Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

arm64: arm_generic: prevent reading stale time

Browse source 
Currently arch_counter_get_cnt{p,v}ct can be speculated, allowing for
stale time values to be read. This could be problematic for the delay
loop and other sensitive functions, as the time delta could jump around
unexpectedly.

This patch adds isbs to arch_counter_get_cnt{p,v}ct, preventing this
possibility.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Mark Rutland 2013-01-15 11:12:29 +00:00
parent 8a4da6e36c
commit 1dac0dd71c
1 changed files with 2 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/arm64/include/asm/arm_generic.h
View file

@ -83,6 +83,7 @@ static inline cycle_t arch_counter_get_cntpct(void)
{ {
cycle_t cval; cycle_t cval;
isb();
asm volatile("mrs %0, cntpct_el0" : "=r" (cval)); asm volatile("mrs %0, cntpct_el0" : "=r" (cval));
return cval; return cval;
@ -92,6 +93,7 @@ static inline cycle_t arch_counter_get_cntvct(void)
{ {
cycle_t cval; cycle_t cval;
isb();
asm volatile("mrs %0, cntvct_el0" : "=r" (cval)); asm volatile("mrs %0, cntvct_el0" : "=r" (cval));
return cval; return cval;