syscall.h

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/*
 * Access to user system call parameters and results
 *
 * Copyright (C) 2008 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License v.2.
 *
 * See asm-generic/syscall.h for descriptions of what we must do here.
 */

#ifndef _ASM_SYSCALL_H
#define _ASM_SYSCALL_H  1

#include <linux/sched.h>

/* ftrace syscalls requires exporting the sys_call_table */
#ifdef CONFIG_FTRACE_SYSCALLS
extern const unsigned long *sys_call_table;
#endif /* CONFIG_FTRACE_SYSCALLS */

static inline long syscall_get_nr(struct task_struct *task,
                  struct pt_regs *regs)
{
    return TRAP(regs) == 0xc00 ? regs->gpr[0] : -1L;
}

static inline void syscall_rollback(struct task_struct *task,
                    struct pt_regs *regs)
{
    regs->gpr[3] = regs->orig_gpr3;
}

static inline long syscall_get_error(struct task_struct *task,
                     struct pt_regs *regs)
{
    return (regs->ccr & 0x10000000) ? -regs->gpr[3] : 0;
}

static inline long syscall_get_return_value(struct task_struct *task,
                        struct pt_regs *regs)
{
    return regs->gpr[3];
}

static inline void syscall_set_return_value(struct task_struct *task,
                        struct pt_regs *regs,
                        int error, long val)
{
    if (error) {
        regs->ccr |= 0x10000000L;
        regs->gpr[3] = -error;
    } else {
        regs->ccr &= ~0x10000000L;
        regs->gpr[3] = val;
    }
}

static inline void syscall_get_arguments(struct task_struct *task,
                     struct pt_regs *regs,
                     unsigned int i, unsigned int n,
                     unsigned long *args)
{
    BUG_ON(i + n > 6);
#ifdef CONFIG_PPC64
    if (test_tsk_thread_flag(task, TIF_32BIT)) {
        /*
         * Zero-extend 32-bit argument values.  The high bits are
         * garbage ignored by the actual syscall dispatch.
         */
        while (n-- > 0)
            args[n] = (u32) regs->gpr[3 + i + n];
        return;
    }
#endif
    memcpy(args, &regs->gpr[3 + i], n * sizeof(args[0]));
}

static inline void syscall_set_arguments(struct task_struct *task,
                     struct pt_regs *regs,
                     unsigned int i, unsigned int n,
                     const unsigned long *args)
{
    BUG_ON(i + n > 6);
    memcpy(&regs->gpr[3 + i], args, n * sizeof(args[0]));
}

#endif  /* _ASM_SYSCALL_H */