Messages in this thread Patch in this message | | | From | Marc Zyngier <> | Subject | [PATCH 01/16] arm64: Use arch_timer_get_rate when trapping CNTFRQ_EL0 | Date | Fri, 21 Jul 2017 18:15:27 +0100 |
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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> --- arch/arm64/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index c7c7088097be..b02295673216 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -519,7 +519,7 @@ static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs) { 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; } -- 2.11.0
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