From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: [PATCH v3 00/12] Rework READ_ONCE() to improve codegen Date: Wed, 15 Apr 2020 17:52:06 +0100 Message-ID: <20200415165218.20251-1-will@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: Received: from mail.kernel.org ([198.145.29.99]:54656 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2410478AbgDOQwt (ORCPT ); Wed, 15 Apr 2020 12:52:49 -0400 Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, kernel-team@android.com, Will Deacon , Michael Ellerman , Peter Zijlstra , Linus Torvalds , Segher Boessenkool , Christian Borntraeger , Luc Van Oostenryck , Arnd Bergmann , Peter Oberparleiter , Masahiro Yamada , Nick Desaulniers Hi everyone, This is version three of the patches I previously posted for improving the code generation of READ_ONCE() and moving the minimum GCC version to 4.8: RFC: https://lore.kernel.org/lkml/20200110165636.28035-1-will@kernel.org v2: https://lore.kernel.org/lkml/20200123153341.19947-1-will@kernel.org Although v2 was queued up by Peter in -tip, it was found to break the build for m68k and sparc32. We fixed m68k during the merge window and I've since posted patches to fix sparc32 here: https://lore.kernel.org/lkml/20200414214011.2699-1-will@kernel.org This series is a refresh on top of 5.7-rc1, the main changes being: * Fix another issue where 'const' is assigned to non-const via WRITE_ONCE(), this time in the tls code * Fix READ_ONCE_NOCHECK() abuse in arm64 checksum code * Added Reviewed-bys and Acks from v2 Hopefully this can be considered for 5.8, along with the sparc32 changes. Cheers, Will Cc: Michael Ellerman Cc: Peter Zijlstra Cc: Linus Torvalds Cc: Segher Boessenkool Cc: Christian Borntraeger Cc: Luc Van Oostenryck Cc: Arnd Bergmann Cc: Peter Oberparleiter Cc: Masahiro Yamada Cc: Nick Desaulniers --->8 Will Deacon (12): compiler/gcc: Emit build-time warning for GCC prior to version 4.8 netfilter: Avoid assigning 'const' pointer to non-const pointer net: tls: Avoid assigning 'const' pointer to non-const pointer fault_inject: Don't rely on "return value" from WRITE_ONCE() arm64: csum: Disable KASAN for do_csum() READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses READ_ONCE: Drop pointer qualifiers when reading from scalar types locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 gcov: Remove old GCC 3.4 support Documentation/process/changes.rst | 2 +- arch/arm/crypto/Kconfig | 12 +- arch/arm64/include/asm/barrier.h | 16 +- arch/arm64/lib/csum.c | 20 +- crypto/Kconfig | 1 - drivers/xen/time.c | 2 +- include/asm-generic/barrier.h | 16 +- include/linux/compiler-gcc.h | 5 +- include/linux/compiler.h | 129 +++---- include/linux/compiler_types.h | 21 ++ init/Kconfig | 5 +- kernel/gcov/Kconfig | 24 -- kernel/gcov/Makefile | 3 +- kernel/gcov/gcc_3_4.c | 573 ------------------------------ lib/fault-inject.c | 4 +- net/netfilter/core.c | 2 +- net/tls/tls_main.c | 2 +- scripts/Kconfig.include | 6 + scripts/gcc-plugins/Kconfig | 2 +- 19 files changed, 126 insertions(+), 719 deletions(-) delete mode 100644 kernel/gcov/gcc_3_4.c -- 2.26.0.110.g2183baf09c-goog