On Thu, 2 Feb 2006, Stephen Rothwell wrote:
>
> Most of the 64 bit architectures will zero extend the first argument to
> compat_sys_{openat,newfstatat,futimesat} which will fail if the 32 bit
> syscall was passed AT_FDCWD (which is a small negative number). Declare
> the first argument to be an unsigned int which will force the correct
> sign extension when the internal functions are called in each case.
Umm.
Wouldn't it be _much_ better to declare the argument as a "long", since
some architectures (alpha, for example) may assume that 32-bit arguments
have been _sign_extended, not zero-extended.
Then, when the "compat_sys_xxxx()" function passes the "long" down to the
_real_ function (which takes an "int"), those architectures (and only
those architectures) that actually have assumptions about high bits will
have the compiler automatically do the right zero- or sign-extensions at
that call-site.
Linus
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