From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <399A6578.906706B5@apus.co.at> Date: Wed, 16 Aug 2000 11:57:12 +0200 From: Rene Pachernegg MIME-Version: 1.0 To: Wolfgang Denk , linuxppc-embedded@lists.linuxppc.org Subject: Re: syscall adressing problem References: <200008101623.SAA11915@denx.local.net> Content-Type: text/plain; charset=us-ascii Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Wolfgang Denk wrote: > In message <3992D331.21C3BD9C@apus.co.at> you wrote: > > > > Further searching leaded to the following: > > Sometimes fopen or open syscall work well > > Whenever they dont work they are call from the libc.so and the > > filename paramter adresses are 0x0fxxxxxx. > > I've seen very similar problems, but on MPC8xx system with more > current kernels. The reason was a change in arch/ppc/lib/string.S > which completely f*cked up the caches (ok - the MPC8xx have smalle > cache line sizes). > Thanks for the quick answer. My cache line size is the standard 32 byte. As I found in older messages from the mailing list, these string.S problems concern only unusual cache line sizes. Anyway I got the 2.2.6 and the 2.2.13 kernel sources and gave it a try --> no success. Then I tried to replace the copy_from_user in sys_open with my own read_through (flushes cache first, then reads memory) function. --> no success. Actually the strings to be passed to the syscall are readable from everywhere in user space, but in kernel space it reads just trash at the same adress. There are (just my opinion) only two possibilities: an adress translation problem in the kernel for adresses < 0x10000000 something is overwriting the memory space of the string - parameters for sys_open regards Rene > > Try (1) disabling caches; and (2) arch/ppc/lib/string.S from an older > (2.2.13) kernel version. > > It's just a guess, but maybe worth a try. > > Wolfgang Denk > > -- > Software Engineering: Embedded and Realtime Systems, Embedded Linux > Phone: (+49)-8142-4596-87 Fax: (+49)-8142-4596-88 Email: wd@denx.de > In an infinite universe all things are possible, including the possi- > bility that the universe does not exist. > - Terry Pratchett, _The Dark Side of the Sun_ ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/