From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: skip register_cpufreq_notifier on ACPI-based systems
Date: Thu, 26 Jan 2017 12:18:11 +0000 [thread overview]
Message-ID: <20170126121811.GD14167@arm.com> (raw)
In-Reply-To: <1485304992-26888-1-git-send-email-pprakash@codeaurora.org>
[adding Sudeep and Lorenzo for comment]
On Tue, Jan 24, 2017 at 05:43:12PM -0700, Prashanth Prakash wrote:
> On ACPI based systems where the topology is setup using the API
> store_cpu_topology, at the moment we do not have necessary code
> to handle a cpufreq notifier, thus resulting in a crash.
What is the "necessary code" that we're missing? Wouldn't it be better
to add that, or explicitly avoid the cpufreq notifier registration if
we're using ACPI?
Will
> Skip register_cpufreq_notifier if raw_capacity is not allocated
> as part of topology initialization.
>
> Stack:
> init_cpu_capacity_callback+0xb4/0x1c8
> notifier_call_chain+0x5c/0xa0
> __blocking_notifier_call_chain+0x58/0xa0
> blocking_notifier_call_chain+0x3c/0x50
> cpufreq_set_policy+0xe4/0x328
> cpufreq_init_policy+0x80/0x100
> cpufreq_online+0x418/0x710
> cpufreq_add_dev+0x118/0x180
> subsys_interface_register+0xa4/0xf8
> cpufreq_register_driver+0x1c0/0x298
> cppc_cpufreq_init+0xdc/0x1000 [cppc_cpufreq]
> do_one_initcall+0x5c/0x168
> do_init_module+0x64/0x1e4
> load_module+0x130c/0x14d0
> SyS_finit_module+0x108/0x120
> el0_svc_naked+0x24/0x28
>
> Patch that added support for popultaing cpu capacity for DT:
> https://patchwork.codeaurora.org/patch/98353/
>
> Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
> ---
> arch/arm64/kernel/topology.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
> index 23e9e13..3f175ce 100644
> --- a/arch/arm64/kernel/topology.c
> +++ b/arch/arm64/kernel/topology.c
> @@ -209,7 +209,7 @@ static void normalize_cpu_capacity(void)
>
> static int __init register_cpufreq_notifier(void)
> {
> - if (cap_parsing_failed)
> + if (cap_parsing_failed || !raw_capacity)
> return -EINVAL;
>
> if (!alloc_cpumask_var(&cpus_to_visit, GFP_KERNEL)) {
> --
> Qualcomm Datacenter Technologies on behalf of Qualcomm Technologies, Inc.
> Qualcomm Technologies, Inc. is a member of the
> Code Aurora Forum, a Linux Foundation Collaborative Project.
>
next prev parent reply other threads:[~2017-01-26 12:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-25 0:43 [PATCH] arm64: skip register_cpufreq_notifier on ACPI-based systems Prashanth Prakash
2017-01-25 12:03 ` Juri Lelli
2017-01-25 15:49 ` Christopher Covington
2017-01-25 16:48 ` Juri Lelli
2017-01-26 17:04 ` Mark Rutland
2017-01-26 12:18 ` Will Deacon [this message]
2017-01-26 15:52 ` Lorenzo Pieralisi
2017-01-26 15:57 ` Will Deacon
2017-01-26 17:31 ` Prakash, Prashanth
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