kernel: add a temporary syscall dispatch system

arch/user/include/mango/machine/init.h

@@ -1,6 +1,7 @@
 #ifndef MANGO_X86_64_INIT_H_
 #define MANGO_X86_64_INIT_H_
 
+#include <stddef.h>
 #include <stdint.h>
 
 #ifdef __cplusplus

arch/user/include/mango/machine/pmap.h

@@ -1,6 +1,8 @@
 #ifndef MANGO_USER_PMAP_H_
 #define MANGO_USER_PMAP_H_
 
+#include <stdint.h>
+
 typedef uintptr_t ml_pmap_t;
 typedef uint64_t ml_pfn_t;
 

arch/x86_64/irq.c

@@ -7,6 +7,7 @@
 #include <mango/machine/irq.h>
 #include <mango/panic.h>
 #include <mango/sched.h>
+#include <mango/syscall.h>
 #include <stddef.h>
 
 #define MAX_ISR_HANDLERS  16
@@ -151,6 +152,8 @@ int idt_init(struct idt_ptr *ptr)
 		init_global_idt();
 	}
 
+	set_syscall_gate((uintptr_t)syscall_gate);
+
 	ptr->i_limit = sizeof(idt) - 1;
 	ptr->i_base = (uintptr_t)&idt;
 
@@ -203,7 +206,7 @@ void irq_dispatch(struct ml_cpu_context *regs)
 void syscall_dispatch(struct ml_cpu_context *regs)
 {
 	unsigned int sysid = regs->rax;
-	virt_addr_t syscall_impl = 0;   // TODO
+	virt_addr_t syscall_impl = syscall_get_func(sysid);
 
 	if (syscall_impl == 0) {
 		regs->rax = KERN_UNSUPPORTED;

include/mango/syscall.h

@@ -0,0 +1,20 @@
+#ifndef MANGO_SYSCALL_H_
+#define MANGO_SYSCALL_H_
+
+#include <mango/handle.h>
+#include <mango/status.h>
+#include <mango/vm.h>
+
+#define SYS_EXIT             1
+#define SYS_VM_OBJECT_CREATE 2
+
+extern kern_status_t sys_exit(int status);
+extern kern_status_t sys_vm_object_create(
+	const char *name,
+	size_t len,
+	enum vm_prot prot,
+	kern_handle_t *out_handle);
+
+extern virt_addr_t syscall_get_func(unsigned int sysid);
+
+#endif

kernel/syscall.c

@@ -0,0 +1,40 @@
+#include <mango/machine/cpu.h>
+#include <mango/printk.h>
+#include <mango/syscall.h>
+
+kern_status_t sys_exit(int status)
+{
+	printk("sys_exit(%d)", status);
+	while (1) {
+		ml_cpu_pause();
+	}
+	return KERN_UNIMPLEMENTED;
+}
+
+kern_status_t sys_vm_object_create(
+	const char *name,
+	size_t len,
+	enum vm_prot prot,
+	kern_handle_t *out_handle)
+{
+	printk("sys_vm_object_create()");
+	return KERN_UNIMPLEMENTED;
+}
+
+#define SYSCALL_TABLE_ENTRY(id, p) [SYS_##id] = (virt_addr_t)(sys_##p)
+
+static const virt_addr_t syscall_table[] = {
+	SYSCALL_TABLE_ENTRY(EXIT, exit),
+	SYSCALL_TABLE_ENTRY(VM_OBJECT_CREATE, vm_object_create),
+};
+static const size_t syscall_table_count
+	= sizeof syscall_table / sizeof syscall_table[0];
+
+virt_addr_t syscall_get_func(unsigned int sysid)
+{
+	if (sysid >= syscall_table_count) {
+		return 0;
+	}
+
+	return syscall_table[sysid];
+}