Right now, there is no notifier that is called on a new cpu, before the new
cpu begins processing interrupts/softirqs.
Various kernel function would need that notification, e.g. kvm works around
by calling smp_call_function_single(), rcu polls cpu_online_map.
The patch adds a CPU_STARTING notification. It also adds a helper function
that sends the message to all cpu_chain handlers.
Tested on x86-64.
All other archs are untested. Especially on sparc, I'm not sure if I got
it right.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
HAVE_AOUT doesn't quite do the same thing as the recently removed
ARCH_SUPPORTS_AOUT config option. That was set even on platforms where
binfmt_aout isn't supported, although it's not entirely clear why.
So it's best just to introduce a new symbol, handled consistently with
other similar HAVE_xxx symbols; with a simple 'select' in the arch Kconfig.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
At the moment, 64-bit platforms (other than Alpha) are all redefining
things for themselves instead of using <asm-generic/statfs.h>.
As is ARM, since it has special requirements w.r.t. padding.
Make <asm-generic/statfs.h> more generic, and they can use it directly.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Return value of filldir callback is just "should we stop here"; it's
not a usable channel for passing error values (i.e. ->readdir() will
forget anything except "is it non-zero").
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Sam Ravnborg did the build-test that the direct header file move works,
I'm just committing it.
This is a pure move:
mkdir arch/alpha/include
git mv include/asm-alpha arch/alpha/include/asm
with no other changes.
Requested-and-tested-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* do not pass nameidata; struct path is all the callers want.
* switch to new helpers:
user_path_at(dfd, pathname, flags, &path)
user_path(pathname, &path)
user_lpath(pathname, &path)
user_path_dir(pathname, &path) (fail if not a directory)
The last 3 are trivial macro wrappers for the first one.
* remove nameidata in callers.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Remove arch-specific show_mem() in favor of the generic version.
This also removes the following redundant information display:
- free pages, printed by show_free_areas()
- free swap pages, printed by show_swap_cache_info()
- pages in swapcache, printed by show_swap_cache_info()
where show_mem() calls show_free_areas(), which calls
show_swap_cache_info().
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Inflate requires some dynamic memory allocation very early in the boot
process and this is provided with a set of four functions:
malloc/free/gzip_mark/gzip_release.
The old inflate code used a mark/release strategy rather than implement
free. This new version instead keeps a count on the number of outstanding
allocations and when it hits zero, it resets the malloc arena.
This allows removing all the mark and release implementations and unifying
all the malloc/free implementations.
The architecture-dependent code must define two addresses:
- free_mem_ptr, the address of the beginning of the area in which
allocations should be made
- free_mem_end_ptr, the address of the end of the area in which
allocations should be made. If set to 0, then no check is made on
the number of allocations, it just grows as much as needed
The architecture-dependent code can also provide an arch_decomp_wdog()
function call. This function will be called several times during the
decompression process, and allow to notify the watchdog that the system is
still running. If an architecture provides such a call, then it must
define ARCH_HAS_DECOMP_WDOG so that the generic inflate code calls
arch_decomp_wdog().
Work initially done by Matt Mackall, updated to a recent version of the
kernel and improved by me.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Mikael Starvik <mikael.starvik@axis.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Acked-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The real option is named AGP_ALPHA_CORE.
Reviewed-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Almost all users of this field need a PFN instead of a physical address,
so replace node_boot_start with node_min_pfn.
[Lee.Schermerhorn@hp.com: fix spurious BUG_ON() in mark_bootmem()]
Signed-off-by: Johannes Weiner <hannes@saeureba.de>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
free_area_init_node() gets passed in the node id as well as the node
descriptor. This is redundant as the function can trivially get the node
descriptor itself by means of NODE_DATA() and the node's id.
I checked all the users and NODE_DATA() seems to be usable everywhere
from where this function is called.
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are a lot of places that define either a single bootmem descriptor or an
array of them. Use only one central array with MAX_NUMNODES items instead.
Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kyle McMartin <kyle@parisc-linux.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The build of the Alpha Linux kernel currently fails[1] with inconsistent
kallsyms data. As I never saw that before, I thought about hardware
problems. But in fact it is a bug in the Linux kernel.
The end of the rodata section is marked with the "__end_rodata" symbol.
This symbol have different aligning constraints than the inittext parts
and therefor the start marked "_sinittext". Because of that the
__end_rodata symbol shifts between < _sinittext and == _sinittext. The
later variant is seen as a code symbol and recorded in the kallsyms data.
On fix would be to move the exception table a little bit and get some
space between that two areas.
[1]: http://buildd.debian.org/fetch.cgi?pkg=linux-2.6&arch=alpha&ver=2.6.25-5&stamp=1213919009&file=log&as=raw
Cc: maximilian attems <max@stro.at>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not even passed on to smp_call_function() anymore, since that
was removed. So kill it.
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
It's never used and the comments refer to nonatomic and retry
interchangably. So get rid of it.
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This converts alpha to use the new helpers for smp_call_function() and
friends, and adds support for smp_call_function_single().
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Which was removed in the hope that generic legacy IDE quirk in
drivers/pci/probe.c is sufficient for Cypress IDE.
It isn't, as this controller has non-standard BAR layout:
secondary channel registers are in the BAR0-1 of the second
PCI function - not in the BAR2-3 of the same function, as the
generic quirk routine assumes.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vast majority of these build failures are gcc-4.3 warnings
about static functions and objects being referenced from
non-static (read: "extern inline") functions, in conjunction
with our -Werror.
We cannot just convert "extern inline" to "static inline",
as people keep suggesting all the time, because "extern inline"
logic is crucial for generic kernel build.
So
- just make sure that all callees of critical "extern inline"
functions are also "extern inline";
- use "static inline", wherever it's possible.
traps.c: work around gcc-4.3 being too smart about array
bounds-checking.
TODO: add "gnu_inline" attribute to all our "extern inline"
functions to ensure desired behaviour with future compilers.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With built-in scsi disk driver, the final link fails with a following
error:
`.exit.text' referenced in section `.rodata' of drivers/built-in.o:
defined in discarded section `.exit.text' of drivers/built-in.o
This happens with -Os (CONFIG_CC_OPTIMIZE_FOR_SIZE=y) with all gcc-4
versions, and also with -O2 and gcc-4.3.
The problem is in sd.c:sd_major() being inlined into __exit function
exit_sd(), and the compiler generating a jump table in .rodata section
for the 'switch' statement in sd_major(). So we have references to
discarded section.
Fixed with a big hammer in the form of -fno-jump-tables.
Note that jump tables vs. discarded sections is a generic problem,
other architectures are just lucky not to suffer from it. But with
a slightly more complex switch/case statement it can be reproduced
on x86 as well. So maybe at some point we should consider
-fno-jump-tables as a generic compile option...
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current IRQ affinity interface does not provide a way to set affinity
for the IRQs that will be allocated/activated in the future.
This patch creates /proc/irq/default_smp_affinity that lets users set
default affinity mask for the newly allocated IRQs. Changing the default
does not affect affinity masks for the currently active IRQs, they
have to be changed explicitly.
Updated based on Paul J's comments and added some more documentation.
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Cc: pj@sgi.com
Cc: a.p.zijlstra@chello.nl
Cc: tglx@linutronix.de
Cc: rdunlap@xenotime.net
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Use the macros in kbuild.h
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Jay Estabrook <jay.estabrook@hp.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Almost all implementations of pci_iomap() in the kernel, including the generic
lib/iomap.c one, copies the content of a struct resource into unsigned long's
which will break on 32 bits platforms with 64 bits resources.
This fixes all definitions of pci_iomap() to use resource_size_t. I also
"fixed" the 64bits arch for consistency.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The functions time_before, time_before_eq, time_after, and time_after_eq are
more robust for comparing jiffies against other values.
So implement usage of the time_after() macro, defined in linux/jiffies.h,
which deals with wrapping correctly
[akpm@linux-foundation.org: fix warning]
Signed-off-by: S.Caglar Onur <caglar@pardus.org.tr>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
__FUNCTION__ is gcc-specific, use __func__
The change in pci-iommu,c should be safe as arena has not been assigned
when we get to this point.
Some were within #if 0 blocks, have changed them and left the blocks
as they appear to be debugging infrastructure.
A #define FN __FUNCTION__ was removed and occurances of FN were replaced
with __func__ as well.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
OSF/1 brk(2) was broken by following one-liner in sys_brk()
(commit 4cc6028d40):
- if (brk < mm->end_code)
+ if (brk < mm->start_brk)
goto out;
The problem is that osf_set_program_attributes()
does update mm->end_code, but not mm->start_brk,
which still contains inappropriate value left from
binary loader, so brk() always fails.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Legacy IDE resources were never properly allocated on most
alpha platforms, so IDE expectedly stopped working after
commit 10f000a2fd (generic
pci_enable_resources).
Always allocate "fixed" PCI resources before doing anything else;
remove Cypress IDE quirk, as it's a generic problem which is
handled in common PCI probe code.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the generic pci_enable_resources() instead of the arch-specific code.
Unlike this arch-specific code, the generic version:
- skips resources unless requested in "mask"
- skips ROM resources unless IORESOURCE_ROM_ENABLE is set
- checks for resource collisions with "!r->parent"
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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>
Make dma_alloc_coherent respect gfp flags (__GFP_COMP is one that
matters).
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Tested-by: Michael Cree <mcree@orcon.net.nz>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
iommu_is_span_boundary in lib/iommu-helper.c was exported for PARISC IOMMUs
(commit 3715863aa1). Alpha's IOMMU can use it.
This removes the check on the boundary size alignment because
iommu_is_span_boundary does.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a boot panic due to a typo in the recent iommu patchset from
FUJITA Tomonori <tomof@acm.org> - the code used dma_get_max_seg_size()
instead of dma_get_seg_boundary().
It also removes a couple of unnecessary BUG_ON() and ALIGN() macros.
Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Reported-and-tested-by: Bob Tracy <rct@frus.com>
Acked-by: FUJITA Tomonori <tomof@acm.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This just removes unused DEBUG_FORCEDAC define in the IOMMU code.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch makes the IOMMU code not allocate a memory area spanning LLD's
segment boundary.
is_span_boundary() judges whether a memory area spans LLD's segment boundary.
If iommu_arena_find_pages() finds such a area, it tries to find the next
available memory area.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
iommu_arena_find_pages duplicates the code to access to the bitmap for free
space management. This patch convert the IOMMU code to have only one place to
access the bitmap, in the popular way that other IOMMUs (e.g. POWER and
SPARC) do.
This patch is preparation for modifications to fix the IOMMU segment boundary
problem.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is preparation for modifications to fix the IOMMU segment boundary
problem.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add path_put() functions for releasing a reference to the dentry and
vfsmount of a struct path in the right order
* Switch from path_release(nd) to path_put(&nd->path)
* Rename dput_path() to path_put_conditional()
[akpm@linux-foundation.org: fix cifs]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the central patch of a cleanup series. In most cases there is no good
reason why someone would want to use a dentry for itself. This series reflects
that fact and embeds a struct path into nameidata.
Together with the other patches of this series
- it enforced the correct order of getting/releasing the reference count on
<dentry,vfsmount> pairs
- it prepares the VFS for stacking support since it is essential to have a
struct path in every place where the stack can be traversed
- it reduces the overall code size:
without patch series:
text data bss dec hex filename
5321639 858418 715768 6895825 6938d1 vmlinux
with patch series:
text data bss dec hex filename
5320026 858418 715768 6894212 693284 vmlinux
This patch:
Switch from nd->{dentry,mnt} to nd->path.{dentry,mnt} everywhere.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix cifs]
[akpm@linux-foundation.org: fix smack]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit d3d74453c3 ("hrtimer: fixup the
HRTIMER_CB_IRQSAFE_NO_SOFTIRQ fallback") broke several archs, and since
only Russell bothered to merge the fix, and Greg to ACK his arch, I'm
sending this for merger.
I have confirmation that the Alpha bit results in a booting kernel.
That leaves: blackfin, frv, sh and sparc untested.
The deadlock in question was found by Russell:
IRQ handle
-> timer_tick() - xtime seqlock held for write
-> update_process_times()
-> run_local_timers()
-> hrtimer_run_queues()
-> hrtimer_get_softirq_time() - tries to get a read lock
Now, Thomas assures me the fix is trivial, only do_timer() needs to be
done under the xtime_lock, and update_process_times() can savely be
removed from under it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Greg Ungerer <gerg@uclinux.org>
CC: Richard Henderson <rth@twiddle.net>
CC: Bryan Wu <bryan.wu@analog.com>
CC: David Howells <dhowells@redhat.com>
CC: Paul Mundt <lethal@linux-sh.org>
CC: William Irwin <wli@holomorphy.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To allow flexible configuration of IDE introduce HAVE_IDE.
All archs except arm, um and s390 unconditionally select it.
For arm the actual configuration determine if IDE is supported.
This is a step towards introducing drivers/Kconfig for arm.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Russell King - ARM Linux <linux@arm.linux.org.uk>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
When the conversion factor between jiffies and milli- or microseconds is
not a single multiply or divide, as for the case of HZ == 300, we currently
do a multiply followed by a divide. The intervening result, however, is
subject to overflows, especially since the fraction is not simplified (for
HZ == 300, we multiply by 300 and divide by 1000).
This is exposed to the user when passing a large timeout to poll(), for
example.
This patch replaces the multiply-divide with a reciprocal multiplication on
32-bit platforms. When the input is an unsigned long, there is no portable
way to do this on 64-bit platforms there is no portable way to do this
since it requires a 128-bit intermediate result (which gcc does support on
64-bit platforms but may generate libgcc calls, e.g. on 64-bit s390), but
since the output is a 32-bit integer in the cases affected, just simplify
the multiply-divide (*3/10 instead of *300/1000).
The reciprocal multiply used can have off-by-one errors in the upper half
of the valid output range. This could be avoided at the expense of having
to deal with a potential 65-bit intermediate result. Since the intent is
to avoid overflow problems and most of the other time conversions are only
semiexact, the off-by-one errors were considered an acceptable tradeoff.
At Ralf Baechle's suggestion, this version uses a Perl script to compute
the necessary constants. We already have dependencies on Perl for kernel
compiles. This does, however, require the Perl module Math::BigInt, which
is included in the standard Perl distribution starting with version 5.8.0.
In order to support older versions of Perl, include a table of canned
constants in the script itself, and structure the script so that
Math::BigInt isn't required if pulling values from said table.
Running the script requires that the HZ value is available from the
Makefile. Thus, this patch also adds the Kconfig variable CONFIG_HZ to the
architectures which didn't already have it (alpha, cris, frv, h8300, m32r,
m68k, m68knommu, sparc, v850, and xtensa.) It does *not* touch the sh or
sh64 architectures, since Paul Mundt has dealt with those separately in the
sh tree.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Ralf Baechle <ralf@linux-mips.org>,
Cc: Sam Ravnborg <sam@ravnborg.org>,
Cc: Paul Mundt <lethal@linux-sh.org>,
Cc: Richard Henderson <rth@twiddle.net>,
Cc: Michael Starvik <starvik@axis.com>,
Cc: David Howells <dhowells@redhat.com>,
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>,
Cc: Hirokazu Takata <takata@linux-m32r.org>,
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Cc: Roman Zippel <zippel@linux-m68k.org>,
Cc: William L. Irwin <sparclinux@vger.kernel.org>,
Cc: Chris Zankel <chris@zankel.net>,
Cc: H. Peter Anvin <hpa@zytor.com>,
Cc: Jan Engelhardt <jengelh@computergmbh.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Suppress A.OUT library support if CONFIG_ARCH_SUPPORTS_AOUT is not set.
Not all architectures support the A.OUT binfmt, so the ELF binfmt should not
be permitted to go looking for A.OUT libraries to load in such a case. Not
only that, but under such conditions A.OUT core dumps are not produced either.
To make this work, this patch also does the following:
(1) Makes the existence of the contents of linux/a.out.h contingent on
CONFIG_ARCH_SUPPORTS_AOUT.
(2) Renames dump_thread() to aout_dump_thread() as it's only called by A.OUT
core dumping code.
(3) Moves aout_dump_thread() into asm/a.out-core.h and makes it inline. This
is then included only where needed. This means that this bit of arch
code will be stored in the appropriate A.OUT binfmt module rather than
the core kernel.
(4) Drops A.OUT support for Blackfin (according to Mike Frysinger it's not
needed) and FRV.
This patch depends on the previous patch to move STACK_TOP[_MAX] out of
asm/a.out.h and into asm/processor.h as they're required whether or not A.OUT
format is available.
[jdike@addtoit.com: uml: re-remove accidentally restored code]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <linux-arch@vger.kernel.org>
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>
