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Diffstat (limited to 'arch/x86/kernel/pvclock.c')
-rw-r--r--arch/x86/kernel/pvclock.c41
1 files changed, 2 insertions, 39 deletions
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 239427ca02af..008b91eefa18 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -41,48 +41,11 @@ void pvclock_set_flags(u8 flags)
41 valid_flags = flags; 41 valid_flags = flags;
42} 42}
43 43
44/*
45 * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
46 * yielding a 64-bit result.
47 */
48static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
49{
50 u64 product;
51#ifdef __i386__
52 u32 tmp1, tmp2;
53#endif
54
55 if (shift < 0)
56 delta >>= -shift;
57 else
58 delta <<= shift;
59
60#ifdef __i386__
61 __asm__ (
62 "mul %5 ; "
63 "mov %4,%%eax ; "
64 "mov %%edx,%4 ; "
65 "mul %5 ; "
66 "xor %5,%5 ; "
67 "add %4,%%eax ; "
68 "adc %5,%%edx ; "
69 : "=A" (product), "=r" (tmp1), "=r" (tmp2)
70 : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
71#elif defined(__x86_64__)
72 __asm__ (
73 "mul %%rdx ; shrd $32,%%rdx,%%rax"
74 : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
75#else
76#error implement me!
77#endif
78
79 return product;
80}
81
82static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow) 44static u64 pvclock_get_nsec_offset(struct pvclock_shadow_time *shadow)
83{ 45{
84 u64 delta = native_read_tsc() - shadow->tsc_timestamp; 46 u64 delta = native_read_tsc() - shadow->tsc_timestamp;
85 return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift); 47 return pvclock_scale_delta(delta, shadow->tsc_to_nsec_mul,
48 shadow->tsc_shift);
86} 49}
87 50
88/* 51/*