From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <39A99B95.6F0109D8@embeddededge.com> Date: Sun, 27 Aug 2000 18:52:05 -0400 From: Dan Malek MIME-Version: 1.0 To: Roman Zippel CC: Dan Malek , Ronald Wahl , Benjamin Herrenschmidt , linuxppc-dev@lists.linuxppc.org Subject: Re: allocating uncachable memory References: Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Roman Zippel wrote: > If you mark the page(s) as reserved it should already do the right thing > on most architectures. The only problem is ioremap doesn't take an array > of pages. Hmmm...I thought reserved didn't imply that much information. The 8xx allocates some memory early to get is reserved, but you still have to perform the PTE updates to get the cache attributes. > Another possibility is __vmalloc(), that already has a protection > argument and you only need a virt_to_xxx() to get the address of the > allocated pages. That's the current plan. If all you need is virt_to_xxx() it's easy. The xxx_to_virt() is nearly impossible. I have a VM implementation that uses (or tries to) mixed large pages, but all of the existing assumptions about memory mapping fail. Everything will have to vmalloc() and then use virt_to_xxx/xxx_to_virt() (which are much more than simple addition macros). I'm waiting for some of the PCI mapping discussions to make sufficient changes to the I/O subsystem so I can just use those. -- Dan ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/