arch/blackfin/kernel/entry.S

   1 /*
   2  * File:         arch/blackfin/kernel/entry.S
   3  * Based on:
   4  * Author:
   5  *
   6  * Created:
   7  * Description:
   8  *
   9  * Modified:
  10  *               Copyright 2004-2006 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, see the file COPYING, or write
  26  * to the Free Software Foundation, Inc.,
  27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  28  */
  29
  30 #include <linux/linkage.h>
  31 #include <asm/thread_info.h>
  32 #include <asm/errno.h>
  33 #include <asm/blackfin.h>
  34 #include <asm/asm-offsets.h>
  35
  36 #include <asm/context.S>
  37
  38 #ifdef CONFIG_EXCPT_IRQ_SYSC_L1
  39 .section .l1.text
  40 #else
  41 .text
  42 #endif
  43
  44 ENTRY(_ret_from_fork)
  45 #ifdef CONFIG_IPIPE
  46         /*
  47          * Hw IRQs are off on entry, and we don't want the scheduling tail
  48          * code to starve high priority domains from interrupts while it
  49          * runs. Therefore we first stall the root stage to have the
  50          * virtual interrupt state reflect IMASK.
  51          */
  52         p0.l = ___ipipe_root_status;
  53         p0.h = ___ipipe_root_status;
  54         r4 = [p0];
  55         bitset(r4, 0);
  56         [p0] = r4;
  57         /*
  58          * Then we may enable hw IRQs, allowing preemption from high
  59          * priority domains. schedule_tail() will do local_irq_enable()
  60          * since Blackfin does not define __ARCH_WANT_UNLOCKED_CTXSW, so
  61          * there is no need to unstall the root domain by ourselves
  62          * afterwards.
  63          */
  64         p0.l = _bfin_irq_flags;
  65         p0.h = _bfin_irq_flags;
  66         r4 = [p0];
  67         sti r4;
  68 #endif /* CONFIG_IPIPE */
  69         SP += -12;
  70         call _schedule_tail;
  71         SP += 12;
  72         r0 = [sp + PT_IPEND];
  73         cc = bittst(r0,1);
  74         if cc jump .Lin_kernel;
  75         RESTORE_CONTEXT
  76         rti;
  77 .Lin_kernel:
  78         bitclr(r0,1);
  79         [sp + PT_IPEND] = r0;
  80         /* do a 'fake' RTI by jumping to [RETI]
  81          * to avoid clearing supervisor mode in child
  82          */
  83         r0 = [sp + PT_PC];
  84         [sp + PT_P0] = r0;
  85
  86         RESTORE_ALL_SYS
  87         jump (p0);
  88 ENDPROC(_ret_from_fork)
  89
  90 ENTRY(_sys_fork)
  91         r0 = -EINVAL;
  92 #if (ANOMALY_05000371)
  93         nop;
  94         nop;
  95         nop;
  96 #endif
  97         rts;
  98 ENDPROC(_sys_fork)
  99
 100 ENTRY(_sys_vfork)
 101         r0 = sp;
 102         r0 += 24;
 103         [--sp] = rets;
 104         SP += -12;
 105         call _bfin_vfork;
 106         SP += 12;
 107         rets = [sp++];
 108         rts;
 109 ENDPROC(_sys_vfork)
 110
 111 ENTRY(_sys_clone)
 112         r0 = sp;
 113         r0 += 24;
 114         [--sp] = rets;
 115         SP += -12;
 116         call _bfin_clone;
 117         SP += 12;
 118         rets = [sp++];
 119         rts;
 120 ENDPROC(_sys_clone)
 121
 122 ENTRY(_sys_rt_sigreturn)
 123         r0 = sp;
 124         r0 += 24;
 125         [--sp] = rets;
 126         SP += -12;
 127         call _do_rt_sigreturn;
 128         SP += 12;
 129         rets = [sp++];
 130         rts;
 131 ENDPROC(_sys_rt_sigreturn)