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Message-Id: <20170721171448.27548-2-marc.zyngier@arm.com>
Date: Fri, 21 Jul 2017 18:14:33 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: unlisted-recipients:; (no To-header on input)
Cc: Mark Rutland <mark.rutland@....com>,
Russell King <linux@...linux.org.uk>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 01/16] 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@....com>
Signed-off-by: Marc Zyngier <marc.zyngier@....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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