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    Contents of /trunk/kernel26-xen/patches-2.6.25-r1/1030-2.6.25-xen-x86_64-Add-sync_cmpxchg.patch

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    Revision 606 - (show annotations) (download)
    Thu May 22 23:13:13 2008 UTC (15 years, 11 months ago) by niro
    File size: 2634 byte(s) 
    -ver bump to 2.6.25-magellan-r1:
- linux-2.6.25.4
- fbcondecor-0.9.4
- squashfs-3.3
- unionfs-2.3.3
- tuxonice-3.0-rc7
- linux-phc-0.3.0
- acpi-dstd-0.9a
- reiser4
- xen-3.2.0
. ipw3945-1.2.2
    1 From 82328d0ef4a109e66264e70692fec273b201ee41 Mon Sep 17 00:00:00 2001
    2 From: Eduardo Habkost <ehabkost@Rawhide-64.localdomain>
    3 Date: Tue, 27 Nov 2007 18:08:41 -0200
    4 Subject: [PATCH] x86_64: Add sync_cmpxchg()
    5
    6 Add a sync_cmpxchg() for x86_64, including a sync_cmpxchg64()
    7 implementation.
    8
    9 Needed for Xen's grant table implementation.
    10
    11 Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
    12 Signed-off-by: Mark McLoughlin <markmc@redhat.com>
    13 ---
    14 include/asm-x86/cmpxchg_64.h | 47 ++++++++++++++++++++++++++++++++++++++++++
    15 1 files changed, 47 insertions(+), 0 deletions(-)
    16
    17 diff --git a/include/asm-x86/cmpxchg_64.h b/include/asm-x86/cmpxchg_64.h
    18 index 56f5b41..1556f64 100644
    19 --- a/include/asm-x86/cmpxchg_64.h
    20 +++ b/include/asm-x86/cmpxchg_64.h
    21 @@ -91,6 +91,45 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
    22 return old;
    23 }
    24
    25 +/*
    26 + * Always use locked operations when touching memory shared with a
    27 + * hypervisor, since the system may be SMP even if the guest kernel
    28 + * isn't.
    29 + */
    30 +static inline unsigned long __sync_cmpxchg(volatile void *ptr,
    31 + unsigned long old,
    32 + unsigned long new, int size)
    33 +{
    34 + unsigned long prev;
    35 + switch (size) {
    36 + case 1:
    37 + __asm__ __volatile__("lock; cmpxchgb %b1,%2"
    38 + : "=a"(prev)
    39 + : "q"(new), "m"(*__xg(ptr)), "0"(old)
    40 + : "memory");
    41 + return prev;
    42 + case 2:
    43 + __asm__ __volatile__("lock; cmpxchgw %w1,%2"
    44 + : "=a"(prev)
    45 + : "r"(new), "m"(*__xg(ptr)), "0"(old)
    46 + : "memory");
    47 + return prev;
    48 + case 4:
    49 + __asm__ __volatile__("lock; cmpxchgl %k1,%2"
    50 + : "=a"(prev)
    51 + : "r"(new), "m"(*__xg(ptr)), "0"(old)
    52 + : "memory");
    53 + return prev;
    54 + case 8:
    55 + __asm__ __volatile__("lock; cmpxchgq %1,%2"
    56 + : "=a"(prev)
    57 + : "r"(new), "m"(*__xg(ptr)), "0"(old)
    58 + : "memory");
    59 + return prev;
    60 + }
    61 + return old;
    62 +}
    63 +
    64 static inline unsigned long __cmpxchg_local(volatile void *ptr,
    65 unsigned long old, unsigned long new, int size)
    66 {
    67 @@ -132,6 +171,14 @@ static inline unsigned long __cmpxchg_local(volatile void *ptr,
    68 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
    69 cmpxchg((ptr), (o), (n)); \
    70 })
    71 +#define sync_cmpxchg(ptr, o, n) \
    72 + ((__typeof__(*(ptr)))__sync_cmpxchg((ptr), (unsigned long)(o), \
    73 + (unsigned long)(n), sizeof(*(ptr))))
    74 +#define sync_cmpxchg64(ptr, o, n) \
    75 + ({ \
    76 + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
    77 + sync_cmpxchg((ptr), (o), (n)); \
    78 + })
    79 #define cmpxchg_local(ptr, o, n) \
    80 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
    81 (unsigned long)(n), sizeof(*(ptr))))
    82 --
    83 1.5.4.1
    84