Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility. Thanks to Peter Zijlstra for fixing the lockdep
warning. Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is
needed on i386 if UML is to run on hosts with varying VMSPLITs without
recompilation.
TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of
an include of pgtable.h from processor.h, which can cause include loops.
On i386, task_size is calculated early in boot by probing the address space in
a binary search to figure out where the boundary between usable and non-usable
memory is. This tries to make sure that a page that is considered to be in
userspace is, or can be made, read-write. I'm concerned about a system-global
VDSO page in kernel memory being hit and considered to be a userspace page.
On x86_64, task_size is just the old value of CONFIG_TOP_ADDR.
A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced
by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it
irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in
arch/um/Makefile are also gone.
I noticed and fixed a missing extern in os.h when adding os_get_task_size.
Note: This has been revised to fix the 32-bit UML on 64-bit host bug that
Miklos ran into.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mark arches that support A.OUT format by including the following in their
master Kconfig files:
config ARCH_SUPPORTS_AOUT
def_bool y
This should also be set if the arch provides compatibility A.OUT support for
an older arch, for instance x86_64 for i386 or sparc64 for sparc.
I've guessed at which arches don't, based on comments in the code, however I'm
sure that some of the ones I've marked as 'yes' actually should be 'no'.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a UML build breakage introduced by commit
1032c0ba9d - it introduces X86_32, with many
things which UML needs depending on it.
This patch adds definitions of X86_32 and RWSEM_XCHGADD_ALGORITHM to
the UML/i386 Kconfig.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The calculation of CONFIG_STUB_CODE and CONFIG_STUB_DATA didn't take into
account anything but 3G/1G and 2G/2G, leaving the other vmsplits out in the
cold.
I'd rather not duplicate the four known host vmsplit cases for each of these
symbols. I'd also like to calculate them based on the highest userspace
address.
The Kconfig language seems not to allow calculation of hex constants, so I
moved this to as-layout.h. CONFIG_STUB_CODE, CONFIG_STUB_DATA, and
CONFIG_STUB_START are now gone. In their place are STUB_CODE, STUB_DATA, and
STUB_START in as-layout.h.
i386 and x86_64 seem to differ as to whether an unadorned constant is an int
or a long, so I cast them to unsigned long so they can be printed
consistently. However, they are also used in stub.S, where C types don't work
so well. So, there are ASM_ versions of these constants for use in stub.S. I
also ifdef-ed the non-asm-friendly portion of as-layout.h.
With this in place, most of the rest of this patch is changing CONFIG_STUB_*
to STUB_*, except in stub.S, where they are changed to ASM_STUB_*.
defconfig has the old symbols deleted.
I also print these addresses out in case there is any problem mapping them on
the host.
The two stub.S files had some trailing whitespace, so that is cleaned up here.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kconfig recognizes the end of help text by receding indentation depth.
Recent patch had broken HOST_VMSPLIT_... choice in arch/um/Kconfig.i386 -
all alternatives are interpreted as part of help text now.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes UML on hosts with non-standard VM splits. We had changed the
config variable that controls UML behavior on such hosts, but not
propogated the change everywhere. In particular, the values of STUB_CODE
and STUB_DATA relied on the old variable.
I also reformatted the HOST_VMSPLIT_3G help to make it more standard.
Spotted by uml@flonatel.org.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Blaisorblade <blaisorblade@yahoo.it>
Cc: Pravin <shindepravin@gmail.com>
Cc: <uml@flonatel.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that various memory splits are enabled, add a config option allowing the
user to compile UML for its need - HOST_2G_2G allowed to choose either 3G/1G
or 2G/2G, and enabling it reduced the usable virtual memory.
Detecting this at run time should be implemented in the future, but we must
make the stop-gap measure work well enough (this is valid in _many_ cases).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A quick hack to allow skas0 mode to run on 2G/2G hosts.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Build fix for user mode linux.
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
*) mark as "EXPERIMENTAL" various items that either aren't very stable or
that are actively crashing the setup of users which don't really need them
(i.e. HIGHMEM and 3-level pagetables on x86 - nobody needs either,
everybody reports "I'm using it and getting trouble").
*) move net/Kconfig near to the rest of network configurations, and
drivers/block/Kconfig near "Block layer" submenu.
*) it's useless and doesn't work well to force NETDEVICES on and to disable
the prompt like it's done. Better remove the attempt, and change that to a
simple "default y if UML".
*) drop the warning about "report problems about HPPFS" - it's redundant
anyway, as that's the usual procedure, and HPPFS users are especially
technical (i.e. they know reporting bugs is _good_).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A few fixups - show the new submenu only for x86 subarchitecture (it does not
make sense to show it for x86_64 users) and remove X86_CMPXCHG, which is now a
duplicate of Kconfig.i386, even though Kconfig doesn't complain (we also miss
the dependency on !M386 CPU).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Using native cmpxchg offers a slight performance improvement in uml/i386.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
To the extent that sub-Kconfig files exist elsewhere in the tree, they are
named Kconfig.foo, rather than the Kconfig_foo that UML has. This patch
brings the names in line with the rest of the tree.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
