1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
47 	if (ucp->uc_link == NULL)  in _ctx_done()
55 		ucp->uc_mcontext.mc_len = 0;  in _ctx_done()
57 		/* Set context to next one in link */  in _ctx_done()
58 		/* XXX - what to do for error, abort? */  in _ctx_done()
59 		setcontext((const ucontext_t *)ucp->uc_link);  in _ctx_done()
74 	else if ((ucp->uc_stack.ss_sp == NULL) ||  in __makecontext()
75 	    (ucp->uc_stack.ss_size < MINSIGSTKSZ)) {  in __makecontext()
77 		 * This should really return -1 with errno set to ENOMEM  in __makecontext()
82 		ucp->uc_mcontext.mc_len = 0;  in __makecontext()
84 	/* XXX - Do we want to sanity check argc? */  in __makecontext()
86 		ucp->uc_mcontext.mc_len = 0;  in __makecontext()
89 	else if (ucp->uc_mcontext.mc_len == sizeof(mcontext_t)) {  in __makecontext()
93 		 *	_ctx_start()	- context start wrapper  in __makecontext()
94 		 *	start()		- user start routine  in __makecontext()
95 		 * 	arg1            - first argument, aligned(16)  in __makecontext()
98 		 *	ucp		- this context, %ebp points here  in __makecontext()
102 		 * start routine from the top of the stack.  After that,  in __makecontext()
103 		 * the top of the stack will be setup with all arguments  in __makecontext()
111 		stack_top = (char *)(ucp->uc_stack.ss_sp +  in __makecontext()
112 		    ucp->uc_stack.ss_size - sizeof(intptr_t));  in __makecontext()
115 		 * Adjust top of stack to allow for 3 pointers (return  in __makecontext()
120 		stack_top = stack_top - (sizeof(intptr_t) * (1 + argc));  in __makecontext()
122 		stack_top = stack_top - (2 * sizeof(intptr_t));  in __makecontext()
126 		 * Setup the top of the stack with the user start routine  in __makecontext()
128 		 * ucontext.  We need to leave a spare spot at the top of  in __makecontext()
129 		 * the stack because setcontext will move eip to the top  in __makecontext()
149 		 * Set the machine context to point to the top of the  in __makecontext()
152 		 * address onto the top of the stack, so allow for this  in __makecontext()
153 		 * by adjusting the stack downward 1 slot.  Also set  in __makecontext()
157 		ucp->uc_mcontext.mc_esi = (int)argp;  in __makecontext()
158 		ucp->uc_mcontext.mc_ebp = 0;  in __makecontext()
159 		ucp->uc_mcontext.mc_esp = (int)stack_top + sizeof(caddr_t);  in __makecontext()
160 		ucp->uc_mcontext.mc_eip = (int)_ctx_start;  in __makecontext()