per cpu data section contains two types of data. One set which is
exclusively accessed by the local cpu and the other set which is per cpu,
but also shared by remote cpus. In the current kernel, these two sets are
not clearely separated out. This can potentially cause the same data
cacheline shared between the two sets of data, which will result in
unnecessary bouncing of the cacheline between cpus.
One way to fix the problem is to cacheline align the remotely accessed per
cpu data, both at the beginning and at the end. Because of the padding at
both ends, this will likely cause some memory wastage and also the
interface to achieve this is not clean.
This patch:
Moves the remotely accessed per cpu data (which is currently marked
as ____cacheline_aligned_in_smp) into a different section, where all the data
elements are cacheline aligned. And as such, this differentiates the local
only data and remotely accessed data cleanly.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: <linux-arch@vger.kernel.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Let's allow page-alignment in general for per-cpu data (wanted by Xen, and
Ingo suggested KVM as well).
Because larger alignments can use more room, we increase the max per-cpu
memory to 64k rather than 32k: it's getting a little tight.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Update all arch/*/kernel/vmlinux.lds.S to not include space for initramfs
when CONFIG_BLK_DEV_INITRAMFS is not selected. This saves another 4 kbytes
on most platfoms (some reserve PAGE_SIZE for initramfs).
Signed-off-by: Jean-Paul Saman <jean-paul.saman@nxp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Print the addresses of non-absolute symbols relative to _text
so that ld will generate relocations. Allowing a relocatable
kernel to relocate them. We can't actually use the symbol names
because kallsyms includes static symbols that are not exported
from their object files.
Add the _text symbol definitions to the architectures which don't
define it otherwise linker will fail.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Add a vmlinux.lds.h helper macro for defining the eight-level initcall table,
teach all the architectures to use it.
This is a prerequisite for a patch which performs initcall synchronisation for
multithreaded-probing.
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
[ Added AVR32 as well ]
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The latest toolchains can produce a new ELF section in DSOs and
dynamically-linked executables. The new section ".gnu.hash" replaces
".hash", and allows for more efficient runtime symbol lookups by the
dynamic linker. The new ld option --hash-style={sysv|gnu|both} controls
whether to produce the old ".hash", the new ".gnu.hash", or both. In some
new systems such as Fedora Core 6, gcc by default passes --hash-style=gnu
to the linker, so that a standard invocation of "gcc -shared" results in
producing a DSO with only ".gnu.hash". The new ".gnu.hash" sections need
to be dealt with the same way as ".hash" sections in all respects; only the
dynamic linker cares about their contents. To work with older dynamic
linkers (i.e. preexisting releases of glibc), a binary must have the old
".hash" section. The --hash-style=both option produces binaries that a new
dynamic linker can use more efficiently, but an old dynamic linker can
still handle.
The new section runs afoul of the custom linker scripts used to build vDSO
images for the kernel. On ia64, the failure mode for this is a boot-time
panic because the vDSO's PT_IA_64_UNWIND segment winds up ill-formed.
This patch addresses the problem in two ways.
First, it mentions ".gnu.hash" in all the linker scripts alongside ".hash".
This produces correct vDSO images with --hash-style=sysv (or old tools),
with --hash-style=gnu, or with --hash-style=both.
Second, it passes the --hash-style=sysv option when building the vDSO
images, so that ".gnu.hash" is not actually produced. This is the most
conservative choice for compatibility with any old userland. There is some
concern that some ancient glibc builds (though not any known old production
system) might choke on --hash-style=both binaries. The optimizations
provided by the new style of hash section do not really matter for a DSO
with a tiny number of symbols, as the vDSO has. If someone wants to use
=gnu or =both for their vDSO builds and worry less about that
compatibility, just change the option and the linker script changes will
make any choice work fine.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Here is a new patch that removes all notion of the pmac, prep,
chrp and openfirmware initialization sections, and then unifies
the sections.h files without those __pmac, etc, sections identifiers
cluttering things up.
Signed-off-by: Jon Loeliger <jdl@freescale.com>
Signed-off-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Discard *.exit.text sections on runtime. We cannot do this on link time
because of the way BUG macros are implemented. If "__exit function" calls
one of those macros, __bug_table section will reference this function.
This is similar to ".altinstructions" situation on i386.
*.exit.data seems to be OK in this respect and is discarded on link
time.
Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Signed-off-by: Tom Rini <trini@kernel.crashing.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The PPC32 kernel puts platform-specific functions into separate sections so
that unneeded parts of it can be freed when we've booted and actually
worked out what we're running on today.
This makes kallsyms ignore those functions, because they're not between
_[se]text or _[se]inittext. Rather than teaching kallsyms about the
various pmac/chrp/etc sections, this patch adds '_[se]extratext' markers
for kallsyms.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Fenghua Yu