From d164dd13f8ad16c1bab95d5ebc8f4192efc503f6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kacper=20S=C5=82omi=C5=84ski?=
 <kacper.slominski72@gmail.com>
Date: Sun, 23 Feb 2020 19:13:25 +0100
Subject: [PATCH] options/posix: implement pthread_self

---
 meson.build                               |  1 +
 options/internal/include/mlibc/thread.hpp | 10 ++++++++++
 options/internal/x86_64/thread.cpp        | 13 +++++++++++++
 options/posix/generic/pthread-stubs.cpp   |  6 ++++--
 4 files changed, 28 insertions(+), 2 deletions(-)
 create mode 100644 options/internal/include/mlibc/thread.hpp
 create mode 100644 options/internal/x86_64/thread.cpp

diff --git a/meson.build b/meson.build
index 31727511..ef181e10 100644
--- a/meson.build
+++ b/meson.build
@@ -135,6 +135,7 @@ internal_sources = [
 	'options/internal/gcc/initfini.cpp',
 	'options/internal/gcc-extra/cxxabi.cpp',
 	'options/internal/x86_64/setjmp.S',
+	'options/internal/x86_64/thread.cpp',
 ]
 
 if not static
diff --git a/options/internal/include/mlibc/thread.hpp b/options/internal/include/mlibc/thread.hpp
new file mode 100644
index 00000000..dad28def
--- /dev/null
+++ b/options/internal/include/mlibc/thread.hpp
@@ -0,0 +1,10 @@
+#ifndef MLIBC_THREAD_HPP
+#define MLIBC_THREAD_HPP
+
+namespace mlibc {
+
+void *get_current_tcb();
+
+}
+
+#endif // MLIBC_THREAD_HPP
diff --git a/options/internal/x86_64/thread.cpp b/options/internal/x86_64/thread.cpp
new file mode 100644
index 00000000..64efb11c
--- /dev/null
+++ b/options/internal/x86_64/thread.cpp
@@ -0,0 +1,13 @@
+#include <mlibc/thread.hpp>
+
+#include <stdint.h>
+
+namespace mlibc {
+
+void *get_current_tcb() {
+	uintptr_t ptr;
+	asm ("movq %%fs:0, %0" : "=r"(ptr));
+	return reinterpret_cast<void *>(ptr);
+}
+
+}
diff --git a/options/posix/generic/pthread-stubs.cpp b/options/posix/generic/pthread-stubs.cpp
index 451a14da..bb9d2a8a 100644
--- a/options/posix/generic/pthread-stubs.cpp
+++ b/options/posix/generic/pthread-stubs.cpp
@@ -10,6 +10,7 @@
 #include <mlibc/allocator.hpp>
 #include <mlibc/debug.hpp>
 #include <mlibc/sysdeps.hpp>
+#include <mlibc/thread.hpp>
 
 static bool enableTrace = false;
 
@@ -100,10 +101,11 @@ int pthread_create(pthread_t *__restrict, const pthread_attr_t *__restrict,
 	__ensure(!"Not implemented");
 	__builtin_unreachable();
 }
+
 pthread_t pthread_self(void) {
-	__ensure(!"Not implemented");
-	__builtin_unreachable();
+	return reinterpret_cast<pthread_t>(mlibc::get_current_tcb());
 }
+
 int pthread_equal(pthread_t, pthread_t) {
 	__ensure(!"Not implemented");
 	__builtin_unreachable();