Hello Alejandro,
On Sun, Dec 04, 2022 at 09:00:20PM +0100, Alejandro Colomar wrote:
> On 12/4/22 10:07, Helge Kreutzmann wrote:
> > Without further ado, the following was found:
> >
> > Issue: of 0 → of I<r0>?
> >
> > "Since the offset argument is 64 bits, and the first argument (I<fd>) is"
> > "passed in I<r0>, the caller must manually split and align the 64-bit value"
> > "so that it is passed in the I<r2>/I<r3> register pair. That means inserting"
> > "a dummy value into I<r1> (the second argument of 0). Care also must be"
> > "taken so that the split follows endian conventions (according to the C ABI"
> > "for the platform)."
>
> The report is invalid:
>
>
> syscall(SYS_readahead, fd, 0,
> (unsigned int) (offset & 0xFFFFFFFF),
> (unsigned int) (offset >> 32),
> count);
>
> Since the offset argument is 64 bits, and the first argu‐
> ment (fd) is passed in r0, the caller must manually split
> and align the 64‐bit value so that it is passed in the
> r2/r3 register pair. That means inserting a dummy value
> into r1 (the second argument of 0). Care also must be
> taken so that the split follows endian conventions (ac‐
> cording to the C ABI for the platform).
>
> It's saying that the second argument in the call above is the value 0.
Noted and thanks for the clarification!
Greetings
Helge
--
Dr. Helge Kreutzmann debian@xxxxxxxxxxxxx
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