From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Will Deacon <will@kernel.org>, linux-arm-kernel@lists.infradead.org
Cc: kernel-team@android.com,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <maz@kernel.org>,
Russell King <rmk+kernel@armlinux.org.uk>
Subject: Re: [PATCH 2/5] arm64: vdso: Remove redundant calls to flush_dcache_page()
Date: Thu, 18 Mar 2021 18:05:06 +0000 [thread overview]
Message-ID: <4f7bc394-f4b1-bcee-29ef-f34af4803102@arm.com> (raw)
In-Reply-To: <20210318170738.7756-3-will@kernel.org>
On 3/18/21 5:07 PM, Will Deacon wrote:
> flush_dcache_page() ensures that the 'PG_dcache_clean' flag for its
> 'page' argument is clear so that cache maintenance will be performed
> if the page is mapped into userspace with execute permissions.
>
> Newly allocated pages have this flag clear, so there is no need to call
> flush_dcache_page() for the compat vdso or signal pages. Remove the
> redundant calls.
>
> Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> ---
> arch/arm64/kernel/vdso.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c
> index 2d057a4dc787..421411981dc3 100644
> --- a/arch/arm64/kernel/vdso.c
> +++ b/arch/arm64/kernel/vdso.c
> @@ -306,7 +306,6 @@ static int aarch32_alloc_kuser_vdso_page(void)
> memcpy((void *)(vdso_page + 0x1000 - kuser_sz), __kuser_helper_start,
> kuser_sz);
> aarch32_vectors_page = virt_to_page(vdso_page);
> - flush_dcache_page(aarch32_vectors_page);
> return 0;
> }
>
> @@ -322,7 +321,6 @@ static int aarch32_alloc_sigpage(void)
>
> memcpy((void *)sigpage, __aarch32_sigret_code_start, sigret_sz);
> aarch32_sig_page = virt_to_page(sigpage);
> - flush_dcache_page(aarch32_sig_page);
> return 0;
> }
>
>
--
Regards,
Vincenzo
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next prev parent reply other threads:[~2021-03-18 18:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 17:07 [PATCH 0/5] Minor improvements to the compat vdso and sigpage Will Deacon
2021-03-18 17:07 ` [PATCH 1/5] arm64: vdso: Use GFP_KERNEL for allocating compat vdso and signal pages Will Deacon
2021-03-18 18:03 ` Vincenzo Frascino
2021-03-24 17:28 ` Catalin Marinas
2021-03-18 17:07 ` [PATCH 2/5] arm64: vdso: Remove redundant calls to flush_dcache_page() Will Deacon
2021-03-18 18:05 ` Vincenzo Frascino [this message]
2021-03-18 17:07 ` [PATCH 3/5] arm64: compat: Allow signal page to be remapped Will Deacon
2021-03-18 18:06 ` Vincenzo Frascino
2021-03-18 17:07 ` [PATCH 4/5] arm64: vdso: Avoid ISB after reading from cntvct_el0 Will Deacon
2021-03-18 18:08 ` Vincenzo Frascino
2021-03-18 17:07 ` [PATCH 5/5] arm64: compat: Poison the compat sigpage Will Deacon
2021-03-18 18:13 ` Vincenzo Frascino
2021-03-24 16:58 ` [PATCH 0/5] Minor improvements to the compat vdso and sigpage Catalin Marinas
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