src/patches/suse-2.6.27.25/patches.arch/x86-vmware-tsc-06-fix-vmware_get_tsc

   1 From: Alok Kataria <akataria@vmware.com>
   2 Subject: x86: VMware: Fix vmware_get_tsc code
   3 Patch-mainline:
   4 References: bnc#441338
   5
   6 Impact: Fix possible failure to calibrate the TSC on Vmware near 4 GHz
   7
   8 The current version of the code to get the tsc frequency from
   9 the VMware hypervisor, will be broken on processor with frequency
  10 (4G-1) HZ, because on such processors eax will have UINT_MAX
  11 and that would be legitimate.
  12 We instead check that EBX did change to decide if we were able to
  13 read the frequency from the hypervisor.
  14
  15 Signed-off-by: Alok N Kataria <akataria@vmware.com>
  16 Signed-off-by: H. Peter Anvin <hpa@zytor.com>
  17 Signed-off-by: Takashi Iwai <tiwai@suse.de>
  18
  19 ---
  20
  21  arch/x86/kernel/cpu/vmware.c |    4 ++--
  22  1 files changed, 2 insertions(+), 2 deletions(-)
  23
  24
  25 diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
  26 index 2ac4394..a0905ec 100644
  27 --- a/arch/x86/kernel/cpu/vmware.c
  28 +++ b/arch/x86/kernel/cpu/vmware.c
  29 @@ -36,7 +36,7 @@
  30                         "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :    \
  31                         "0"(VMWARE_HYPERVISOR_MAGIC),                   \
  32                         "1"(VMWARE_PORT_CMD_##cmd),                     \
  33 -                       "2"(VMWARE_HYPERVISOR_PORT), "3"(0) :           \
  34 +                       "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) :    \
  35                         "memory");
  36
  37  static inline int __vmware_platform(void)
  38 @@ -53,7 +53,7 @@ static unsigned long __vmware_get_tsc_khz(void)
  39
  40          VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
  41
  42 -        if (eax == (uint32_t)-1)
  43 +        if (ebx == UINT_MAX)
  44                  return 0;
  45          tsc_hz = eax | (((uint64_t)ebx) << 32);
  46          do_div(tsc_hz, 1000);