From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 07294F519; Thu, 25 Jul 2024 14:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721919119; cv=none; b=WNGQE1nAq7MHJkbTCBxxQq9Y6CP4m/xm7SYB24O/V4lBAptbptEynmiOWxIXTQiggolwsp9ixVeqZjQ2YmgVkhxftrGhFAr1vRlsOwGeIQXxkbozivqa6/brdYq9aMU4UpiIjHC/j/glvzL9pYnE/WPalHJgltU8sPZx7QYQX3Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721919119; c=relaxed/simple; bh=2WaCDGe+hKRJuviBPSza/eZja65aAcN4vJ19XYYtrqY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DEyYdsk0Xwc3p7dDM3i//zggfxdmDAj+pr7RNsW3oTNGGzMSMrLsyRlBMRBtrATyKta2SK17EYMEXJPzN4UGeR0Y1ibTJN2FbNVZZw5QK6QVLg7NF9Hdk+KME4XkeZ8ZuADPAFNtxwG+8/VvmZ/z9A60n/GBbX+Qw7KPjQTfVOs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=rondybkz; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="rondybkz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84C87C116B1; Thu, 25 Jul 2024 14:51:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1721919118; bh=2WaCDGe+hKRJuviBPSza/eZja65aAcN4vJ19XYYtrqY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rondybkzsybEgAHnZr+DttN1ffDH0qqsTn0zTHsoHBujKYqo8W6RigO/6WcmzieXP 9wPXYnGtaHOzEvi1B4vX/+/baph4SilCZGPI8nQMKtUw+Y2rAC5VwBMvl5UxbASvmg gD0u6FF3BjWuCFr3nJ6rdy0OmhB7yVzhCsoCQS6w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masahiro Yamada , Ard Biesheuvel , "Russell King (Oracle)" , John Stultz Subject: [PATCH 5.15 03/87] ARM: 9324/1: fix get_user() broken with veneer Date: Thu, 25 Jul 2024 16:36:36 +0200 Message-ID: <20240725142738.556287262@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240725142738.422724252@linuxfoundation.org> References: <20240725142738.422724252@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Masahiro Yamada commit 24d3ba0a7b44c1617c27f5045eecc4f34752ab03 upstream. The 32-bit ARM kernel stops working if the kernel grows to the point where veneers for __get_user_* are created. AAPCS32 [1] states, "Register r12 (IP) may be used by a linker as a scratch register between a routine and any subroutine it calls. It can also be used within a routine to hold intermediate values between subroutine calls." However, bl instructions buried within the inline asm are unpredictable for compilers; hence, "ip" must be added to the clobber list. This becomes critical when veneers for __get_user_* are created because veneers use the ip register since commit 02e541db0540 ("ARM: 8323/1: force linker to use PIC veneers"). [1]: https://github.com/ARM-software/abi-aa/blob/2023Q1/aapcs32/aapcs32.rst Signed-off-by: Masahiro Yamada Reviewed-by: Ard Biesheuvel Signed-off-by: Russell King (Oracle) Cc: John Stultz Signed-off-by: Greg Kroah-Hartman --- arch/arm/include/asm/uaccess.h | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) --- a/arch/arm/include/asm/uaccess.h +++ b/arch/arm/include/asm/uaccess.h @@ -124,16 +124,6 @@ extern int __get_user_64t_1(void *); extern int __get_user_64t_2(void *); extern int __get_user_64t_4(void *); -#define __GUP_CLOBBER_1 "lr", "cc" -#ifdef CONFIG_CPU_USE_DOMAINS -#define __GUP_CLOBBER_2 "ip", "lr", "cc" -#else -#define __GUP_CLOBBER_2 "lr", "cc" -#endif -#define __GUP_CLOBBER_4 "lr", "cc" -#define __GUP_CLOBBER_32t_8 "lr", "cc" -#define __GUP_CLOBBER_8 "lr", "cc" - #define __get_user_x(__r2, __p, __e, __l, __s) \ __asm__ __volatile__ ( \ __asmeq("%0", "r0") __asmeq("%1", "r2") \ @@ -141,7 +131,7 @@ extern int __get_user_64t_4(void *); "bl __get_user_" #__s \ : "=&r" (__e), "=r" (__r2) \ : "0" (__p), "r" (__l) \ - : __GUP_CLOBBER_##__s) + : "ip", "lr", "cc") /* narrowing a double-word get into a single 32bit word register: */ #ifdef __ARMEB__ @@ -163,7 +153,7 @@ extern int __get_user_64t_4(void *); "bl __get_user_64t_" #__s \ : "=&r" (__e), "=r" (__r2) \ : "0" (__p), "r" (__l) \ - : __GUP_CLOBBER_##__s) + : "ip", "lr", "cc") #else #define __get_user_x_64t __get_user_x #endif