From: Linus Torvalds
> Sent: 24 April 2022 22:42
>
> On Sun, Apr 24, 2022 at 2:37 PM Linus Torvalds
> wrote:
> >
> > Finally, for the same reason - please don't use ">> 8". Because I do
> > not believe that bit 8 is well-defined in your arithmetic. The *sign*
> > bit will be, but I'm not
From: Mikulas Patocka
> Sent: 25 April 2022 12:04
>
> On Mon, 25 Apr 2022, David Laight wrote:
>
> > From: Linus Torvalds
> > > Sent: 24 April 2022 22:42
> > >
> > > On Sun, Apr 24, 2022 at 2:37 PM Linus Torvalds
> > > wrote:
> > > >
> > > > Finally, for the same reason - please don't use ">>
On Mon, 25 Apr 2022, David Laight wrote:
> From: Mikulas Patocka
> > Sent: 25 April 2022 12:04
> >
> > On Mon, 25 Apr 2022, David Laight wrote:
> >
> > > From: Linus Torvalds
> > > > Sent: 24 April 2022 22:42
> > > >
> > > > On Sun, Apr 24, 2022 at 2:37 PM Linus Torvalds
> > > > wrote:
> >
On Mon, 25 Apr 2022, David Laight wrote:
> From: Linus Torvalds
> > Sent: 24 April 2022 22:42
> >
> > On Sun, Apr 24, 2022 at 2:37 PM Linus Torvalds
> > wrote:
> > >
> > > Finally, for the same reason - please don't use ">> 8". Because I do
> > > not believe that bit 8 is well-defined in
On Sun, Apr 24, 2022 at 2:37 PM Linus Torvalds
wrote:
>
> Finally, for the same reason - please don't use ">> 8". Because I do
> not believe that bit 8 is well-defined in your arithmetic. The *sign*
> bit will be, but I'm not convinced bit 8 is.
Hmm.. I think it's ok. It can indeed overflow in
On Sun, Apr 24, 2022 at 1:54 PM Mikulas Patocka wrote:
>
> + *
> + * Explanation of the logic:
> + * (ch - '9' - 1) is negative if ch <= '9'
> + * ('0' - 1 - ch) is negative if ch >= '0'
True, but...
Please, just to make me happier, make the sign of 'ch' be something
very explicit. Right now
On Sun, 2022-04-24 at 16:54 -0400, Mikulas Patocka wrote:
> This patch changes the function hex_to_bin so that it contains no branches
> and no memory accesses.
[]
> +++ linux-2.6/lib/hexdump.c 2022-04-24 18:51:20.0 +0200
[]
> + * the next line is similar to the previous one, but we need
The function hex2bin is used to load cryptographic keys into device mapper
targets dm-crypt and dm-integrity. It should take constant time
independent on the processed data, so that concurrently running
unprivileged code can't infer any information about the keys via
microarchitectural convert
