MODPOST __copy_from_user module compilation issue

Hi,

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I checked the definition of the function and the include path. Eventually I put the EXPORT_SYMBOL(__copy_from_user); line into the arch/nios2/mm/uaccess.c file.

Don't know if it's only a workaround, because it seems strange that other users haven't encountered such errors.

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You mean that you don't have the description EXPORT_SYMBOL(__copy_from_user); in your 'uaccess.c' file ?

Modules are loaded dynamically and the linker must resolve the locations. To do this, the kernel must expose the symbol's location, and you need the macro 'EXPORT_SYMBOL(symbol)' if you want to use the 'symbol' in your module. In fact, the symbols

EXPORT_SYMBOL(__copy_from_user);
EXPORT_SYMBOL(copy_from_user);
EXPORT_SYMBOL(__copy_to_user);
EXPORT_SYMBOL(copy_to_user);
EXPORT_SYMBOL(get_ds);
EXPORT_SYMBOL(get_fs);
EXPORT_SYMBOL(set_fs);

are exported in my 'arch/nios2/mm/uaccess.c'.

The macro 'EXPORT_SYMBOL' exports symbols as follows

/* For every exported symbol, place a struct in the __ksymtab section */# define __EXPORT_SYMBOL(sym, sec)                
    extern typeof(sym) sym;                    
    __CRC_SYMBOL(sym, sec)                    
    static const char __kstrtab_##sym            
    __attribute__((section("__ksymtab_strings"), aligned(1))) 
    = MODULE_SYMBOL_PREFIX# sym;                        
    static const struct kernel_symbol __ksymtab_##sym    
    __used                            
    __attribute__((section("__ksymtab" sec), unused))    
    = { (unsigned long)&sym, __kstrtab_##sym }
# define EXPORT_SYMBOL(sym)                    
    __EXPORT_SYMBOL(sym, "")

And it seems that Wind River guys did not test the module loadings at all. Please see this

http://www.alteraforum.com/forum/showpost.php?p=78791&postcount=48

.

Kazu