[U-Boot] [PATCH v3] ARM: Avoid compiler optimization for usages of readb, writeb and friends.
Wolfgang Denk
wd at denx.de
Mon Jan 17 22:59:37 CET 2011
Dear Dirk Behme,
In message <4D2B3036.4010506 at googlemail.com> you wrote:
>
> The question I was thinking about with my patch was "what's Right
> Thing?" ;)
The Right Thing i not to make specific assumptions how the compiler
might handle volatile pointers.
> It's my understanding that we don't fix read*() and write*() because
> they are broken. We touch them to work around a broken tool chain.
No. Please re-read volatile-considered-harmful.txt in the
linux/Documentation directory: "accessing I/O memory directly through
pointers is frowned upon and does not work on all architectures.
Those accessors are written to prevent unwanted optimization".
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
It is dangerous to be sincere unless you are also stupid.
- George Bernard Shaw
More information about the U-Boot
mailing list