From: Catalin Marinas <catalin.marinas@arm.com>
To: Reiji Watanabe <reijiw@google.com>
Cc: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
linux-arm-kernel@lists.infradead.org,
Peter Shier <pshier@google.com>,
Ricardo Koller <ricarkol@google.com>,
Oliver Upton <oupton@google.com>,
Jing Zhang <jingzhangos@google.com>,
Raghavendra Rao Anata <rananta@google.com>
Subject: Re: [PATCH v2 2/2] arm64: mte: DC {GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1
Date: Fri, 3 Dec 2021 18:51:55 +0000 [thread overview]
Message-ID: <YapnS7NJ6z36YapU@arm.com> (raw)
In-Reply-To: <YapiHEdG05hW69Td@arm.com>
On Fri, Dec 03, 2021 at 06:29:48PM +0000, Catalin Marinas wrote:
> On Sun, Nov 07, 2021 at 11:11:49PM -0800, Reiji Watanabe wrote:
> > diff --git a/arch/arm64/lib/mte.S b/arch/arm64/lib/mte.S
> > index e83643b3995f..e62c048af337 100644
> > --- a/arch/arm64/lib/mte.S
> > +++ b/arch/arm64/lib/mte.S
> > @@ -43,17 +43,23 @@ SYM_FUNC_END(mte_clear_page_tags)
> > * x0 - address to the beginning of the page
> > */
> > SYM_FUNC_START(mte_zero_clear_page_tags)
> > + and x0, x0, #(1 << MTE_TAG_SHIFT) - 1 // clear the tag
> > mrs x1, dczid_el0
> > + tbnz x1, #4, 2f // Branch if DC GZVA is prohibited
> > and w1, w1, #0xf
> > mov x2, #4
> > lsl x1, x2, x1
> > - and x0, x0, #(1 << MTE_TAG_SHIFT) - 1 // clear the tag
> >
> > 1: dc gzva, x0
> > add x0, x0, x1
> > tst x0, #(PAGE_SIZE - 1)
> > b.ne 1b
> > ret
> > +
> > +2: stzg x0, [x0], #16
>
> Nitpick: MTE_GRANULE_SIZE instead of 16.
>
> > + tst x0, #(PAGE_SIZE - 1)
> > + b.ne 2b
> > + ret
> > SYM_FUNC_END(mte_zero_clear_page_tags)
>
> We can use stz2g here since we know it's always a PAGE_SIZE and an even
> number of tag granules.
I should have replied on v3. The comment is the same.
--
Catalin
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next prev parent reply other threads:[~2021-12-03 18:54 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-08 7:11 [PATCH v2 0/2] arm64: DC {ZVA,GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1 Reiji Watanabe
2021-11-08 7:11 ` [PATCH v2 1/2] arm64: clear_page() shouldn't use DC ZVA " Reiji Watanabe
2021-11-16 23:00 ` Robin Murphy
2021-11-18 8:18 ` Reiji Watanabe
2021-11-18 11:42 ` Robin Murphy
2021-11-08 7:11 ` [PATCH v2 2/2] arm64: mte: DC {GVA,GZVA} shouldn't be used " Reiji Watanabe
2021-12-03 18:29 ` Catalin Marinas
2021-12-03 18:51 ` Catalin Marinas [this message]
2021-12-04 8:03 ` Reiji Watanabe
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