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