From patchwork Thu Jun 12 15:42:35 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 4342911 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 03EC6BEEAA for ; Thu, 12 Jun 2014 15:45:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0E67420373 for ; Thu, 12 Jun 2014 15:45:01 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2785620375 for ; Thu, 12 Jun 2014 15:45:00 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wv79l-00051T-69; Thu, 12 Jun 2014 15:43:13 +0000 Received: from mail-wg0-f42.google.com ([74.125.82.42]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wv79e-0004oY-J1 for linux-arm-kernel@lists.infradead.org; Thu, 12 Jun 2014 15:43:08 +0000 Received: by mail-wg0-f42.google.com with SMTP id z12so1423408wgg.1 for ; Thu, 12 Jun 2014 08:42:44 -0700 (PDT) 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; bh=ynRixNvX5kAlYasKOMqfB3QI6RUqKtSP8DRMoL/yrfw=; b=hMWRvHVUFvG25mXzxBaSdkGFZB8xprV8NKQezwaEmZbJZ7ZLXLoAj+k6HVsx30JgJW ny1lEPHF7zWPR7aUEKQSK2MZvX4lzDQsjgvJjGVlC8ZZyFJt9eoJHaJgb7G6jrh4SNwf xuEH+T/SpeIF9/LrHGSgb1g8etkvB04XldkVnxK7u+D8JJjMteT5V+x5RrEFFrblNLHK 3ugfA8zahLr+tBrQtxCsAhUlAERpNTPAjTx/xuV6V+H+rMSDon/G89zvcPRAmwuFPCD/ H1ji96CHz4SsadODVd6aY3AE/Kx6YGWBVGChwBUgk/ckN61fQz0HuwyYNpcJEv8888Zk TKvg== X-Gm-Message-State: ALoCoQkNAZyd+T0xaA5V+0KxW2KHuBmj2dJzvITUaXgUqXg5IcVE//3Se9AQvPjiONN34N3f8Wbo X-Received: by 10.180.97.131 with SMTP id ea3mr7410226wib.35.1402587763889; Thu, 12 Jun 2014 08:42:43 -0700 (PDT) Received: from sundance.lan (cpc4-aztw19-0-0-cust157.18-1.cable.virginm.net. [82.33.25.158]) by mx.google.com with ESMTPSA id s14sm2186087wij.1.2014.06.12.08.42.42 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Jun 2014 08:42:42 -0700 (PDT) From: Daniel Thompson To: Russell King Subject: [PATCH v3] ARM: add get_user() support for 8 byte types Date: Thu, 12 Jun 2014 16:42:35 +0100 Message-Id: <1402587755-29245-1-git-send-email-daniel.thompson@linaro.org> X-Mailer: git-send-email 1.9.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140612_084306_839982_129F7383 X-CRM114-Status: GOOD ( 16.05 ) X-Spam-Score: -0.7 (/) Cc: Nicolas Pitre , Daniel Thompson , linaro-kernel@lists.linaro.org, patches@linaro.org, linux-kernel@vger.kernel.org, Rob Clark , Arnd Bergmann , linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP A new atomic modeset/pageflip ioctl being developed in DRM requires get_user() to work for 64bit types (in addition to just put_user()). v1: original v2: pass correct size to check_uaccess, and better handling of narrowing double word read with __get_user_xb() (Russell King's suggestion) v3: fix a couple of checkpatch issues Signed-off-by: Rob Clark Signed-off-by: Daniel Thompson Cc: Russell King - ARM Linux --- Notes: I'd like to wake this patch up again. It was rejected back in 2012 on the grounds that other architectures (notably x86-32) didn't implement this so adding for ARM risked portability problems in drivers. However shortly after the discussion (in fact I believe that as a *result* of that discussion) support for 64-bit get_user() was added for x86-32. A quick review of different architectures uaccess.h shows that ARM is in the minority (even after excluding 64-bit architectures) in not implementing this feature. The reasons to wake it up are the same as before. Recent contributions, including to DRM[1] and binder[2] would prefer to use the 64-bit values in their interfaces without gotchas like having to use copy_from_user(). [1] http://thread.gmane.org/gmane.comp.video.dri.devel/102135/focus=102149 [2] http://thread.gmane.org/gmane.linux.kernel/1653448/focus=1653449 arch/arm/include/asm/uaccess.h | 18 +++++++++++++++++- arch/arm/lib/getuser.S | 17 ++++++++++++++++- 2 files changed, 33 insertions(+), 2 deletions(-) diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h index 75d9579..5f7db3fb 100644 --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -107,6 +107,7 @@ static inline void set_fs(mm_segment_t fs) extern int __get_user_1(void *); extern int __get_user_2(void *); extern int __get_user_4(void *); +extern int __get_user_8(void *); #define __GUP_CLOBBER_1 "lr", "cc" #ifdef CONFIG_CPU_USE_DOMAINS @@ -115,6 +116,7 @@ extern int __get_user_4(void *); #define __GUP_CLOBBER_2 "lr", "cc" #endif #define __GUP_CLOBBER_4 "lr", "cc" +#define __GUP_CLOBBER_8 "lr", "cc" #define __get_user_x(__r2,__p,__e,__l,__s) \ __asm__ __volatile__ ( \ @@ -125,11 +127,19 @@ extern int __get_user_4(void *); : "0" (__p), "r" (__l) \ : __GUP_CLOBBER_##__s) +/* narrowing a double-word get into a single 32bit word register: */ +#ifdef BIG_ENDIAN +#define __get_user_xb(__r2, __p, __e, __l, __s) \ + __get_user_x(__r2, (uintptr_t)__p + 4, __e, __l, __s) +#else +#define __get_user_xb __get_user_x +#endif + #define __get_user_check(x,p) \ ({ \ unsigned long __limit = current_thread_info()->addr_limit - 1; \ register const typeof(*(p)) __user *__p asm("r0") = (p);\ - register unsigned long __r2 asm("r2"); \ + register typeof(x) __r2 asm("r2"); \ register unsigned long __l asm("r1") = __limit; \ register int __e asm("r0"); \ switch (sizeof(*(__p))) { \ @@ -142,6 +152,12 @@ extern int __get_user_4(void *); case 4: \ __get_user_x(__r2, __p, __e, __l, 4); \ break; \ + case 8: \ + if (sizeof((x)) < 8) \ + __get_user_xb(__r2, __p, __e, __l, 4); \ + else \ + __get_user_x(__r2, __p, __e, __l, 8); \ + break; \ default: __e = __get_user_bad(); break; \ } \ x = (typeof(*(p))) __r2; \ diff --git a/arch/arm/lib/getuser.S b/arch/arm/lib/getuser.S index 9b06bb4..ed98707 100644 --- a/arch/arm/lib/getuser.S +++ b/arch/arm/lib/getuser.S @@ -18,7 +18,7 @@ * Inputs: r0 contains the address * r1 contains the address limit, which must be preserved * Outputs: r0 is the error code - * r2 contains the zero-extended value + * r2, r3 contains the zero-extended value * lr corrupted * * No other registers must be altered. (see @@ -66,6 +66,19 @@ ENTRY(__get_user_4) mov pc, lr ENDPROC(__get_user_4) +ENTRY(__get_user_8) + check_uaccess r0, 8, r1, r2, __get_user_bad +#ifdef CONFIG_THUMB2_KERNEL +5: TUSER(ldr) r2, [r0] +6: TUSER(ldr) r3, [r0, #4] +#else +5: TUSER(ldr) r2, [r0], #4 +6: TUSER(ldr) r3, [r0] +#endif + mov r0, #0 + mov pc, lr +ENDPROC(__get_user_8) + __get_user_bad: mov r2, #0 mov r0, #-EFAULT @@ -77,4 +90,6 @@ ENDPROC(__get_user_bad) .long 2b, __get_user_bad .long 3b, __get_user_bad .long 4b, __get_user_bad + .long 5b, __get_user_bad + .long 6b, __get_user_bad .popsection