Commit 491a7866 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

stackleak: allow to specify arch specific stackleak poison function 



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: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230405130841.1350565-2-hca@linux.ibm.com


Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent ccf7c3fb

kernel/stackleak.c

+13 −4
Original line number Diff line number Diff line
@@ -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;