lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/lib/mlibc/sysdeps/lemon/generic/thread.cpp b/lib/mlibc/sysdeps/lemon/generic/thread.cpp
new file mode 100644
index 0000000..42cd758
--- /dev/null
+++ b/lib/mlibc/sysdeps/lemon/generic/thread.cpp
@@ -0,0 +1,53 @@
+#include <mlibc/thread-entry.hpp>
+#include <mlibc/all-sysdeps.hpp>
+#include <mlibc/tcb.hpp>
+#include <bits/ensure.h>
+#include <sys/mman.h>
+#include <stdint.h>
+#include <stddef.h>
+
+extern "C" void __mlibc_enter_thread(void *entry, void *user_arg, Tcb *tcb) {
+	// Wait until our parent sets up the TID.
+	while(!__atomic_load_n(&tcb->tid, __ATOMIC_RELAXED))
+		mlibc::sys_futex_wait(&tcb->tid, 0, nullptr);
+
+	if(mlibc::sys_tcb_set(tcb))
+		__ensure(!"sys_tcb_set() failed");
+
+	tcb->invokeThreadFunc(entry, user_arg);
+
+	auto self = reinterpret_cast<Tcb *>(tcb);
+
+	__atomic_store_n(&self->didExit, 1, __ATOMIC_RELEASE);
+	mlibc::sys_futex_wake(&self->didExit);
+
+	mlibc::sys_thread_exit();
+}
+
+namespace mlibc {
+
+static constexpr size_t default_stacksize = 0x200000;
+
+int sys_prepare_stack(void **stack, void *entry, void *user_arg, void *tcb, size_t *stack_size, size_t *guard_size, void **stack_base) {
+	if (!*stack_size)
+		*stack_size = default_stacksize;
+	*guard_size = 0;
+
+	if (*stack) {
+		*stack_base = *stack;
+	} else {
+		*stack_base = mmap(nullptr, *stack_size,
+						PROT_READ | PROT_WRITE,
+						MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+	}
+	
+	uintptr_t *sp = reinterpret_cast<uintptr_t *>(reinterpret_cast<uintptr_t>(*stack_base) + *stack_size);
+
+	*--sp = reinterpret_cast<uintptr_t>(tcb);
+	*--sp = reinterpret_cast<uintptr_t>(user_arg);
+	*--sp = reinterpret_cast<uintptr_t>(entry);
+	*stack = reinterpret_cast<void*>(sp);
+	return 0;
+}
+
+} //namespace mlibc