Messages in this thread | | | Date | Wed, 12 Apr 2023 10:03:46 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH 1/2] stackleak: allow to specify arch specific stackleak poison function |
| |
On Wed, Apr 05, 2023 at 03:08:40PM +0200, Heiko Carstens wrote: > Factor out the code that fills the stack with the stackleak poison value > in order to allow architectures to provide a faster implementation. > > Acked-by: Vasily Gorbik <gor@linux.ibm.com> > Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
As on patch 2, it might be nicer to have a noinstr-safe memset64() and use that directly, but I don't have strong feelings either way, and I'll defer to Kees's judgement:
Acked-by: Mark Rutland <mark.rutland@arm.com>
Thanks, Mark.
> --- > kernel/stackleak.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/kernel/stackleak.c b/kernel/stackleak.c > index c2c33d2202e9..34c9d81eea94 100644 > --- a/kernel/stackleak.c > +++ b/kernel/stackleak.c > @@ -70,6 +70,18 @@ late_initcall(stackleak_sysctls_init); > #define skip_erasing() false > #endif /* CONFIG_STACKLEAK_RUNTIME_DISABLE */ > > +#ifndef __stackleak_poison > +static __always_inline void __stackleak_poison(unsigned long erase_low, > + unsigned long erase_high, > + unsigned long poison) > +{ > + while (erase_low < erase_high) { > + *(unsigned long *)erase_low = poison; > + erase_low += sizeof(unsigned long); > + } > +} > +#endif > + > static __always_inline void __stackleak_erase(bool on_task_stack) > { > const unsigned long task_stack_low = stackleak_task_low_bound(current); > @@ -101,10 +113,7 @@ static __always_inline void __stackleak_erase(bool on_task_stack) > else > erase_high = task_stack_high; > > - while (erase_low < erase_high) { > - *(unsigned long *)erase_low = STACKLEAK_POISON; > - erase_low += sizeof(unsigned long); > - } > + __stackleak_poison(erase_low, erase_high, STACKLEAK_POISON); > > /* Reset the 'lowest_stack' value for the next syscall */ > current->lowest_stack = task_stack_high; > -- > 2.37.2 >
| |