arch/hexagon/include/asm/processor.h

   1 /*
   2  * Process/processor support for the Hexagon architecture
   3  *
   4  * Copyright (c) 2010-2011, Code Aurora Forum. 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" */
  34 struct task_struct;
  35
  36 /*  this is defined in arch/process.c  */
  37 extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
  38 extern unsigned long thread_saved_pc(struct task_struct *tsk);
  39
  40 extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
  41
  42 /*
  43  * thread_struct is supposed to be for context switch data.
  44  * Specifically, to hold the state necessary to perform switch_to...
  45  */
  46 struct thread_struct {
  47         void *switch_sp;
  48 };
  49
  50 /*
  51  * initializes thread_struct
  52  * The only thing we have in there is switch_sp
  53  * which doesn't really need to be initialized.
  54  */
  55
  56 #define INIT_THREAD { \
  57 }
  58
  59 #define cpu_relax() __vmyield()
  60
  61 /*
  62  * "Unlazying all lazy status" occurs here.
  63  */
  64 static inline void prepare_to_copy(struct task_struct *tsk)
  65 {
  66 }
  67
  68 /*
  69  * Decides where the kernel will search for a free chunk of vm space during
  70  * mmaps.
  71  * See also arch_get_unmapped_area.
  72  * Doesn't affect if you have MAX_FIXED in the page flags set though...
  73  *
  74  * Apparently the convention is that ld.so will ask for "unmapped" private
  75  * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
  76  * via MAP_FIXED at the lower * addresses starting at VA=0x0.
  77  *
  78  * If the two requests collide, you get authentic segfaulting action, so
  79  * you have to kick the "unmapped" base requests higher up.
  80  */
  81 #define TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE/3))
  82
  83
  84 #define task_pt_regs(task) \
  85         ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
  86
  87 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
  88 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
  89
  90 /*  Free all resources held by a thread; defined in process.c  */
  91 extern void release_thread(struct task_struct *dead_task);
  92
  93 /* Get wait channel for task P.  */
  94 extern unsigned long get_wchan(struct task_struct *p);
  95
  96 /*  The following stuff is pretty HEXAGON specific.  */
  97
  98 /*  This is really just here for __switch_to.
  99     Offsets are pulled via asm-offsets.c  */
 100
 101 /*
 102  * No real reason why VM and native switch stacks should be different.
 103  * Ultimately this should merge.  Note that Rev C. ABI called out only
 104  * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
 105  * dealt with automagically by allocframe), but the current ABI has
 106  * more, R16-R27.  By saving more, the worst case is that we waste some
 107  * cycles if building with the old compilers.
 108  */
 109
 110 struct hexagon_switch_stack {
 111         unsigned long long      r1716;
 112         unsigned long long      r1918;
 113         unsigned long long      r2120;
 114         unsigned long long      r2322;
 115         unsigned long long      r2524;
 116         unsigned long long      r2726;
 117         unsigned long           fp;
 118         unsigned long           lr;
 119 };
 120
 121 #endif /* !__ASSEMBLY__ */
 122
 123 #endif