> -----Original Message----- > From: linux-mips-bounce@xxxxxxxxxxxxxx > [mailto:linux-mips-bounce@xxxxxxxxxxxxxx] On Behalf Of Atsushi Nemoto > Sent: Friday, November 17, 2006 4:13 AM > To: Trevor Hamm > Cc: linux-mips@xxxxxxxxxxxxxx > Subject: Re: Problems booting Linux 2.6.18.1 on MIPS34K core > > Thanks. I re-read your report and wonder why this happens only on > power-up time. > > If flush_data_cache_page or update_mmu_cache were broken, the problem > can happen on every restart. > This page does eventually get flushed to main memory on the first boot, but unfortunately the call to __update_cache() happens after this page was copied through copy_user_highpage(). The source of the problem seems to be with squashfs. When I compare booting a kernel using squashfs to one using cramfs (which always seems to boot successfully on power-up), both are reading the troublesome page from /lib/ld-uClibc.so, and both are calling flush_dcache_page() on this page. But in the case of cramfs, flush_dcache_page() causes an immediate cache flush of that page (mapping_mapped(mapping) in __flush_dcache_page() is returning non-zero), while squashfs just marks the page as dirty and defers the cache flush (mapping_mapped(mapping) is returning zero). I have no idea what causes this difference in behaviour, but right now it appears to be a bug in squashfs rather than the linux-mips kernel. Trevor
