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[2001:4830:134:3::11]) by mx.google.com with ESMTPS id p68si22487899qgp.56.2016.04.04.07.37.33 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 04 Apr 2016 07:37:33 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) client-ip=2001:4830:134:3::11; Authentication-Results: mx.google.com; dkim=fail header.i=@linaro.org; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 2001:4830:134:3::11 as permitted sender) smtp.mailfrom=qemu-devel-bounces+patch=linaro.org@nongnu.org; dmarc=fail (p=NONE dis=NONE) header.from=linaro.org Received: from localhost ([::1]:59022 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an5dF-0007XK-Bq for patch@linaro.org; Mon, 04 Apr 2016 10:37:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43311) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an5bg-0005Th-KD for qemu-devel@nongnu.org; Mon, 04 Apr 2016 10:35:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1an5be-0004Br-HU for qemu-devel@nongnu.org; Mon, 04 Apr 2016 10:35:56 -0400 Received: from mail-qg0-x22e.google.com ([2607:f8b0:400d:c04::22e]:36167) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1an5be-0004Bm-CV for qemu-devel@nongnu.org; Mon, 04 Apr 2016 10:35:54 -0400 Received: by mail-qg0-x22e.google.com with SMTP id f52so55964029qga.3 for ; Mon, 04 Apr 2016 07:35:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=xG7tjwm+lrHzYgvRDbyX0Ox0Otme2NXUgzpTQU2Dywg=; b=Obrpm44CafTixkZ6xyk3yYcaxPqbtVBNd9KH7efBgmQ9p8bunsf4VCwtcEBNM84Ul5 bpZVH3SM3HGgThCGROZH7SNvSPtZ0MyNdLYU/+rV9CEc/kyOVQwElAd3ggEw+6/BaKia sDGaUW+K7riNhR3D5yqLzmYyxKOwh9pyXuoPw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=xG7tjwm+lrHzYgvRDbyX0Ox0Otme2NXUgzpTQU2Dywg=; b=CKg5UPakMFNXrWzFi2Rs2zzyFw3//P4akT8u0A9ZKv+Grot+/aya3JAYv/GFSXK15N eZYUzShFH0tOeXrSewqkJxbGlz34vrup9kQ8uBrAgaJU35580H0WN/5+ud9L7AszSe2G jaz538a4VI7UL/mX2D10TicxPLT4iSqpJSfLBKY8+XDlO38NCTD2OUJrJ0jGQWbhDYOr JGfsv58nDD6pUJf+LbVxUXdQ6vzBzbaUlzLfm9/mzLal6Rirv7Pki0yfZElldp1FpmL5 IQna6HlLRYLkmz+ba//m0T48CHfWMAyv7Fv3NiTPT+FrVVxwLgrC0Gqd4WqFO9dAZPmx CVCQ== X-Gm-Message-State: AD7BkJJomb2xkk6FFQ3QJ28u3Kfb4VIozpSrSjOgPF/aTlkiNyakB+MXhFvGsYEJEaz9l09Z X-Received: by 10.194.60.235 with SMTP id k11mr986289wjr.148.1459780553651; Mon, 04 Apr 2016 07:35:53 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id ei9sm29496795wjd.40.2016.04.04.07.35.50 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 04 Apr 2016 07:35:51 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id 725073E0951; Mon, 4 Apr 2016 15:35:51 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: peter.maydell@linaro.org Date: Mon, 4 Apr 2016 15:35:49 +0100 Message-Id: <1459780549-12942-3-git-send-email-alex.bennee@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1459780549-12942-1-git-send-email-alex.bennee@linaro.org> References: <1459780549-12942-1-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:400d:c04::22e Cc: =?UTF-8?q?Alex=20Benn=C3=A9e?= , pbonzini@redhat.com, sbruno@freebsd.org, qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH v2 2/2] include/qemu/atomic: add compile time asserts X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org To be safely portable no atomic access should be trying to do more than the natural word width of the host. The most common abuse is trying to atomically access 64 bit values on a 32 bit host. This patch adds some QEMU_BUILD_BUG_ON to the __atomic instrinsic paths to create a build failure if (sizeof(*ptr) > sizeof(void *)). Signed-off-by: Alex Bennée --- include/qemu/atomic.h | 58 ++++++++++++++++++++++++++++++--------------------- 1 file changed, 34 insertions(+), 24 deletions(-) -- 2.7.4 diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index 8f1d8d9..5bc4d6c 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -42,30 +42,34 @@ * loads/stores past the atomic operation load/store. However there is * no explicit memory barrier for the processor. */ -#define atomic_read(ptr) \ - ({ \ - typeof(*ptr) _val; \ - __atomic_load(ptr, &_val, __ATOMIC_RELAXED); \ - _val; \ +#define atomic_read(ptr) \ + ({ \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ + typeof(*ptr) _val; \ + __atomic_load(ptr, &_val, __ATOMIC_RELAXED); \ + _val; \ }) -#define atomic_set(ptr, i) do { \ - typeof(*ptr) _val = (i); \ - __atomic_store(ptr, &_val, __ATOMIC_RELAXED); \ +#define atomic_set(ptr, i) do { \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ + typeof(*ptr) _val = (i); \ + __atomic_store(ptr, &_val, __ATOMIC_RELAXED); \ } while(0) /* Atomic RCU operations imply weak memory barriers */ -#define atomic_rcu_read(ptr) \ - ({ \ - typeof(*ptr) _val; \ - __atomic_load(ptr, &_val, __ATOMIC_CONSUME); \ - _val; \ +#define atomic_rcu_read(ptr) \ + ({ \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ + typeof(*ptr) _val; \ + __atomic_load(ptr, &_val, __ATOMIC_CONSUME); \ + _val; \ }) -#define atomic_rcu_set(ptr, i) do { \ - typeof(*ptr) _val = (i); \ - __atomic_store(ptr, &_val, __ATOMIC_RELEASE); \ +#define atomic_rcu_set(ptr, i) do { \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ + typeof(*ptr) _val = (i); \ + __atomic_store(ptr, &_val, __ATOMIC_RELEASE); \ } while(0) /* atomic_mb_read/set semantics map Java volatile variables. They are @@ -79,6 +83,7 @@ #if defined(_ARCH_PPC) #define atomic_mb_read(ptr) \ ({ \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ typeof(*ptr) _val; \ __atomic_load(ptr, &_val, __ATOMIC_RELAXED); \ smp_rmb(); \ @@ -86,22 +91,25 @@ }) #define atomic_mb_set(ptr, i) do { \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ typeof(*ptr) _val = (i); \ smp_wmb(); \ __atomic_store(ptr, &_val, __ATOMIC_RELAXED); \ smp_mb(); \ } while(0) #else -#define atomic_mb_read(ptr) \ - ({ \ - typeof(*ptr) _val; \ - __atomic_load(ptr, &_val, __ATOMIC_SEQ_CST); \ - _val; \ +#define atomic_mb_read(ptr) \ + ({ \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ + typeof(*ptr) _val; \ + __atomic_load(ptr, &_val, __ATOMIC_SEQ_CST); \ + _val; \ }) -#define atomic_mb_set(ptr, i) do { \ - typeof(*ptr) _val = (i); \ - __atomic_store(ptr, &_val, __ATOMIC_SEQ_CST); \ +#define atomic_mb_set(ptr, i) do { \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ + typeof(*ptr) _val = (i); \ + __atomic_store(ptr, &_val, __ATOMIC_SEQ_CST); \ } while(0) #endif @@ -109,6 +117,7 @@ /* All the remaining operations are fully sequentially consistent */ #define atomic_xchg(ptr, i) ({ \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ typeof(*ptr) _new = (i), _old; \ __atomic_exchange(ptr, &_new, &_old, __ATOMIC_SEQ_CST); \ _old; \ @@ -117,6 +126,7 @@ /* Returns the eventual value, failed or not */ #define atomic_cmpxchg(ptr, old, new) \ ({ \ + QEMU_BUILD_BUG_ON(sizeof(*ptr) > sizeof(void *)); \ typeof(*ptr) _old = (old), _new = (new); \ __atomic_compare_exchange(ptr, &_old, &_new, false, \ __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); \