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 18:29:48 +0000 [thread overview]
Message-ID: <YapiHEdG05hW69Td@arm.com> (raw)
In-Reply-To: <20211108071149.823570-3-reijiw@google.com>
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.
--
Catalin
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next prev parent reply other threads:[~2021-12-03 18:31 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 [this message]
2021-12-03 18:51 ` Catalin Marinas
2021-12-04 8:03 ` Reiji Watanabe
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