1  /* Machine dependent pthreads code.  Hurd/i386 version.
       2     Copyright (C) 2000-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library;  if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <errno.h>
      20  
      21  #include <mach.h>
      22  #include <mach/machine/thread_status.h>
      23  #include <mach/i386/mach_i386.h>
      24  #include <mach/mig_errors.h>
      25  #include <mach/thread_status.h>
      26  
      27  #define HURD_TLS_DESC_DECL(desc, tcb)					      \
      28    struct descriptor desc =						      \
      29      {				/* low word: */				      \
      30        0xffff			/* limit 0..15 */			      \
      31        | (((unsigned int) (tcb)) << 16) /* base 0..15 */			      \
      32        ,				/* high word: */			      \
      33        ((((unsigned int) (tcb)) >> 16) & 0xff) /* base 16..23 */		      \
      34        | ((0x12 | 0x60 | 0x80) << 8) /* access = ACC_DATA_W|ACC_PL_U|ACC_P */  \
      35        | (0xf << 16)		/* limit 16..19 */			      \
      36        | ((4 | 8) << 20)		/* granularity = SZ_32|SZ_G */		      \
      37        | (((unsigned int) (tcb)) & 0xff000000) /* base 24..31 */		      \
      38      }
      39  
      40  int
      41  __thread_set_pcsptp (thread_t thread,
      42  		     int set_ip, void *ip,
      43  		     int set_sp, void *sp,
      44  		     int set_tp, void *tp)
      45  {
      46    error_t err;
      47    struct i386_thread_state state;
      48    mach_msg_type_number_t state_count;
      49  
      50    state_count = i386_THREAD_STATE_COUNT;
      51  
      52    err = __thread_get_state (thread, i386_REGS_SEGS_STATE,
      53  			    (thread_state_t) &state, &state_count);
      54    if (err)
      55      return err;
      56  
      57    if (set_sp)
      58      state.uesp = (unsigned int) sp;
      59    if (set_ip)
      60      state.eip = (unsigned int) ip;
      61    if (set_tp)
      62      {
      63        HURD_TLS_DESC_DECL (desc, tp);
      64        int sel;
      65  
      66      asm ("mov %%gs, %w0": "=q" (sel):"0" (0));
      67        if (__builtin_expect (sel, 0x48) & 4)	/* LDT selector */
      68  	err = __i386_set_ldt (thread, sel, &desc, 1);
      69        else
      70  	err = __i386_set_gdt (thread, &sel, desc);
      71        if (err)
      72  	return err;
      73        state.gs = sel;
      74      }
      75  
      76    err = __thread_set_state (thread, i386_REGS_SEGS_STATE,
      77  			    (thread_state_t) &state, i386_THREAD_STATE_COUNT);
      78    if (err)
      79      return err;
      80  
      81    return 0;
      82  }