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authorAlok Kataria <akataria@vmware.com>2008-11-03 22:31:28 +0300
committerH. Peter Anvin <hpa@zytor.com>2008-11-03 22:35:57 +0300
commit6bdbfe99916398dbb28d83833cc04757110f2738 (patch)
tree7783c666ff16ce70022946c070dd058ae2a74989 /arch/x86/kernel
parent395628ef4ea12ff0748099f145363b5e33c69acb (diff)
downloadlinux-6bdbfe99916398dbb28d83833cc04757110f2738.tar.xz
x86: VMware: Fix vmware_get_tsc code
Impact: Fix possible failure to calibrate the TSC on Vmware near 4 GHz The current version of the code to get the tsc frequency from the VMware hypervisor, will be broken on processor with frequency (4G-1) HZ, because on such processors eax will have UINT_MAX and that would be legitimate. We instead check that EBX did change to decide if we were able to read the frequency from the hypervisor. Signed-off-by: Alok N Kataria <akataria@vmware.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r--arch/x86/kernel/cpu/vmware.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 2ac4394fcb90..a0905ecfe7d2 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -36,7 +36,7 @@
"=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) : \
"0"(VMWARE_HYPERVISOR_MAGIC), \
"1"(VMWARE_PORT_CMD_##cmd), \
- "2"(VMWARE_HYPERVISOR_PORT), "3"(0) : \
+ "2"(VMWARE_HYPERVISOR_PORT), "3"(UINT_MAX) : \
"memory");
static inline int __vmware_platform(void)
@@ -53,7 +53,7 @@ static unsigned long __vmware_get_tsc_khz(void)
VMWARE_PORT(GETHZ, eax, ebx, ecx, edx);
- if (eax == (uint32_t)-1)
+ if (ebx == UINT_MAX)
return 0;
tsc_hz = eax | (((uint64_t)ebx) << 32);
do_div(tsc_hz, 1000);