On Tue, 12 Feb 2019 at 01:26, Gao, Liming <[email protected]> wrote: > > Ard: > I agree your comments not to add PCD until there is the real problem. >
Pushed as 1a35dd723bbf..c0959b4426b2 Thanks all > Thanks > Liming > >-----Original Message----- > >From: edk2-devel [mailto:[email protected]] On Behalf Of Ard > >Biesheuvel > >Sent: Tuesday, February 12, 2019 1:32 AM > >To: Leif Lindholm <[email protected]> > >Cc: Kinney, Michael D <[email protected]>; edk2- > >[email protected]; Gao, Liming <[email protected]> > >Subject: Re: [edk2] [PATCH] MdePkg/BaseLib: implement SpeculationBarrier() > >for ARM and AArch64 > > > >On Mon, 11 Feb 2019 at 15:41, Leif Lindholm <[email protected]> wrote: > >> > >> On Wed, Feb 06, 2019 at 12:08:22AM +0000, Ard Biesheuvel wrote: > >> > Replace the dummy C implementation of SpeculationBarrier() with > >> > implementations consisting of the recommended DSB SY + ISB sequence, > >> > as recommended by ARM in the whitepaper "Cache Speculation Side- > >channels" > >> > version 2.4, dated October 2018. > >> > > >> > Contributed-under: TianoCore Contribution Agreement 1.1 > >> > Signed-off-by: Ard Biesheuvel <[email protected]> > >> > >> Patch looks fine. > >> Reviewed-by: Leif Lindholm <[email protected]> > >> > >> Question: do we expect performance impact to be sufficient to > >> motivate a Pcd to be able to disable the barrier on unaffected > >> processors? > >> > > > >Currently, these are only used on some codepaths in the MM component > >of the variable store, which do not look like hot paths to me. > > > >In general, I think it should be fine to defer doing something like > >this until someone highlights it as an actual problem (and has the > >numbers to prove it) > > > > > >> > --- > >> > MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S | 39 > >++++++++++++++++++++ > >> > MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm | 38 > >+++++++++++++++++++ > >> > MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S | 39 > >++++++++++++++++++++ > >> > MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm | 39 > >++++++++++++++++++++ > >> > MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c | 30 > >> > --------------- > >> > MdePkg/Library/BaseLib/BaseLib.inf | 7 +++- > >> > 6 files changed, 160 insertions(+), 32 deletions(-) > >> > > >> > diff --git a/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S > >b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S > >> > new file mode 100644 > >> > index 000000000000..500bdadca5d2 > >> > --- /dev/null > >> > +++ b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.S > >> > @@ -0,0 +1,39 @@ > >> > +##------------------------------------------------------------------------------ > >> > +# > >> > +# SpeculationBarrier() for AArch64 > >> > +# > >> > +# Copyright (c) 2019, Linaro Ltd. 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 > >> > +# 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. > >> > +# > >> > +##------------------------------------------------------------------------------ > >> > + > >> > +.text > >> > +.p2align 2 > >> > + > >> > +GCC_ASM_EXPORT(SpeculationBarrier) > >> > + > >> > + > >> > +#/** > >> > +# Uses as a barrier to stop speculative execution. > >> > +# > >> > +# Ensures that no later instruction will execute speculatively, until > >> > all > >prior > >> > +# instructions have completed. > >> > +# > >> > +#**/ > >> > +#VOID > >> > +#EFIAPI > >> > +#SpeculationBarrier ( > >> > +# VOID > >> > +# ); > >> > +# > >> > +ASM_PFX(SpeculationBarrier): > >> > + dsb sy > >> > + isb > >> > + ret > >> > diff --git a/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm > >b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm > >> > new file mode 100644 > >> > index 000000000000..0c4b915b7798 > >> > --- /dev/null > >> > +++ b/MdePkg/Library/BaseLib/AArch64/SpeculationBarrier.asm > >> > @@ -0,0 +1,38 @@ > >> > +;------------------------------------------------------------------------------ > >> > +; > >> > +; SpeculationBarrier() for AArch64 > >> > +; > >> > +; Copyright (c) 2019, Linaro Ltd. 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 > >> > +; 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. > >> > +; > >> > +;------------------------------------------------------------------------------ > >> > + > >> > + EXPORT SpeculationBarrier > >> > + AREA BaseLib_LowLevel, CODE, READONLY > >> > + > >> > +;/** > >> > +; Uses as a barrier to stop speculative execution. > >> > +; > >> > +; Ensures that no later instruction will execute speculatively, until > >> > all prior > >> > +; instructions have completed. > >> > +; > >> > +;**/ > >> > +;VOID > >> > +;EFIAPI > >> > +;SpeculationBarrier ( > >> > +; VOID > >> > +; ); > >> > +; > >> > +SpeculationBarrier > >> > + dsb sy > >> > + isb > >> > + ret > >> > + > >> > + END > >> > diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S > >b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S > >> > new file mode 100644 > >> > index 000000000000..7857558aba17 > >> > --- /dev/null > >> > +++ b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.S > >> > @@ -0,0 +1,39 @@ > >> > +##------------------------------------------------------------------------------ > >> > +# > >> > +# SpeculationBarrier() for AArch64 > >> > +# > >> > +# Copyright (c) 2019, Linaro Ltd. 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 > >> > +# 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. > >> > +# > >> > +##------------------------------------------------------------------------------ > >> > + > >> > +.text > >> > +.p2align 2 > >> > + > >> > +GCC_ASM_EXPORT(SpeculationBarrier) > >> > + > >> > + > >> > +#/** > >> > +# Uses as a barrier to stop speculative execution. > >> > +# > >> > +# Ensures that no later instruction will execute speculatively, until > >> > all > >prior > >> > +# instructions have completed. > >> > +# > >> > +#**/ > >> > +#VOID > >> > +#EFIAPI > >> > +#SpeculationBarrier ( > >> > +# VOID > >> > +# ); > >> > +# > >> > +ASM_PFX(SpeculationBarrier): > >> > + dsb > >> > + isb > >> > + bx lr > >> > diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm > >b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm > >> > new file mode 100644 > >> > index 000000000000..425cd3de9e22 > >> > --- /dev/null > >> > +++ b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.asm > >> > @@ -0,0 +1,39 @@ > >> > +;------------------------------------------------------------------------------ > >> > +; > >> > +; SpeculationBarrier() for AArch64 > >> > +; > >> > +; Copyright (c) 2019, Linaro Ltd. 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 > >> > +; 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. > >> > +; > >> > +;------------------------------------------------------------------------------ > >> > + > >> > + EXPORT SpeculationBarrier > >> > + > >> > + AREA MemoryBarriers, CODE, READONLY > >> > + > >> > +;/** > >> > +; Uses as a barrier to stop speculative execution. > >> > +; > >> > +; Ensures that no later instruction will execute speculatively, until > >> > all prior > >> > +; instructions have completed. > >> > +; > >> > +;**/ > >> > +;VOID > >> > +;EFIAPI > >> > +;SpeculationBarrier ( > >> > +; VOID > >> > +; ); > >> > +; > >> > +SpeculationBarrier > >> > + dsb > >> > + isb > >> > + bx lr > >> > + > >> > + END > >> > diff --git a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c > >b/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c > >> > deleted file mode 100644 > >> > index 8a6165a10227..000000000000 > >> > --- a/MdePkg/Library/BaseLib/Arm/SpeculationBarrier.c > >> > +++ /dev/null > >> > @@ -1,30 +0,0 @@ > >> > -/** @file > >> > - SpeculationBarrier() function for ARM. > >> > - > >> > - Copyright (C) 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. > >> > - > >> > -**/ > >> > - > >> > - > >> > -/** > >> > - Uses as a barrier to stop speculative execution. > >> > - > >> > - Ensures that no later instruction will execute speculatively, until > >> > all prior > >> > - instructions have completed. > >> > - > >> > -**/ > >> > -VOID > >> > -EFIAPI > >> > -SpeculationBarrier ( > >> > - VOID > >> > - ) > >> > -{ > >> > -} > >> > diff --git a/MdePkg/Library/BaseLib/BaseLib.inf > >b/MdePkg/Library/BaseLib/BaseLib.inf > >> > index d195c5417b2e..f25a067a2335 100644 > >> > --- a/MdePkg/Library/BaseLib/BaseLib.inf > >> > +++ b/MdePkg/Library/BaseLib/BaseLib.inf > >> > @@ -552,7 +552,6 @@ > >> > [Sources.ARM] > >> > Arm/InternalSwitchStack.c > >> > Arm/Unaligned.c > >> > - Arm/SpeculationBarrier.c > >> > Math64.c | RVCT > >> > Math64.c | MSFT > >> > > >> > @@ -564,6 +563,7 @@ > >> > Arm/CpuPause.asm | RVCT > >> > Arm/CpuBreakpoint.asm | RVCT > >> > Arm/MemoryFence.asm | RVCT > >> > + Arm/SpeculationBarrier.S | RVCT > >> > > >> > Arm/SwitchStack.asm | MSFT > >> > Arm/SetJumpLongJump.asm | MSFT > >> > @@ -573,6 +573,7 @@ > >> > Arm/CpuPause.asm | MSFT > >> > Arm/CpuBreakpoint.asm | MSFT > >> > Arm/MemoryFence.asm | MSFT > >> > + Arm/SpeculationBarrier.asm | MSFT > >> > > >> > Arm/Math64.S | GCC > >> > Arm/SwitchStack.S | GCC > >> > @@ -582,11 +583,11 @@ > >> > Arm/SetJumpLongJump.S | GCC > >> > Arm/CpuBreakpoint.S | GCC > >> > Arm/MemoryFence.S | GCC > >> > + Arm/SpeculationBarrier.S | GCC > >> > > >> > [Sources.AARCH64] > >> > Arm/InternalSwitchStack.c > >> > Arm/Unaligned.c > >> > - Arm/SpeculationBarrier.c > >> > Math64.c > >> > > >> > AArch64/MemoryFence.S | GCC > >> > @@ -596,6 +597,7 @@ > >> > AArch64/GetInterruptsState.S | GCC > >> > AArch64/SetJumpLongJump.S | GCC > >> > AArch64/CpuBreakpoint.S | GCC > >> > + AArch64/SpeculationBarrier.S | GCC > >> > > >> > AArch64/MemoryFence.asm | MSFT > >> > AArch64/SwitchStack.asm | MSFT > >> > @@ -604,6 +606,7 @@ > >> > AArch64/GetInterruptsState.asm | MSFT > >> > AArch64/SetJumpLongJump.asm | MSFT > >> > AArch64/CpuBreakpoint.asm | MSFT > >> > + AArch64/SpeculationBarrier.asm | MSFT > >> > > >> > [Packages] > >> > MdePkg/MdePkg.dec > >> > -- > >> > 2.17.1 > >> > > >_______________________________________________ > >edk2-devel mailing list > >[email protected] > >https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
