diff options
Diffstat (limited to 'absl/base/internal/sysinfo.cc')
| -rw-r--r-- | absl/base/internal/sysinfo.cc | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/absl/base/internal/sysinfo.cc b/absl/base/internal/sysinfo.cc index 9e0140fa..00e98b66 100644 --- a/absl/base/internal/sysinfo.cc +++ b/absl/base/internal/sysinfo.cc @@ -284,6 +284,30 @@ pid_t GetTID() { return syscall(SYS_gettid); } +#elif defined(__akaros__) + +pid_t GetTID() { + // Akaros has a concept of "vcore context", which is the state the program + // is forced into when we need to make a user-level scheduling decision, or + // run a signal handler. This is analogous to the interrupt context that a + // CPU might enter if it encounters some kind of exception. + // + // There is no current thread context in vcore context, but we need to give + // a reasonable answer if asked for a thread ID (e.g., in a signal handler). + // Thread 0 always exists, so if we are in vcore context, we return that. + // + // Otherwise, we know (since we are using pthreads) that the uthread struct + // current_uthread is pointing to is the first element of a + // struct pthread_tcb, so we extract and return the thread ID from that. + // + // TODO(dcross): Akaros anticipates moving the thread ID to the uthread + // structure at some point. We should modify this code to remove the cast + // when that happens. + if (in_vcore_context()) + return 0; + return reinterpret_cast<struct pthread_tcb *>(current_uthread)->id; +} + #else // Fallback implementation of GetTID using pthread_getspecific. |