From: Mark Rutland <mark.rutland@arm.com> To: Dave Martin <Dave.Martin@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 11:29:13 +0100 [thread overview] Message-ID: <20180601102913.ougz2vshzzttvuaj@lakrids.cambridge.arm.com> (raw) In-Reply-To: <20180516090121.GQ7753@e103592.cambridge.arm.com> 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>. > > > > > > 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. Thanks, Mark.
WARNING: multiple messages have this Message-ID (diff)
From: mark.rutland@arm.com (Mark Rutland) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 06/18] arm64: move sve_user_{enable, disable} to <asm/fpsimd.h> Date: Fri, 1 Jun 2018 11:29:13 +0100 [thread overview] Message-ID: <20180601102913.ougz2vshzzttvuaj@lakrids.cambridge.arm.com> (raw) In-Reply-To: <20180516090121.GQ7753@e103592.cambridge.arm.com> 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>. > > > > > > 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. Thanks, Mark.
next prev parent reply other threads:[~2018-06-01 10:29 UTC|newest] Thread overview: 126+ 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 ` Mark Rutland 2018-05-14 9:46 ` [PATCH 01/18] arm64: consistently use unsigned long for thread flags Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 9:57 ` Dave Martin 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 9:46 ` Mark Rutland 2018-05-14 10:00 ` Dave Martin 2018-05-14 10:00 ` Dave Martin 2018-05-14 10:08 ` Mark Rutland 2018-05-14 10:08 ` Mark Rutland 2018-05-14 11:20 ` Dave Martin 2018-05-14 11:20 ` Dave Martin 2018-05-14 11:56 ` Robin Murphy 2018-05-14 11:56 ` Robin Murphy 2018-05-14 12:06 ` Mark Rutland 2018-05-14 12:06 ` Mark Rutland 2018-05-14 12:41 ` Dave Martin 2018-05-14 12:41 ` Dave Martin 2018-05-14 13:10 ` Mark Rutland 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 9:46 ` Mark Rutland 2018-05-14 10:04 ` Dave Martin 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 9:46 ` Mark Rutland 2018-05-14 10:05 ` Dave Martin 2018-05-14 10:05 ` Dave Martin 2018-05-14 9:46 ` [PATCH 05/18] arm64: kill change_cpacr() Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 10:06 ` Dave Martin 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 9:46 ` [PATCH 06/18] arm64: move sve_user_{enable, disable} " Mark Rutland 2018-05-14 11:06 ` Dave Martin 2018-05-14 11:06 ` Dave Martin 2018-05-15 10:39 ` Mark Rutland 2018-05-15 10:39 ` Mark Rutland 2018-05-15 12:19 ` Dave Martin 2018-05-15 12:19 ` Dave Martin 2018-05-15 16:33 ` Mark Rutland 2018-05-15 16:33 ` Mark Rutland 2018-05-16 9:01 ` Dave Martin 2018-05-16 9:01 ` Dave Martin 2018-06-01 10:29 ` Mark Rutland [this message] 2018-06-01 10:29 ` Mark Rutland 2018-06-01 10:42 ` Dave Martin 2018-06-01 10:42 ` Dave Martin 2018-05-14 9:46 ` [PATCH 07/18] arm64: remove sigreturn wrappers Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 11:07 ` Dave Martin 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 9:46 ` Mark Rutland 2018-05-14 11:07 ` Dave Martin 2018-05-14 11:07 ` Dave Martin 2018-05-14 11:41 ` Mark Rutland 2018-05-14 11:41 ` Mark Rutland 2018-05-14 12:53 ` Dave Martin 2018-05-14 12:53 ` Dave Martin 2018-05-14 20:24 ` Dominik Brodowski 2018-05-14 20:24 ` Dominik Brodowski 2018-05-15 8:22 ` Mark Rutland 2018-05-15 8:22 ` Mark Rutland 2018-05-15 10:01 ` Dominik Brodowski 2018-05-15 10:01 ` Dominik Brodowski 2018-05-15 10:13 ` Mark Rutland 2018-05-15 10:13 ` Mark Rutland 2018-05-14 18:00 ` Dominik Brodowski 2018-05-14 18:00 ` Dominik Brodowski 2018-05-15 8:18 ` Mark Rutland 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 ` Mark Rutland 2018-05-14 9:46 ` [PATCH 10/18] arm64: convert native/compat syscall entry " Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 11:07 ` Dave Martin 2018-05-14 11:07 ` Dave Martin 2018-05-14 11:58 ` Mark Rutland 2018-05-14 11:58 ` Mark Rutland 2018-05-14 14:43 ` Dave Martin 2018-05-14 14:43 ` Dave Martin 2018-05-14 15:01 ` Mark Rutland 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 9:46 ` Mark Rutland 2018-05-14 11:07 ` Dave Martin 2018-05-14 11:07 ` Dave Martin 2018-05-14 9:46 ` [PATCH 12/18] kernel: add ksys_personality() Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 11:08 ` Dave Martin 2018-05-14 11:08 ` Dave Martin 2018-05-14 12:07 ` Christoph Hellwig 2018-05-14 12:07 ` Christoph Hellwig 2018-05-15 9:56 ` Mark Rutland 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 9:46 ` Mark Rutland 2018-05-14 17:14 ` Mark Rutland 2018-05-14 17:14 ` Mark Rutland 2018-05-14 20:34 ` Dominik Brodowski 2018-05-14 20:34 ` Dominik Brodowski 2018-05-15 9:53 ` Mark Rutland 2018-05-15 9:53 ` Mark Rutland 2018-05-15 9:58 ` Dominik Brodowski 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 ` Mark Rutland 2018-05-14 9:46 ` [PATCH 15/18] arm64: use {COMPAT,}SYSCALL_DEFINE0 for sigreturn Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 9:46 ` [PATCH 16/18] arm64: use SYSCALL_DEFINE6() for mmap Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 9:46 ` [PATCH 17/18] arm64: convert compat wrappers to C Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 12:10 ` Christoph Hellwig 2018-05-14 12:10 ` Christoph Hellwig 2018-05-14 12:43 ` Mark Rutland 2018-05-14 12:43 ` Mark Rutland 2018-05-14 9:46 ` [PATCH 18/18] arm64: implement syscall wrappers Mark Rutland 2018-05-14 9:46 ` Mark Rutland 2018-05-14 20:57 ` Dominik Brodowski 2018-05-14 20:57 ` Dominik Brodowski 2018-05-15 8:37 ` Mark Rutland 2018-05-15 8:37 ` Mark Rutland
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