Print args when tracing syscall;
Change envsc's type to suit execve.

Add primitive kmalloc module (not being used yet).

Only hart 0 update ticks, so tickslock isn't needed at present.

Develop

Fix potential bugs of fs (eput and '0xff').

Pass most usertests on QEMU.

Abandon defs.h and some files;

Console

Fix xargs bugs.