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linux-next/arch/arc/include/asm/syscall.h
Vineet Gupta 352c1d95e3 ARC: stop using pt_regs->orig_r8
Historically, pt_regs have had orig_r8, an overloaded container for
  (1) backup copy of r8 (syscall number Trap Exceptions)
  (2) additional system state: (syscall/Exception/Interrupt)

There is no point in keeping (1) since syscall number is never clobbered
in-place, in pt_regs, unlike r0 which duals as first syscall arg as well
as syscall return value and in case of syscall restart, the orig arg0
needs restoring (from orig_r0)  after having been updated in-place with
syscall ret value.

This further paves way to convert (2) to contain ECR itself (rather than
current madeup values)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-06-22 19:23:26 +05:30

72 lines
1.6 KiB
C

/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _ASM_ARC_SYSCALL_H
#define _ASM_ARC_SYSCALL_H 1
#include <linux/err.h>
#include <linux/sched.h>
#include <asm/unistd.h>
#include <asm/ptrace.h> /* in_syscall() */
static inline long
syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
if (user_mode(regs) && in_syscall(regs))
return regs->r8;
else
return -1;
}
static inline void
syscall_rollback(struct task_struct *task, struct pt_regs *regs)
{
regs->r0 = regs->orig_r0;
}
static inline long
syscall_get_error(struct task_struct *task, struct pt_regs *regs)
{
/* 0 if syscall succeeded, otherwise -Errorcode */
return IS_ERR_VALUE(regs->r0) ? regs->r0 : 0;
}
static inline long
syscall_get_return_value(struct task_struct *task, struct pt_regs *regs)
{
return regs->r0;
}
static inline void
syscall_set_return_value(struct task_struct *task, struct pt_regs *regs,
int error, long val)
{
regs->r0 = (long) error ?: val;
}
/*
* @i: argument index [0,5]
* @n: number of arguments; n+i must be [1,6].
*/
static inline void
syscall_get_arguments(struct task_struct *task, struct pt_regs *regs,
unsigned int i, unsigned int n, unsigned long *args)
{
unsigned long *inside_ptregs = &(regs->r0);
inside_ptregs -= i;
BUG_ON((i + n) > 6);
while (n--) {
args[i++] = (*inside_ptregs);
inside_ptregs--;
}
}
#endif