This was an optimization that made memcpy type benchmarks a little
faster on ancient (Circa 1998) IDT Winchip CPUs. In real-life
workloads, it wasn't even noticable, and I doubt anyone is running
benchmarks on 16 year old silicon any more.
Given this code has likely seen very little use over the last decade,
let's just remove it.
Signed-off-by: Dave Jones <davej@fedoraproject.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Per Alan Cox, Nx586 did not support WP in supervisor mode, making it a
386 by Linux kernel standards. As such, it is too unsupported now.
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Link: http://lkml.kernel.org/r/20121128205203.05868eab@pyramind.ukuu.org.uk
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The main goal here is to have the resulting .config no carry any
options that aren't enabled and can't be (i.e such where the
default is "no" and can't be changed), so that if any such
option later gets a user visible prompt, the user will actually
be prompted on a "make ...oldconfig" rather than keeping the
previously invisible option disabled.
There's a little bit of other trivial cleanup mixed in here.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/504DEE19020000780009A285@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Building in support for either of these CPUs is pointless when
e.g. M686 was selected (since such a kernel would use cmov
instructions, which aren't available on these older CPUs).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Link: http://lkml.kernel.org/r/4F58875A02000078000770E0@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently cache alignment among nodes in the kernel is still 128
bytes on x86 NUMA machines - we got that X86_INTERNODE_CACHE_SHIFT
default from old P4 processors.
But now most modern x86 CPUs use the same size: 64 bytes from L1 to
last level L3. so let's remove the incorrect setting, and directly
use the L1 cache size to do SMP cache line alignment.
This patch saves some memory space on kernel data, and it also
improves the cache locality of kernel data.
The System.map is quite different with/without this change:
before patch after patch
...
000000000000b000 d tlb_vector_| 000000000000b000 d tlb_vector
000000000000b080 d cpu_loops_p| 000000000000b040 d cpu_loops_
...
Signed-off-by: Alex Shi <alex.shi@intel.com>
Cc: asit.k.mallick@intel.com
Link: http://lkml.kernel.org/r/1330774047-18597-1-git-send-email-alex.shi@intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move CMPXCHG_DOUBLE and rename it to HAVE_CMPXCHG_DOUBLE so architectures
can simply select the option if it is supported.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move CMPXCHG_LOCAL and rename it to HAVE_CMPXCHG_LOCAL so architectures
can simply select the option if it is supported.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A simple implementation that only supports the word size and does not
have a fallback mode (would require a spinlock).
Add 32 and 64 bit support for cmpxchg_double. cmpxchg double uses
the cmpxchg8b or cmpxchg16b instruction on x86 processors to compare
and swap 2 machine words. This allows lockless algorithms to move more
context information through critical sections.
Set a flag CONFIG_CMPXCHG_DOUBLE to signal that support for double word
cmpxchg detection has been build into the kernel. Note that each subsystem
using cmpxchg_double has to implement a fall back mechanism as long as
we offer support for processors that do not implement cmpxchg_double.
Reviewed-by: H. Peter Anvin <hpa@zytor.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Christoph Lameter <cl@linux.com>
Link: http://lkml.kernel.org/r/20110601172614.173427964@linux.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Currently the option resides under X86_EXTENDED_PLATFORM due to historical
nonstandard A20M# handling. However that is no longer the case and so Elan can
be treated as part of the standard processor choice Kconfig option.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Link: http://lkml.kernel.org/r/1302245177.31620.47.camel@localhost.localdomain
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
They were generated by 'codespell' and then manually reviewed.
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: trivial@kernel.org
LKML-Reference: <1300389856-1099-3-git-send-email-lucas.demarchi@profusion.mobi>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Testing on the OLPC XO-1.5 (VIA C7-M 1000MHz CPU) shows a partial_csum()
speed increase by a factor of 1.5 when we switch to the Pentium-optimized
version.
Signed-off-by: Daniel Drake <dsd@laptop.org>
Cc: dilinger@queued.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This isn't being referenced anywhere, and the selects done from
it can be easily done together with all the other X86 ones.
v2: Also adjust UML's Kconfig.x86.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <4D7603DA02000078000351C1@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option
is used to configure any non-standard kernel with a much larger scope than
only small devices.
This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes
references to the option throughout the kernel. A new CONFIG_EMBEDDED
option is added that automatically selects CONFIG_EXPERT when enabled and
can be used in the future to isolate options that should only be
considered for embedded systems (RISC architectures, SLOB, etc).
Calling the option "EXPERT" more accurately represents its intention: only
expert users who understand the impact of the configuration changes they
are making should enable it.
Reviewed-by: Ingo Molnar <mingo@elte.hu>
Acked-by: David Woodhouse <david.woodhouse@intel.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Greg KH <gregkh@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Robin Holt <holt@sgi.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>
Provide support as far as the hardware capabilities of the x86 cpus
allow.
Define CONFIG_CMPXCHG_LOCAL in Kconfig.cpu to allow core code to test for
fast cpuops implementations.
V1->V2:
- Take out the definition for this_cpu_cmpxchg_8 and move it into
a separate patch.
tj: - Reordered ops to better follow this_cpu_* organization.
- Renamed macro temp variables similar to their existing
neighbours.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, fpu: Use static_cpu_has() to implement use_xsave()
x86: Add new static_cpu_has() function using alternatives
x86, fpu: Use the proper asm constraint in use_xsave()
x86, fpu: Unbreak FPU emulation
x86: Introduce 'struct fpu' and related API
x86: Eliminate TS_XSAVE
x86-32: Don't set ignore_fpu_irq in simd exception
x86: Merge kernel_math_error() into math_error()
x86: Merge simd_math_error() into math_error()
x86-32: Rework cache flush denied handler
Fix trivial conflict in arch/x86/kernel/process.c
The cache flush denied error is an erratum on some AMD 486 clones. If an invd
instruction is executed in userspace, the processor calls exception 19 (13 hex)
instead of #GP (13 decimal). On cpus where XMM is not supported, redirect
exception 19 to do_general_protection(). Also, remove die_if_kernel(), since
this was the last user.
Signed-off-by: Brian Gerst <brgerst@gmail.com>
LKML-Reference: <1269176446-2489-2-git-send-email-brgerst@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Support for the PMU's BTS features has been upstreamed in
v2.6.32, but we still have the old and disabled ptrace-BTS,
as Linus noticed it not so long ago.
It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without
regard for other uses (perf) and doesn't provide the flexibility
needed for perf either.
Its users are ptrace-block-step and ptrace-bts, since ptrace-bts
was never used and ptrace-block-step can be implemented using a
much simpler approach.
So axe all 3000 lines of it. That includes the *locked_memory*()
APIs in mm/mlock.c as well.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Markus Metzger <markus.t.metzger@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20100325135413.938004390@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86-64, rwsem: Avoid store forwarding hazard in __downgrade_write
x86-64, rwsem: 64-bit xadd rwsem implementation
x86: Fix breakage of UML from the changes in the rwsem system
x86-64: support native xadd rwsem implementation
x86: clean up rwsem type system
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>
This reverts commit ae1b22f6e4.
As Linus said in 982d007a6e: "There was something really messy about
cmpxchg8b and clone CPU's, so if you enable it on other CPUs later, do it
carefully."
This breaks lguest for those configs, but we can fix that by emulating
if we have to.
Fixes: http://bugzilla.kernel.org/show_bug.cgi?id=14884
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (36 commits)
x86, mm: Correct the implementation of is_untracked_pat_range()
x86/pat: Trivial: don't create debugfs for memtype if pat is disabled
x86, mtrr: Fix sorting of mtrr after subtracting
x86: Move find_smp_config() earlier and avoid bootmem usage
x86, platform: Change is_untracked_pat_range() to bool; cleanup init
x86: Change is_ISA_range() into an inline function
x86, mm: is_untracked_pat_range() takes a normal semiclosed range
x86, mm: Call is_untracked_pat_range() rather than is_ISA_range()
x86: UV SGI: Don't track GRU space in PAT
x86: SGI UV: Fix BAU initialization
x86, numa: Use near(er) online node instead of roundrobin for NUMA
x86, numa, bootmem: Only free bootmem on NUMA failure path
x86: Change crash kernel to reserve via reserve_early()
x86: Eliminate redundant/contradicting cache line size config options
x86: When cleaning MTRRs, do not fold WP into UC
x86: remove "extern" from function prototypes in <asm/proto.h>
x86, mm: Report state of NX protections during boot
x86, mm: Clean up and simplify NX enablement
x86, pageattr: Make set_memory_(x|nx) aware of NX support
x86, sleep: Always save the value of EFER
...
Fix up conflicts (added both iommu_shutdown and is_untracked_pat_range)
to 'struct x86_platform_ops') in
arch/x86/include/asm/x86_init.h
arch/x86/kernel/x86_init.c
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, msr, cpumask: Use struct cpumask rather than the deprecated cpumask_t
x86, cpuid: Simplify the code in cpuid_open
x86, cpuid: Remove the bkl from cpuid_open()
x86, msr: Remove the bkl from msr_open()
x86: AMD Geode LX optimizations
x86, msr: Unify rdmsr_on_cpus/wrmsr_on_cpus
Rather than having X86_L1_CACHE_BYTES and X86_L1_CACHE_SHIFT
(with inconsistent defaults), just having the latter suffices as
the former can be easily calculated from it.
To be consistent, also change X86_INTERNODE_CACHE_BYTES to
X86_INTERNODE_CACHE_SHIFT, and set it to 7 (128 bytes) for NUMA
to account for last level cache line size (which here matters
more than L1 cache line size).
Finally, make sure the default value for X86_L1_CACHE_SHIFT,
when X86_GENERIC is selected, is being seen before that for the
individual CPU model options (other than on x86-64, where
GENERIC_CPU is part of the choice construct, X86_GENERIC is a
separate option on ix86).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Ravikiran Thirumalai <kiran@scalex86.org>
Acked-by: Nick Piggin <npiggin@suse.de>
LKML-Reference: <4AFD5710020000780001F8F0@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 79e1dd05d1 "x86: Provide an alternative() based
cmpxchg64()" broke lguest, even on systems which have cmpxchg8b
support. The emulation code gets used until alternatives get
run, but it contains native instructions, not their paravirt
alternatives.
The simplest fix is to turn this code off except for 386 and 486
builds.
Reported-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: lguest@ozlabs.org
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <200910261426.05769.rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add CPU optimizations for AMD Geode LX.
Signed-off-by: Matteo Croce <technoboy85@gmail.com>
LKML-Reference: <40101cc30910010811v5d15ff4cx9dd57c9cc9b4b045@mail.gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Try to avoid the 'alternates()' code when we can statically
determine that cmpxchg8b is fine. We already have that
CONFIG_x86_CMPXCHG64 (enabled by PAE support), and we could easily
also enable it for some of the CPU cases.
Note, this patch only adds CMPXCHG8B for the obvious Intel CPU's,
not for others. (There was something really messy about cmpxchg8b
and clone CPU's, so if you enable it on other CPUs later, do it
carefully.)
If we avoid that asm-alternative thing when we can assume the
instruction exists, we'll generate less support crud, and we'll
avoid the whole issue with that extra 'nop' for padding instruction
sizes etc.
LKML-Reference: <alpine.LFD.2.01.0909301743150.6996@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add another option when selecting CPU family so the kernel can be
optimized for Intel Atom CPUs. If GCC supports tuning options for
Intel Atom they will be used.
Signed-off-by: Tobias Doerffel <tobias.doerffel@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1251018457-19157-1-git-send-email-tobias.doerffel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Oleg Nesterov found a couple of races in the ptrace-bts code
and fixes are queued up for it but they did not get ready in time
for the merge window. We'll merge them in v2.6.31 - until then
mark the feature as CONFIG_BROKEN. There's no user-space yet
making use of this so it's not a big issue.
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
there should be no difference, except:
* the 64bit variant now also initializes the padlock unit.
* ->c_early_init() is executed again from ->c_init()
* the 64bit fixups made into 32bit path.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: herbert@gondor.apana.org.au
LKML-Reference: <1237029843-28076-2-git-send-email-sebastian@breakpoint.cc>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
- Consistent alignment of help text
- Use the ---help--- keyword everywhere consistently as a visual separator
- fix whitespace mismatches
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Some lines exceed the 80 char width making them unreadable.
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix:
arch/x86/mm/tlb.c:47: error: ‘CONFIG_X86_INTERNODE_CACHE_BYTES’ undeclared here (not in a function)
The CONFIG_X86_INTERNODE_CACHE_BYTES symbol is only defined on 64-bit,
because vsmp support is 64-bit only. Define it on 32-bit too - where it
will always be equal to X86_L1_CACHE_BYTES.
Also move the default of X86_L1_CACHE_BYTES (which is separate from the
more commonly used L1_CACHE_SHIFT kconfig symbol) from 128 bytes to
64 bytes.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Right now the generic cacheline size is 128 bytes - that is wasteful
when structures are aligned, as all modern x86 CPUs have an (effective)
cacheline sizes of 64 bytes.
It was set to 128 bytes due to some cacheline aliasing problems on
older P4 systems, but those are many years old and we dont optimize
for them anymore. (They'll still get the 128 bytes cacheline size if
the kernel is specifically built for Pentium 4)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Impact: add new ftrace plugin
A prototype for a BTS ftrace plug-in.
The tracer collects branch trace in a cyclic buffer for each cpu.
The tracer is not configurable and the trace for each snapshot is
appended when doing cat /debug/tracing/trace.
This is a proof of concept that will be extended with future patches
to become a (hopefully) useful tool.
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Improve the help text of the X86_PTRACE_BTS config.
Make X86_DS invisible and depend on X86_PTRACE_BTS.
Reported-by: Roland Dreier <rdreier@cisco.com>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The Winchip-2 and Winchip-2A cpu choices select the
same options for kernel and compiler.
Merge them to save few bytes and reduce confusion.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
deselecting one of the CPU type CONFIG_CPU_SUP_* config options
can render a kernel unbootable. Make sure this option is only
available if CONFIG_EMBEDDED is enabled.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
extend the help text of the CONFIG_CPU_SUP_* config options to
express what it does and what effects it has.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
