From: Catalin Marinas <catalin.marinas@arm.com>
To: Sergey Dyasly <s.dyasly@samsung.com>
Cc: "linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Russell King <linux@arm.linux.org.uk>,
Guan Xuetao <gxt@mprc.pku.edu.cn>,
"nicolas.pitre@linaro.org" <nicolas.pitre@linaro.org>,
James Bottomley <JBottomley@parallels.com>,
Will Deacon <Will.Deacon@arm.com>,
Arnd Bergmann <arnd.bergmann@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
Dmitry Safonov <d.safonov@partner.samsung.com>
Subject: Re: [PATCH] ARM: use default ioremap alignment for SMP or LPAE
Date: Thu, 22 Jan 2015 10:04:41 +0000 [thread overview]
Message-ID: <20150122100441.GA19811@e104818-lin.cambridge.arm.com> (raw)
In-Reply-To: <1421911075-8814-1-git-send-email-s.dyasly@samsung.com>
On Thu, Jan 22, 2015 at 07:17:55AM +0000, Sergey Dyasly wrote:
> 16MB alignment for ioremap mappings was added by commit a069c896d0d6 ("[ARM]
> 3705/1: add supersection support to ioremap()") in order to support supersection
> mappings. But __arm_ioremap_pfn_caller uses section and supersection mappings
> only in !SMP && !LPAE case. There is no need for such big alignment if either
> SMP or LPAE is enabled.
[...]
> diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
> index 184def0..c3ef139 100644
> --- a/arch/arm/include/asm/memory.h
> +++ b/arch/arm/include/asm/memory.h
> @@ -78,10 +78,12 @@
> */
> #define XIP_VIRT_ADDR(physaddr) (MODULES_VADDR + ((physaddr) & 0x000fffff))
>
> +#if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
> /*
> * Allow 16MB-aligned ioremap pages
> */
> #define IOREMAP_MAX_ORDER 24
> +#endif
Actually, I think we could make this depend only on CONFIG_IO_36. That's
the only scenario where we get the supersections matter, and maybe make
CONFIG_IO_36 dependent on !SMP or !ARM_LPAE. My assumption is that we
don't support single zImage with CPU_XSC3 enabled (but I haven't
followed the latest developments here).
--
Catalin
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next prev parent reply other threads:[~2015-01-22 10:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-22 7:17 Sergey Dyasly
2015-01-22 10:04 ` Catalin Marinas [this message]
2015-01-22 11:03 ` Arnd Bergmann
2015-01-23 14:52 ` Catalin Marinas
2015-01-23 15:31 ` Arnd Bergmann
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