From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 348D12C81 for ; Wed, 20 Oct 2021 07:51:00 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3E15A2F; Wed, 20 Oct 2021 00:50:54 -0700 (PDT) Received: from [192.168.1.131] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2B0273F70D; Wed, 20 Oct 2021 00:50:51 -0700 (PDT) Subject: Re: [PATCH v2 1/4] arm64: vdso32: drop the test for dmb ishld To: Nick Desaulniers , Catalin Marinas , Will Deacon Cc: llvm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Nathan Chancellor , Christian Biesinger , Simon Marchi References: <20211019223646.1146945-1-ndesaulniers@google.com> <20211019223646.1146945-2-ndesaulniers@google.com> From: Vincenzo Frascino Message-ID: Date: Wed, 20 Oct 2021 09:51:18 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20211019223646.1146945-2-ndesaulniers@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 10/20/21 12:36 AM, Nick Desaulniers wrote: > Binutils added support for this instruction in commit > e797f7e0b2bedc9328d4a9a0ebc63ca7a2dbbebc which shipped in 2.24 (just > missing the 2.33 release) but was cherry-picked into 2.23 in commit s/just missing the 2.33 release/just missing the 2.23 release/ > 27a50d6755bae906bc73b4ec1a8b448467f0bea1. Thanks to Christian and Simon > for helping me with the patch archaeology. > > According to Documentation/process/changes.rst, the minimum supported > version of binutils is 2.23. Since all supported versions of GAS support > this instruction, drop the assembler invocation, preprocessor > flags/guards, and the cross assembler macro that's now unused. > > This also avoids a recursive self reference in a follow up cleanup > patch. > > Cc: Christian Biesinger > Cc: Simon Marchi > Signed-off-by: Nick Desaulniers Otherwise: Reviewed-by: Vincenzo Frascino > --- > Changes v1 -> v2: > * Fix typos (2.33 -> 2.23, 2.34 -> 2.24) as per Christian. > > arch/arm64/include/asm/vdso/compat_barrier.h | 2 +- > arch/arm64/kernel/vdso32/Makefile | 8 -------- > 2 files changed, 1 insertion(+), 9 deletions(-) > > diff --git a/arch/arm64/include/asm/vdso/compat_barrier.h b/arch/arm64/include/asm/vdso/compat_barrier.h > index 3fd8fd6d8fc2..fb60a88b5ed4 100644 > --- a/arch/arm64/include/asm/vdso/compat_barrier.h > +++ b/arch/arm64/include/asm/vdso/compat_barrier.h > @@ -20,7 +20,7 @@ > > #define dmb(option) __asm__ __volatile__ ("dmb " #option : : : "memory") > > -#if __LINUX_ARM_ARCH__ >= 8 && defined(CONFIG_AS_DMB_ISHLD) > +#if __LINUX_ARM_ARCH__ >= 8 > #define aarch32_smp_mb() dmb(ish) > #define aarch32_smp_rmb() dmb(ishld) > #define aarch32_smp_wmb() dmb(ishst) > diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile > index 3dba0c4f8f42..89299a26638b 100644 > --- a/arch/arm64/kernel/vdso32/Makefile > +++ b/arch/arm64/kernel/vdso32/Makefile > @@ -29,8 +29,6 @@ cc32-option = $(call try-run,\ > $(CC_COMPAT) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2)) > cc32-disable-warning = $(call try-run,\ > $(CC_COMPAT) -W$(strip $(1)) -c -x c /dev/null -o "$$TMP",-Wno-$(strip $(1))) > -cc32-as-instr = $(call try-run,\ > - printf "%b\n" "$(1)" | $(CC_COMPAT) $(VDSO_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) > > # We cannot use the global flags to compile the vDSO files, the main reason > # being that the 32-bit compiler may be older than the main (64-bit) compiler > @@ -113,12 +111,6 @@ endif > VDSO_AFLAGS := $(VDSO_CAFLAGS) > VDSO_AFLAGS += -D__ASSEMBLY__ > > -# Check for binutils support for dmb ishld > -dmbinstr := $(call cc32-as-instr,dmb ishld,-DCONFIG_AS_DMB_ISHLD=1) > - > -VDSO_CFLAGS += $(dmbinstr) > -VDSO_AFLAGS += $(dmbinstr) > - > # From arm vDSO Makefile > VDSO_LDFLAGS += -Bsymbolic --no-undefined -soname=linux-vdso.so.1 > VDSO_LDFLAGS += -z max-page-size=4096 -z common-page-size=4096 > -- Regards, Vincenzo