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From: James Morse <james.morse@arm.com>
To: Dongjiu Geng <gengdongjiu@huawei.com>
Cc: catalin.marinas@arm.com, will.deacon@arm.com,
	marc.zyngier@arm.com, christoffer.dall@linaro.org,
	mark.rutland@arm.com, ard.biesheuvel@linaro.org,
	robin.murphy@arm.com, cov@codeaurora.org, Dave.Martin@arm.com,
	suzuki.poulose@arm.com, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH v1 0/3] manually add Error Synchronization Barrier at exception handler entry and exit
Date: Wed, 01 Nov 2017 11:32:57 +0000	[thread overview]
Message-ID: <59F9B0E9.5090609@arm.com> (raw)
In-Reply-To: <1509563697-6359-1-git-send-email-gengdongjiu@huawei.com>

Hi Dongjiu Geng,

On 01/11/17 19:14, Dongjiu Geng wrote:
> Some hardware platform can support RAS Extension, but not support IESB,
> such as Huawei's platform, so software need to insert Synchronization Barrier
> operations at exception handler entry.
> 
> This series patches are based on  James's series patches "SError rework +
> RAS&IESB for firmware first support". In Huawei's platform, we do not
> support IESB, so software needs to insert that.

Surely you don't implement it because your CPU doesn't need it. Can
unrecoverable errors really cross an exception without becoming an SError?

The ESB instruction does the barrier, but it also consumes any pending SError.
As it is this series will silently consume-and-discard uncontainable errors.



Thanks,

James

WARNING: multiple messages have this Message-ID (diff)
From: james.morse@arm.com (James Morse)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v1 0/3] manually add Error Synchronization Barrier at exception handler entry and exit
Date: Wed, 01 Nov 2017 11:32:57 +0000	[thread overview]
Message-ID: <59F9B0E9.5090609@arm.com> (raw)
In-Reply-To: <1509563697-6359-1-git-send-email-gengdongjiu@huawei.com>

Hi Dongjiu Geng,

On 01/11/17 19:14, Dongjiu Geng wrote:
> Some hardware platform can support RAS Extension, but not support IESB,
> such as Huawei's platform, so software need to insert Synchronization Barrier
> operations at exception handler entry.
> 
> This series patches are based on  James's series patches "SError rework +
> RAS&IESB for firmware first support". In Huawei's platform, we do not
> support IESB, so software needs to insert that.

Surely you don't implement it because your CPU doesn't need it. Can
unrecoverable errors really cross an exception without becoming an SError?

The ESB instruction does the barrier, but it also consumes any pending SError.
As it is this series will silently consume-and-discard uncontainable errors.



Thanks,

James

  parent reply	other threads:[~2017-11-01 11:34 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-01 19:14 [PATCH v1 0/3] manually add Error Synchronization Barrier at exception handler entry and exit Dongjiu Geng
2017-11-01 19:14 ` Dongjiu Geng
2017-11-01 19:14 ` Dongjiu Geng
2017-11-01 11:21 ` Robin Murphy
2017-11-01 11:21   ` Robin Murphy
2017-11-01 11:32 ` James Morse [this message]
2017-11-01 11:32   ` James Morse
2017-11-01 12:44   ` gengdongjiu
2017-11-01 12:44     ` gengdongjiu
2017-11-01 12:44     ` gengdongjiu
2017-11-01 19:14 ` [PATCH v1 1/3] arm64: add a macro for SError synchronization Dongjiu Geng
2017-11-01 19:14   ` Dongjiu Geng
2017-11-01 19:14   ` Dongjiu Geng
2017-11-01 11:24   ` Robin Murphy
2017-11-01 11:24     ` Robin Murphy
2017-11-01 12:54     ` gengdongjiu
2017-11-01 12:54       ` gengdongjiu
2017-11-01 12:54       ` gengdongjiu
2017-11-01 13:31       ` Robin Murphy
2017-11-01 13:31         ` Robin Murphy
2017-11-01 14:16       ` Mark Rutland
2017-11-01 14:16         ` Mark Rutland
2017-11-01 14:16         ` Mark Rutland
2017-11-02  8:52         ` gengdongjiu
2017-11-02  8:52           ` gengdongjiu
2017-11-02  8:52           ` gengdongjiu
2017-11-01 19:14 ` [PATCH v1 2/3] arm64: add error synchronization barrier in kernel_entry/kernel_exit Dongjiu Geng
2017-11-01 19:14   ` Dongjiu Geng
2017-11-01 19:14   ` Dongjiu Geng
2017-11-04 17:34   ` kbuild test robot
2017-11-04 17:34     ` kbuild test robot
2017-11-04 17:34     ` kbuild test robot
2017-11-01 19:14 ` [PATCH v1 3/3] KVM: arm64: add ESB in exception handler entry and exit Dongjiu Geng
2017-11-01 19:14   ` Dongjiu Geng
2017-11-01 19:14   ` Dongjiu Geng
2017-11-04 18:49   ` kbuild test robot
2017-11-04 18:49     ` kbuild test robot
2017-11-04 18:49     ` kbuild test robot

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