1  /*
       2   * Copyright (c) 2015-2022 The strace developers.
       3   * All rights reserved.
       4   *
       5   * SPDX-License-Identifier: LGPL-2.1-or-later
       6   */
       7  
       8  static unsigned int xtensa_probe_naregs(struct tcb *tcp)
       9  {
      10  	struct user_pt_regs tmp = xtensa_regs;
      11  	unsigned int n = 8;
      12  
      13  	do {
      14  		n *= 2;
      15  		xtensa_regs.windowbase = n / 4;
      16  	} while (n < ARRAY_SIZE(xtensa_regs.a) &&
      17  		 set_regs(tcp->pid) == 0);
      18  	xtensa_regs = tmp;
      19  	set_regs(tcp->pid);
      20  	return n;
      21  }
      22  
      23  /* Return -1 on error or 1 on success (never 0!). */
      24  static int
      25  arch_get_syscall_args(struct tcb *tcp)
      26  {
      27  	static const unsigned int syscall_regs[MAX_ARGS] = { 6, 3, 4, 5, 8, 9 };
      28  	static unsigned int naregs_mask;
      29  
      30  	if (naregs_mask == 0)
      31  		naregs_mask = xtensa_probe_naregs(tcp) - 1;
      32  
      33  	for (unsigned int i = 0; i < n_args(tcp); ++i)
      34  		tcp->u_arg[i] = xtensa_regs.a[(xtensa_regs.windowbase * 4 +
      35  					       syscall_regs[i]) & naregs_mask];
      36  	return 1;
      37  }