From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751841AbcGIFCG (ORCPT ); Sat, 9 Jul 2016 01:02:06 -0400 Received: from 51.23-broadband.acttv.in ([106.51.23.179]:20973 "EHLO arvind-ThinkPad-Edge-E431" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750931AbcGIFCA (ORCPT ); Sat, 9 Jul 2016 01:02:00 -0400 X-Greylist: delayed 26169 seconds by postgrey-1.27 at vger.kernel.org; Sat, 09 Jul 2016 01:01:59 EDT From: Arvind Yadav To: scottwood@freescale.com Cc: qiang.zhao@freescale.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux@roeck-us.net, Arvind Yadav Subject: [PATCH v1] Specific requirement of type casting for 64-bit architectures. Date: Sat, 9 Jul 2016 03:15:45 +0530 Message-Id: <1468014345-14016-1-git-send-email-arvind.yadav.cs@gmail.com> X-Mailer: git-send-email 1.9.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org -Return type of 'qe_muram_alloc' is 'unsigned long', That Was trying to assigned in ucc_fast_tx_virtual_fifo_base_offset and ucc_fast_rx_virtual_fifo_base_offset. It will work on 32-bit architectures But data can be loss on 64-bit architectures if 'qe_muram_alloc' will return greater then MAX value of 'unsigned int'. -Passing value in IS_ERR_VALUE() is wrong, as they pass an 'unsigned int' into a function, It will through this compilation warning. " include/linux/err.h:21:49: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) ^ include/linux/compiler.h:170:42: note: in definition of macro ‘unlikely’ # define unlikely(x) __builtin_expect(!!(x), 0) " -Most users of IS_ERR_VALUE() in the kernel are wrong, as they pass an 'unsigned int' into a function that takes an 'unsigned long' argument. This happens to work because the type is sign-extended on 64-bit architectures before it gets converted into an unsigned type. However, anything that passes an 'unsigned short' or 'unsigned int' argument into IS_ERR_VALUE() is guaranteed to be broken, as are 8-bit integers and types that are wider than 'unsigned long'. Signed-off-by: Arvind Yadav --- drivers/soc/fsl/qe/ucc_fast.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) diff --git a/drivers/soc/fsl/qe/ucc_fast.c b/drivers/soc/fsl/qe/ucc_fast.c index a768931..208b198 100644 --- a/drivers/soc/fsl/qe/ucc_fast.c +++ b/drivers/soc/fsl/qe/ucc_fast.c @@ -141,6 +141,7 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc struct ucc_fast __iomem *uf_regs; u32 gumr; int ret; + unsigned long ret_muram; if (!uf_info) return -EINVAL; @@ -265,28 +266,34 @@ int ucc_fast_init(struct ucc_fast_info * uf_info, struct ucc_fast_private ** ucc gumr |= uf_info->mode; out_be32(&uf_regs->gumr, gumr); - /* Allocate memory for Tx Virtual Fifo */ - uccf->ucc_fast_tx_virtual_fifo_base_offset = - qe_muram_alloc(uf_info->utfs, UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT); - if (IS_ERR_VALUE(uccf->ucc_fast_tx_virtual_fifo_base_offset)) { + ret_muram = + qe_muram_alloc(uf_info->utfs, + UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT); + + if (IS_ERR_VALUE(ret_muram)) { printk(KERN_ERR "%s: cannot allocate MURAM for TX FIFO\n", __func__); uccf->ucc_fast_tx_virtual_fifo_base_offset = 0; ucc_fast_free(uccf); return -ENOMEM; + } else { + /* Allocate memory for Tx Virtual Fifo */ + uccf->ucc_fast_tx_virtual_fifo_base_offset = (u32)ret_muram; } - /* Allocate memory for Rx Virtual Fifo */ - uccf->ucc_fast_rx_virtual_fifo_base_offset = + ret_muram = qe_muram_alloc(uf_info->urfs + UCC_FAST_RECEIVE_VIRTUAL_FIFO_SIZE_FUDGE_FACTOR, UCC_FAST_VIRT_FIFO_REGS_ALIGNMENT); - if (IS_ERR_VALUE(uccf->ucc_fast_rx_virtual_fifo_base_offset)) { + if (IS_ERR_VALUE(ret_muram)) { printk(KERN_ERR "%s: cannot allocate MURAM for RX FIFO\n", __func__); uccf->ucc_fast_rx_virtual_fifo_base_offset = 0; ucc_fast_free(uccf); return -ENOMEM; + } else { + /* Allocate memory for Rx Virtual Fifo */ + uccf->ucc_fast_rx_virtual_fifo_base_offset = (u32)ret_muram; } /* Set Virtual Fifo registers */ -- 1.9.1