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| author | Keir Fraser <keir.fraser@citrix.com> | 2007-11-21 11:38:51 +0000 |
|---|---|---|
| committer | Keir Fraser <keir.fraser@citrix.com> | 2007-11-21 11:38:51 +0000 |
| commit | bfa574998d0556c260f0e9fef1e0bf409f363d78 (patch) | |
| tree | c251fb135e62e7670e145974bb90b56ad18cd29d /xen/include/asm-x86/system.h | |
| parent | 8163649f9e2a6c48b3391bd05e2b4d83af1b4e8a (diff) | |
| download | xen-bfa574998d0556c260f0e9fef1e0bf409f363d78.tar.gz xen-bfa574998d0556c260f0e9fef1e0bf409f363d78.tar.bz2 xen-bfa574998d0556c260f0e9fef1e0bf409f363d78.zip | |
x86: Make IDT/GDT/LDT updates safe.
This involves either determining that the entry will not be
read/written while the update takes place, or atomically making the
entry 'present', or doing the entire write atomically, as appropriate.
This issue raised, and original patch provided, by Jan Beulich.
Signed-off-by: Keir Fraser <keir.fraser@eu.citrix.com>
Diffstat (limited to 'xen/include/asm-x86/system.h')
| -rw-r--r-- | xen/include/asm-x86/system.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/xen/include/asm-x86/system.h b/xen/include/asm-x86/system.h index c464e1d454..7d000522e7 100644 --- a/xen/include/asm-x86/system.h +++ b/xen/include/asm-x86/system.h @@ -256,6 +256,17 @@ static always_inline unsigned long long __cmpxchg8b( }) #endif +static inline void atomic_write64(uint64_t *p, uint64_t v) +{ +#ifdef __i386__ + uint64_t w = *p, x; + while ( (x = __cmpxchg8b(p, w, v)) != w ) + w = x; +#else + *p = v; +#endif +} + #if defined(__i386__) #define mb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory") #define rmb() __asm__ __volatile__ ("lock; addl $0,0(%%esp)": : :"memory") |