From: Robin Murphy <robin.murphy@arm.com>
To: Steven Price <steven.price@arm.com>, will@kernel.org
Cc: iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 08/10] iommu/io-pgtable-arm: Rationalise TTBRn handling
Date: Mon, 28 Oct 2019 18:51:55 +0000 [thread overview]
Message-ID: <a74dcecd-7061-ce4b-85e1-deaadd0f71a4@arm.com> (raw)
In-Reply-To: <5324d888-857a-b07c-439c-4ae4ea3a9784@arm.com>
On 28/10/2019 15:09, Steven Price wrote:
[...]
>> --- a/drivers/iommu/io-pgtable-arm-v7s.c
>> +++ b/drivers/iommu/io-pgtable-arm-v7s.c
>> @@ -822,15 +822,13 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
>> /* Ensure the empty pgd is visible before any actual TTBR write */
>> wmb();
>>
>> - /* TTBRs */
>> - cfg->arm_v7s_cfg.ttbr[0] = virt_to_phys(data->pgd) |
>> - ARM_V7S_TTBR_S | ARM_V7S_TTBR_NOS |
>> - (cfg->coherent_walk ?
>> - (ARM_V7S_TTBR_IRGN_ATTR(ARM_V7S_RGN_WBWA) |
>> - ARM_V7S_TTBR_ORGN_ATTR(ARM_V7S_RGN_WBWA)) :
>> - (ARM_V7S_TTBR_IRGN_ATTR(ARM_V7S_RGN_NC) |
>> - ARM_V7S_TTBR_ORGN_ATTR(ARM_V7S_RGN_NC)));
>> - cfg->arm_v7s_cfg.ttbr[1] = 0;
>> + /* TTBR */
>> + cfg->arm_v7s_cfg.ttbr = virt_to_phys(data->pgd) | ARM_V7S_TTBR_S |
>> + (cfg->coherent_walk ? (ARM_V7S_TTBR_NOS |
>> + ARM_V7S_TTBR_IRGN_ATTR(ARM_V7S_RGN_WBWA) |
>> + ARM_V7S_TTBR_ORGN_ATTR(ARM_V7S_RGN_WBWA)) :
>> + (ARM_V7S_TTBR_IRGN_ATTR(ARM_V7S_RGN_NC) |
>> + ARM_V7S_TTBR_ORGN_ATTR(ARM_V7S_RGN_NC)));
>
> ARM_V7S_TTBR_NOS seems to have sneaked into the cfg->coherent_walk
> condition here - which you haven't mentioned in the commit log, so it
> doesn't look like it should be in this commit.
Ah, yes, it's taken a while to remember whether this was something
important that got muddled up in rebasing, but it's actually just
trivial cleanup. For !coherent_walk, the non-cacheable output attribute
makes shareable accesses implicitly outer-shareable, so setting TTBR.NOS
for that case actually does nothing except look misleading. Thus this is
essentially just a cosmetic change included in the reformatting for
clarity and consistency with the LPAE version. I'll call that out in the
commit message, thanks for spotting!
Robin.
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next prev parent reply other threads:[~2019-10-28 18:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-25 18:08 [PATCH v2 00/10] iommu/io-pgtable: Cleanup and prep for split tables Robin Murphy
2019-10-25 18:08 ` [PATCH v2 01/10] iommu/io-pgtable: Make selftest gubbins consistently __init Robin Murphy
2019-10-25 18:08 ` [PATCH v2 02/10] iommu/io-pgtable-arm: Rationalise size check Robin Murphy
2019-10-25 18:08 ` [PATCH v2 03/10] iommu/io-pgtable-arm: Simplify bounds checks Robin Murphy
2019-10-25 18:08 ` [PATCH v2 04/10] iommu/io-pgtable-arm: Simplify start level lookup Robin Murphy
2019-10-25 18:08 ` [PATCH v2 05/10] iommu/io-pgtable-arm: Simplify PGD size handling Robin Murphy
2019-10-25 18:08 ` [PATCH v2 06/10] iommu/io-pgtable-arm: Simplify level indexing Robin Murphy
2019-11-04 18:17 ` Will Deacon
2019-11-04 18:36 ` Robin Murphy
2019-11-04 19:20 ` Will Deacon
2019-10-25 18:08 ` [PATCH v2 07/10] iommu/io-pgtable-arm: Rationalise MAIR handling Robin Murphy
2019-11-04 18:20 ` Will Deacon
2019-11-04 18:43 ` Robin Murphy
2019-11-04 19:20 ` Will Deacon
2019-11-04 19:57 ` Will Deacon
2019-10-25 18:08 ` [PATCH v2 08/10] iommu/io-pgtable-arm: Rationalise TTBRn handling Robin Murphy
2019-10-28 15:09 ` Steven Price
2019-10-28 18:51 ` Robin Murphy [this message]
2019-11-04 18:36 ` Will Deacon
2019-11-04 19:12 ` Robin Murphy
2019-11-22 22:40 ` Jordan Crouse
2019-10-25 18:08 ` [PATCH v2 09/10] iommu/io-pgtable-arm: Rationalise TCR handling Robin Murphy
2019-11-04 19:14 ` Will Deacon
2019-11-04 23:27 ` Jordan Crouse
[not found] ` <20191120151142.GA26714@willie-the-truck>
2019-11-22 15:51 ` Robin Murphy
2019-11-25 7:58 ` Will Deacon
2019-11-22 22:03 ` Jordan Crouse
2019-10-25 18:08 ` [PATCH v2 10/10] iommu/io-pgtable-arm: Prepare for TTBR1 usage Robin Murphy
2019-11-04 23:40 ` Jordan Crouse
2019-11-20 19:18 ` Will Deacon
2019-11-22 22:03 ` Jordan Crouse
2019-11-04 19:22 ` [PATCH v2 00/10] iommu/io-pgtable: Cleanup and prep for split tables Will Deacon
2019-11-04 20:20 ` Will Deacon
2020-01-10 15:09 ` Will Deacon
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