > }
> > > >
> > > > can still fire, in which case it's futile checking for CONFIG_ARM64_SVE
> > > > in most of the SVE support code.
> > >
> > > We already rely on BUILD_BUG() not firing in paths that can be trivially
> > > optimized away. e.g. in the cmpxchg code.
> >
> > Fair enough. I had been unsure on this point.
> >
> > If you want to put a BUILD_BUG_ON(!IS_ENABLED(CONFIG_ARM64_SVE)) in
> > sve_user_enable() and build with CONFIG_ARM64_SVE=n to check it works,
> > then I'd be fine with that.
> >
> > This doesn't capture the runtime part of the condition, but it's better
> > than nothing.
>
> For the moment, I've kept the stubs, but placed a BUILD_BUG() in each,
> as per the above rationale.
>
> We generally do that rather than than BUILD_BUG_ON(!IS_ENABLED(...)) in
> a common definition, and it's more in keeping with the other stubs in
> <asm/fpsimd.h>.
OK, fine by me.
> > > > > > > diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> > > > > > > index 088940387a4d..79a81c7d85c6 100644
> > > > > > > --- a/arch/arm64/kernel/fpsimd.c
> > > > > > > +++ b/arch/arm64/kernel/fpsimd.c
> > > > > > > @@ -159,7 +159,6 @@ static void sve_free(struct task_struct *task)
> > > > > > > __sve_free(task);
> > > > > > > }
> > > > > > >
> > > > > > > -
> > > > > >
> > > > > > Hmmm, Ack. Check for conflicts with the KVM FPSIMD rework [1] (though
> > > > > > trivial).
> > > > >
> > > > > I'll assume that Ack stands regardless. :)
> > > >
> > > > Actually, I was just commenting on the deleted blank line...
> > >
> > > Ah. I've restored that now.
> >
> > I meant Ack to the deletion. It looks like the blank line was
> > spuriously introduced in the first place. But it doesn't hugely matter
> > either way.
>
> Ok. I've dropped that for now to minimize the potential for conflicts,
> but we can clean this up later.
No big deal either way.
Cheers
---Dave
next prev parent reply other threads:[~2018-06-01 10:42 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-14 9:46 [PATCH 00/18] arm64: invoke syscalls with pt_regs Mark Rutland
2018-05-14 9:46 ` [PATCH 01/18] arm64: consistently use unsigned long for thread flags Mark Rutland
2018-05-14 9:57 ` Dave Martin
2018-05-14 9:46 ` [PATCH 02/18] arm64: move SCTLR_EL{1,2} assertions to <asm/sysreg.h> Mark Rutland
2018-05-14 10:00 ` Dave Martin
2018-05-14 10:08 ` Mark Rutland
2018-05-14 11:20 ` Dave Martin
2018-05-14 11:56 ` Robin Murphy
2018-05-14 12:06 ` Mark Rutland
2018-05-14 12:41 ` Dave Martin
2018-05-14 13:10 ` Mark Rutland
2018-05-14 9:46 ` [PATCH 03/18] arm64: introduce sysreg_clear_set() Mark Rutland
2018-05-14 10:04 ` Dave Martin
2018-05-14 9:46 ` [PATCH 04/18] arm64: kill config_sctlr_el1() Mark Rutland
2018-05-14 10:05 ` Dave Martin
2018-05-14 9:46 ` [PATCH 05/18] arm64: kill change_cpacr() Mark Rutland
2018-05-14 10:06 ` Dave Martin
2018-05-14 9:46 ` [PATCH 06/18] arm64: move sve_user_{enable,disable} to <asm/fpsimd.h> Mark Rutland
2018-05-14 11:06 ` [PATCH 06/18] arm64: move sve_user_{enable, disable} " Dave Martin
2018-05-15 10:39 ` Mark Rutland
2018-05-15 12:19 ` Dave Martin
2018-05-15 16:33 ` Mark Rutland
2018-05-16 9:01 ` Dave Martin
2018-06-01 10:29 ` Mark Rutland
2018-06-01 10:42 ` Dave Martin [this message]
2018-05-14 9:46 ` [PATCH 07/18] arm64: remove sigreturn wrappers Mark Rutland
2018-05-14 11:07 ` Dave Martin
2018-05-14 9:46 ` [PATCH 08/18] arm64: convert raw syscall invocation to C Mark Rutland
2018-05-14 11:07 ` Dave Martin
2018-05-14 11:41 ` Mark Rutland
2018-05-14 12:53 ` Dave Martin
2018-05-14 20:24 ` Dominik Brodowski
2018-05-15 8:22 ` Mark Rutland
2018-05-15 10:01 ` Dominik Brodowski
2018-05-15 10:13 ` Mark Rutland
2018-05-14 18:00 ` Dominik Brodowski
2018-05-15 8:18 ` Mark Rutland
2018-05-14 9:46 ` [PATCH 09/18] arm64: convert syscall trace logic " Mark Rutland
2018-05-14 9:46 ` [PATCH 10/18] arm64: convert native/compat syscall entry " Mark Rutland
2018-05-14 11:07 ` Dave Martin
2018-05-14 11:58 ` Mark Rutland
2018-05-14 14:43 ` Dave Martin
2018-05-14 15:01 ` Mark Rutland
2018-05-14 9:46 ` [PATCH 11/18] arm64: zero GPRs upon entry from EL0 Mark Rutland
2018-05-14 11:07 ` Dave Martin
2018-05-14 9:46 ` [PATCH 12/18] kernel: add ksys_personality() Mark Rutland
2018-05-14 11:08 ` Dave Martin
2018-05-14 12:07 ` Christoph Hellwig
2018-05-15 9:56 ` Mark Rutland
2018-05-14 9:46 ` [PATCH 13/18] kernel: add kcompat_sys_{f,}statfs64() Mark Rutland
2018-05-14 17:14 ` Mark Rutland
2018-05-14 20:34 ` Dominik Brodowski
2018-05-15 9:53 ` Mark Rutland
2018-05-15 9:58 ` Dominik Brodowski
2018-05-14 9:46 ` [PATCH 14/18] arm64: remove in-kernel call to sys_personality() Mark Rutland
2018-05-14 9:46 ` [PATCH 15/18] arm64: use {COMPAT,}SYSCALL_DEFINE0 for sigreturn Mark Rutland
2018-05-14 9:46 ` [PATCH 16/18] arm64: use SYSCALL_DEFINE6() for mmap Mark Rutland
2018-05-14 9:46 ` [PATCH 17/18] arm64: convert compat wrappers to C Mark Rutland
2018-05-14 12:10 ` Christoph Hellwig
2018-05-14 12:43 ` Mark Rutland
2018-05-14 9:46 ` [PATCH 18/18] arm64: implement syscall wrappers Mark Rutland
2018-05-14 20:57 ` Dominik Brodowski
2018-05-15 8:37 ` Mark Rutland
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