From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794444757; b=um5UtVmRtM9QEVmP3UoPuOuQ1oVK0KlEsGebm55DdWN2yOH8bUwJOA5HIfG8iiwlhbGe PbgjnGsLAfWJLdGuBMgvJISeeyUzaaYCwhW11JzQ4HxeFswkFDl5EPkk4YWi2GkXawAE8 jGxy9seasprpJf5jLRNvfv+kghDD9nIBrab2iVNF9RaSugJsY86Ek2FVp7Oob3Tpg02yC R1TC9l6eOmT9jvKGkk8TJYXvSiaBZAiFIF/WvxX2Ljimem24Mbk4vulGlfKMVQ6RDX22P gT8fUat3hKz5Mc873qxdeta8u4+9vDxahQzfncIsmLTX/K8Yoou/2EBYJqXuKMn3iNg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794444757; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=bYcr9YAu4elj14HSG2RihmlFTMnciZd6zAktJzPVO8A=; b=K9fCk5DfLLAeo2Wcx7lUd3wyJCQL0QJKFAKFr3Rc0nyQxtI6dZYtXlVOKmnysSikJKSy s4GgkX/C0J7JYiaFPNk2zJlziZcE1bVofJegz9lIAG+kkPZd4F0OE5HMbtDfS+daITMsF C0wuEDE7SvyFy3sAsoEjo/VmHMIxRu/y/9Uvs6sBr8/9hlcKbEoAok9b/NETpClKxlzKg Vj6KJwP6mABvEOBrbWwAEaR72kB+qGEstXOHvjR80GIGpIydeUuhjjKCSglP96nRh3W7t ZvXjjvjf4zYius6UjMn7jP0zcPi30uYLIo+j03lgsucRaog+xFwJpxnOsKAbM5czn1A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dQTUiuJf; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A4155606A887; Thu, 12 Nov 2026 00:52:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=dQTUiuJf Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85C921F00A06; Thu, 12 Nov 2026 00:52:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794444757; bh=bYcr9YAu4elj14HSG2RihmlFTMnciZd6zAktJzPVO8A=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=dQTUiuJfWsmyjtPd6PfUTpsxMMMdEhzeu4Tai0hFQIb4Plepq0zYbNNT9Vj63Hd9u J0hT/WaVqDvSnT0U+RBhZv/nM++7PfkLhE/AqDFex+e4P7ln5cfgAh+ylNIkNFsz2k CHDd2DeVBxiBxAM7t4WAGQpnBnzpd9/icWFnxQ3Bom1iEKlnlrcWLM9I+Mh2KWkFBs VVPId0l9/2wkNU6pnmcxxHQMaLK3DMAjOcICb7DPKI9jdFSzjonYl6wa3CLe88x5nX LjyuUMIJwiXH+p4z0MHq/vjdYUJyhxZazMknEFA04TZ+QBpVxtxHWzCittHR9t0017 CA38FTVznZuRQ== From: Nathan Chancellor Date: Wed, 11 Nov 2026 17:52:07 -0700 Subject: [PATCH v2 5/6] Eliminate CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261111-kconfig-toolchain-updates-v2-5-b2d9415c1757@kernel.org> References: <20261111-kconfig-toolchain-updates-v2-0-b2d9415c1757@kernel.org> In-Reply-To: <20261111-kconfig-toolchain-updates-v2-0-b2d9415c1757@kernel.org> To: Nathan Chancellor , Nicolas Schier Cc: Julian Braha , Nick Desaulniers , Bill Wendling , Justin Stitt , Arnd Bergmann , Kees Cook , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, llvm@lists.linux.dev, Linus Torvalds , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Charlie Jenkins , Paul Walmsley , Palmer Dabbelt , linux-riscv@lists.infradead.org X-Mailer: b4 0.17-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=6902; i=nathan@kernel.org; h=from:subject:message-id; bh=bW5KxTW+9OHxQgzWmPo5TtmY1egR4+hUkTkjVgF1xis=; b=owGbwMvMwCUmm602sfCA1DTG02pJDFlfefe/6ttz6tfhHBbtvu/HN6lZFQf71/XXz8rRs3x75 N4Ud/X8jlIWBjEuBlkxRZbqx6rHDQ3nnGW8cWoSzBxWJpAhDFycAjARcw5Ghns2mq07vvPNldm2 uKXN4tTRnMs3FCI+aM6XTb/it3YTgxojwyuNIjeu82+PyHIyi9sZnOjzbrm7k21af7FsgoePRVE FDwA= X-Developer-Key: i=nathan@kernel.org; a=openpgp; fpr=2437CB76E544CB6AB3D9DFD399739260CB6CB716 Commit 1aa0e8b144b6 ("Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug") added CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT to avoid a bug in clang's asm goto with outputs support when a tied output was used. The fix in clang was to match GCC's documented behavior. Now that the minimum supported version of clang has long been bumped past the version where the fix landed (clang-14), any compiler that satisfies the dependencies of CONFIG_CC_HAS_ASM_GOTO_OUTPUT will support tied outputs properly. Eliminate CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT in favor of just checking for CONFIG_CC_HAS_ASM_GOTO_OUTPUT directly. Signed-off-by: Nathan Chancellor --- Cc: Linus Torvalds Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: x86@kernel.org Cc: "H. Peter Anvin" Cc: Charlie Jenkins Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: linux-riscv@lists.infradead.org --- arch/riscv/lib/csum.c | 4 +-- arch/x86/include/asm/uaccess.h | 82 ++++++++++++++++++++---------------------- scripts/Kconfig.toolchain | 5 --- 3 files changed, 41 insertions(+), 50 deletions(-) diff --git a/arch/riscv/lib/csum.c b/arch/riscv/lib/csum.c index c2b8986a0d39..cd461a7b61a5 100644 --- a/arch/riscv/lib/csum.c +++ b/arch/riscv/lib/csum.c @@ -142,7 +142,7 @@ do_csum_with_alignment(const unsigned char *buff, int len) end = (const unsigned long *)(buff + len); csum = do_csum_common(ptr, end, data); -#ifdef CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT +#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT if (IS_ENABLED(CONFIG_RISCV_ISA_ZBB) && IS_ENABLED(CONFIG_TOOLCHAIN_HAS_ZBB) && riscv_has_extension_likely(RISCV_ISA_EXT_ZBB)) { @@ -186,7 +186,7 @@ do_csum_with_alignment(const unsigned char *buff, int len) return csum >> 16; } -#endif /* CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT */ +#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */ #ifndef CONFIG_32BIT csum += ror64(csum, 32); csum >>= 32; diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index f4700ad6b5ec..64b648e59df0 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -248,6 +248,44 @@ do { \ : [umem] "m" (__m(addr)) \ : : label) +#define __try_cmpxchg_user_asm(itype, ltype, _ptr, _pold, _new, label) ({ \ + bool success; \ + __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ + __typeof__(*(_ptr)) __old = *_old; \ + __typeof__(*(_ptr)) __new = (_new); \ + asm_goto_output("\n" \ + "1: " LOCK_PREFIX "cmpxchg"itype" %[new], %[ptr]\n"\ + _ASM_EXTABLE_UA(1b, %l[label]) \ + : "=@ccz" (success), \ + [ptr] "+m" (*_ptr), \ + [old] "+a" (__old) \ + : [new] ltype (__new) \ + : "memory" \ + : label); \ + if (unlikely(!success)) \ + *_old = __old; \ + likely(success); }) + +#ifdef CONFIG_X86_32 +#define __try_cmpxchg64_user_asm(_ptr, _pold, _new, label) ({ \ + bool success; \ + __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ + __typeof__(*(_ptr)) __old = *_old; \ + __typeof__(*(_ptr)) __new = (_new); \ + asm_goto_output("\n" \ + "1: " LOCK_PREFIX "cmpxchg8b %[ptr]\n" \ + _ASM_EXTABLE_UA(1b, %l[label]) \ + : "=@ccz" (success), \ + "+A" (__old), \ + [ptr] "+m" (*_ptr) \ + : "b" ((u32)__new), \ + "c" ((u32)((u64)__new >> 32)) \ + : "memory" \ + : label); \ + if (unlikely(!success)) \ + *_old = __old; \ + likely(success); }) +#endif // CONFIG_X86_32 #else // !CONFIG_CC_HAS_ASM_GOTO_OUTPUT #ifdef CONFIG_X86_32 @@ -313,48 +351,6 @@ do { \ : [umem] "m" (__m(addr)), \ "0" (err)) -#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT - -#ifdef CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT -#define __try_cmpxchg_user_asm(itype, ltype, _ptr, _pold, _new, label) ({ \ - bool success; \ - __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ - __typeof__(*(_ptr)) __old = *_old; \ - __typeof__(*(_ptr)) __new = (_new); \ - asm_goto_output("\n" \ - "1: " LOCK_PREFIX "cmpxchg"itype" %[new], %[ptr]\n"\ - _ASM_EXTABLE_UA(1b, %l[label]) \ - : "=@ccz" (success), \ - [ptr] "+m" (*_ptr), \ - [old] "+a" (__old) \ - : [new] ltype (__new) \ - : "memory" \ - : label); \ - if (unlikely(!success)) \ - *_old = __old; \ - likely(success); }) - -#ifdef CONFIG_X86_32 -#define __try_cmpxchg64_user_asm(_ptr, _pold, _new, label) ({ \ - bool success; \ - __typeof__(_ptr) _old = (__typeof__(_ptr))(_pold); \ - __typeof__(*(_ptr)) __old = *_old; \ - __typeof__(*(_ptr)) __new = (_new); \ - asm_goto_output("\n" \ - "1: " LOCK_PREFIX "cmpxchg8b %[ptr]\n" \ - _ASM_EXTABLE_UA(1b, %l[label]) \ - : "=@ccz" (success), \ - "+A" (__old), \ - [ptr] "+m" (*_ptr) \ - : "b" ((u32)__new), \ - "c" ((u32)((u64)__new >> 32)) \ - : "memory" \ - : label); \ - if (unlikely(!success)) \ - *_old = __old; \ - likely(success); }) -#endif // CONFIG_X86_32 -#else // !CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT #define __try_cmpxchg_user_asm(itype, ltype, _ptr, _pold, _new, label) ({ \ int __err = 0; \ bool success; \ @@ -410,7 +406,7 @@ do { \ *_old = __old; \ likely(__result); }) #endif // CONFIG_X86_32 -#endif // CONFIG_CC_HAS_ASM_GOTO_TIED_OUTPUT +#endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT /* FIXME: this hack is definitely wrong -AK */ struct __large_struct { unsigned long buf[100]; }; diff --git a/scripts/Kconfig.toolchain b/scripts/Kconfig.toolchain index 6520a06a9103..9454ef5294d5 100644 --- a/scripts/Kconfig.toolchain +++ b/scripts/Kconfig.toolchain @@ -120,11 +120,6 @@ config CC_HAS_ASM_GOTO_OUTPUT depends on !GCC_ASM_GOTO_OUTPUT_BROKEN depends on $(success,echo 'int foo(int x) { asm goto ("": "=r"(x) ::: bar); return x; bar: return 0; }' | $(CC) -x c - -c -o /dev/null) -config CC_HAS_ASM_GOTO_TIED_OUTPUT - depends on CC_HAS_ASM_GOTO_OUTPUT - # Detect buggy gcc and clang, fixed in gcc-11 clang-14. - def_bool $(success,echo 'int foo(int *x) { asm goto (".long (%l[bar]) - .": "+m"(*x) ::: bar); return *x; bar: return 0; }' | $CC -x c - -c -o /dev/null) - config TOOLS_SUPPORT_RELR def_bool $(success,env "CC=$(CC)" "LD=$(LD)" "NM=$(NM)" "OBJCOPY=$(OBJCOPY)" $(srctree)/scripts/tools-support-relr.sh) -- 2.56.0