• Tejun Heo's avatar
    percpu: Always align percpu output section to PAGE_SIZE · 0415b00d
    Tejun Heo authored
    Percpu allocator honors alignment request upto PAGE_SIZE and both the
    percpu addresses in the percpu address space and the translated kernel
    addresses should be aligned accordingly.  The calculation of the
    former depends on the alignment of percpu output section in the kernel
    image.
    
    The linker script macros PERCPU_VADDR() and PERCPU() are used to
    define this output section and the latter takes @align parameter.
    Several architectures are using @align smaller than PAGE_SIZE breaking
    percpu memory alignment.
    
    This patch removes @align parameter from PERCPU(), renames it to
    PERCPU_SECTION() and makes it always align to PAGE_SIZE.  While at it,
    add PCPU_SETUP_BUG_ON() checks such that alignment problems are
    reliably detected and remove percpu alignment comment recently added
    in workqueue.c as the condition would trigger BUG way before reaching
    there.
    
    For um, this patch raises the alignment of percpu area.  As the area
    is in .init, there shouldn't be any noticeable difference.
    
    This problem was discovered by David Howells while debugging boot
    failure on mn10300.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Acked-by: default avatarMike Frysinger <vapier@gentoo.org>
    Cc: uclinux-dist-devel@blackfin.uclinux.org
    Cc: David Howells <dhowells@redhat.com>
    Cc: Jeff Dike <jdike@addtoit.com>
    Cc: user-mode-linux-devel@lists.sourceforge.net
    0415b00d
percpu.c 55.5 KB