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authorMarc Zyngier <marc.zyngier@arm.com>2017-07-21 19:15:27 +0200
committerWill Deacon <will.deacon@arm.com>2017-08-01 13:14:06 +0200
commitc6f97add0f2ac83b98b06dbdda58fa47638ae7b0 (patch)
treec8cb6bd8f2298b13a329c0d5c9fb6507614ae783
parentLinux 4.13-rc3 (diff)
downloadlinux-c6f97add0f2ac83b98b06dbdda58fa47638ae7b0.tar.xz
linux-c6f97add0f2ac83b98b06dbdda58fa47638ae7b0.zip
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>
-rw-r--r--arch/arm64/kernel/traps.c2
1 files changed, 1 insertions, 1 deletions
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;
}