Re: [PATCH] MdePkg/BaseLib: Globally include ChkStk.c

["Marvin Häuser" <Marvin.Haeuser@outlook.com>]

Hey Tim,

The compiler has no information regarding the size of the stack and hence cannot determine an overflow.
This is basically a warning that stack of a single function is big enough to reach past the Guard Page and ensures it will be accessed.

Yao,

I just realized there already is Stack protection code in edk2, I was only aware of Heap protection.
Wouldn't a proper implementation make sense now to maybe not expand the stack, but at least runtime-error?

Regards,
Marvin

> -----Original Message-----
> From: Tim Lewis <tim.lewis@insyde.com>
> Sent: Wednesday, May 9, 2018 3:28 AM
> To: 'Yao, Jiewen' <jiewen.yao@intel.com>; Marvin.Haeuser@outlook.com;
> edk2-devel@lists.01.org
> Subject: RE: [edk2] [PATCH] MdePkg/BaseLib: Globally include ChkStk.c
> 
> I think that this is a fatal error in EDK2. It basically says, "we are out of stack
> space." The alternative is: the system hangs in an unexpected way since the
> stack overflows into other pages.
> 
> Tim
> 
> -----Original Message-----
> From: edk2-devel <edk2-devel-bounces@lists.01.org> On Behalf Of Yao,
> Jiewen
> Sent: Tuesday, May 8, 2018 5:25 PM
> To: Marvin.Haeuser@outlook.com; edk2-devel@lists.01.org
> Subject: Re: [edk2] [PATCH] MdePkg/BaseLib: Globally include ChkStk.c
> 
> We discussed internally in Intel.
> 
> The quick workaround is: use /Gs65536. :-)
> 
> At the same time, our recommendation is to revisit the code which triggers
> this error. Why this function need such a big stack? And try to reduce the
> local stack usage.
> 
> What is why we still use /Gs32768 as default, instead of /Gs65536.
> 
> Thank you
> Yao Jiewen
> 
> 
> > -----Original Message-----
> > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> > Marvin H?user
> > Sent: Tuesday, May 8, 2018 5:21 PM
> > To: edk2-devel@lists.01.org
> > Cc: Yao, Jiewen <jiewen.yao@intel.com>
> > Subject: Re: [edk2] [PATCH] MdePkg/BaseLib: Globally include ChkStk.c
> >
> > Oh, if you are prefering a good implementation, I will be all for
> > that. This was just a 'quick workaround', same as currently done for GCC.
> > I'm actually unsure whether a good implementation is possible with a
> > flat memory model. It will likely be mere luck whether there is enough
> > space free below the stack, except for maybe when it's located very
> > high (preferably past the 32-bit space).
> > Has there been any prior discussion on this topic? Would be interested
> > to follow up if there was.
> >
> > Thanks,
> > Marvin
> >
> > > -----Original Message-----
> > > From: Yao, Jiewen <jiewen.yao@intel.com>
> > > Sent: Wednesday, May 9, 2018 2:13 AM
> > > To: Marvin.Haeuser@outlook.com; edk2-devel@lists.01.org
> > > Cc: Gao, Liming <liming.gao@intel.com>
> > > Subject: RE: [PATCH] MdePkg/BaseLib: Globally include ChkStk.c
> > >
> > > There are some open source implementation:
> > > MSVC: https://github.com/ispc/ispc/issues/542
> > > GCC:
> > >
> https://android.googlesource.com/toolchain/gcc/+/b094d6c4bf572654a03
> > > 1e cc4afe675154c886dc5/gcc-4.4.3/gcc/config/i386/chkstk.asm
> > >
> > > The compiler generated code assumes the stack is enlarged after we
> > > can chkstk.
> > >
> > > I agree empty function can make build pass.
> > > But more important, we need make it work if there is a need to
> > > increase the stack.
> > > The potential issue is that the later code (after chkstk) assumes
> > > the stack is increased, but actually it is not.
> > >
> > > That is why I ask how this is validated.
> > >
> > > Thank you
> > > Yao Jiewen
> > >
> > >
> > > > -----Original Message-----
> > > > From: Marvin Häuser [mailto:Marvin.Haeuser@outlook.com]
> > > > Sent: Tuesday, May 8, 2018 4:58 PM
> > > > To: edk2-devel@lists.01.org
> > > > Cc: Yao, Jiewen <jiewen.yao@intel.com>; Gao, Liming
> > > > <liming.gao@intel.com>
> > > > Subject: RE: [PATCH] MdePkg/BaseLib: Globally include ChkStk.c
> > > >
> > > > Hey Yao,
> > > >
> > > > As far as I am aware, all __chkstk does is access the stack in 4
> > > > KB intervals from the current location to the maximum requested
> > > > location to eventually hit the Windows Guard Page, which then
> > > > triggers the stack
> > > increase.
> > > > Because I do not know of any equivalent concept in edk2 and the
> > > > intrinsic was already disabled for GCC, I supposed it was a good
> > > > idea to do so globally. Are the potential issues I am not aware of?
> > > >
> > > > Thanks,
> > > > Marvin.
> > > >
> > > > > -----Original Message-----
> > > > > From: Yao, Jiewen <jiewen.yao@intel.com>
> > > > > Sent: Wednesday, May 9, 2018 1:52 AM
> > > > > To: Marvin.Haeuser@outlook.com; edk2-devel@lists.01.org
> > > > > Cc: Gao, Liming <liming.gao@intel.com>
> > > > > Subject: RE: [PATCH] MdePkg/BaseLib: Globally include ChkStk.c
> > > > >
> > > > > HI Marvin
> > > > > Would you mind to share the information on how you test this
> update?
> > > > >
> > > > >
> > > > > Per my experience, chkstk not only does the check but also does
> > > > > the real work to allocate more stack.
> > > > >
> > > > > /Gs can be used to indicate the size (/Gs[num] control stack
> > > > > checking calls)
> > > > >
> > > > > We use /Gs32768 by default, see tools_def.txt.
> > > > >
> > > > > Usually, we just increase this value to override the default
> > > > > one, if we hit this issue.
> > > > >
> > > > > Thank you
> > > > > Yao Jiewen
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On
> > > > > > Behalf Of Marvin H?user
> > > > > > Sent: Tuesday, May 8, 2018 4:37 PM
> > > > > > To: edk2-devel@lists.01.org
> > > > > > Cc: Gao, Liming <liming.gao@intel.com>
> > > > > > Subject: Re: [edk2] [PATCH] MdePkg/BaseLib: Globally include
> > > > > > ChkStk.c
> > > > > >
> > > > > > Hey Liming,
> > > > > >
> > > > > > According to the MSDN documentation, the call will be inserted
> > > > > > for a stack usage past a defined threshold - 4 KB for IA32, 8
> > > > > > KB for X64
> > > (source:
> > > > > > https://msdn.microsoft.com/en-
> us/library/ms648426(v=vs.85).aspx).
> > > > > >
> > > > > > Thanks,
> > > > > > Marvin
> > > > > >
> > > > > > > -----Ursprüngliche Nachricht-----
> > > > > > > Von: Gao, Liming <liming.gao@intel.com>
> > > > > > > Gesendet: Montag, 7. Mai 2018 14:16
> > > > > > > An: Marvin.Haeuser@outlook.com; edk2-devel@lists.01.org
> > > > > > > Cc: Kinney, Michael D <michael.d.kinney@intel.com>
> > > > > > > Betreff: RE: [PATCH] MdePkg/BaseLib: Globally include
> > > > > > > ChkStk.c
> > > > > > >
> > > > > > > Marvin:
> > > > > > >   In VS compiler, what case will trig this intrinsic function?
> > > > > > >
> > > > > > > Thanks
> > > > > > > Liming
> > > > > > > > -----Original Message-----
> > > > > > > > From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org]
> > > > > > > > On Behalf Of Marvin H?user
> > > > > > > > Sent: Saturday, May 5, 2018 10:25 PM
> > > > > > > > To: edk2-devel@lists.01.org
> > > > > > > > Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Gao,
> > > > > > > > Liming <liming.gao@intel.com>
> > > > > > > > Subject: [edk2] [PATCH] MdePkg/BaseLib: Globally include
> > > > > > > > ChkStk.c
> > > > > > > >
> > > > > > > > Initially added for GCC build support, this patch includes
> > > > > > > > the function for all compilers and all architectures. This
> > > > > > > > is done as huge variables on the stack may cause the
> > > > > > > > generation of calls to this intrinsic function for
> > > > > > > > Microsoft compilers, even for the IA32 architecture, too.
> > > > > > > >
> > > > > > > > Contributed-under: TianoCore Contribution Agreement 1.1
> > > > > > > > Signed-off-by: Marvin Haeuser
> <Marvin.Haeuser@outlook.com>
> > > > > > > > ---
> > > > > > > >  MdePkg/Library/BaseLib/{ChkStkGcc.c => ChkStk.c} | 48
> > > > > > > > ++++++++++------
> > > > > > > ----
> > > > > > > >  MdePkg/Library/BaseLib/BaseLib.inf               |  4 +-
> > > > > > > >  2 files changed, 26 insertions(+), 26 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/MdePkg/Library/BaseLib/ChkStkGcc.c
> > > > > > > > b/MdePkg/Library/BaseLib/ChkStk.c similarity index 74%
> > > > > > > > rename from MdePkg/Library/BaseLib/ChkStkGcc.c
> > > > > > > > rename to MdePkg/Library/BaseLib/ChkStk.c index
> > > > > > > > ecba3853b159..59e6d73f9331 100644
> > > > > > > > --- a/MdePkg/Library/BaseLib/ChkStkGcc.c
> > > > > > > > +++ b/MdePkg/Library/BaseLib/ChkStk.c
> > > > > > > > @@ -1,24 +1,24 @@
> > > > > > > > -/** @file
> > > > > > > > -  Provides hack function for passng GCC build.
> > > > > > > > -
> > > > > > > > -  Copyright (c) 2006 - 2008, Intel Corporation. All
> > > > > > > > rights reserved.<BR>
> > > > > > > > -  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
> > > > > > > > -  http://opensource.org/licenses/bsd-license.php.
> > > > > > > > -
> > > > > > > > -  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON
> AN
> > > "AS
> > > > > IS"
> > > > > > > > BASIS,
> > > > > > > > -  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND,
> > > EITHER
> > > > > > > EXPRESS OR IMPLIED.
> > > > > > > > -
> > > > > > > > -**/
> > > > > > > > -
> > > > > > > > -#include "BaseLibInternals.h"
> > > > > > > > -
> > > > > > > > -/**
> > > > > > > > -  Hack function for passing GCC build.
> > > > > > > > -**/
> > > > > > > > -VOID
> > > > > > > > -__chkstk()
> > > > > > > > -{
> > > > > > > > -}
> > > > > > > > -
> > > > > > > > +/** @file
> > > > > > > > +  Provides hack function for passing build.
> > > > > > > > +
> > > > > > > > +  Copyright (c) 2006 - 2018, Intel Corporation. All
> > > > > > > > + rights reserved.<BR>  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
> > > > > > > > + http://opensource.org/licenses/bsd-
> > > > > > > license.php.
> > > > > > > > +
> > > > > > > > +  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON
> AN
> > > "AS
> > > > > IS"
> > > > > > > > + BASIS,  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> > > KIND,
> > > > > > > EITHER EXPRESS OR IMPLIED.
> > > > > > > > +
> > > > > > > > +**/
> > > > > > > > +
> > > > > > > > +#include "BaseLibInternals.h"
> > > > > > > > +
> > > > > > > > +/**
> > > > > > > > +  Hack function for passing build.
> > > > > > > > +**/
> > > > > > > > +VOID
> > > > > > > > +__chkstk()
> > > > > > > > +{
> > > > > > > > +}
> > > > > > > > +
> > > > > > > > diff --git a/MdePkg/Library/BaseLib/BaseLib.inf
> > > > > > > > b/MdePkg/Library/BaseLib/BaseLib.inf
> > > > > > > > index 5fbbd02a94b6..d23a6db2581a 100644
> > > > > > > > --- a/MdePkg/Library/BaseLib/BaseLib.inf
> > > > > > > > +++ b/MdePkg/Library/BaseLib/BaseLib.inf
> > > > > > > > @@ -1,7 +1,7 @@
> > > > > > > >  ## @file
> > > > > > > >  #  Base Library implementation.
> > > > > > > >  #
> > > > > > > > -#  Copyright (c) 2007 - 2016, Intel Corporation. All
> > > > > > > > rights reserved.<BR>
> > > > > > > > +#  Copyright (c) 2007 - 2018, Intel Corporation. All
> > > > > > > > +rights reserved.<BR>
> > > > > > > >  #  Portions copyright (c) 2008 - 2009, Apple Inc. All
> > > > > > > > rights reserved.<BR>  #  Portions copyright (c) 2011 -
> > > > > > > > 2013,
> ARM Ltd.
> > > > > > > > All rights reserved.<BR>  # @@ -64,6 +64,7 @@ [Sources]
> > > > > > > >    SafeString.c
> > > > > > > >    String.c
> > > > > > > >    FilePaths.c
> > > > > > > > +  ChkStk.c
> > > > > > > >    BaseLibInternals.h
> > > > > > > >
> > > > > > > >  [Sources.Ia32]
> > > > > > > > @@ -781,7 +782,6 @@ [Sources.X64]
> > > > > > > >    X64/DisableCache.S | GCC
> > > > > > > >    X64/RdRand.nasm| GCC
> > > > > > > >    X64/RdRand.S | GCC
> > > > > > > > -  ChkStkGcc.c  | GCC
> > > > > > > >
> > > > > > > >  [Sources.IPF]
> > > > > > > >    Ipf/AccessGp.s
> > > > > > > > --
> > > > > > > > 2.17.0.windows.1
> > > > > > > >
> > > > > > > > _______________________________________________
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> >
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