From 71aa64a7d4ec3242cb623e6fc1388ee22a7ff62a Mon Sep 17 00:00:00 2001
From: flysand7 <thebumboni@gmail.com>
Date: Sat, 26 Aug 2023 13:53:58 +1100
Subject: [PATCH] threads work on linux!

---
 arch/sysv_x86-64/thread-entry.asm | 22 ++++++++++++++--------
 os/linux/tinyrt.c                 | 12 +++++-------
 test.c                            |  8 --------
 tests/threaded.c                  | 21 +++++++++++----------
 4 files changed, 30 insertions(+), 33 deletions(-)
 delete mode 100644 test.c

diff --git a/arch/sysv_x86-64/thread-entry.asm b/arch/sysv_x86-64/thread-entry.asm
index 6605efb..df61895 100644
--- a/arch/sysv_x86-64/thread-entry.asm
+++ b/arch/sysv_x86-64/thread-entry.asm
@@ -2,7 +2,7 @@
 bits 64
 
 section .text
-global _cia_clone
+global _cia_start_thread
 
 ; flags, &stack[-2], &parent_tid, &child_tid, 0
 
@@ -23,14 +23,15 @@ global _cia_clone
 ;     0 if returning as a parent
 ;     1 if returning as a child
 ;     negative value if there was an error making the thread
-_cia_clone:
+_cia_start_thread:
     mov r10, rcx
-    sub rsi, 8
-    ; As a child thread we wanna return to the same place as the parent
-    mov rax, qword [rsp]
-    mov qword [rsi], rax
-    ; ; Copy child tid ptr
-    ; mov qword [rsi + 0], rcx
+    ; Setup child stack
+    sub rsi, 24
+    mov rax, [rsp]
+    mov [rsi+16], rax
+    mov rax, [rsp+8]
+    mov [rsi+8], rax
+    mov [rsi], r9
     ; Call syscall right away, since the order of the first 5 arguments
     ; matches with the argument order of the function
     mov rax, 56 ; SYS_CLONE
@@ -38,5 +39,10 @@ _cia_clone:
     ; Check to see if we're child
     test eax, eax
     jnz .exit
+    ; If child, jump to thread function
+    pop rax ; thread_fn
+    pop rdi ; ctx
+    call rax
+    hlt
 .exit:
     ret
diff --git a/os/linux/tinyrt.c b/os/linux/tinyrt.c
index 9c40c8d..16ffe90 100644
--- a/os/linux/tinyrt.c
+++ b/os/linux/tinyrt.c
@@ -1,13 +1,14 @@
 
 // See src/tinyrt.h file for the interface this file implements
 
-extern i64 _cia_clone(
+extern i64 _cia_start_thread(
     u64 flags,
     void *stack_base,
     int *parent_tid,
     int *child_tid,
     void *tls,
-    u64 stack_size
+    void (*thread_fn)(void *ctx),
+    void *ctx
 );
 
 _Noreturn static void _rt_program_exit(int code) {
@@ -21,7 +22,7 @@ static _RT_Status _rt_thread_current(_RT_Thread *thread) {
 static _RT_Status _rt_thread_create(_RT_Thread *thread, void (*thread_fn)(void *ctx), void *ctx) {
     // Create the memory for stack
     u64 mmap_prot = PROT_READ|PROT_WRITE;
-    u64 mmap_flags = MAP_PRIVATE|MAP_ANONYMOUS;
+    u64 mmap_flags = MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE;
     u64 stack_size = 0x10000;
     void *stack_base = sys_mmap(0, stack_size, mmap_prot, mmap_flags, -1, 0);
     if((i64)stack_base < 0) {
@@ -43,13 +44,10 @@ static _RT_Status _rt_thread_create(_RT_Thread *thread, void (*thread_fn)(void *
     int *parent_tid = &temp_permanent_storage[1];
     *child_tid = 1;
     *parent_tid = 0;
-    i64 ret = _cia_clone(flags, stack, parent_tid, child_tid, 0, stack_size);
+    i64 ret = _cia_start_thread(flags, stack, parent_tid, child_tid, 0, thread_fn, ctx);
     if(ret < 0) {
         return _RT_ERROR_GENERIC;
     }
-    if(!ret) {
-        thread_fn(ctx);
-    }
     return _RT_STATUS_OK;
 }
 
diff --git a/test.c b/test.c
deleted file mode 100644
index 692a89e..0000000
--- a/test.c
+++ /dev/null
@@ -1,8 +0,0 @@
-
-#define __USE_GNU
-
-#include <sched.h>
-
-#ifdef CLONE_FILES
-    #define MYMACRO 1
-#endif
diff --git a/tests/threaded.c b/tests/threaded.c
index 8623306..9761e63 100644
--- a/tests/threaded.c
+++ b/tests/threaded.c
@@ -3,23 +3,24 @@
 #include <stdlib.h>
 #include <threads.h>
 
+static void print_str(char *str) {
+    int str_len = 0;
+    while(str[str_len] != 0) {
+        ++str_len;
+    }
+    fwrite(str, 1, str_len, stdout);
+}
+
 int thrd_func(void *arg) {
-    char string[] = "child thread: ok!\n";
-    fwrite(string, 1, sizeof string-1, stdout);
-    // exit(1);
+    print_str("child thread: ok!\n");
     for(;;);
     return 0;
 }
 
 int main() {
-    {char string[] = "main thread: before!\n";
-    fwrite(string, 1, sizeof string-1, stdout);}
-    
+    print_str("main thread: before\n");
     thrd_t thrd;
     thrd_create(&thrd, thrd_func, NULL);
-    
-    {char string[] = "main thread: after!\n";
-    fwrite(string, 1, sizeof string-1, stdout);}
-    for(;;);
+    print_str("main thread: after!\n");
     return 0;
 }