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  1. 26 7月, 2008 3 次提交
  3. 25 7月, 2008 1 次提交
    • A
      PAGE_ALIGN(): correctly handle 64-bit values on 32-bit architectures · 27ac792c
      由 Andrea Righi 提交于 
      On 32-bit architectures PAGE_ALIGN() truncates 64-bit values to the 32-bit
boundary. For example:

	u64 val = PAGE_ALIGN(size);

always returns a value < 4GB even if size is greater than 4GB.

The problem resides in PAGE_MASK definition (from include/asm-x86/page.h for
example):

#define PAGE_SHIFT      12
#define PAGE_SIZE       (_AC(1,UL) << PAGE_SHIFT)
#define PAGE_MASK       (~(PAGE_SIZE-1))
...
#define PAGE_ALIGN(addr)       (((addr)+PAGE_SIZE-1)&PAGE_MASK)

The "~" is performed on a 32-bit value, so everything in "and" with
PAGE_MASK greater than 4GB will be truncated to the 32-bit boundary.
Using the ALIGN() macro seems to be the right way, because it uses
typeof(addr) for the mask.

Also move the PAGE_ALIGN() definitions out of include/asm-*/page.h in
include/linux/mm.h.

See also lkml discussion: http://lkml.org/lkml/2008/6/11/237

[akpm@linux-foundation.org: fix drivers/media/video/uvc/uvc_queue.c]
[akpm@linux-foundation.org: fix v850]
[akpm@linux-foundation.org: fix powerpc]
[akpm@linux-foundation.org: fix arm]
[akpm@linux-foundation.org: fix mips]
[akpm@linux-foundation.org: fix drivers/media/video/pvrusb2/pvrusb2-dvb.c]
[akpm@linux-foundation.org: fix drivers/mtd/maps/uclinux.c]
[akpm@linux-foundation.org: fix powerpc]
Signed-off-by: NAndrea Righi <righi.andrea@gmail.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      27ac792c
  5. 24 7月, 2008 1 次提交
  7. 23 7月, 2008 4 次提交
  9. 01 5月, 2008 2 次提交
  11. 29 4月, 2008 1 次提交
  13. 17 4月, 2008 1 次提交
  15. 03 4月, 2008 1 次提交
    • C
      kvm: provide kvm.h for all architecture: fixes headers_install · dd135ebb
      由 Christian Borntraeger 提交于 
      Currently include/linux/kvm.h is not considered by make headers_install,
because Kbuild cannot handle " unifdef-$(CONFIG_FOO) += foo.h.  This problem
was introduced by

commit fb56dbb3
Author: Avi Kivity <avi@qumranet.com>
Date:   Sun Dec 2 10:50:06 2007 +0200

    KVM: Export include/linux/kvm.h only if $ARCH actually supports KVM

    Currently, make headers_check barfs due to <asm/kvm.h>, which <linux/kvm.h>
    includes, not existing.  Rather than add a zillion <asm/kvm.h>s, export kvm.
    only if the arch actually supports it.
Signed-off-by: NAvi Kivity <avi@qumranet.com>

which makes this an 2.6.25 regression.

One way of solving the issue is to enhance Kbuild, but Avi and David conviced
me, that changing headers_install is not the way to go.  This patch changes
the definition for linux/kvm.h to unifdef-y.

If  unifdef-y is used for linux/kvm.h "make headers_check" will fail on all
architectures without asm/kvm.h.  Therefore, this patch also provides
asm/kvm.h on all architectures.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NAvi Kivity <avi@qumranet.com>
Cc: Sam Ravnborg <sam@ravnborg.org
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dd135ebb
  17. 05 3月, 2008 2 次提交
  19. 15 2月, 2008 2 次提交
  21. 10 2月, 2008 1 次提交
  23. 09 2月, 2008 1 次提交
    • H
      avoid overflows in kernel/time.c · bdc80787
      由 H. Peter Anvin 提交于 
      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: NH. 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bdc80787
  25. 08 2月, 2008 2 次提交
  27. 07 2月, 2008 1 次提交
  29. 06 2月, 2008 1 次提交
  31. 03 2月, 2008 1 次提交
  33. 01 2月, 2008 2 次提交
  35. 29 1月, 2008 1 次提交
  37. 06 11月, 2007 1 次提交
  39. 24 10月, 2007 3 次提交
  41. 23 10月, 2007 5 次提交
  43. 20 10月, 2007 3 次提交