root/include/asm-x86/syscall.h

INCLUDED FROM

DEFINITIONS

1. syscall_get_nr
2. syscall_rollback
3. syscall_get_error
4. syscall_get_return_value
5. syscall_set_return_value
6. syscall_get_arguments
7. syscall_set_arguments
8. syscall_get_arguments
9. syscall_set_arguments

/*
 * 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>
#include <linux/err.h>

static inline long syscall_get_nr(struct task_struct *task,
                                  struct pt_regs *regs)
{
        /*
         * We always sign-extend a -1 value being set here,
         * so this is always either -1L or a syscall number.
         */
        return regs->orig_ax;
}

static inline void syscall_rollback(struct task_struct *task,
                                    struct pt_regs *regs)
{
        regs->ax = regs->orig_ax;
}

static inline long syscall_get_error(struct task_struct *task,
                                     struct pt_regs *regs)
{
        unsigned long error = regs->ax;
#ifdef CONFIG_IA32_EMULATION
        /*
         * TS_COMPAT is set for 32-bit syscall entries and then
         * remains set until we return to user mode.
         */
        if (task_thread_info(task)->status & TS_COMPAT)
                /*
                 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
                 * and will match correctly in comparisons.
                 */
                error = (long) (int) error;
#endif
        return IS_ERR_VALUE(error) ? error : 0;
}

static inline long syscall_get_return_value(struct task_struct *task,
                                            struct pt_regs *regs)
{
        return regs->ax;
}

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

#ifdef CONFIG_X86_32

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);
        memcpy(args, &regs->bx + 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->bx + i, args, n * sizeof(args[0]));
}

#else    /* CONFIG_X86_64 */

static inline void syscall_get_arguments(struct task_struct *task,
                                         struct pt_regs *regs,
                                         unsigned int i, unsigned int n,
                                         unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
        if (task_thread_info(task)->status & TS_COMPAT)
                switch (i + n) {
                case 6:
                        if (!n--) break;
                        *args++ = regs->bp;
                case 5:
                        if (!n--) break;
                        *args++ = regs->di;
                case 4:
                        if (!n--) break;
                        *args++ = regs->si;
                case 3:
                        if (!n--) break;
                        *args++ = regs->dx;
                case 2:
                        if (!n--) break;
                        *args++ = regs->cx;
                case 1:
                        if (!n--) break;
                        *args++ = regs->bx;
                case 0:
                        if (!n--) break;
                default:
                        BUG();
                        break;
                }
        else
# endif
                switch (i + n) {
                case 6:
                        if (!n--) break;
                        *args++ = regs->r9;
                case 5:
                        if (!n--) break;
                        *args++ = regs->r8;
                case 4:
                        if (!n--) break;
                        *args++ = regs->r10;
                case 3:
                        if (!n--) break;
                        *args++ = regs->dx;
                case 2:
                        if (!n--) break;
                        *args++ = regs->si;
                case 1:
                        if (!n--) break;
                        *args++ = regs->di;
                case 0:
                        if (!n--) break;
                default:
                        BUG();
                        break;
                }
}

static inline void syscall_set_arguments(struct task_struct *task,
                                         struct pt_regs *regs,
                                         unsigned int i, unsigned int n,
                                         const unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
        if (task_thread_info(task)->status & TS_COMPAT)
                switch (i + n) {
                case 6:
                        if (!n--) break;
                        regs->bp = *args++;
                case 5:
                        if (!n--) break;
                        regs->di = *args++;
                case 4:
                        if (!n--) break;
                        regs->si = *args++;
                case 3:
                        if (!n--) break;
                        regs->dx = *args++;
                case 2:
                        if (!n--) break;
                        regs->cx = *args++;
                case 1:
                        if (!n--) break;
                        regs->bx = *args++;
                case 0:
                        if (!n--) break;
                default:
                        BUG();
                }
        else
# endif
                switch (i + n) {
                case 6:
                        if (!n--) break;
                        regs->r9 = *args++;
                case 5:
                        if (!n--) break;
                        regs->r8 = *args++;
                case 4:
                        if (!n--) break;
                        regs->r10 = *args++;
                case 3:
                        if (!n--) break;
                        regs->dx = *args++;
                case 2:
                        if (!n--) break;
                        regs->si = *args++;
                case 1:
                        if (!n--) break;
                        regs->di = *args++;
                case 0:
                        if (!n--) break;
                default:
                        BUG();
                }
}

#endif  /* CONFIG_X86_32 */

#endif  /* _ASM_SYSCALL_H */