linux-kernel - Re: [PATCH V2] mips: kernel: fix detect_memory

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Message-ID: <Znp12j23mf1bUEqp@alpha.franken.de>
Date: Tue, 25 Jun 2024 09:46:34 +0200
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Shiji Yang <yangshiji66@...look.com>
Cc: linux-mips@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Javier Martinez Canillas <javierm@...hat.com>,
	Khalid Aziz <khalid@...ehiking.org>, Baoquan He <bhe@...hat.com>,
	Jiaxun Yang <jiaxun.yang@...goat.com>,
	Serge Semin <fancer.lancer@...il.com>, linux-kernel@...r.kernel.org,
	Mieczyslaw Nalewaj <namiltd@...oo.com>
Subject: Re: [PATCH V2] mips: kernel: fix detect_memory_region() function

On Tue, Jun 25, 2024 at 09:44:44AM +0800, Shiji Yang wrote:
>  	for (size = sz_min; size < sz_max; size <<= 1) {
> -		if (!memcmp(dm, dm + size, sizeof(detect_magic)))
> -			break;
> +		__raw_writel(MIPS_MEM_TEST_PATTERN, dm);
> +		if (__raw_readl(dm) == __raw_readl(dm + size)) {
> +			__raw_writel(~MIPS_MEM_TEST_PATTERN, dm);
> +			if (__raw_readl(dm) == __raw_readl(dm + size))
> +				break;
> +		}

you are testing memory, so just use pointers. __raw_readl and __raw_writel
are for io regions (which should be ioremppaed before usage).

Thomas.

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