diff options
author | Michele Papalini <micpapal+fdio@cisco.com> | 2017-02-24 08:00:33 +0000 |
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committer | Gerrit Code Review <gerrit@fd.io> | 2017-02-24 08:00:33 +0000 |
commit | 4df7f4cc98b6288177df256e1db70ddc3f7d00db (patch) | |
tree | 55e71277b419e4830ae641868ab8e751c8b86972 /libparc/parc/developer/parc_TimingIntel.c | |
parent | f28308bd99381ef5f1e178e2e1f870f245e35873 (diff) | |
parent | ec688b4723a041044226358bcd4dd6e2da39da49 (diff) |
Merge "Initial commit: cframework. Longbow and Libparc" into cframework/master
Diffstat (limited to 'libparc/parc/developer/parc_TimingIntel.c')
-rwxr-xr-x | libparc/parc/developer/parc_TimingIntel.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/libparc/parc/developer/parc_TimingIntel.c b/libparc/parc/developer/parc_TimingIntel.c new file mode 100755 index 00000000..c690515c --- /dev/null +++ b/libparc/parc/developer/parc_TimingIntel.c @@ -0,0 +1,89 @@ +/* + * Copyright (c) 2017 Cisco and/or its affiliates. + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at: + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/** + * Executes either the RDTSC or RDTSCP instruction, depending on platform availability + * + */ + +#include <config.h> +#include <stdio.h> + +#define PARCTIMING_ENABLE +#include <parc/developer/parc_Timing.h> + +#ifdef PARCTIMING_INTEL +static bool _useRdtscp = false; +static bool _needCheckRdtscp = true; + +#include <cpuid.h> + +static void +_checkRdtscp(void) +{ + // See the CPUID instruction for description of the codes. + + // determine the maximum extended information set + unsigned maxextended = __get_cpuid_max(0x80000000, NULL); + + // RDTSCP status flag is in the 0x800000001 feature set + const unsigned feature = 0x80000001; + const unsigned rdtscp_feature = 1 << 27; + + if (maxextended >= feature) { + unsigned eax, ebx, ecx, edx; + + int success = __get_cpuid(feature, &eax, &ebx, &ecx, &edx); + if (success) { + _useRdtscp = (edx & rdtscp_feature ? true : false); + } + } +} +#endif // PARCTIMING_INTEL + +void +parcTiminIntel_RuntimeInit(void) +{ +#ifdef PARCTIMING_INTEL + if (_needCheckRdtscp) { + _needCheckRdtscp = false; + _checkRdtscp(); + } +#endif // PARCTIMING_INTEL +} + +void +parcTimingIntel_rdtsc(unsigned *hi, unsigned *lo) +{ + /* + * Older CPUs do not support RDTSCP, which is the better instruction to use. + * If we did not detect this opcode in autoconf, use the older RDTSC + */ + +#ifdef PARCTIMING_INTEL + if (_useRdtscp) { + __asm volatile ("RDTSCP\n\t" + "mov %%edx,%0\n\t" + "mov %%eax,%1\n\t" + "CPUID\n\t" : "=r" (*hi), "=r" (*lo):: "%rax", "%rbx", "%rcx", "%rdx"); + } else { + __asm volatile ("RDTSC\n\t" + "mov %%edx,%0\n\t" + "mov %%eax,%1\n\t" + "CPUID\n\t" : "=r" (*hi), "=r" (*lo):: "%rax", "%rbx", "%rcx", "%rdx"); + } +#endif // PARCTIMING_INTEL +} + |