[BOOTDATA] Set the 'BootExecute' SMSS value to an empty value as we do not want AutoC...
[reactos.git] / boot / environ / lib / platform / time.c
1 /*
2 * COPYRIGHT: See COPYING.ARM in the top level directory
3 * PROJECT: ReactOS UEFI Boot Library
4 * FILE: boot/environ/lib/platform/time.c
5 * PURPOSE: Boot Library Time Management Routines
6 * PROGRAMMER: Alex Ionescu (alex.ionescu@reactos.org)
7 */
8
9 /* INCLUDES ******************************************************************/
10
11 #include "bl.h"
12
13 /* DATA VARIABLES ************************************************************/
14
15 ULONGLONG BlpTimePerformanceFrequency;
16
17 /* FUNCTIONS *****************************************************************/
18
19 NTSTATUS
20 BlpTimeMeasureTscFrequency (
21 VOID
22 )
23 {
24 #if defined(_M_IX86) || defined(_M_X64)
25 ULONG Count;
26 INT CpuInfo[4];
27 ULONGLONG TimeStamp1, TimeStamp2, Delta;
28
29 /* Check if the ISVM bit it set, meaning we're in a hypervisor */
30 __cpuid(CpuInfo, 1);
31 Count = CpuInfo[2] & 0x80000000 ? 10 : 1;
32
33 /* Loop trying to get an accurate TSC */
34 do
35 {
36 /* Stall for 1us and get count 1 */
37 EfiStall(1);
38 TimeStamp1 = __rdtsc();
39
40 /* Stall for 1000us and get count 2*/
41 EfiStall(1000);
42 TimeStamp2 = __rdtsc();
43
44 /* Stall for 9000us and get the difference */
45 EfiStall(9000);
46 Delta = __rdtsc() - TimeStamp2;
47
48 /* Keep going as long as the TSC is fluctuating */
49 --Count;
50 } while (((TimeStamp2 - TimeStamp1) > Delta) && (Count));
51
52 /* Set the frequency based on the two measurements we took */
53 BlpTimePerformanceFrequency = 125 * (Delta - (TimeStamp2 - TimeStamp1)) & 0x1FFFFFFFFFFFFFF;
54 return STATUS_SUCCESS;
55 #else
56 EfiPrintf(L"BlpTimeMeasureTscFrequency not implemented for this platform.\r\n");
57 return STATUS_NOT_IMPLEMENTED;
58 #endif
59 }
60
61 NTSTATUS
62 BlpTimeCalibratePerformanceCounter (
63 VOID
64 )
65 {
66 #if defined(_M_IX86) || defined(_M_X64)
67 INT CpuInfo[4];
68
69 /* Check if the ISVM bit it set, meaning we're in a hypervisor */
70 __cpuid(CpuInfo, 1);
71 if (CpuInfo[2] & 0x80000000)
72 {
73 /* Get the Hypervisor Identification Leaf */
74 __cpuid(CpuInfo, 0x40000001);
75
76 /* Is this Hyper-V? */
77 if (CpuInfo[0] == '1#vH')
78 {
79 /* Get the Hypervisor Feature Identification Leaf */
80 __cpuid(CpuInfo, 0x40000003);
81
82 /* Check if HV_X64_MSR_REFERENCE_TSC is present */
83 if (CpuInfo[3] & 0x100)
84 {
85 /* Read the TSC frequency from the MSR */
86 BlpTimePerformanceFrequency = __readmsr(0x40000022);
87 return STATUS_SUCCESS;
88 }
89 }
90 }
91
92 /* On other systems, compute it */
93 return BlpTimeMeasureTscFrequency();
94 #else
95 EfiPrintf(L"BlpTimeCalibratePerformanceCounter not implemented for this platform.\r\n");
96 return STATUS_NOT_IMPLEMENTED;
97 #endif
98 }
99
100 ULONGLONG
101 BlTimeQueryPerformanceCounter (
102 _Out_opt_ PLARGE_INTEGER Frequency
103 )
104 {
105 #if defined(_M_IX86) || defined(_M_X64)
106 /* Check if caller wants frequency */
107 if (Frequency)
108 {
109 /* Return it */
110 Frequency->QuadPart = BlpTimePerformanceFrequency;
111 }
112
113 /* Return the TSC value */
114 return __rdtsc();
115 #else
116 EfiPrintf(L"BlTimeQueryPerformanceCounter not implemented for this platform.\r\n");
117 return 0;
118 #endif
119 };