Messages in this thread | | | From | Linus Torvalds <> | Date | Tue, 7 Sep 2021 21:55:08 -0700 | Subject | Re: [PATCH] Enable '-Werror' by default for all kernel builds |
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On Tue, Sep 7, 2021 at 9:28 PM Guenter Roeck <linux@roeck-us.net> wrote: > > It is seen with gcc 11.x whenever a memXXX or strXXX function parameter > is a pointer to a fixed address.
I wonder why I don't see it with gcc 11.2 here on x86-64.
> gcc is happy if "(void *) 0xfffc1f2c" > is passed to a global function which does nothing but return the address, > such as: > > void *sanitize_address(void *address) > { > return address; > }
We have had reasons to do things like that before for somewhat similar (well, opposite) reasons - trying to disassociate some pointer from its originating symbol type.
Look at RELOC_HIDE().
It might be worth it having something similar for "absolute_pointer()".
Entirely untested "written-in-the-MUA" garbage:
#define absolute_pointer(val) \ ({ void *__res; __asm__("":"=r" (__res):"0" ((unsigned long)(val))); __res; })
I dunno.
Linus
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