From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/4] efi/arm64: unmap the kernel while executing UEFI services
Date: Fri, 26 Jan 2018 17:05:06 +0000 [thread overview]
Message-ID: <20180126170505.GE16008@arm.com> (raw)
In-Reply-To: <20180125103131.19168-5-ard.biesheuvel@linaro.org>
On Thu, Jan 25, 2018 at 10:31:31AM +0000, Ard Biesheuvel wrote:
> Now that all UEFI runtime service wrappers ensure that byref
> arguments are moved into the UEFI marshalling buffer (which
> is not part of the kernel mapping), we can proceed and unmap
> the kernel while UEFI runtime service calls are in progress.
>
> This is done by setting the EPD1 bit and flushing the TLB of
> the local CPU. This makes it independent of KPTI or whether
> non-global mappings are being used.
One snag with this is that it will break SPE, so I'd prefer this behaviour
to be predicated on kpti so that the arm64_kernel_unmapped_at_el0() check
in drivers/perf/arm_spe_pmu.c remains valid.
Will
next prev parent reply other threads:[~2018-01-26 17:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 10:31 [PATCH 0/4] efi/arm64: unmap the kernel during runtime service calls Ard Biesheuvel
2018-01-25 10:31 ` [PATCH 1/4] efi: arm64: Check whether x18 is preserved by runtime services calls Ard Biesheuvel
2018-01-26 15:05 ` Will Deacon
2018-01-25 10:31 ` [PATCH 2/4] efi/arm64: map the stack and entry wrapper into the UEFI page tables Ard Biesheuvel
2018-01-26 16:57 ` Will Deacon
2018-01-26 17:03 ` Ard Biesheuvel
2018-01-26 17:09 ` Will Deacon
2018-01-25 10:31 ` [PATCH 3/4] efi/arm64: marshall runtime services arguments via buffer in TTBR0 Ard Biesheuvel
2018-01-25 10:31 ` [PATCH 4/4] efi/arm64: unmap the kernel while executing UEFI services Ard Biesheuvel
2018-01-26 17:05 ` Will Deacon [this message]
2018-01-26 17:06 ` Ard Biesheuvel
2018-01-26 17:10 ` Will Deacon
2018-01-29 14:51 ` [PATCH 0/4] efi/arm64: unmap the kernel during runtime service calls Jeffrey Hugo
2018-01-29 14:55 ` Ard Biesheuvel
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