Re: copy_from_user broken on i386 since 2.5.57

[Bill Davidsen]

On Wed, 22 Jan 2003, Andrew Morton wrote:

> Brice Goglin <[e-mail]> wrote:
> >
> > Hi,
> > 
> > Trying to compile a very very simple module for 2.5,
> > I got an error from gcc saying that assembly code
> > is incorrect.
> > This problem appeared in 2.5.57 and is still here
> > in 2.5.59.
> > I only tried on i386.
> > 
> > Here's a very simple example code :
> > 
> > #define __KERNEL__
> > #define MODULE
> > #include "linux/module.h"
> > #include "asm/uaccess.h"
> > 
> > int func(void *to, const void *from) {
> >   return __copy_from_user(to, from, 1);
> > }
> > 
> > 
> > Here's gcc report :
> > 
> > mp760:~/tmp% gcc user.c -c -o user.o -Ipath_to_2.5.57/include
> > /tmp/cceAbcRd.s: Assembler messages:
> > /tmp/cceAbcRd.s:120: Error: `%al' not allowed with `movl'
> > /tmp/cceAbcRd.s:124: Error: `%al' not allowed with `xorl'
> > /tmp/cceAbcRd.s:209: Warning: using `%eax' instead of `%ax' due to `l' suffix
> > /tmp/cceAbcRd.s:213: Warning: using `%eax' instead of `%ax' due to `l' suffix
> > /tmp/cceAbcRd.s:213: Warning: using `%eax' instead of `%ax' due to `l' suffix
> 
> Add `-O2' to the compiler switches.
> 
> No, I don't know either ;)

So, does this actually fix the problem or simply optimize the suspect code
out of existance until some later date?

-- 
bill davidsen <[e-mail]>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.