syscall.h

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/*
 * Access to user system call parameters and results
 *
 * See asm-generic/syscall.h for descriptions of what we must do here.
 */

#ifndef _ASM_ARM_SYSCALL_H
#define _ASM_ARM_SYSCALL_H

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

#include <asm/unistd.h>

#define NR_syscalls (__NR_syscalls)

extern const unsigned long sys_call_table[];

static inline int syscall_get_nr(struct task_struct *task,
                 struct pt_regs *regs)
{
    return task_thread_info(task)->syscall;
}

static inline void syscall_rollback(struct task_struct *task,
                    struct pt_regs *regs)
{
    regs->ARM_r0 = regs->ARM_ORIG_r0;
}

static inline long syscall_get_error(struct task_struct *task,
                     struct pt_regs *regs)
{
    unsigned long error = regs->ARM_r0;
    return IS_ERR_VALUE(error) ? error : 0;
}

static inline long syscall_get_return_value(struct task_struct *task,
                        struct pt_regs *regs)
{
    return regs->ARM_r0;
}

static inline void syscall_set_return_value(struct task_struct *task,
                        struct pt_regs *regs,
                        int error, long val)
{
    regs->ARM_r0 = (long) error ? error : val;
}

#define SYSCALL_MAX_ARGS 7

static inline void syscall_get_arguments(struct task_struct *task,
                     struct pt_regs *regs,
                     unsigned int i, unsigned int n,
                     unsigned long *args)
{
    if (i + n > SYSCALL_MAX_ARGS) {
        unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i;
        unsigned int n_bad = n + i - SYSCALL_MAX_ARGS;
        pr_warning("%s called with max args %d, handling only %d\n",
               __func__, i + n, SYSCALL_MAX_ARGS);
        memset(args_bad, 0, n_bad * sizeof(args[0]));
        n = SYSCALL_MAX_ARGS - i;
    }

    if (i == 0) {
        args[0] = regs->ARM_ORIG_r0;
        args++;
        i++;
        n--;
    }

    memcpy(args, &regs->ARM_r0 + 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)
{
    if (i + n > SYSCALL_MAX_ARGS) {
        pr_warning("%s called with max args %d, handling only %d\n",
               __func__, i + n, SYSCALL_MAX_ARGS);
        n = SYSCALL_MAX_ARGS - i;
    }

    if (i == 0) {
        regs->ARM_ORIG_r0 = args[0];
        args++;
        i++;
        n--;
    }

    memcpy(&regs->ARM_r0 + i, args, n * sizeof(args[0]));
}

#endif /* _ASM_ARM_SYSCALL_H */