arm64: Use arch_timer_get_rate when trapping CNTFRQ_EL0
In an ideal world, CNTFRQ_EL0 always contains the timer frequency
for the kernel to use. Sadly, we get quite a few broken systems
where the firmware authors cannot be bothered to program that
register on all CPUs, and rely on DT to provide that frequency.
So when trapping CNTFRQ_EL0, make sure to return the actual rate
(as known by the kernel), and not CNTFRQ_EL0.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index d48f470..8a62648 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -523,7 +523,7 @@
{
int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
- pt_regs_write_reg(regs, rt, read_sysreg(cntfrq_el0));
+ pt_regs_write_reg(regs, rt, arch_timer_get_rate());
regs->pc += 4;
}