The Intel Architecture Optimization Reference Manual states that a short
load that follows a long store to the same object will suffer a store
forwading penalty, particularly if the two accesses use different addresses.
Trivially, a long load that follows a short store will also suffer a penalty.
__downgrade_write() in rwsem incurs both penalties: the increment operation
will not be able to reuse a recently-loaded rwsem value, and its result will
not be reused by any recently-following rwsem operation.
A comment in the code states that this is because 64-bit immediates are
special and expensive; but while they are slightly special (only a single
instruction allows them), they aren't expensive: a test shows that two loops,
one loading a 32-bit immediate and one loading a 64-bit immediate, both take
1.5 cycles per iteration.
Fix this by changing __downgrade_write to use the same add instruction on
i386 and on x86_64, so that it uses the same operand size as all the other
rwsem functions.
Signed-off-by: Avi Kivity <avi@redhat.com>
LKML-Reference: <1266049992-17419-1-git-send-email-avi@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
For x86-64, 32767 threads really is not enough. Change rwsem_count_t
to a signed long, so that it is 64 bits on x86-64.
This required the following changes to the assembly code:
a) %z0 doesn't work on all versions of gcc! At least gcc 4.4.2 as
shipped with Fedora 12 emits "ll" not "q" for 64 bits, even for
integer operands. Newer gccs apparently do this correctly, but
avoid this problem by using the _ASM_ macros instead of %z.
b) 64 bits immediates are only allowed in "movq $imm,%reg"
constructs... no others. Change some of the constraints to "e",
and fix the one case where we would have had to use an invalid
immediate -- in that case, we only care about the upper half
anyway, so just access the upper half.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <tip-bafaecd11df15ad5b1e598adc7736afcd38ee13d@git.kernel.org>
The patches 5d0b7235d8 and
bafaecd11d broke the UML build:
On Sun, 17 Jan 2010, Ingo Molnar wrote:
>
> FYI, -tip testing found that these changes break the UML build:
>
> kernel/built-in.o: In function `__up_read':
> /home/mingo/tip/arch/x86/include/asm/rwsem.h:192: undefined reference to `call_rwsem_wake'
> kernel/built-in.o: In function `__up_write':
> /home/mingo/tip/arch/x86/include/asm/rwsem.h:210: undefined reference to `call_rwsem_wake'
> kernel/built-in.o: In function `__downgrade_write':
> /home/mingo/tip/arch/x86/include/asm/rwsem.h:228: undefined reference to `call_rwsem_downgrade_wake'
> kernel/built-in.o: In function `__down_read':
> /home/mingo/tip/arch/x86/include/asm/rwsem.h:112: undefined reference to `call_rwsem_down_read_failed'
> kernel/built-in.o: In function `__down_write_nested':
> /home/mingo/tip/arch/x86/include/asm/rwsem.h:154: undefined reference to `call_rwsem_down_write_failed'
> collect2: ld returned 1 exit status
Add lib/rwsem_64.o to the UML subarch objects to fix.
LKML-Reference: <alpine.LFD.2.00.1001171023440.13231@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This one is much faster than the spinlock based fallback rwsem code,
with certain artifical benchmarks having shown 300%+ improvement on
threaded page faults etc.
Again, note the 32767-thread limit here. So this really does need that
whole "make rwsem_count_t be 64-bit and fix the BIAS values to match"
extension on top of it, but that is conceptually a totally independent
issue.
NOT TESTED! The original patch that this all was based on were tested by
KAMEZAWA Hiroyuki, but maybe I screwed up something when I created the
cleaned-up series, so caveat emptor..
Also note that it _may_ be a good idea to mark some more registers
clobbered on x86-64 in the inline asms instead of saving/restoring them.
They are inline functions, but they are only used in places where there
are not a lot of live registers _anyway_, so doing for example the
clobbers of %r8-%r11 in the asm wouldn't make the fast-path code any
worse, and would make the slow-path code smaller.
(Not that the slow-path really matters to that degree. Saving a few
unnecessary registers is the _least_ of our problems when we hit the slow
path. The instruction/cycle counting really only matters in the fast
path).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.1001121810410.17145@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
The fast version of the rwsems (the code that uses xadd) has
traditionally only worked on x86-32, and as a result it mixes different
kinds of types wildly - they just all happen to be 32-bit. We have
"long", we have "__s32", and we have "int".
To make it work on x86-64, the types suddenly matter a lot more. It can
be either a 32-bit or 64-bit signed type, and both work (with the caveat
that a 32-bit counter will only have 15 bits of effective write
counters, so it's limited to 32767 users). But whatever type you
choose, it needs to be used consistently.
This makes a new 'rwsem_counter_t', that is a 32-bit signed type. For a
64-bit type, you'd need to also update the BIAS values.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.1001121755220.17145@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Using kernel_stack_pointer() allows 32-bit and 64-bit versions to
be merged. This is more correct for 64-bit, since the old %rsp is
always saved on the stack.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1263397555-27695-1-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Use a macro to define the cache sizes when cachesize > 1 MB.
This is less typing, and less prone to introducing bugs like we
saw in e02e0e1a13, and means we
don't have to do maths when adding new non-power-of-2 updates
like those seen recently.
Signed-off-by: Dave Jones <davej@redhat.com>
LKML-Reference: <20100104144735.GA18390@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This makes gcc use the right register names and instruction operand sizes
automatically for the rwsem inline asm statements.
So instead of using "(%%eax)" to specify the memory address that is the
semaphore, we use "(%1)" or similar. And instead of forcing the operation
to always be 32-bit, we use "%z0", taking the size from the actual
semaphore data structure itself.
This doesn't actually matter on x86-32, but if we want to use the same
inline asm for x86-64, we'll need to have the compiler generate the proper
64-bit names for the registers (%rax instead of %eax), and if we want to
use a 64-bit counter too (in order to avoid the 15-bit limit on the
write counter that limits concurrent users to 32767 threads), we'll need
to be able to generate instructions with "q" accesses rather than "l".
Since this header currently isn't enabled on x86-64, none of that matters,
but we do want to use the xadd version of the semaphores rather than have
to take spinlocks to do a rwsem. The mm->mmap_sem can be heavily contended
when you have lots of threads all taking page faults, and the fallback
rwsem code that uses a spinlock performs abysmally badly in that case.
[ hpa: modified the patch to skip size suffixes entirely when they are
redundant due to register operands. ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <alpine.LFD.2.00.1001121613560.17145@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Merge the now identical code from asm/atomic_32.h and asm/atomic_64.h
into asm/atomic.h.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1262883215-4034-4-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Prepare for merging into asm/atomic.h.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1262883215-4034-3-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Split atomic64_t functions out into separate headers, since they will
not be practical to merge between 32 and 64 bits.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1262883215-4034-2-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
In order to avoid unnecessary chains of branches, rather than
implementing memcpy()/memset()'s access to their alternative
implementations via a jump, patch the (larger) original function
directly.
The memcpy() part of this is slightly subtle: while alternative
instruction patching does itself use memcpy(), with the
replacement block being less than 64-bytes in size the main loop
of the original function doesn't get used for copying memcpy_c()
over memcpy(), and hence we can safely write over its beginning.
Also note that the CFI annotations are fine for both variants of
each of the functions.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB8D30200007800026AF2@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In order to avoid unnecessary chains of branches, rather than
implementing copy_user_generic() as a function consisting of
just a single (possibly patched) branch, instead properly deal
with patching call instructions in the alternative instructions
framework, and move the patching into the callers.
As a follow-on, one could also introduce something like
__EXPORT_SYMBOL_ALT() to avoid patching call sites in modules.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The early ioremap fixmap entries cover half (or for 32-bit
non-PAE, a quarter) of a page table, yet they got
uncondtitionally aligned so far to a 256-entry boundary. This is
not necessary if the range of page table entries anyway falls
into a single page table.
This buys back, for (theoretically) 50% of all configurations
(25% of all non-PAE ones), at least some of the lowmem
necessarily lost with commit e621bd1895.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <4B2BB66F0200007800026AD6@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Optimize hweight32 by using the same technique in hweight64.
The proof of this technique can be found in the commit log for
f9b4192923 ("bitops: hweight()
speedup").
The userspace benchmark on x86_32 showed 20% speedup with
bitmap_weight() which uses hweight32 to count bits for each
unsigned long on 32bit architectures.
int main(void)
{
#define SZ (1024 * 1024 * 512)
static DECLARE_BITMAP(bitmap, SZ) = {
[0 ... 100] = 1,
};
return bitmap_weight(bitmap, SZ);
}
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <1258603932-4590-1-git-send-email-akinobu.mita@gmail.com>
[ only x86 sets ARCH_HAS_FAST_MULTIPLIER so we do this via the x86 tree]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc-2.6:
SYSCTL: Add a mutex to the page_alloc zone order sysctl
SYSCTL: Print binary sysctl warnings (nearly) only once
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (34 commits)
classmate-laptop: add support for Classmate PC ACPI devices
hp-wmi: Fix two memleaks
acer-wmi, msi-wmi: Remove needless DMI MODULE_ALIAS
dell-wmi: do not keep driver loaded on unsupported boxes
wmi: Free the allocated acpi objects through wmi_get_event_data
drivers/platform/x86/acerhdf.c: check BIOS information whether it begins with string of table
acerhdf: add new BIOS versions
acerhdf: limit modalias matching to supported
toshiba_acpi: convert to seq_file
asus_acpi: convert to seq_file
ACPI: do not select ACPI_DOCK from ATA_ACPI
sony-laptop: enumerate rfkill devices using SN06
sony-laptop: rfkill support for newer models
ACPI: fix OSC regression that caused aer and pciehp not to load
MAINTAINERS: add maintainer for msi-wmi driver
fujitu-laptop: fix tests of acpi_evaluate_integer() return value
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c: avoid cross-CPU interrupts by using smp_call_function_any()
ACPI: processor: remove _PDC object list from struct acpi_processor
ACPI: processor: change acpi_processor_set_pdc() interface
ACPI: processor: open code acpi_processor_cleanup_pdc
...
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2/trivial: Use le16_to_cpu for a disk value in xattr.c
ocfs2/trivial: Use proper mask for 2 places in hearbeat.c
Ocfs2: Let ocfs2 support fiemap for symlink and fast symlink.
Ocfs2: Should ocfs2 support fiemap for S_IFDIR inode?
ocfs2: Use FIEMAP_EXTENT_SHARED
fiemap: Add new extent flag FIEMAP_EXTENT_SHARED
ocfs2: replace u8 by __u8 in ocfs2_fs.h
ocfs2: explicit declare uninitialized var in user_cluster_connect()
ocfs2-devel: remove redundant OCFS2_MOUNT_POSIX_ACL check in ocfs2_get_acl_nolock()
ocfs2: return -EAGAIN instead of EAGAIN in dlm
ocfs2/cluster: Make fence method configurable - v2
ocfs2: Set MS_POSIXACL on remount
ocfs2: Make acl use the default
ocfs2: Always include ACL support
* 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm:
VIDEO: cyberpro: pci_request_regions needs a persistent name
ARM: dma-isa: request cascade channel after registering it
ARM: footbridge: trim down old ISA rtc setup
ARM: fix PAGE_KERNEL
ARM: Fix wrong shared bit for CPU write buffer bug test
ARM: 5857/1: ARM: dmabounce: fix build
ARM: 5856/1: Fix bug of uart0 platfrom data for nuc900
ARM: 5855/1: putc support for nuc900
ARM: 5854/1: fix compiling error for NUC900
ARM: 5849/1: ARMv7: fix Oprofile events count
ARM: add missing include to nwflash.c
ARM: Kill CONFIG_CPU_32
ARM: Convert VFP/Crunch/XscaleCP thread_release() to exit_thread()
ARM: 5853/1: ARM: Fix build break on ARM v6 and v7
* 'sh/for-2.6.33' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6:
sh: Ensure all PG_dcache_dirty pages are written back.
sh: mach-ecovec24: setup.c detailed correction
serial: sh-sci: Convert tremaining ctrl_xxx I/O routines to __raw_xxx.
serial: sh-sci: earlyprintk zero uartclk fix
sh: Only use bl bit toggling for sleeping idle.
sh: Restore bl bit toggling in idle loop.
sh: Fix up MAX_DMA_CHANNELS definition when DMA is disabled.
sh: dmaengine support for SH7785
sh: dmaengine support for sh7724.
Don't pass a name pointer from the kernel stack, it will not survive
and will result in corrupted /proc/iomem output.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This fixes a "start_kernel(): bug: interrupts were enabled early".
rtc_cmos now takes care of initializing the ISA RTC and reading the
current time and date from it; there's no need to repeat that here,
thereby causing interrupts to be enabled too early.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
PAGE_KERNEL should not be executable; any area marked executable can
be prefetched into the instruction cache. We don't want vmalloc areas
to be read in this way.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Do not spam the logs needlessly with the sole info that
edac_pci_dev_parity_clear is being called.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Currently, the module does not initialize fully when the DIMMs aren't
ECC but remains still loaded. Propagate the error when no instance of
the driver is properly initialized and prevent further loading.
Reorganize and polish error handling in amd64_edac_init() while at it.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Fix use-after-free errors by pushing all memory-freeing calls to the end
of amd64_remove_one_instance().
Reported-by: Darren Jenkins <darrenrjenkins@gmail.com>
LKML-Reference: <1261370306.11354.52.camel@ICE-BOX>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Fix the case when amd64_debug_display_dimm_sizes() reports only half the
amount of DRAM on it because it doesn't account for when the single DCT
operates in 128-bit mode and merges chip selects from different DIMMs.
Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de>
LKML-Reference: <200912112202.48173.johannes.hirte@fem.tu-ilmenau.de>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
This add supports for devices like keyboard, backlight, tablet and
accelerometer.
This work is supported by International Syst S/A.
[randy.dunlap@oracle.com: cmpc_acpi: depends on ACPI]
[akpm@linux-foundation.org: readability tweaks]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
With some of the cache rework an address aliasing optimization was added,
but this managed to fail on certain mappings resulting in pages with
PG_dcache_dirty set never writing back their dcache lines. This patch
reverts to the earlier behaviour of simply always writing back when the
dirty bit is set.
Signed-off-by: Markus Pietrek <Markus.Pietrek@emtrion.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
o remove unused define
o add device name comment
Signed-off-by: Kuninori Morimoto <morimoto.kuninori@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
ctrl_xxx() is an antiquated SH interface, while __raw_xxx is the standard
API that accomplishes the same thing. As such, this converts the
remaining sh-sci straggles over, which enables the driver to be wired up
for ARM SH-Mobile CPUs as well.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This establishes a sensible max baud rate for the earlyprintk cases where
the port's uartclk has not yet been determined.
Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Now that we have WMI autoloading
the DMI matching is not needed anymore.
Signed-off-by: Thomas Renninger <trenn@suse.de>
Acked-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Acked-by: Anisse Astier <anisse@astier.eu>
Signed-off-by: Len Brown <len.brown@intel.com>
There is no point in having the driver loaded in memory if we fail
to locate particular WMI GUID.
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Acked-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
These function allocate an acpi object by calling wmi_get_event_data, which
then calls acpi_evaluate_object, and it is not freed afterwards.
And kernel doc is fixed for parameters of wmi_get_event_data.
Signed-off-by: Anisse Astier <anisse@astier.eu>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Carlos Corbacho <carlos@strangeworlds.co.uk>
Signed-off-by: Len Brown <len.brown@intel.com>
