[kernel] Improve process init

Move process init from each process needing a main.s with _start to
crt0.s in libc. Also change to a sysv-like initial stack with a
j6-specific array of initialization values after the program arguments.

src/drivers/fb/main.cpp

@@ -1,25 +1,16 @@
 #include <stdint.h>
 #include <stdlib.h>
 
-#include "j6/types.h"
+#include "j6/init.h"
 #include "j6/errors.h"
 #include "j6/signals.h"
+#include "j6/types.h"
 
 #include <j6libc/syscalls.h>
 
 extern "C" {
-	void _init_libc(j6_process_init *);
 	int main(int, const char **);
-}
-
-j6_handle_t sys = j6_handle_invalid;
-size_t size = 0;
-
-void
-_init_libc(j6_process_init *init)
-{
-	sys = init->handles[0];
-	size = reinterpret_cast<size_t>(init->handles[1]);
+	void _get_init(size_t *initc, struct j6_init_value **initv);
 }
 
 int
@@ -27,12 +18,25 @@ main(int argc, const char **argv)
 {
 	_syscall_system_log("fb driver starting");
 
-	if (size == 0)
+	size_t initc = 0;
+	j6_init_value *initv = nullptr;
+	_get_init(&initc, &initv);
+
+	j6_init_framebuffer *fb = nullptr;
+	for (unsigned i = 0; i < initc; ++i) {
+		if (initv[i].type == j6_init_desc_framebuffer) {
+			fb = reinterpret_cast<j6_init_framebuffer*>(initv[i].value);
+			break;
+		}
+	}
+
+	if (!fb)
 		return 1;
 
-	uint32_t *fb = reinterpret_cast<uint32_t*>(0x100000000);
+	uint32_t *fbp = reinterpret_cast<uint32_t*>(fb->addr);
+	size_t size = fb->size;
 	for (size_t i=0; i < size/4; ++i) {
-		fb[i] = 0xff;
+		fbp[i] = 0xff;
 	}
 
 	_syscall_system_log("fb driver done, exiting");

src/drivers/fb/main.s

@@ -1,24 +0,0 @@
-section .bss
-mymessage:
-	resq 1024
-
-extern main
-extern _init_libc
-extern exit
-
-section .text
-
-global _start
-_start:
-	mov rbp, rsp
-
-	mov rdi, rsp
-	call _init_libc
-
-	mov rdi, 0
-	mov rsi, 0
-
-	call main
-
-	mov rdi, rax
-	call exit

src/drivers/nulldrv/main.cpp

@@ -11,7 +11,7 @@
 #include "serial.h"
 
 char inbuf[1024];
-j6_handle_t sys = j6_handle_invalid;
+extern j6_handle_t __handle_sys;
 j6_handle_t endp = j6_handle_invalid;
 
 extern "C" {
@@ -51,12 +51,6 @@ thread_proc()
 	_syscall_thread_exit(0);
 }
 
-void
-_init_libc(j6_process_init *init)
-{
-	sys = init->handles[0];
-}
-
 int
 main(int argc, const char **argv)
 {
@@ -65,6 +59,9 @@ main(int argc, const char **argv)
 
 	_syscall_system_log("main thread starting");
 
+	for (int i = 0; i < argc; ++i)
+		_syscall_system_log(argv[i]);
+
 	void *base = malloc(0x1000);
 	if (!base)
 		return 1;
@@ -97,7 +94,7 @@ main(int argc, const char **argv)
 	if (tag != 17)
 		_syscall_system_log("GOT WRONG TAG FROM SENDRECV");
 
-	result = _syscall_system_bind_irq(sys, endp, 3);
+	result = _syscall_system_bind_irq(__handle_sys, endp, 3);
 	if (result != j6_status_ok)
 		return result;
 

src/drivers/nulldrv/main.s

@@ -1,24 +0,0 @@
-section .bss
-mymessage:
-	resq 1024
-
-extern main
-extern _init_libc
-extern exit
-
-section .text
-
-global _start
-_start:
-	mov rbp, rsp
-
-	mov rdi, rsp
-	call _init_libc
-
-	mov rdi, 0
-	mov rsi, 0
-
-	call main
-
-	mov rdi, rax
-	call exit