bsd-user/arm/target_arch_thread.h

   1 /*
   2  *  arm thread support
   3  *
   4  *  Copyright (c) 2013 Stacey D. Son
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #ifndef TARGET_ARCH_THREAD_H
  21 #define TARGET_ARCH_THREAD_H
  22
  23 /* Compare to arm/arm/vm_machdep.c cpu_set_upcall_kse() */
  24 static inline void target_thread_set_upcall(CPUARMState *env, abi_ulong entry,
  25     abi_ulong arg, abi_ulong stack_base, abi_ulong stack_size)
  26 {
  27     abi_ulong sp;
  28
  29     /*
  30      * Make sure the stack is properly aligned.
  31      * arm/include/param.h (STACKLIGN() macro)
  32      */
  33     sp = (u_int)(stack_base + stack_size) & ~0x7;
  34
  35     /* sp = stack base */
  36     env->regs[13] = sp;
  37     /* pc = start function entry */
  38     env->regs[15] = entry & 0xfffffffe;
  39     /* r0 = arg */
  40     env->regs[0] = arg;
  41     env->spsr = ARM_CPU_MODE_USR;
  42     /*
  43      * Thumb mode is encoded by the low bit in the entry point (since ARM can't
  44      * execute at odd addresses). When it's set, set the Thumb bit (T) in the
  45      * CPSR.
  46      */
  47     cpsr_write(env, (entry & 1) * CPSR_T, CPSR_T, CPSRWriteByInstr);
  48 }
  49
  50 static inline void target_thread_init(struct target_pt_regs *regs,
  51         struct image_info *infop)
  52 {
  53     abi_long stack = infop->start_stack;
  54     memset(regs, 0, sizeof(*regs));
  55     regs->ARM_cpsr = ARM_CPU_MODE_USR;
  56     /*
  57      * Thumb mode is encoded by the low bit in the entry point (since ARM can't
  58      * execute at odd addresses). When it's set, set the Thumb bit (T) in the
  59      * CPSR.
  60      */
  61     if (infop->entry & 1) {
  62         regs->ARM_cpsr |= CPSR_T;
  63     }
  64     regs->ARM_pc = infop->entry & 0xfffffffe;
  65     regs->ARM_sp = stack;
  66     regs->ARM_lr = infop->entry & 0xfffffffe;
  67     /*
  68      * FreeBSD kernel passes the ps_strings pointer in r0. This is used by some
  69      * programs to set status messages that we see in ps. bsd-user doesn't
  70      * support that functionality, so it's ignored. When set to 0, FreeBSD's csu
  71      * code ignores it. For the static case, r1 and r2 are effectively ignored
  72      * by the csu __startup() routine. For the dynamic case, rtld saves r0 but
  73      * generates r1 and r2 and passes them into the csu _startup.
  74      *
  75      * r0 ps_strings 0 passed since ps arg setting not supported
  76      * r1 obj_main   ignored by _start(), so 0 passed
  77      * r2 cleanup    generated by rtld or ignored by _start(), so 0 passed
  78      */
  79 }
  80
  81 #endif /* TARGET_ARCH_THREAD_H */