From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 69C2521D491A7 for ; Wed, 2 Aug 2017 05:10:16 -0700 (PDT) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga104.jf.intel.com with ESMTP; 02 Aug 2017 05:12:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,311,1498546800"; d="scan'208";a="1158194613" Received: from fmsmsx103.amr.corp.intel.com ([10.18.124.201]) by orsmga001.jf.intel.com with ESMTP; 02 Aug 2017 05:12:26 -0700 Received: from fmsmsx102.amr.corp.intel.com (10.18.124.200) by FMSMSX103.amr.corp.intel.com (10.18.124.201) with Microsoft SMTP Server (TLS) id 14.3.319.2; Wed, 2 Aug 2017 05:12:26 -0700 Received: from shsmsx104.ccr.corp.intel.com (10.239.4.70) by FMSMSX102.amr.corp.intel.com (10.18.124.200) with Microsoft SMTP Server (TLS) id 14.3.319.2; Wed, 2 Aug 2017 05:12:25 -0700 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.146]) by SHSMSX104.ccr.corp.intel.com ([10.239.4.70]) with mapi id 14.03.0319.002; Wed, 2 Aug 2017 20:12:24 +0800 From: "Gao, Liming" To: "Marvin.Haeuser@outlook.com" , "edk2-devel@lists.01.org" CC: "Kinney, Michael D" Thread-Topic: [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() function. Thread-Index: AQHTA5vus1udQdORhEegPjUTqWKZfaJjLSJAgAADdaCABJ2G8IAAEHiQgAkqlhA= Date: Wed, 2 Aug 2017 12:12:24 +0000 Message-ID: <4A89E2EF3DFEDB4C8BFDE51014F606A14D75EAD3@shsmsx102.ccr.corp.intel.com> References: <4A89E2EF3DFEDB4C8BFDE51014F606A14D75CC1D@shsmsx102.ccr.corp.intel.com> In-Reply-To: Accept-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] MIME-Version: 1.0 Subject: Re: [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() function. X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Aug 2017 12:10:16 -0000 Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Marvin: How about directly use PCD checker with IsNodeInList()? ASSERT (IsNodeInList (FirstEntry, SecondEntry)); =3D=3D> ASSERT (FeaturePcdGet (PcdVerifyNodeInList) && IsNodeInList (FirstEntry, Se= condEntry))|| InternalBaseLibIsListValid (FirstEntry)); Thanks Liming >-----Original Message----- >From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of >Marvin H?user >Sent: Friday, July 28, 2017 12:20 AM >To: edk2-devel@lists.01.org >Cc: Kinney, Michael D ; Gao, Liming > >Subject: Re: [edk2] [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() functio= n. > >Hi Liming, > >Comments are inline. Thanks for your response! > >Regards, >Marvin. > >> -----Original Message----- >> From: Gao, Liming [mailto:liming.gao@intel.com] >> Sent: Thursday, July 27, 2017 5:32 PM >> To: Marvin.Haeuser@outlook.com; edk2-devel@lists.01.org >> Cc: Kinney, Michael D >> Subject: RE: [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() function. >> >> Marvin: >> Once this API is exposed as the public library API, what code will you >update >> to consume this API? > >The code which gave me the idea for this patch is this: >https://github.com/tianocore/edk2-platforms/blob/devel- >MinPlatform/Silicon/Intel/KabylakeSiliconPkg/Pch/PchSmiDispatcher/Smm/Io >Trap.c#L508 >ForwardLink is obviously checked against EFI_BAD_POINTER to verify whether >the entry is still valid. Though, after being freed, the value stored in t= his >location may just be overwritten. >The code linked currently doesn't seem to do anything as ForwardLink is ne= ver >set to EFI_BAD_POINTER, though it can be updated with IsNodeInList() to >function (regardless of the entry being freed). >It seems to me that this is a leftover from the EDK era as EDK's >RemoveEntryList() does set the Links to EFI_BAD_POINTER. > >> >> And, for the patch, I have two comments. >> 1) Original logic uses PcdVerifyNodeInList to turn on the verification o= f >> NodeInList. New logic always turns on it. Because this check takes much >> overhead, this PCD is FALSE as the default value in MdePkg.dec. >> 2) In IsListEmpty(), ASSERT() is missing for InternalBaseLibIsListValid >> (ListHead). > >Sorry for these oversights. Would you prefer an internal, static function = or a >macro to do the PCD check and following the ASSERTin v2? > >> >> Thanks >> Liming >> > -----Original Message----- >> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of >> > Marvin H?user >> > Sent: Tuesday, July 25, 2017 12:53 AM >> > To: edk2-devel@lists.01.org >> > Cc: Kinney, Michael D >> > Subject: Re: [edk2] [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() >> function. >> > >> > Hey Mike, >> > >> > In contrast to setting 'BackLink' and 'ForwardLink' to dummy values >> > such as EFI_BAD_POINTER, verifying that a node is part of a known list >> > is a safe way to determine whether a link is still valid without >> > needing to keep the memory allocated. If the Node, which had its links >> > set to dummys, is freed, the dummy values may be overwriten and the >> > check would pass despite the node being invalid. This can, for example= , be >> used in OpenKabylake's PchSmiDispatcher, which does the described check >> against EFI_BAD_POINTER (though if I remember correctly, the value is >> actually never explicitely set). The issue is that some function may pas= s a >> handle that was unregistered to the function. IsNodeInList() can be used= to >> determine whether it was previously removed. >> > >> > Thanks for your response! >> > >> > Regards, >> > Marvin. >> > >> > > -----Original Message----- >> > > From: Kinney, Michael D [mailto:michael.d.kinney@intel.com] >> > > Sent: Monday, July 24, 2017 6:31 PM >> > > To: Marvin H=E4user ; edk2- >> > > devel@lists.01.org; Kinney, Michael D >> > > Cc: Gao, Liming >> > > Subject: RE: [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() function= . >> > > >> > > Hi Marvin, >> > > >> > > Can you provide a few more details on why you would like to see tis >> > > internal function promoted to a library class API? >> > > >> > > Thanks, >> > > >> > > Mike >> > > >> > > > -----Original Message----- >> > > > From: Marvin H=E4user [mailto:Marvin.Haeuser@outlook.com] >> > > > Sent: Sunday, July 23, 2017 3:11 AM >> > > > To: edk2-devel@lists.01.org >> > > > Cc: Kinney, Michael D ; Gao, Liming >> > > > >> > > > Subject: [PATCH 1/2] MdePkg/BaseLib: Add IsNodeInList() function. >> > > > >> > > > This patch adds IsNodeInList() to BaseLib, which verifies the >> > > > given Node is part of the doubly-linked List provided. >> > > > >> > > > Contributed-under: TianoCore Contribution Agreement 1.1 >> > > > Signed-off-by: Marvin Haeuser >> > > > --- >> > > > MdePkg/Library/BaseLib/LinkedList.c | 70 >> > > > +++++++++++++++++++- >> > > > MdePkg/Include/Library/BaseLib.h | 25 +++++++ >> > > > MdePkg/Library/BaseLib/BaseLibInternals.h | 28 -------- >> > > > 3 files changed, 94 insertions(+), 29 deletions(-) >> > > > >> > > > diff --git a/MdePkg/Library/BaseLib/LinkedList.c >> > > > b/MdePkg/Library/BaseLib/LinkedList.c >> > > > index ba373f4b7be3..b364ae41c647 100644 >> > > > --- a/MdePkg/Library/BaseLib/LinkedList.c >> > > > +++ b/MdePkg/Library/BaseLib/LinkedList.c >> > > > @@ -1,7 +1,7 @@ >> > > > /** @file >> > > > Linked List Library Functions. >> > > > >> > > > - Copyright (c) 2006 - 2013, Intel Corporation. All rights >> > > > reserved.
>> > > > + Copyright (c) 2006 - 2017, Intel Corporation. All rights >> > > > reserved.
>> > > > This program and the accompanying materials >> > > > are licensed and made available under the terms and conditions >> > > > of the BSD License >> > > > which accompanies this distribution. The full text of the >> > > > license may be found at @@ -113,6 +113,74 @@ >> > > > InternalBaseLibIsNodeInList ( } >> > > > >> > > > /** >> > > > + Checks whether Node is part of a doubly-linked list. >> > > > + >> > > > + If List is NULL, then ASSERT(). >> > > > + If List->ForwardLink is NULL, then ASSERT(). >> > > > + If List->BackLink is NULL, then ASSERT(). >> > > > + If Node is NULL, then ASSERT(); If PcdMaximumLinkedListLength >> > > > + is not zero, and List contains >> > > > more than >> > > > + PcdMaximumLinkedListLength nodes, then ASSERT(). >> > > > + >> > > > + @param List A pointer to a node in a linked list. >> > > > + @param Node A pointer to the node to locate. >> > > > + >> > > > + @retval TRUE Node is in List. >> > > > + @retval FALSE Node isn't in List, or List is invalid. >> > > > + >> > > > +**/ >> > > > +BOOLEAN >> > > > +EFIAPI >> > > > +IsNodeInList ( >> > > > + IN CONST LIST_ENTRY *List, >> > > > + IN CONST LIST_ENTRY *Node >> > > > + ) >> > > > +{ >> > > > + UINTN Count; >> > > > + CONST LIST_ENTRY *Ptr; >> > > > + >> > > > + // >> > > > + // Test the validity of List and Node // ASSERT (List !=3D >> > > > + NULL); ASSERT (List->ForwardLink !=3D NULL); ASSERT >> > > > + (List->BackLink !=3D NULL); ASSERT (Node !=3D NULL); >> > > > + >> > > > + // >> > > > + // ASSERT List not too long >> > > > + // >> > > > + ASSERT (InternalBaseLibIsNodeInList (ListHead, Entry, FALSE)); >> > > > + >> > > > + Count =3D 0; >> > > > + Ptr =3D List; >> > > > + >> > > > + // >> > > > + // Check to see if Node is a member of List. >> > > > + // Exit early if the number of nodes in List >=3D >> > > > PcdMaximumLinkedListLength >> > > > + // >> > > > + do { >> > > > + Ptr =3D Ptr->ForwardLink; >> > > > + if (PcdGet32 (PcdMaximumLinkedListLength) > 0) { >> > > > + Count++; >> > > > + >> > > > + // >> > > > + // Return if the linked list is too long >> > > > + // >> > > > + if (Count =3D=3D PcdGet32 (PcdMaximumLinkedListLength)) { >> > > > + return (BOOLEAN)(Ptr =3D=3D Node); >> > > > + } >> > > > + } >> > > > + >> > > > + if (Ptr =3D=3D Node) { >> > > > + return TRUE; >> > > > + } >> > > > + } while (Ptr !=3D List); >> > > > + >> > > > + return FALSE; >> > > > +} >> > > > + >> > > > +/** >> > > > Initializes the head node of a doubly-linked list, and returns >> > > > the pointer to >> > > > the head node of the doubly-linked list. >> > > > >> > > > diff --git a/MdePkg/Include/Library/BaseLib.h >> > > > b/MdePkg/Include/Library/BaseLib.h >> > > > index 791849b80406..4f3f4fd51f3f 100644 >> > > > --- a/MdePkg/Include/Library/BaseLib.h >> > > > +++ b/MdePkg/Include/Library/BaseLib.h >> > > > @@ -2869,6 +2869,31 @@ PathCleanUpDirectories( >> > > > >> > > > >> > > > /** >> > > > + Checks whether Node is part of a doubly-linked list. >> > > > + >> > > > + If List is NULL, then ASSERT(). >> > > > + If List->ForwardLink is NULL, then ASSERT(). >> > > > + If List->BackLink is NULL, then ASSERT(). >> > > > + If Node is NULL, then ASSERT(); If PcdMaximumLinkedListLength >> > > > + is not zero, and List contains >> > > > more than >> > > > + PcdMaximumLinkedListLength nodes, then ASSERT(). >> > > > + >> > > > + @param List A pointer to a node in a linked list. >> > > > + @param Node A pointer to the node to locate. >> > > > + >> > > > + @retval TRUE Node is in List. >> > > > + @retval FALSE Node isn't in List, or List is invalid. >> > > > + >> > > > +**/ >> > > > +BOOLEAN >> > > > +EFIAPI >> > > > +IsNodeInList ( >> > > > + IN CONST LIST_ENTRY *List, >> > > > + IN CONST LIST_ENTRY *Node >> > > > + ); >> > > > + >> > > > + >> > > > +/** >> > > > Initializes the head node of a doubly linked list, and returns >> > > > the pointer to >> > > > the head node of the doubly linked list. >> > > > >> > > > diff --git a/MdePkg/Library/BaseLib/BaseLibInternals.h >> > > > b/MdePkg/Library/BaseLib/BaseLibInternals.h >> > > > index ea387ce37d27..9dca97a0dcc9 100644 >> > > > --- a/MdePkg/Library/BaseLib/BaseLibInternals.h >> > > > +++ b/MdePkg/Library/BaseLib/BaseLibInternals.h >> > > > @@ -340,34 +340,6 @@ InternalSwitchStack ( >> > > > >> > > > >> > > > /** >> > > > - Worker function that locates the Node in the List. >> > > > - >> > > > - By searching the List, finds the location of the Node in List. >> > > > At the same time, >> > > > - verifies the validity of this list. >> > > > - >> > > > - If List is NULL, then ASSERT(). >> > > > - If List->ForwardLink is NULL, then ASSERT(). >> > > > - If List->backLink is NULL, then ASSERT(). >> > > > - If Node is NULL, then ASSERT(); >> > > > - If PcdMaximumLinkedListLength is not zero, and prior to >> > > > insertion the number >> > > > - of nodes in ListHead, including the ListHead node, is greater >> > > > than or >> > > > - equal to PcdMaximumLinkedListLength, then ASSERT(). >> > > > - >> > > > - @param List A pointer to a node in a linked list. >> > > > - @param Node A pointer to one nod. >> > > > - >> > > > - @retval TRUE Node is in List. >> > > > - @retval FALSE Node isn't in List, or List is invalid. >> > > > - >> > > > -**/ >> > > > -BOOLEAN >> > > > -EFIAPI >> > > > -IsNodeInList ( >> > > > - IN CONST LIST_ENTRY *List, >> > > > - IN CONST LIST_ENTRY *Node >> > > > - ); >> > > > - >> > > > -/** >> > > > Worker function that returns a bit field from Operand. >> > > > >> > > > Returns the bitfield specified by the StartBit and the EndBit >> > > > from Operand. >> > > > -- >> > > > 2.12.2.windows.2 >> > >> > _______________________________________________ >> > 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