arch/hexagon/include/asm/processor.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Process/processor support for the Hexagon architecture
   4  *
   5  * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved.
   6  */
   7
   8 #ifndef _ASM_PROCESSOR_H
   9 #define _ASM_PROCESSOR_H
  10
  11 #ifndef __ASSEMBLY__
  12
  13 #include <asm/mem-layout.h>
  14 #include <asm/registers.h>
  15 #include <asm/hexagon_vm.h>
  16
  17 /*  task_struct, defined elsewhere, is the "process descriptor" */
  18 struct task_struct;
  19
  20 extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
  21
  22 /*
  23  * thread_struct is supposed to be for context switch data.
  24  * Specifically, to hold the state necessary to perform switch_to...
  25  */
  26 struct thread_struct {
  27         void *switch_sp;
  28 };
  29
  30 /*
  31  * initializes thread_struct
  32  * The only thing we have in there is switch_sp
  33  * which doesn't really need to be initialized.
  34  */
  35
  36 #define INIT_THREAD { \
  37 }
  38
  39 #define cpu_relax() __vmyield()
  40
  41 /*
  42  * Decides where the kernel will search for a free chunk of vm space during
  43  * mmaps.
  44  * See also arch_get_unmapped_area.
  45  * Doesn't affect if you have MAX_FIXED in the page flags set though...
  46  *
  47  * Apparently the convention is that ld.so will ask for "unmapped" private
  48  * memory to be allocated SOMEWHERE, but it also asks for memory explicitly
  49  * via MAP_FIXED at the lower * addresses starting at VA=0x0.
  50  *
  51  * If the two requests collide, you get authentic segfaulting action, so
  52  * you have to kick the "unmapped" base requests higher up.
  53  */
  54 #define TASK_UNMAPPED_BASE      (PAGE_ALIGN(TASK_SIZE/3))
  55
  56
  57 #define task_pt_regs(task) \
  58         ((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
  59
  60 #define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
  61 #define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
  62
  63 /*  Free all resources held by a thread; defined in process.c  */
  64 extern void release_thread(struct task_struct *dead_task);
  65
  66 /* Get wait channel for task P.  */
  67 extern unsigned long get_wchan(struct task_struct *p);
  68
  69 /*  The following stuff is pretty HEXAGON specific.  */
  70
  71 /*  This is really just here for __switch_to.
  72     Offsets are pulled via asm-offsets.c  */
  73
  74 /*
  75  * No real reason why VM and native switch stacks should be different.
  76  * Ultimately this should merge.  Note that Rev C. ABI called out only
  77  * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
  78  * dealt with automagically by allocframe), but the current ABI has
  79  * more, R16-R27.  By saving more, the worst case is that we waste some
  80  * cycles if building with the old compilers.
  81  */
  82
  83 struct hexagon_switch_stack {
  84         union {
  85                 struct {
  86                         unsigned long r16;
  87                         unsigned long r17;
  88                 };
  89                 unsigned long long      r1716;
  90         };
  91         union {
  92                 struct {
  93                         unsigned long r18;
  94                         unsigned long r19;
  95                 };
  96                 unsigned long long      r1918;
  97         };
  98         union {
  99                 struct {
 100                         unsigned long r20;
 101                         unsigned long r21;
 102                 };
 103                 unsigned long long      r2120;
 104         };
 105         union {
 106                 struct {
 107                         unsigned long r22;
 108                         unsigned long r23;
 109                 };
 110                 unsigned long long      r2322;
 111         };
 112         union {
 113                 struct {
 114                         unsigned long r24;
 115                         unsigned long r25;
 116                 };
 117                 unsigned long long      r2524;
 118         };
 119         union {
 120                 struct {
 121                         unsigned long r26;
 122                         unsigned long r27;
 123                 };
 124                 unsigned long long      r2726;
 125         };
 126
 127         unsigned long           fp;
 128         unsigned long           lr;
 129 };
 130
 131 #endif /* !__ASSEMBLY__ */
 132
 133 #endif