From: Catalin Marinas <catalin.marinas@arm.com>
To: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
clang-built-linux@googlegroups.com, x86@kernel.org,
Will Deacon <will.deacon@arm.com>, Arnd Bergmann <arnd@arndb.de>,
Russell King <linux@armlinux.org.uk>,
Paul Burton <paul.burton@mips.com>,
Thomas Gleixner <tglx@linutronix.de>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Borislav Petkov <bp@alien8.de>, Stephen Boyd <sboyd@kernel.org>,
Mark Salyzyn <salyzyn@android.com>,
Kees Cook <keescook@chromium.org>,
Peter Collingbourne <pcc@google.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Andrei Vagin <avagin@openvz.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Marc Zyngier <maz@kernel.org>,
Mark Rutland <Mark.Rutland@arm.com>,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH v3 18/26] arm64: Introduce asm/vdso/processor.h
Date: Mon, 16 Mar 2020 10:34:54 +0000 [thread overview]
Message-ID: <20200316103437.GD3005@mbp> (raw)
In-Reply-To: <c2c0157a-107a-debf-100f-0d97781add7c@arm.com>
On Mon, Mar 16, 2020 at 09:42:32AM +0000, Vincenzo Frascino wrote:
> you should not really work on Sunday ;-)
I was getting bored ;).
> On 3/15/20 6:30 PM, Catalin Marinas wrote:
> > On Fri, Mar 13, 2020 at 03:43:37PM +0000, Vincenzo Frascino wrote:
> >> --- /dev/null
> >> +++ b/arch/arm64/include/asm/vdso/processor.h
> >> @@ -0,0 +1,31 @@
> >> +/* SPDX-License-Identifier: GPL-2.0-only */
> >> +/*
> >> + * Copyright (C) 2020 ARM Ltd.
> >> + */
> >> +#ifndef __ASM_VDSO_PROCESSOR_H
> >> +#define __ASM_VDSO_PROCESSOR_H
> >> +
> >> +#ifndef __ASSEMBLY__
> >> +
> >> +#include <asm/page-def.h>
> >> +
> >> +#ifdef CONFIG_COMPAT
> >> +#if defined(CONFIG_ARM64_64K_PAGES) && defined(CONFIG_KUSER_HELPERS)
> >> +/*
> >> + * With CONFIG_ARM64_64K_PAGES enabled, the last page is occupied
> >> + * by the compat vectors page.
> >> + */
> >> +#define TASK_SIZE_32 UL(0x100000000)
> >> +#else
> >> +#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE)
> >> +#endif /* CONFIG_ARM64_64K_PAGES */
> >> +#endif /* CONFIG_COMPAT */
> >
> > Just curious, what's TASK_SIZE_32 used for in the vDSO code? You don't
> > seem to move TASK_SIZE.
> >
>
> I tried to fine grain the headers as much as I could in order to avoid
> unneeded/unwanted inclusions:
> * TASK_SIZE_32 is used to verify ABI consistency on vdso32 (please refer to
> arch/arm64/kernel/vdso32/vgettimeofday.c).
I see. But the test is probably useless. With 4K pages, TASK_SIZE_32 is
1UL << 32, so you can't have a u32 greater than this. So I'd argue that
the ABI compatibility here doesn't matter.
With 16K or 64K pages, TASK_SIZE_32 is slightly smaller but arm32 never
supported it.
What's the side-effect of dropping this check altogether?
--
Catalin
next prev parent reply other threads:[~2020-03-16 10:35 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-13 15:43 [PATCH v3 00/26] Introduce common headers for vDSO Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 01/26] linux/const.h: Extract common header " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 02/26] linux/bits.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 03/26] linux/limits.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 04/26] x86:Introduce asm/vdso/clocksource.h Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 05/26] arm: Introduce asm/vdso/clocksource.h Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 06/26] arm64: " Vincenzo Frascino
2020-03-15 18:29 ` Catalin Marinas
2020-03-13 15:43 ` [PATCH v3 07/26] mips: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 08/26] linux/clocksource.h: Extract common header for vDSO Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 09/26] linux/math64.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 10/26] linux/time.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 11/26] linux/time32.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 12/26] linux/time64.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 13/26] linux/jiffies.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 14/26] linux/ktime.h: " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 15/26] common: Introduce processor.h Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 16/26] scripts: Fix the inclusion order in modpost Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 17/26] linux/elfnote.h: Replace elf.h with UAPI equivalent Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 18/26] arm64: Introduce asm/vdso/processor.h Vincenzo Frascino
2020-03-15 18:30 ` Catalin Marinas
2020-03-16 9:42 ` Vincenzo Frascino
2020-03-16 10:22 ` Mark Rutland
2020-03-16 10:26 ` Catalin Marinas
2020-03-16 10:29 ` Mark Rutland
2020-03-16 10:30 ` Vincenzo Frascino
2020-03-16 10:29 ` Vincenzo Frascino
2020-03-16 10:34 ` Catalin Marinas [this message]
2020-03-16 10:55 ` Vincenzo Frascino
2020-03-16 11:22 ` Catalin Marinas
2020-03-16 13:35 ` Vincenzo Frascino
2020-03-16 14:43 ` Catalin Marinas
2020-03-16 15:33 ` Vincenzo Frascino
2020-03-16 15:49 ` Catalin Marinas
2020-03-16 16:05 ` Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 19/26] arm64: vdso: Include common headers in the vdso library Vincenzo Frascino
2020-03-15 18:30 ` Catalin Marinas
2020-03-13 15:43 ` [PATCH v3 20/26] arm64: vdso32: " Vincenzo Frascino
2020-03-15 18:30 ` Catalin Marinas
2020-03-13 15:43 ` [PATCH v3 21/26] arm64: Introduce asm/vdso/arch_timer.h Vincenzo Frascino
2020-03-15 18:32 ` Catalin Marinas
2020-03-16 15:37 ` Vincenzo Frascino
2020-04-09 13:26 ` Will Deacon
2020-04-09 13:36 ` Vincenzo Frascino
2020-03-16 10:28 ` Mark Rutland
2020-03-13 15:43 ` [PATCH v3 22/26] mips: vdso: Enable mips to use common headers Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 23/26] x86: vdso: Enable x86 " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 24/26] arm: vdso: Enable arm " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 25/26] lib: vdso: Enable " Vincenzo Frascino
2020-03-13 15:43 ` [PATCH v3 26/26] arm64: vdso32: Enable Clang Compilation Vincenzo Frascino
2020-03-16 9:17 ` Catalin Marinas
2020-03-13 16:19 ` [PATCH v3 00/26] Introduce common headers for vDSO Dmitry Safonov
2020-03-15 10:02 ` Thomas Gleixner
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