LXR linux/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" */
  18struct task_struct;
  19
  20extern 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 */
  26struct 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  */
  64extern void release_thread(struct task_struct *dead_task);
  65
  66/* Get wait channel for task P.  */
  67extern 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
  83struct 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
 134