syscall.h

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/*
 * Access to user system call parameters and results
 *
 *  Copyright IBM Corp. 2008
 *  Author(s): Martin Schwidefsky ([email protected])
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 */

#ifndef _ASM_SYSCALL_H
#define _ASM_SYSCALL_H  1

#include <linux/audit.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <asm/ptrace.h>

/*
 * The syscall table always contains 32 bit pointers since we know that the
 * address of the function to be called is (way) below 4GB.  So the "int"
 * type here is what we want [need] for both 32 bit and 64 bit systems.
 */
extern const unsigned int sys_call_table[];

static inline long syscall_get_nr(struct task_struct *task,
                  struct pt_regs *regs)
{
    return test_tsk_thread_flag(task, TIF_SYSCALL) ?
        (regs->int_code & 0xffff) : -1;
}

static inline void syscall_rollback(struct task_struct *task,
                    struct pt_regs *regs)
{
    regs->gprs[2] = regs->orig_gpr2;
}

static inline long syscall_get_error(struct task_struct *task,
                     struct pt_regs *regs)
{
    return IS_ERR_VALUE(regs->gprs[2]) ? regs->gprs[2] : 0;
}

static inline long syscall_get_return_value(struct task_struct *task,
                        struct pt_regs *regs)
{
    return regs->gprs[2];
}

static inline void syscall_set_return_value(struct task_struct *task,
                        struct pt_regs *regs,
                        int error, long val)
{
    regs->gprs[2] = error ? -error : val;
}

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 mask = -1UL;

    BUG_ON(i + n > 6);
#ifdef CONFIG_COMPAT
    if (test_tsk_thread_flag(task, TIF_31BIT))
        mask = 0xffffffff;
#endif
    while (n-- > 0)
        if (i + n > 0)
            args[n] = regs->gprs[2 + i + n] & mask;
    if (i == 0)
        args[0] = regs->orig_gpr2 & mask;
}

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);
    while (n-- > 0)
        if (i + n > 0)
            regs->gprs[2 + i + n] = args[n];
    if (i == 0)
        regs->orig_gpr2 = args[0];
}

static inline int syscall_get_arch(struct task_struct *task,
                   struct pt_regs *regs)
{
#ifdef CONFIG_COMPAT
    if (test_tsk_thread_flag(task, TIF_31BIT))
        return AUDIT_ARCH_S390;
#endif
    return sizeof(long) == 8 ? AUDIT_ARCH_S390X : AUDIT_ARCH_S390;
}
#endif  /* _ASM_SYSCALL_H */