Commit graph

112 commits

Author SHA1 Message Date
Borislav Petkov
bab9a3da93 x86, msr: execute on the correct CPU subset
Make rdmsr_on_cpus/wrmsr_on_cpus execute on the current CPU only if it
is in the supplied bitmask.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-08-03 14:48:13 -07:00
Linus Torvalds
69ca06c945 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  cfq-iosched: reset oom_cfqq in cfq_set_request()
  block: fix sg SG_DXFER_TO_FROM_DEV regression
  block: call blk_scsi_ioctl_init()
  Fix congestion_wait() sync/async vs read/write confusion
2009-07-10 14:29:58 -07:00
Linus Torvalds
85be928c41 Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (50 commits)
  perf report: Add "Fractal" mode output - support callchains with relative overhead rate
  perf_counter tools: callchains: Manage the cumul hits on the fly
  perf report: Change default callchain parameters
  perf report: Use a modifiable string for default callchain options
  perf report: Warn on callchain output request from non-callchain file
  x86: atomic64: Inline atomic64_read() again
  x86: atomic64: Clean up atomic64_sub_and_test() and atomic64_add_negative()
  x86: atomic64: Improve atomic64_xchg()
  x86: atomic64: Export APIs to modules
  x86: atomic64: Improve atomic64_read()
  x86: atomic64: Code atomic(64)_read and atomic(64)_set in C not CPP
  x86: atomic64: Fix unclean type use in atomic64_xchg()
  x86: atomic64: Make atomic_read() type-safe
  x86: atomic64: Reduce size of functions
  x86: atomic64: Improve atomic64_add_return()
  x86: atomic64: Improve cmpxchg8b()
  x86: atomic64: Improve atomic64_read()
  x86: atomic64: Move the 32-bit atomic64_t implementation to a .c file
  x86: atomic64: The atomic64_t data type should be 8 bytes aligned on 32-bit too
  perf report: Annotate variable initialization
  ...
2009-07-10 14:25:03 -07:00
Jens Axboe
8aa7e847d8 Fix congestion_wait() sync/async vs read/write confusion
Commit 1faa16d228 accidentally broke
the bdi congestion wait queue logic, causing us to wait on congestion
for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-10 20:31:53 +02:00
Eric Dumazet
a79f0da80a x86: atomic64: Inline atomic64_read() again
Now atomic64_read() is light weight (no register pressure and
small icache), we can inline it again.

Also use "=&A" constraint instead of "+A" to avoid warning
about unitialized 'res' variable. (gcc had to force 0 in eax/edx)

  $ size vmlinux.prev vmlinux.after
     text    data     bss     dec     hex filename
  4908667  451676 1684868 7045211  6b805b vmlinux.prev
  4908651  451676 1684868 7045195  6b804b vmlinux.after

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <4A4E1AA2.30002@gmail.com>
[ Also fix typo in atomic64_set() export ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-04 11:45:00 +02:00
Ingo Molnar
ddf9a003d3 x86: atomic64: Clean up atomic64_sub_and_test() and atomic64_add_negative()
Linus noticed that the variable name 'old_val' is
confusingly named in these functions - the correct
naming is 'new_val'.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907030942260.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 21:15:08 +02:00
Ingo Molnar
3a8d1788b3 x86: atomic64: Improve atomic64_xchg()
Remove the read-first logic from atomic64_xchg() and simplify
the loop.

This function was the last user of __atomic64_read() - remove it.

Also, change the 'real_val' assumption from the somewhat quirky
1ULL << 32 value to the (just as arbitrary, but simpler) value
of 0.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <tip-05118ab8859492ac9ddda0154cf90e37b0a4a0b0@git.kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 20:23:55 +02:00
Ingo Molnar
1fde902d52 x86: atomic64: Export APIs to modules
atomic64_t primitives are used by a handful of drivers,
so export the APIs consistently. These were inlined
before.

Also mark atomic64_32.o a core object, so that the symbols
are available even if not linked to core kernel pieces.

Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <tip-05118ab8859492ac9ddda0154cf90e37b0a4a0b0@git.kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 20:23:52 +02:00
Eric Dumazet
67d7178f8f x86: atomic64: Improve atomic64_read()
Optimize atomic64_read() as a special open-coded
cmpxchg8b variant. This generates nicer code:

arch/x86/lib/atomic64_32.o:

   text	   data	    bss	    dec	    hex	filename
    435	      0	      0	    435	    1b3	atomic64_32.o.before
    431	      0	      0	    431	    1af	atomic64_32.o.after

md5:
   bd8ab95e69c93518578bfaf0ea3be4d9  atomic64_32.o.before.asm
   2bdfd4bd1f6b7b61b7fc127aef90ce3b  atomic64_32.o.after.asm

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 14:42:59 +02:00
Mike Galbraith
3fd382cedf x86: Add missing annotation to arch/x86/lib/copy_user_64.S::copy_to_user
While examining symbol generation in perf_counter tools, I
noticed that copy_to_user() had no size in vmlinux's symtab.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
LKML-Reference: <1246512440.13293.3.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 14:34:17 +02:00
Ingo Molnar
199e23780a x86: atomic64: Fix unclean type use in atomic64_xchg()
Linus noticed that atomic64_xchg() uses atomic_read(), which
happens to work because atomic_read() is a macro so the
.counter value gets u64-read on 32-bit too - but this is really
bogus and serious bugs are waiting to happen.

Fix atomic64_xchg() to use __atomic64_read() instead.

No code changed:

arch/x86/lib/atomic64_32.o:

   text	   data	    bss	    dec	    hex	filename
    435	      0	      0	    435	    1b3	atomic64_32.o.before
    435	      0	      0	    435	    1b3	atomic64_32.o.after

md5:
   bd8ab95e69c93518578bfaf0ea3be4d9  atomic64_32.o.before.asm
   bd8ab95e69c93518578bfaf0ea3be4d9  atomic64_32.o.after.asm

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 13:26:46 +02:00
Ingo Molnar
3ac805d2af x86: atomic64: Reduce size of functions
cmpxchg8b is a huge instruction in terms of register footprint,
we almost never want to inline it, not even within the same
code module.

GCC 4.3 still messes up for two functions, under-judging the
true cost of this instruction - so annotate two key functions
to reduce the bloat:

arch/x86/lib/atomic64_32.o:

   text	   data	    bss	    dec	    hex	filename
   1763	      0	      0	   1763	    6e3	atomic64_32.o.before
    435	      0	      0	    435	    1b3	atomic64_32.o.after

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 13:26:43 +02:00
Ingo Molnar
824975ef19 x86: atomic64: Improve atomic64_add_return()
Linus noted (based on Eric Dumazet's numbers) that we would
probably be better off not trying an atomic_read() in
atomic64_add_return() but intead intentionally let the first
cmpxchg8b fail - to get a cache-friendly 'give me ownership
of this cacheline' transaction. That can then be followed
by the real cmpxchg8b which sets the value local to the CPU.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 13:26:42 +02:00
Eric Dumazet
69237f94e6 x86: atomic64: Improve cmpxchg8b()
Rewrite cmpxchg8b() to not use %edi register but a generic "+m"
constraint, to increase compiler freedom in code generation and
possibly better code.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 13:26:41 +02:00
Eric Dumazet
aacf682fd8 x86: atomic64: Improve atomic64_read()
Linus noticed that the 32-bit version of atomic64_read() was
being overly complex with re-reading the value and doing a
retry loop over that.

Instead we can just rely on cmpxchg8b returning either the new
value or returning the current value.

We can use any 'old' value, which will be faster as it can be
loaded via immediates. Using some value that is not equal to
the real value in memory the instruction gets faster.

This also has the advantage that the CPU could avoid dirtying
the cacheline.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 13:26:40 +02:00
Ingo Molnar
b7882b7c65 x86: atomic64: Move the 32-bit atomic64_t implementation to a .c file
Linus noted that the atomic64_t primitives are all inlines
currently which is crazy because these functions have a large
register footprint anyway.

Move them to a separate file: arch/x86/lib/atomic64_32.c

Also, while at it, rename all uses of 'unsigned long long' to
the much shorter u64.

This makes the appearance of the prototypes a lot nicer - and
it also uncovered a few bugs where (yet unused) API variants
had 'long' as their return type instead of u64.

[ More intrusive changes are not yet done in this patch. ]

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-07-03 13:26:39 +02:00
Mike Galbraith
9e314996e3 x86: Fix symbol annotation for arch/x86/lib/clear_page_64.S::clear_page_c
Noticed the zero-sized function symbol while looking at 'perf' profiles,
it causes the profiler to display those addresses in hexa.

Turns out that this was wrong/bogus for an eternity.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Alexander van Heukelum <heukelum@fastmail.fm>
Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
LKML-Reference: <1246366820.6538.1.camel@marge.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-30 23:43:15 +02:00
Pallipadi, Venkatesh
e888d7facd x86, delay: tsc based udelay should have rdtsc_barrier
delay_tsc needs rdtsc_barrier to provide proper delay.

Output from a test driver using hpet to cross check delay
provided by udelay().

Before:
[   86.794363] Expected delay 5us actual 4679ns
[   87.154362] Expected delay 5us actual 698ns
[   87.514162] Expected delay 5us actual 4539ns
[   88.653716] Expected delay 5us actual 4539ns
[   94.664106] Expected delay 10us actual 9638ns
[   95.049351] Expected delay 10us actual 10126ns
[   95.416110] Expected delay 10us actual 9568ns
[   95.799216] Expected delay 10us actual 9638ns
[  103.624104] Expected delay 10us actual 9707ns
[  104.020619] Expected delay 10us actual 768ns
[  104.419951] Expected delay 10us actual 9707ns

After:
[   50.983320] Expected delay 5us actual 5587ns
[   51.261807] Expected delay 5us actual 5587ns
[   51.565715] Expected delay 5us actual 5657ns
[   51.861171] Expected delay 5us actual 5587ns
[   52.164704] Expected delay 5us actual 5726ns
[   52.487457] Expected delay 5us actual 5657ns
[   52.789338] Expected delay 5us actual 5726ns
[   57.119680] Expected delay 10us actual 10755ns
[   57.893997] Expected delay 10us actual 10615ns
[   58.261287] Expected delay 10us actual 10755ns
[   58.620505] Expected delay 10us actual 10825ns
[   58.941035] Expected delay 10us actual 10755ns
[   59.320903] Expected delay 10us actual 10615ns
[   61.306311] Expected delay 10us actual 10755ns
[   61.520542] Expected delay 10us actual 10615ns

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-06-25 16:47:40 -07:00
Linus Torvalds
9063c61fd5 x86, 64-bit: Clean up user address masking
The discussion about using "access_ok()" in get_user_pages_fast() (see
commit 7f81890687: "x86: don't use
'access_ok()' as a range check in get_user_pages_fast()" for details and
end result), made us notice that x86-64 was really being very sloppy
about virtual address checking.

So be way more careful and straightforward about masking x86-64 virtual
addresses:

 - All the VIRTUAL_MASK* variants now cover half of the address
   space, it's not like we can use the full mask on a signed
   integer, and the larger mask just invites mistakes when
   applying it to either half of the 48-bit address space.

 - /proc/kcore's kc_offset_to_vaddr() becomes a lot more
   obvious when it transforms a file offset into a
   (kernel-half) virtual address.

 - Unify/simplify the 32-bit and 64-bit USER_DS definition to
   be based on TASK_SIZE_MAX.

This cleanup and more careful/obvious user virtual address checking also
uncovered a buglet in the x86-64 implementation of strnlen_user(): it
would do an "access_ok()" check on the whole potential area, even if the
string itself was much shorter, and thus return an error even for valid
strings. Our sloppy checking had hidden this.

So this fixes 'strnlen_user()' to do this properly, the same way we
already handled user strings in 'strncpy_from_user()'.  Namely by just
checking the first byte, and then relying on fault handling for the
rest.  That always works, since we impose a guard page that cannot be
mapped at the end of the user space address space (and even if we
didn't, we'd have the address space hole).

Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-20 15:40:00 -07:00
Borislav Petkov
b034c19f9f x86: MSR: add methods for writing of an MSR on several CPUs
Provide for concurrent MSR writes on all the CPUs in the cpumask. Also,
add a temporary workaround for smp_call_function_many which skips the
CPU we're executing on.

Bart: zero out rv struct which is allocated on stack.

CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-06-10 12:18:43 +02:00
Borislav Petkov
6bc1096d7a x86: MSR: add a struct representation of an MSR
Add a struct representing a 64bit MSR pair consisting of a low and high
register part and convert msr_info to use it. Also, rename msr-on-cpu.c
to msr.c.

Side note: Put the cpumask.h include in __KERNEL__ space thus fixing an
allmodconfig build failure in the headers_check target.

CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
2009-06-10 12:18:42 +02:00
Ingo Molnar
f3b6eaf014 x86: memcpy, clean up
Impact: cleanup

Make this file more readable by bringing it more in line
with the usual kernel style.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-12 12:21:17 +01:00
Jan Beulich
dd1ef4ec47 x86-64: remove unnecessary spill/reload of rbx from memcpy
Impact: micro-optimization

This should slightly improve its performance.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B8F641.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-12 12:04:47 +01:00
Jeremy Fitzhardinge
0341c14da4 x86: use _types.h headers in asm where available
In general, the only definitions that assembly files can use
are in _types.S headers (where available), so convert them.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-02-13 11:35:01 -08:00
Andi Kleen
e0a96129db x86: use early clobbers in usercopy*.c
Impact: fix rare (but currently harmless) miscompile with certain configs and gcc versions

Hugh Dickins noticed that strncpy_from_user() was miscompiled
in some circumstances with gcc 4.3.

Thanks to Hugh's excellent analysis it was easy to track down.

Hugh writes:

> Try building an x86_64 defconfig 2.6.29-rc1 kernel tree,
> except not quite defconfig, switch CONFIG_PREEMPT_NONE=y
> and CONFIG_PREEMPT_VOLUNTARY off (because it expands a
> might_fault() there, which hides the issue): using a
> gcc 4.3.2 (I've checked both openSUSE 11.1 and Fedora 10).
>
> It generates the following:
>
> 0000000000000000 <__strncpy_from_user>:
>    0:   48 89 d1                mov    %rdx,%rcx
>    3:   48 85 c9                test   %rcx,%rcx
>    6:   74 0e                   je     16 <__strncpy_from_user+0x16>
>    8:   ac                      lods   %ds:(%rsi),%al
>    9:   aa                      stos   %al,%es:(%rdi)
>    a:   84 c0                   test   %al,%al
>    c:   74 05                   je     13 <__strncpy_from_user+0x13>
>    e:   48 ff c9                dec    %rcx
>   11:   75 f5                   jne    8 <__strncpy_from_user+0x8>
>   13:   48 29 c9                sub    %rcx,%rcx
>   16:   48 89 c8                mov    %rcx,%rax
>   19:   c3                      retq
>
> Observe that "sub %rcx,%rcx; mov %rcx,%rax", whereas gcc 4.2.1
> (and many other configs) say "sub %rcx,%rdx; mov %rdx,%rax".
> Isn't it returning 0 when it ought to be returning strlen?

The asm constraints for the strncpy_from_user() result were missing an
early clobber, which tells gcc that the last output arguments
are written before all input arguments are read.

Also add more early clobbers in the rest of the file and fix 32-bit
usercopy.c in the same way.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
[ since this API is rarely used and no in-kernel user relies on a 'len'
  return value (they only rely on negative return values) this miscompile
  was never noticed in the field. But it's worth fixing it nevertheless. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-21 09:43:17 +01:00
Ingo Molnar
d1a76187a5 Merge commit 'v2.6.28-rc2' into core/locking
Conflicts:
	arch/um/include/asm/system.h
2008-10-28 16:54:49 +01:00
Ingo Molnar
0afe2db213 Merge branch 'x86/unify-cpu-detect' into x86-v28-for-linus-phase4-D
Conflicts:
	arch/x86/kernel/cpu/common.c
	arch/x86/kernel/signal_64.c
	include/asm-x86/cpufeature.h
2008-10-11 20:23:20 +02:00
Ingo Molnar
1d18ef4895 x86: some lock annotations for user copy paths, v3
- add annotation back to clear_user()
- change probe_kernel_address() to _inatomic*() method

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-11 21:42:59 +02:00
Nick Piggin
3ee1afa308 x86: some lock annotations for user copy paths, v2
- introduce might_fault()
 - handle the atomic user copy paths correctly

[ mingo@elte.hu: move might_sleep() outside of in_atomic(). ]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-11 09:44:21 +02:00
Nick Piggin
c10d38dda1 x86: some lock annotations for user copy paths
copy_to/from_user and all its variants (except the atomic ones) can take a
page fault and perform non-trivial work like taking mmap_sem and entering
the filesyste/pagecache.

Unfortunately, this often escapes lockdep because a common pattern is to
use it to read in some arguments just set up from userspace, or write data
back to a hot buffer. In those cases, it will be unlikely for page reclaim
to get a window in to cause copy_*_user to fault.

With the new might_lock primitives, add some annotations to x86. I don't
know if I caught all possible faulting points (it's a bit of a maze, and I
didn't really look at 32-bit). But this is a starting point.

Boots and runs OK so far.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-10 13:48:49 +02:00
Andi Kleen
fb481dd56a x86: drop -funroll-loops for csum_partial_64.c
Impact: performance optimization

I did some rebenchmarking with modern compilers and dropping
-funroll-loops makes the function consistently go faster by a few
percent.  So drop that flag.

Thanks to Richard Guenther for a hint.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-09-04 08:42:06 -07:00
H. Peter Anvin
b30a72a7ed Merge branch 'x86/urgent' into x86/cpu
Conflicts:

	arch/x86/kernel/cpu/cyrix.c
2008-08-27 19:17:07 -07:00
H. Peter Anvin
bdd314616f x86: msr-on-cpu: remove unnecessary level of abstraction
Remove an unnecessary level of abstraction in the msr-on-cpu library.
Although this duplicates some code, the duplicated code is less than
the additional code, and this way should be faster.

Additionally, change the order of the functions to make the regular
structure of this file more obvious.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-08-25 22:45:50 -07:00
H. Peter Anvin
94d4ac2f4a Merge branch 'x86/urgent' into x86/cleanups 2008-08-25 22:45:37 -07:00
H. Peter Anvin
c6f31932d0 x86: msr: propagate errors from smp_call_function_single()
Propagate error (-ENXIO) from smp_call_function_single().  These
errors can happen when a CPU is unplugged while the MSR driver is
open.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-08-25 17:45:48 -07:00
Thomas Petazzoni
8bfcb3960f x86: make movsl_mask definition non-CPU specific
movsl_mask is currently defined in arch/x86/kernel/cpu/intel.c, which
contains code specific to Intel CPUs. However, movsl_mask is used in
the non-CPU specific code in arch/x86/lib/usercopy_32.c, which breaks
the compilation when support for Intel CPUs is compiled out.

This patch solves this problem by moving movsl_mask's definition close
to its users in arch/x86/lib/usercopy_32.c.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: michael@free-electrons.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-18 16:05:45 +02:00
Paolo Ciarrocchi
3492cdf017 x86: coding style fixes to arch/x86/lib/string_32.c
Before:
total: 21 errors, 0 warnings, 237 lines checked

After:
total: 0 errors, 0 warnings, 237 lines checked

paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/string_32.o.*
c55d059ef1612b32a8bb2771a72ae0d5  /tmp/string_32.o.after
c55d059ef1612b32a8bb2771a72ae0d5  /tmp/string_32.o.before

Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-15 16:53:25 +02:00
Paolo Ciarrocchi
209b580fd8 x86: coding style fixes to arch/x86/lib/strstr_32.c
Before:
total: 3 errors, 0 warnings, 31 lines checked

After:
total: 0 errors, 0 warnings, 31 lines checked

paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/strstr_32.o.*
c96006ec3387862e5bacb139207a3098  /tmp/strstr_32.o.after
c96006ec3387862e5bacb139207a3098  /tmp/strstr_32.o.before

Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-15 16:53:24 +02:00
Vitaly Mayatskikh
afd962a9e8 x86: wrong register was used in align macro
New ALIGN_DESTINATION macro has sad typo: r8d register was used instead
of ecx in fixup section. This can be considered as a regression.

Register ecx was also wrongly loaded with value in r8d in
copy_user_nocache routine.

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-30 10:10:39 -07:00
Ingo Molnar
1a781a777b Merge branch 'generic-ipi' into generic-ipi-for-linus
Conflicts:

	arch/powerpc/Kconfig
	arch/s390/kernel/time.c
	arch/x86/kernel/apic_32.c
	arch/x86/kernel/cpu/perfctr-watchdog.c
	arch/x86/kernel/i8259_64.c
	arch/x86/kernel/ldt.c
	arch/x86/kernel/nmi_64.c
	arch/x86/kernel/smpboot.c
	arch/x86/xen/smp.c
	include/asm-x86/hw_irq_32.h
	include/asm-x86/hw_irq_64.h
	include/asm-x86/mach-default/irq_vectors.h
	include/asm-x86/mach-voyager/irq_vectors.h
	include/asm-x86/smp.h
	kernel/Makefile

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-15 21:55:59 +02:00
Ingo Molnar
5806b81ac1 Merge branch 'auto-ftrace-next' into tracing/for-linus
Conflicts:

	arch/x86/kernel/entry_32.S
	arch/x86/kernel/process_32.c
	arch/x86/kernel/process_64.c
	arch/x86/lib/Makefile
	include/asm-x86/irqflags.h
	kernel/Makefile
	kernel/sched.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-14 16:11:52 +02:00
Jeremy Fitzhardinge
27cb0a75ba x86: fix compile error in current tip.git
Gas 2.15 complains about 32-bit registers being used in lea.

  AS      arch/x86/lib/copy_user_64.o
/local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S: Assembler messages:
/local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S:188: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression
/local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_64.S:257: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression
  AS      arch/x86/lib/copy_user_nocache_64.o
/local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_nocache_64.S: Assembler messages:
/local/scratch-2/jeremy/hg/xen/paravirt/linux/arch/x86/lib/copy_user_nocache_64.S:107: Error: `(%edx,%ecx,8)' is not a valid 64 bit base/index expression

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-10 21:55:59 +02:00
Vitaly Mayatskikh
ad2fc2cd92 x86: fix copy_user on x86
Switch copy_user_generic_string(), copy_user_generic_unrolled() and
__copy_user_nocache() from custom tail handlers to generic
copy_user_tail_handle().

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 15:51:16 +02:00
Vitaly Mayatskikh
1129585a08 x86: introduce copy_user_handle_tail() routine
Introduce generic C routine for handling necessary tail operations after
protection fault in copy_*_user on x86.

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 15:51:03 +02:00
Glauber Costa
5cbbc3b1eb x86: merge putuser asm functions.
putuser_32.S and putuser_64.S are merged into putuser.S.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 09:14:13 +02:00
Glauber Costa
2528de431d x86: use macros from asm.h.
In putuser_32.S and putuser_64.S, replace things like .quad, .long,
and explicit references to [r|e]ax for the apropriate macros
in asm/asm.h.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 09:14:12 +02:00
Glauber Costa
efea505d83 x86: don't use word-size specifiers in putuser files.
Remove them where unambiguous.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 09:14:11 +02:00
Glauber Costa
766ed42821 x86: replace function headers by macros.
In putuser_64.S, do it the i386 way, and replace the code
in beginning and end of functions with macros, since it's
always the same thing. Save lines.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 09:14:10 +02:00
Glauber Costa
663aa96df3 x86: change testing logic in putuser_64.S.
Instead of operating over a register we need to put back
into normal state afterwards (the memory position), just
sub from rbx, which is trashed anyway. We can save a few instructions.

Also, this is the i386 way.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 09:14:09 +02:00
Glauber Costa
0ada316403 x86: pass argument to putuser_64 functions in ax register.
This is consistent with i386 usage.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-09 09:14:08 +02:00