On Wed, 02 Jun 2010, Modestas Vainius wrote: > Hello, > > this bug [1] is back to the "very common" department with eglibc 2.11 (libc6- > dev_2.11.1-1) builds. Majority of KDE applications are failing to build on > hppa again. Is there really nothing what could be done to fix it? I will just say it is very tricky. I think a fix is possible (arm and mips had similar cache problems) but the victim replacement present in PA8800/PA8900 caches makes the problem especially difficult for hardware using these processors. I have spent the last few months testing various alternatives and have now done hundreds of kernel builds. I did post some experimental patches that fix the problem on UP kernels. However, the problem is not resolved for SMP kernels. The minifail test is a good one to demonstrate the problem. Indeed, a very similar test was given in the thread below: http://readlist.com/lists/vger.kernel.org/linux-kernel/54/270861.html This thread also discusses the PA8800 problem: http://readlist.com/lists/vger.kernel.org/linux-kernel/54/271417.html I currently surmise that we have a problem with the cache victim replacement, although the cause isn't clear. I did find recently that the cache prefetch in copy_user_page_asm extends to the line beyond the end of the page, but fixing this doesn't resolve the problem. I am still experimenting with using equivalent aliasing. It does help to flush in ptep_set_wrprotect. Dave -- J. David Anglin dave.anglin@xxxxxxxxxxxxxx National Research Council of Canada (613) 990-0752 (FAX: 952-6602) -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
