From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFF78C77B61 for ; Mon, 24 Apr 2023 13:33:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232539AbjDXNdr (ORCPT ); Mon, 24 Apr 2023 09:33:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232560AbjDXNd3 (ORCPT ); Mon, 24 Apr 2023 09:33:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 144AD8690 for ; Mon, 24 Apr 2023 06:33:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id B82CB62332 for ; Mon, 24 Apr 2023 13:33:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB8EBC433D2; Mon, 24 Apr 2023 13:33:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1682343188; bh=/W9s31DHC7xP0Q+IyCK4NLGcdW4czDtsgWCdEtzKh/U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=EMZk132QcwXAv8QNVH1qmKXVROJbT5mfoNA+kC+8IPQp5krflQuCG/F8wBM7n1JTq /7ugOjDAJmbcACoPDj4S4uxC5MCc6NArUwQcWmjudxfGDlTnKuD0DQGLsOtm7UZgA2 8rnSNw0Kdmz/JbjvKeLcVcSKvM632rsOakdIay04= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Arnd Bergmann , Huacai Chen Subject: [PATCH 6.2 097/110] LoongArch: Make -mstrict-align configurable Date: Mon, 24 Apr 2023 15:17:59 +0200 Message-Id: <20230424131140.190795824@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230424131136.142490414@linuxfoundation.org> References: <20230424131136.142490414@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Huacai Chen commit 41596803302d83a67a80dc1efef4e51ac46acabb upstream. Introduce Kconfig option ARCH_STRICT_ALIGN to make -mstrict-align be configurable. Not all LoongArch cores support h/w unaligned access, we can use the -mstrict-align build parameter to prevent unaligned accesses. CPUs with h/w unaligned access support: Loongson-2K2000/2K3000/3A5000/3C5000/3D5000. CPUs without h/w unaligned access support: Loongson-2K500/2K1000. This option is enabled by default to make the kernel be able to run on all LoongArch systems. But you can disable it manually if you want to run kernel only on systems with h/w unaligned access support in order to optimise for performance. Reviewed-by: Arnd Bergmann Signed-off-by: Huacai Chen Signed-off-by: Greg Kroah-Hartman --- arch/loongarch/Kconfig | 19 +++++++++++++++++++ arch/loongarch/Makefile | 5 +++++ arch/loongarch/kernel/Makefile | 4 +++- arch/loongarch/kernel/traps.c | 9 +++++++-- 4 files changed, 34 insertions(+), 3 deletions(-) --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -94,6 +94,7 @@ config LOONGARCH select HAVE_DYNAMIC_FTRACE_WITH_ARGS select HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_EBPF_JIT + select HAVE_EFFICIENT_UNALIGNED_ACCESS if !ARCH_STRICT_ALIGN select HAVE_EXIT_THREAD select HAVE_FAST_GUP select HAVE_FTRACE_MCOUNT_RECORD @@ -441,6 +442,24 @@ config ARCH_IOREMAP protection support. However, you can enable LoongArch DMW-based ioremap() for better performance. +config ARCH_STRICT_ALIGN + bool "Enable -mstrict-align to prevent unaligned accesses" if EXPERT + default y + help + Not all LoongArch cores support h/w unaligned access, we can use + -mstrict-align build parameter to prevent unaligned accesses. + + CPUs with h/w unaligned access support: + Loongson-2K2000/2K3000/3A5000/3C5000/3D5000. + + CPUs without h/w unaligned access support: + Loongson-2K500/2K1000. + + This option is enabled by default to make the kernel be able to run + on all LoongArch systems. But you can disable it manually if you want + to run kernel only on systems with h/w unaligned access support in + order to optimise for performance. + config KEXEC bool "Kexec system call" select KEXEC_CORE --- a/arch/loongarch/Makefile +++ b/arch/loongarch/Makefile @@ -91,10 +91,15 @@ KBUILD_CPPFLAGS += -DVMLINUX_LOAD_ADDRES # instead of .eh_frame so we don't discard them. KBUILD_CFLAGS += -fno-asynchronous-unwind-tables +ifdef CONFIG_ARCH_STRICT_ALIGN # Don't emit unaligned accesses. # Not all LoongArch cores support unaligned access, and as kernel we can't # rely on others to provide emulation for these accesses. KBUILD_CFLAGS += $(call cc-option,-mstrict-align) +else +# Optimise for performance on hardware supports unaligned access. +KBUILD_CFLAGS += $(call cc-option,-mno-strict-align) +endif KBUILD_CFLAGS += -isystem $(shell $(CC) -print-file-name=include) --- a/arch/loongarch/kernel/Makefile +++ b/arch/loongarch/kernel/Makefile @@ -8,13 +8,15 @@ extra-y := vmlinux.lds obj-y += head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \ traps.o irq.o idle.o process.o dma.o mem.o io.o reset.o switch.o \ elf.o syscall.o signal.o time.o topology.o inst.o ptrace.o vdso.o \ - alternative.o unaligned.o unwind.o + alternative.o unwind.o obj-$(CONFIG_ACPI) += acpi.o obj-$(CONFIG_EFI) += efi.o obj-$(CONFIG_CPU_HAS_FPU) += fpu.o +obj-$(CONFIG_ARCH_STRICT_ALIGN) += unaligned.o + ifdef CONFIG_FUNCTION_TRACER ifndef CONFIG_DYNAMIC_FTRACE obj-y += mcount.o ftrace.o --- a/arch/loongarch/kernel/traps.c +++ b/arch/loongarch/kernel/traps.c @@ -371,9 +371,14 @@ int no_unaligned_warning __read_mostly = asmlinkage void noinstr do_ale(struct pt_regs *regs) { - unsigned int *pc; irqentry_state_t state = irqentry_enter(regs); +#ifndef CONFIG_ARCH_STRICT_ALIGN + die_if_kernel("Kernel ale access", regs); + force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr); +#else + unsigned int *pc; + perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, regs->csr_badvaddr); /* @@ -397,8 +402,8 @@ asmlinkage void noinstr do_ale(struct pt sigbus: die_if_kernel("Kernel ale access", regs); force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr); - out: +#endif irqentry_exit(regs, state); }