From 0ed2f796d7723af8321f35d4ef5e6781ea41e36d Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Thu, 18 Aug 2022 14:11:31 +0200
Subject: syscall/fork: FORK_SHAREMEM for primitive "threads"

---
 src/user/app/tests/kernel/threads.c | 24 ++++++++++++++++++++++++
 src/user/app/tests/tests.c          |  1 +
 src/user/app/tests/tests.h          |  1 +
 src/user/lib/thread.S               |  8 ++++++++
 src/user/lib/thread.c               | 11 +++++++++++
 src/user/lib/thread.h               |  4 ++++
 6 files changed, 49 insertions(+)
 create mode 100644 src/user/app/tests/kernel/threads.c
 create mode 100644 src/user/lib/thread.S
 create mode 100644 src/user/lib/thread.c
 create mode 100644 src/user/lib/thread.h

(limited to 'src/user')

diff --git a/src/user/app/tests/kernel/threads.c b/src/user/app/tests/kernel/threads.c
new file mode 100644
index 0000000..9f08c39
--- /dev/null
+++ b/src/user/app/tests/kernel/threads.c
@@ -0,0 +1,24 @@
+#include "../tests.h"
+#include <camellia/flags.h>
+#include <camellia/syscalls.h>
+#include <user/lib/esemaphore.h>
+#include <user/lib/thread.h>
+
+int global_n;
+
+static void basic_thread(void *sem) {
+	global_n = 10;
+	esem_signal(sem);
+}
+
+static void test_basic_thread(void) {
+	struct evil_sem *sem = esem_new(0);
+	global_n = 0;
+	thread_create(FORK_NOREAP, basic_thread, sem);
+	esem_wait(sem);
+	test(global_n == 10);
+}
+
+void r_k_threads(void) {
+	run_test(test_basic_thread);
+}
diff --git a/src/user/app/tests/tests.c b/src/user/app/tests/tests.c
index 2157e60..f9b085a 100644
--- a/src/user/app/tests/tests.c
+++ b/src/user/app/tests/tests.c
@@ -17,6 +17,7 @@ int main(void) {
 	r_k_misc();
 	r_k_miscsyscall();
 	r_k_path();
+	r_k_threads();
 	r_libc_esemaphore();
 	r_libc_string();
 	r_s_printf();
diff --git a/src/user/app/tests/tests.h b/src/user/app/tests/tests.h
index 79169c9..d092115 100644
--- a/src/user/app/tests/tests.h
+++ b/src/user/app/tests/tests.h
@@ -11,6 +11,7 @@ void r_k_fs(void);
 void r_k_misc(void);
 void r_k_miscsyscall(void);
 void r_k_path(void);
+void r_k_threads(void);
 void r_libc_esemaphore(void);
 void r_libc_string(void);
 void r_s_printf(void);
diff --git a/src/user/lib/thread.S b/src/user/lib/thread.S
new file mode 100644
index 0000000..3cd3500
--- /dev/null
+++ b/src/user/lib/thread.S
@@ -0,0 +1,8 @@
+.section .text
+.global chstack
+.type chstack, @function
+// _Noreturn void chstack(void *arg, void (*fn)(void*), void *esp);
+chstack:
+	mov %rdx, %rsp
+	call *%rsi
+	jmp 0 // "exit"
diff --git a/src/user/lib/thread.c b/src/user/lib/thread.c
new file mode 100644
index 0000000..25d98a9
--- /dev/null
+++ b/src/user/lib/thread.c
@@ -0,0 +1,11 @@
+#include <camellia/flags.h>
+#include <camellia/syscalls.h>
+#include <stdlib.h>
+#include <user/lib/thread.h>
+
+void thread_create(int flags, void (*fn)(void*), void *arg) {
+	if (!_syscall_fork(flags | FORK_SHAREMEM, NULL)) {
+		void *stack = malloc(4096);
+		chstack(arg, fn, stack + 4096);
+	}
+}
diff --git a/src/user/lib/thread.h b/src/user/lib/thread.h
new file mode 100644
index 0000000..0d7376a
--- /dev/null
+++ b/src/user/lib/thread.h
@@ -0,0 +1,4 @@
+#pragma once
+
+void thread_create(int flags, void (*fn)(void*), void *arg);
+_Noreturn void chstack(void *arg, void (*fn)(void*), void *esp);
-- 
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