From c6f97add0f2ac83b98b06dbdda58fa47638ae7b0 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 21 Jul 2017 18:15:27 +0100 Subject: [PATCH] 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 Signed-off-by: Marc Zyngier Signed-off-by: Will Deacon --- 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 d48f47080213..8a62648848e5 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -523,7 +523,7 @@ 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