"Eric W. Biederman" <[email protected]> writes:
> On x86_64 we have to be careful with calculating the physical
> address of kernel symbols. Both because of compiler odditities
> and because the symbols live in a different range of the virtual
> address space.
>
> Having a defintition of __pa_symbol that works on both x86_64 and
> i386 simplifies writing code that works for both x86_64 and
> i386 that has these kinds of dependencies.
>
> So this patch adds the trivial i386 __pa_symbol definition.
>
> Signed-off-by: Eric W. Biederman <[email protected]>
> ---
> include/asm-i386/page.h | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/include/asm-i386/page.h b/include/asm-i386/page.h
> index f5bf544..eceb7f5 100644
> --- a/include/asm-i386/page.h
> +++ b/include/asm-i386/page.h
> @@ -124,6 +124,7 @@ #define PAGE_OFFSET ((unsigned long)__P
> #define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
> #define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE)
> #define __pa(x) ((unsigned long)(x)-PAGE_OFFSET)
> +#define __pa_symbol(x) __pa(x)
Actually PAGE_OFFSET arithmetic on symbols is outside ISO C and gcc
misoptimizes it occassionally. You would need to use HIDE_RELOC
or similar. That is why x86-64 has the magic.
-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
