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
 63extern unsigned long __get_wchan(struct task_struct *p);
 64
 65/*  The following stuff is pretty HEXAGON specific.  */
 66
 67/*  This is really just here for __switch_to.
 68    Offsets are pulled via asm-offsets.c  */
 69
 70/*
 71 * No real reason why VM and native switch stacks should be different.
 72 * Ultimately this should merge.  Note that Rev C. ABI called out only
 73 * R24-27 as callee saved GPRs needing explicit attention (R29-31 being
 74 * dealt with automagically by allocframe), but the current ABI has
 75 * more, R16-R27.  By saving more, the worst case is that we waste some
 76 * cycles if building with the old compilers.
 77 */
 78
 79struct hexagon_switch_stack {
 80	union {
 81		struct {
 82			unsigned long r16;
 83			unsigned long r17;
 84		};
 85		unsigned long long	r1716;
 86	};
 87	union {
 88		struct {
 89			unsigned long r18;
 90			unsigned long r19;
 91		};
 92		unsigned long long	r1918;
 93	};
 94	union {
 95		struct {
 96			unsigned long r20;
 97			unsigned long r21;
 98		};
 99		unsigned long long	r2120;
100	};
101	union {
102		struct {
103			unsigned long r22;
104			unsigned long r23;
105		};
106		unsigned long long	r2322;
107	};
108	union {
109		struct {
110			unsigned long r24;
111			unsigned long r25;
112		};
113		unsigned long long	r2524;
114	};
115	union {
116		struct {
117			unsigned long r26;
118			unsigned long r27;
119		};
120		unsigned long long	r2726;
121	};
122
123	unsigned long		fp;
124	unsigned long		lr;
125};
126
127#endif /* !__ASSEMBLY__ */
128
129#endif