蜗牛科技

PTR_LA		$28, init_thread_union
PTR_LI		sp, _THREAD_SIZE - 32
PTR_ADDU	sp, $28
set_saved_sp	sp, t0, t1
PTR_SUBU	sp, 4 * SZREG		# init stack pointer
j		start_kernel

/*
 * Initial thread structure.
 *
 * We need to make sure that this is 8192-byte aligned due to the
 * way process stacks are handled. This is done by making sure
 * the linker maps this in the .text segment right after head.S,
 * and making head.S ensure the proper alignment.
 *
 * The things we do for performance..
 */
union thread_union init_thread_union
	__attribute__((__section__(".data.init_task"),
				   __aligned__(THREAD_SIZE))) =
		{ INIT_THREAD_INFO(init_task) };
/*
 * Initial task structure.
 *
 * All other task structs will be allocated on slabs in fork.c
 */
struct task_struct init_task = INIT_TASK(init_task);

union thread_union {
	struct thread_info thread_info;
	unsigned long stack[THREAD_SIZE/sizeof(long)];
};

/*
 * low level task data that entry.S needs immediate access to
 * - this struct should fit entirely inside of one cache line
 * - this struct shares the supervisor stack pages
 * - if the contents of this structure are changed, the assembly constants
 *   must also be changed
 */
struct thread_info {
	struct task_struct	*task;		/* main task structure */
	struct exec_domain	*exec_domain;	/* execution domain */
	unsigned long		flags;		/* low level flags */
	unsigned long		tp_value;	/* thread pointer */
	__u32			cpu;		/* current CPU */
	int			preempt_count;	/* 0 => preemptable, <0 => BUG */
	mm_segment_t		addr_limit;	/* thread address space:
						   0-0xBFFFFFFF for user-thead
						   0-0xFFFFFFFF for kernel-thread
						*/
	struct restart_block	restart_block;
	struct pt_regs		*regs;
};