From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 31 Oct 2003 12:28:55 -0500 Subject: Re: Max RAM for Linux only 1GB? From: John Whitney To: Prakash Kanthi , "Mailing List: linuxppc-embedded" Message-ID: In-Reply-To: <20031031165821.17006.qmail@web41215.mail.yahoo.com> Mime-version: 1.0 Content-type: text/plain; charset="US-ASCII" Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Prakash, The easiest route it to turn on highmem support (CONFIG_HIGHMEM). As far as I know, this does work for the PowerPC. My understanding is that the kernel doesn't directly use this memory, but will allow user-space programs to use it (mapped into their memory space), which should in turn free up the memory the kernel DOES use. I think you'll need to start playing with the kernel start address if you want the kernel to benefit directly from the additional memory. I know this has been done successfully to 0xA0000000, not sure about all the way down to 0x80000000 (but I can't think of why it wouldn't off the top of my head). John On 10/31/03 11:58 AM, "Prakash Kanthi" wrote: > > Folks, > > I have over 1GB DIMM RAM on my board running PPC 405. > How can i ioremap that to my OS? As Linux virtual > space starts at 0xC0000000, we have only 1GB more for > all virtual space mappings. > > Even if i move 0xC0000000 to 0x80000000, what will > happen to TLB settings? Any problem there to map 1GB > additional RAM? > > Any idea as to how i can do this? > > Thanks, > Prakash > > > > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/