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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 <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 */