From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3C7D4A56.9000308@embeddededge.com> Date: Wed, 27 Feb 2002 16:06:30 -0500 From: Dan Malek MIME-Version: 1.0 To: David Ashley Cc: linuxppc-embedded@lists.linuxppc.org Subject: Re: Linux 2.4.17 bug, mmap of /dev/mem References: <200202272104.g1RL4bv06375@xdr.com> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: David Ashley wrote: > I've traced the problem down to arch/ppc/mm/hashtable.S. When > there is a page fault, the function hash_page gets called. In the case of a 603 core, hash_page is called for DSI (Data Access) faults. However, if the feature indicates there is no HPTE, the hash_page function is patched to simply return. You can't look at the code in hashtable.S and know how it is going to work for a particular implementation because it is patched at initialization to change it's behavior. > .....This does > some hashing and writes the hash values into a table located at > 0xc0180000. When your kernel boots, does it print a message to indicate it has allocated a hash table? > In arch/ppc/mm/ppc_mmu.c the function MMU_init_hw is called, but > since the 8260 doesn't have the CPU_FTR_HPTE_TABLE feature, the > hash table is never allocated and the hash_page_patch_* never get updated. Oh, I just looked at a variety of different versions back to 2.4.11, and it is patched just as I described above. -- Dan ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/