From: Catalin Marinas <catalin.marinas@arm.com>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Mark Rutland <Mark.Rutland@arm.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
linux-mips@vger.kernel.org,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Will Deacon <will@kernel.org>,
linux-arch@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
x86@kernel.org, Russell King <linux@armlinux.org.uk>,
clang-built-linux@googlegroups.com,
Ingo Molnar <mingo@redhat.com>, Kees Cook <keescook@chromium.org>,
Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Collingbourne <pcc@google.com>,
linux-arm-kernel@lists.infradead.org,
Andrei Vagin <avagin@openvz.org>,
Nick Desaulniers <ndesaulniers@google.com>,
linux-kernel@vger.kernel.org, Mark Salyzyn <salyzyn@android.com>,
Paul Burton <paul.burton@mips.com>
Subject: Re: [PATCH v5 18/26] arm64: vdso32: Code clean up
Date: Sat, 21 Mar 2020 12:06:36 +0000 [thread overview]
Message-ID: <20200321120635.GA3052@mbp> (raw)
In-Reply-To: <158474646622.125146.3263940499372231797@swboyd.mtv.corp.google.com>
On Fri, Mar 20, 2020 at 04:21:06PM -0700, Stephen Boyd wrote:
> Quoting Vincenzo Frascino (2020-03-20 07:53:43)
> > The compat vdso library had some checks that are not anymore relevant.
>
> Can we get the information on why they aren't relevant anymore in the
> commit text? I'd rather not find this commit three years from now and
> have no idea why it was applied.
Good point. But I'd rather say that the original reason for adding them
was bogus (ABI compatibility between arm64 compat and arm32, when arm32
vdso never got them).
There may be some (very hard to justify) reason to add them if we want
compatibility between vdso and syscall fallback on addresses greater
than TASK_SIZE. The vdso code generates a SIGSEGV or SIGBUS while the
syscall returns -EFAULT. However, you'd have similar mismatch on
unmapped addresses below TASK_SIZE which cannot be handled by the vdso
(not a simple comparison).
I think the vdsotest code should be adjusted accordingly.
--
Catalin
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next prev parent reply other threads:[~2020-03-21 12:06 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-20 14:53 [PATCH v5 00/26] Introduce common headers for vDSO Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 01/26] linux/const.h: Extract common header " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 02/26] linux/bits.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 03/26] linux/limits.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 04/26] x86:Introduce asm/vdso/clocksource.h Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 05/26] arm: Introduce asm/vdso/clocksource.h Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 06/26] arm64: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 07/26] mips: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 08/26] linux/clocksource.h: Extract common header for vDSO Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 09/26] linux/math64.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 10/26] linux/time.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 11/26] linux/time32.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 12/26] linux/time64.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 13/26] linux/jiffies.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 14/26] linux/ktime.h: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 15/26] common: Introduce processor.h Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 16/26] scripts: Fix the inclusion order in modpost Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 17/26] linux/elfnote.h: Replace elf.h with UAPI equivalent Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 18/26] arm64: vdso32: Code clean up Vincenzo Frascino
2020-03-20 15:26 ` Catalin Marinas
2020-03-20 23:21 ` Stephen Boyd
2020-03-21 12:06 ` Catalin Marinas [this message]
2020-03-20 14:53 ` [PATCH v5 19/26] arm64: Introduce asm/vdso/processor.h Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 20/26] arm64: vdso: Include common headers in the vdso library Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 21/26] arm64: vdso32: " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 22/26] mips: vdso: Enable mips to use common headers Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 23/26] x86: vdso: Enable x86 " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 24/26] arm: vdso: Enable arm " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 25/26] lib: vdso: Enable " Vincenzo Frascino
2020-03-20 14:53 ` [PATCH v5 26/26] arm64: vdso32: Enable Clang Compilation Vincenzo Frascino
2020-03-20 23:15 ` Stephen Boyd
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