LXR linux/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/*  must be a macro  */
  31#define current_text_addr() ({ __label__ _l; _l: &&_l; })
  32
  33/*  task_struct, defined elsewhere, is the "process descriptor" */
  34struct task_struct;
  35
  36/*  this is defined in arch/process.c  */
  37extern unsigned long thread_saved_pc(struct task_struct *tsk);
  38
  39extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
  40
  41/*
  42 * thread_struct is supposed to be for context switch data.
  43 * Specifically, to hold the state necessary to perform switch_to...
  44 */
  45struct thread_struct {
  46        void *switch_sp;
  47};
  48
  49/*
  50 * initializes thread_struct
  51 * The only thing we have in there is switch_sp
  52 * which doesn't really need to be initialized.
  53 */
  54
  55#define INIT_THREAD { \
  56}
  57
  58#define cpu_relax() __vmyield()
  59#define cpu_relax_lowlatency() cpu_relax()
  60
  61/*
  62 * Decides where the kernel will search for a free chunk of vm space during
  63 * mmaps.
  64 * See also arch_get_unmapped_area.
  65 * Doesn't affect if you have MAX_FIXED in the page flags set though...
  66 *
  67 * Apparently the convention is that ld.so will ask for "unmapped" private
  68 * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
  69 * via MAP_FIXED at the lower * addresses starting at VA=0x0.
  70 *
  71 * If the two requests collide, you get authentic segfaulting action, so
  72 * you have to kick the "unmapped" base requests higher up.
  73 */
  74#define TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE/3))
  75
  76
  77#define task_pt_regs(task) \
  78        ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
  79
  80#define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
  81#define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
  82
  83/*  Free all resources held by a thread; defined in process.c  */
  84extern void release_thread(struct task_struct *dead_task);
  85
  86/* Get wait channel for task P.  */
  87extern unsigned long get_wchan(struct task_struct *p);
  88
  89/*  The following stuff is pretty HEXAGON specific.  */
  90
  91/*  This is really just here for __switch_to.
  92    Offsets are pulled via asm-offsets.c  */
  93
  94/*
  95 * No real reason why VM and native switch stacks should be different.
  96 * Ultimately this should merge.  Note that Rev C. ABI called out only
  97 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
  98 * dealt with automagically by allocframe), but the current ABI has
  99 * more, R16-R27.  By saving more, the worst case is that we waste some
 100 * cycles if building with the old compilers.
 101 */
 102
 103struct hexagon_switch_stack {
 104        union {
 105                struct {
 106                        unsigned long r16;
 107                        unsigned long r17;
 108                };
 109                unsigned long long      r1716;
 110        };
 111        union {
 112                struct {
 113                        unsigned long r18;
 114                        unsigned long r19;
 115                };
 116                unsigned long long      r1918;
 117        };
 118        union {
 119                struct {
 120                        unsigned long r20;
 121                        unsigned long r21;
 122                };
 123                unsigned long long      r2120;
 124        };
 125        union {
 126                struct {
 127                        unsigned long r22;
 128                        unsigned long r23;
 129                };
 130                unsigned long long      r2322;
 131        };
 132        union {
 133                struct {
 134                        unsigned long r24;
 135                        unsigned long r25;
 136                };
 137                unsigned long long      r2524;
 138        };
 139        union {
 140                struct {
 141                        unsigned long r26;
 142                        unsigned long r27;
 143                };
 144                unsigned long long      r2726;
 145        };
 146
 147        unsigned long           fp;
 148        unsigned long           lr;
 149};
 150
 151#endif /* !__ASSEMBLY__ */
 152
 153#endif
 154