I prefer to have the code consistent between this patch with [PATCH v2 5/6] MdeModulePkg/Crc32: Fix possible out of range left shift.
Both to use (UINT32) typecast or 1U. Liming, Do you have any comment? Thanks, Star -----Original Message----- From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of Hao Wu Sent: Thursday, September 21, 2017 2:46 PM To: edk2-devel@lists.01.org Cc: Wu, Hao A <hao.a...@intel.com>; Dong, Eric <eric.d...@intel.com>; Zeng, Star <star.z...@intel.com> Subject: [edk2] [PATCH v2 6/6] MdeModulePkg/AtaAtapiPassThru: Fix possible out of range left shift REF: https://bugzilla.tianocore.org/show_bug.cgi?id=699 Within function AhciModeInitialization(), left shift operations of 'BIT0' in the following statements: "if ((PortImplementBitMap & (BIT0 << Port)) != 0) {" will incur possible out of range left shift when Port is 31, since "1 << 31" is possible to exceed the range of type 'int' (signed). According to the C11 spec, Section 6.5.7: > 4 The result of E1 << E2 is E1 left-shifted E2 bit positions; vacated > bits are filled with zeros. If E1 has an unsigned type, the value > of the result is E1 * 2^E2 , reduced modulo one more than the > maximum value representable in the result type. If E1 has a signed > type and nonnegative value, and E1 * 2^E2 is representable in the > result type, then that is the resulting value; otherwise, the > behavior is undefined. This commit explicitly cast 'BIT0' with UINT32 to resolve this issue. Cc: Steven Shi <steven....@intel.com> Cc: Star Zeng <star.z...@intel.com> Cc: Eric Dong <eric.d...@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Hao Wu <hao.a...@intel.com> --- MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c index b954de8101..e6de5d65bc 100644 --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/AhciMode.c @@ -1,7 +1,7 @@ /** @file The file for AHCI mode of ATA host controller. - Copyright (c) 2010 - 2016, Intel Corporation. All rights reserved.<BR> + Copyright (c) 2010 - 2017, Intel Corporation. All rights + reserved.<BR> (C) Copyright 2015 Hewlett Packard Enterprise Development LP<BR> This program and the accompanying materials are licensed and made available under the terms and conditions of the BSD License @@ -2314,7 +2314,7 @@ AhciModeInitialization ( } for (Port = 0; Port < EFI_AHCI_MAX_PORTS; Port ++) { - if ((PortImplementBitMap & (BIT0 << Port)) != 0) { + if ((PortImplementBitMap & (((UINT32)BIT0) << Port)) != 0) { // // According to AHCI spec, MaxPortNumber should be equal or greater than the number of implemented ports. // -- 2.12.0.windows.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel