From: Linus Torvalds
> ...
> You could literally do something like
>
> /* Make it canonical in case we flipped the high bit */
> addr = (long)(addr<<1)>>1;
Isn't it safer to use a mask and let the compiler decide if two
shifts are a good implementation?
addr &= ~HIGH_MAGIC_BIT;
From: Linus Torvalds
> ...
> You could literally do something like
>
> /* Make it canonical in case we flipped the high bit */
> addr = (long)(addr<<1)>>1;
Isn't it safer to use a mask and let the compiler decide if two
shifts are a good implementation?
addr &= ~HIGH_MAGIC_BIT;
On Thu, 30 Aug 2018, Linus Torvalds wrote:
> On Thu, Aug 30, 2018 at 6:49 PM Tony Luck wrote:
> >
> > Just checking "do we have a non-canonical address" at the bottom of that
> > call stack and flipping bit 63 back on again seems like a bad idea.
>
> You could literally do something like
>
>
On Thu, 30 Aug 2018, Linus Torvalds wrote:
> On Thu, Aug 30, 2018 at 6:49 PM Tony Luck wrote:
> >
> > Just checking "do we have a non-canonical address" at the bottom of that
> > call stack and flipping bit 63 back on again seems like a bad idea.
>
> You could literally do something like
>
>
On Thu, Aug 30, 2018 at 6:49 PM Tony Luck wrote:
>
> Just checking "do we have a non-canonical address" at the bottom of that
> call stack and flipping bit 63 back on again seems like a bad idea.
You could literally do something like
/* Make it canonical in case we flipped the high bit */
On Thu, Aug 30, 2018 at 6:49 PM Tony Luck wrote:
>
> Just checking "do we have a non-canonical address" at the bottom of that
> call stack and flipping bit 63 back on again seems like a bad idea.
You could literally do something like
/* Make it canonical in case we flipped the high bit */
On Thu, Aug 30, 2018 at 6:30 PM Linus Torvalds
wrote:
>
> On Thu, Aug 30, 2018 at 2:45 PM Tony Luck wrote:
> >
> > Fix is to move one step at a time. First mark the page not present
> > (using the decoy address). Then it is safe to use the actual address
> > of the 1:1 mapping to mark it "uc",
On Thu, Aug 30, 2018 at 6:30 PM Linus Torvalds
wrote:
>
> On Thu, Aug 30, 2018 at 2:45 PM Tony Luck wrote:
> >
> > Fix is to move one step at a time. First mark the page not present
> > (using the decoy address). Then it is safe to use the actual address
> > of the 1:1 mapping to mark it "uc",
On Thu, Aug 30, 2018 at 2:45 PM Tony Luck wrote:
>
> Fix is to move one step at a time. First mark the page not present
> (using the decoy address). Then it is safe to use the actual address
> of the 1:1 mapping to mark it "uc", and finally as present.
Can't we do it in one step, but make sure
On Thu, Aug 30, 2018 at 2:45 PM Tony Luck wrote:
>
> Fix is to move one step at a time. First mark the page not present
> (using the decoy address). Then it is safe to use the actual address
> of the 1:1 mapping to mark it "uc", and finally as present.
Can't we do it in one step, but make sure
The trick with flipping bit 63 to avoid loading the address of the
1:1 mapping of the poisoned page while we update the 1:1 map used
to work when we wanted to unmap the page. But it falls down horribly
when we try to directly set the page as uncacheable.
The problem is that when we change the
The trick with flipping bit 63 to avoid loading the address of the
1:1 mapping of the poisoned page while we update the 1:1 map used
to work when we wanted to unmap the page. But it falls down horribly
when we try to directly set the page as uncacheable.
The problem is that when we change the
12 matches
Mail list logo
