From: Vladimir Murzin <vladimir.murzin@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: maz@kernel.org, kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH] ARM: virt: Relax arch timer version check during early boot
Date: Mon, 20 Jan 2020 10:46:05 +0000 [thread overview]
Message-ID: <eb889279-87f2-d674-9299-169794c285eb@arm.com> (raw)
In-Reply-To: <1579097798-106243-1-git-send-email-vladimir.murzin@arm.com>
+ Marc
+ kvmarm@lists.cs.columbia.edu
On 1/15/20 2:16 PM, Vladimir Murzin wrote:
> Updates to the Generic Timer architecture allow ID_PFR1.GenTimer to
> have values other than 0 or 1. At the moment, Linux is quite strict in
> the way it handles this field at early boot and will not configure
> arch timer if it doesn't find the value 1.
>
> Since here use ubfx for arch timer version extraction (hyb-stub build
> with -march=armv7-a, so it is safe)
>
> To help backports (even though the code was correct at the time of writing)
> Fixes: 8ec58be9f3ff ("ARM: virt: arch_timers: enable access to physical timers")
> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> ---
> arch/arm/kernel/hyp-stub.S | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
> index ae50203..6607fa8 100644
> --- a/arch/arm/kernel/hyp-stub.S
> +++ b/arch/arm/kernel/hyp-stub.S
> @@ -146,10 +146,9 @@ ARM_BE8(orr r7, r7, #(1 << 25)) @ HSCTLR.EE
> #if !defined(ZIMAGE) && defined(CONFIG_ARM_ARCH_TIMER)
> @ make CNTP_* and CNTPCT accessible from PL1
> mrc p15, 0, r7, c0, c1, 1 @ ID_PFR1
> - lsr r7, #16
> - and r7, #0xf
> - cmp r7, #1
> - bne 1f
> + ubfx r7, r7, #16, #4
> + teq r7, #0
> + beq 1f
> mrc p15, 4, r7, c14, c1, 0 @ CNTHCTL
> orr r7, r7, #3 @ PL1PCEN | PL1PCTEN
> mcr p15, 4, r7, c14, c1, 0 @ CNTHCTL
>
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next parent reply other threads:[~2020-01-20 10:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1579097798-106243-1-git-send-email-vladimir.murzin@arm.com>
2020-01-20 10:46 ` Vladimir Murzin [this message]
2020-01-20 11:14 ` [PATCH] ARM: virt: Relax arch timer version check during early boot Marc Zyngier
2020-01-20 11:34 ` Vladimir Murzin
2020-01-20 11:56 ` Marc Zyngier
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