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* Process/processor support for the Hexagon architecture
* Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
#ifndef __ASSEMBLY__
#include <asm/mem-layout.h>
#include <asm/registers.h>
#include <asm/hexagon_vm.h>
/* must be a macro */
#define current_text_addr() ({ __label__ _l; _l: &&_l; })
/* task_struct, defined elsewhere, is the "process descriptor" */
struct task_struct;
/* this is defined in arch/process.c */
extern pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
extern unsigned long thread_saved_pc(struct task_struct *tsk);
extern void start_thread(struct pt_regs *, unsigned long, unsigned long);
* thread_struct is supposed to be for context switch data.
* Specifically, to hold the state necessary to perform switch_to...
struct thread_struct {
void *switch_sp;
* initializes thread_struct
* The only thing we have in there is switch_sp
* which doesn't really need to be initialized.
#define INIT_THREAD { \
#define cpu_relax() __vmyield()
* Decides where the kernel will search for a free chunk of vm space during
* mmaps.
* See also arch_get_unmapped_area.
* Doesn't affect if you have MAX_FIXED in the page flags set though...
* Apparently the convention is that will ask for "unmapped" private
* memory to be allocated SOMEWHERE, but it also asks for memory explicitly
* via MAP_FIXED at the lower * addresses starting at VA=0x0.
* If the two requests collide, you get authentic segfaulting action, so
* you have to kick the "unmapped" base requests higher up.
#define task_pt_regs(task) \
((struct pt_regs *)(task_stack_page(task) + THREAD_SIZE) - 1)
#define KSTK_EIP(tsk) (pt_elr(task_pt_regs(tsk)))
#define KSTK_ESP(tsk) (pt_psp(task_pt_regs(tsk)))
/* Free all resources held by a thread; defined in process.c */
extern void release_thread(struct task_struct *dead_task);
/* Get wait channel for task P. */
extern unsigned long get_wchan(struct task_struct *p);
/* The following stuff is pretty HEXAGON specific. */
/* This is really just here for __switch_to.
Offsets are pulled via asm-offsets.c */
* No real reason why VM and native switch stacks should be different.
* Ultimately this should merge. Note that Rev C. ABI called out only
* R24-27 as callee saved GPRs needing explicit attention (R29-31 being
* dealt with automagically by allocframe), but the current ABI has
* more, R16-R27. By saving more, the worst case is that we waste some
* cycles if building with the old compilers.
struct hexagon_switch_stack {
unsigned long long r1716;
unsigned long long r1918;
unsigned long long r2120;
unsigned long long r2322;
unsigned long long r2524;
unsigned long long r2726;
unsigned long fp;
unsigned long lr;
#endif /* !__ASSEMBLY__ */