kernel: munmap syscall

kernel-src/sys/syscalls/munmap.c

@@ -0,0 +1,27 @@
+#include <kernel/syscalls.h>
+#include <kernel/vmm.h>
+#include <errno.h>
+
+syscallret_t syscall_munmap(context_t *ctx, void *addr, size_t length) {
+	syscallret_t ret = {
+		.ret = -1,
+		.errno = 0
+	};
+
+	if (addr > USERSPACE_END) {
+		ret.errno = EFAULT;
+		return ret;
+	}
+
+	if (length == 0 || length % PAGE_SIZE > 0) {
+		ret.errno = EINVAL;
+		return ret;
+	}
+
+	vmm_unmap(addr, length / PAGE_SIZE, 0);
+
+	ret.ret = 0;
+	ret.errno = 0;
+
+	return ret;
+}