arch/hexagon/include/asm/processor.h

   1 /*
   2  * Process/processor support for the Hexagon architecture
   3  *
   4  * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
   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 version 2 and
   8  * only version 2 as published by the Free Software Foundation.
   9  *
  10  * This program 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
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA.
  19  */
  20
  21 #ifndef _ASM_PROCESSOR_H
  22 #define _ASM_PROCESSOR_H
  23
  24 #ifndef __ASSEMBLY__
  25
  26 #include <asm/mem-layout.h>
  27 #include <asm/registers.h>
  28 #include <asm/hexagon_vm.h>
  29
  30 /*  task_struct, defined elsewhere, is the "process descriptor" */
  31 struct task_struct;
  32
  33 extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
  34
  35 /*
  36  * thread_struct is supposed to be for context switch data.
  37  * Specifically, to hold the state necessary to perform switch_to...
  38  */
  39 struct thread_struct {
  40         void *switch_sp;
  41 };
  42
  43 /*
  44  * initializes thread_struct
  45  * The only thing we have in there is switch_sp
  46  * which doesn't really need to be initialized.
  47  */
  48
  49 #define INIT_THREAD { \
  50 }
  51
  52 #define cpu_relax() __vmyield()
  53
  54 /*
  55  * Decides where the kernel will search for a free chunk of vm space during
  56  * mmaps.
  57  * See also arch_get_unmapped_area.
  58  * Doesn't affect if you have MAX_FIXED in the page flags set though...
  59  *
  60  * Apparently the convention is that ld.so will ask for "unmapped" private
  61  * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
  62  * via MAP_FIXED at the lower * addresses starting at VA=0x0.
  63  *
  64  * If the two requests collide, you get authentic segfaulting action, so
  65  * you have to kick the "unmapped" base requests higher up.
  66  */
  67 #define TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE/3))
  68
  69
  70 #define task_pt_regs(task) \
  71         ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
  72
  73 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
  74 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
  75
  76 /*  Free all resources held by a thread; defined in process.c  */
  77 extern void release_thread(struct task_struct *dead_task);
  78
  79 /* Get wait channel for task P.  */
  80 extern unsigned long get_wchan(struct task_struct *p);
  81
  82 /*  The following stuff is pretty HEXAGON specific.  */
  83
  84 /*  This is really just here for __switch_to.
  85     Offsets are pulled via asm-offsets.c  */
  86
  87 /*
  88  * No real reason why VM and native switch stacks should be different.
  89  * Ultimately this should merge.  Note that Rev C. ABI called out only
  90  * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
  91  * dealt with automagically by allocframe), but the current ABI has
  92  * more, R16-R27.  By saving more, the worst case is that we waste some
  93  * cycles if building with the old compilers.
  94  */
  95
  96 struct hexagon_switch_stack {
  97         union {
  98                 struct {
  99                         unsigned long r16;
 100                         unsigned long r17;
 101                 };
 102                 unsigned long long      r1716;
 103         };
 104         union {
 105                 struct {
 106                         unsigned long r18;
 107                         unsigned long r19;
 108                 };
 109                 unsigned long long      r1918;
 110         };
 111         union {
 112                 struct {
 113                         unsigned long r20;
 114                         unsigned long r21;
 115                 };
 116                 unsigned long long      r2120;
 117         };
 118         union {
 119                 struct {
 120                         unsigned long r22;
 121                         unsigned long r23;
 122                 };
 123                 unsigned long long      r2322;
 124         };
 125         union {
 126                 struct {
 127                         unsigned long r24;
 128                         unsigned long r25;
 129                 };
 130                 unsigned long long      r2524;
 131         };
 132         union {
 133                 struct {
 134                         unsigned long r26;
 135                         unsigned long r27;
 136                 };
 137                 unsigned long long      r2726;
 138         };
 139
 140         unsigned long           fp;
 141         unsigned long           lr;
 142 };
 143
 144 #endif /* !__ASSEMBLY__ */
 145
 146 #endif