Rewrite init app in C, introduce MSL (MOP3 System Library)

libmsl/Makefile

@@ -0,0 +1,28 @@
+cc := clang
+o :=
+c :=
+cflags  := -isystem .
+buildtype ?= release
+
+include src.mk
+include ../generic/flags.mk
+include ../$(platform)/flags.mk
+
+all: build/libmsl.a
+
+build/libmsl.a: $(o)
+	llvm-ar rcs $@ $^
+
+%.o: %.c
+	$(cc) -c -o $@ $(cflags) $<
+
+%.o: %.S
+	$(cc) -c -o $@ $(cflags) $<
+
+clean:
+	rm -f $(o) build/libmsl.a
+
+format:
+	clang-format -i $$(git ls-files '*.c' '*.h')
+
+.PHONY: all clean format

libmsl/amd64/.gitignore

@@ -0,0 +1 @@
+*.o

libmsl/amd64/_start.S

@@ -0,0 +1,8 @@
+.global _start
+_start:
+  xorq %rbp, %rbp
+  movq %rsp, %rbp
+  andq $-16, %rsp
+  subq $8, %rsp
+
+  callq __premain

libmsl/amd64/src.mk

@@ -0,0 +1,6 @@
+c += amd64/syscall.c
+
+S += amd64/_start.S
+
+o += amd64/_start.o \
+		 amd64/syscall.o

libmsl/amd64/syscall.c

@@ -0,0 +1,23 @@
+#include <stddef.h>
+#include <stdint.h>
+#include <amd64/syscall.h>
+
+int msl_amd64_syscall (int syscall_num, uintptr_t a1, uintptr_t a2, uintptr_t a3, uintptr_t a4, uintptr_t a5, uintptr_t a6) {
+  uint64_t result;
+  __asm__ volatile (
+    "movq %1, %%rax\n"
+    "movq %2, %%rdi\n"
+    "movq %3, %%rsi\n"
+    "movq %4, %%rdx\n"
+    "movq %5, %%r10\n"
+    "movq %6, %%r8\n"
+    "movq %7, %%r9\n"
+    "syscall\n"
+    "movq %%rax, %0\n"
+    : "=r"(result)
+    : "r"((uint64_t)syscall_num), "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5), "r"(a6)
+    : "memory", "cc", "rcx", "r11"
+  );
+  return (int)result;
+}
+

libmsl/amd64/syscall.h

@@ -0,0 +1,8 @@
+#ifndef _LIBMSL_AMD64_SYSCALL_H
+#define _LIBMSL_AMD64_SYSCALL_H
+
+#include <stdint.h>
+
+int msl_amd64_syscall (int syscall_num, uintptr_t a1, uintptr_t a2, uintptr_t a3, uintptr_t a4, uintptr_t a5, uintptr_t a6);
+
+#endif // _LIBMSL_AMD64_SYSCALL_H

libmsl/init/.gitignore

@@ -0,0 +1 @@
+*.o

libmsl/init/__premain.c

@@ -0,0 +1,22 @@
+#include <stdint.h>
+#include <m/proc.h>
+
+extern volatile uint8_t __bss_start[];
+extern volatile uint8_t __bss_end[];
+
+extern void app_main (void);
+
+static void msl_clear_bss (void) {
+  uint8_t *p = (uint8_t*)__bss_start;
+  while (p < __bss_end) {
+    *p++ = 0;
+  }
+}
+
+void __premain (void) {
+  msl_clear_bss ();
+
+  app_main ();
+
+  m_proc_quit ();
+}

libmsl/init/src.mk

@@ -0,0 +1,3 @@
+c += init/__premain.c
+
+o += init/__premain.o

libmsl/m/.gitignore

@@ -0,0 +1 @@
+*.o

libmsl/m/proc.c

@@ -0,0 +1,10 @@
+#include <m/syscall.h>
+#include <m/syscall_defs.h>
+
+int m_proc_quit (void) {
+  return m_syscall (SYS_PROC_QUIT, 0, 0, 0, 0, 0, 0);
+}
+
+int m_proc_test (void) {
+  return m_syscall (SYS_PROC_TEST, 0, 0, 0, 0, 0, 0);
+}

libmsl/m/proc.h

@@ -0,0 +1,8 @@
+#ifndef _LIBMSL_M_PROC_H
+#define _LIBMSL_M_PROC_H
+
+int m_proc_quit (void);
+
+int m_proc_test (void);
+
+#endif // _LIBMSL_M_PROC_H

libmsl/m/src.mk

@@ -0,0 +1,3 @@
+c += m/proc.c
+
+o += m/proc.o

libmsl/m/syscall.h

@@ -0,0 +1,11 @@
+#ifndef _LIBMSL_M_SYSCALL_H
+#define _LIBMSL_M_SYSCALL_H
+
+#include <m/syscall_defs.h>
+
+#if defined(__x86_64__)
+  #include <amd64/syscall.h>
+  #define m_syscall msl_amd64_syscall
+#endif
+
+#endif // _LIBMSL_M_SYSCALL_H

libmsl/src.mk

@@ -0,0 +1,3 @@
+include $(platform)/src.mk
+include init/src.mk
+include m/src.mk