From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: "Gao, Liming" <liming.gao@intel.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>,
"Kinney, Michael D" <michael.d.kinney@intel.com>,
"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Subject: Re: [PATCH] MdePkg/BaseLib: implement SpeculationBarrier() for ARM and AArch64
Date: Tue, 12 Feb 2019 21:58:50 +0000 [thread overview]
Message-ID: <CAKv+Gu_3Mazhe9KJ8dC=e768bEBY_3Z7oDOLiSRL=zVYTczhPw@mail.gmail.com> (raw)
In-Reply-To: <4A89E2EF3DFEDB4C8BFDE51014F606A14E3DB3BF@SHSMSX104.ccr.corp.intel.com>
On Tue, 12 Feb 2019 at 01:26, Gao, Liming <liming.gao@intel.com> 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:edk2-devel-bounces@lists.01.org] On Behalf Of Ard
> >Biesheuvel
> >Sent: Tuesday, February 12, 2019 1:32 AM
> >To: Leif Lindholm <leif.lindholm@linaro.org>
> >Cc: Kinney, Michael D <michael.d.kinney@intel.com>; edk2-
> >devel@lists.01.org; Gao, Liming <liming.gao@intel.com>
> >Subject: Re: [edk2] [PATCH] MdePkg/BaseLib: implement SpeculationBarrier()
> >for ARM and AArch64
> >
> >On Mon, 11 Feb 2019 at 15:41, Leif Lindholm <leif.lindholm@linaro.org> 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 <ard.biesheuvel@linaro.org>
> >>
> >> Patch looks fine.
> >> Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
> >>
> >> 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
> >edk2-devel@lists.01.org
> >https://lists.01.org/mailman/listinfo/edk2-devel
prev parent reply other threads:[~2019-02-12 21:59 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-06 0:08 [PATCH] MdePkg/BaseLib: implement SpeculationBarrier() for ARM and AArch64 Ard Biesheuvel
2019-02-11 14:27 ` Gao, Liming
2019-02-11 14:41 ` Leif Lindholm
2019-02-11 17:32 ` Ard Biesheuvel
2019-02-12 0:26 ` Gao, Liming
2019-02-12 21:58 ` Ard Biesheuvel [this message]
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