From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Picco Date: Wed, 05 Mar 2014 13:11:08 +0000 Subject: Re: [PATCH] sparc64 - strict devmem Message-Id: <20140305131108.GZ29427@zareason> List-Id: References: <1393866035-7939-1-git-send-email-bpicco@meloft.net> In-Reply-To: <1393866035-7939-1-git-send-email-bpicco@meloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sparclinux@vger.kernel.org Hi, David Miller wrote: [Tue Mar 04 2014, 03:46:26PM EST] > From: Bob Picco > Date: Mon, 3 Mar 2014 12:00:35 -0500 > > > From: bob picco > > > > This patch adds support to enable STRICT_DEVMEM for sparc64. By selecting the > > new config option you enable this feature. > > > > CC: Sam Ravnborg > > Signed-off-by: Bob Picco > > Ok, I looked more deeply into this and I'm going to rescind my request > to use kern_addr_valid(). Okay. > > This devmem_is_allowed() seems to also want to allow non-RAM MMIO > accesses too. Yes, this is my bad. I expected this issue to come up in the first round but forgot. I wasn't certain general MMIO access via /dev/mem is of value to sparc64. One could always turn off the config option. > > So using the iomem resource is probably the way to go. > > Two things: > > 1) We have to make sure caching will be disabled and the side-effect > bit will be set in accesses to non-RAM pages. > > 2) Our implementation of devmem_is_allowed() should be aligned as > much as possible with other implementations. Perhaps powerpc > is the best example to use. I'll take a peek at powerpc. thanx and you're welcome, bob > > Thanks. > > > -- > To unsubscribe from this list: send the line "unsubscribe sparclinux" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html