Re: [PATCH] arm64: armv8_deprecated: Fix warning in isndep cpuhp starting process

From: "lihuisong (C)" <lihuisong@huawei.com>
To: Wei Li <liwei391@huawei.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Joel Granados <j.granados@samsung.com>,
	Luis Chamberlain <mcgrof@kernel.org>
Cc: <xiexiuqi@huawei.com>, <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] arm64: armv8_deprecated: Fix warning in isndep cpuhp starting process
Date: Wed, 15 May 2024 15:46:54 +0800	[thread overview]
Message-ID: <d81a6b50-4761-3eb5-f708-6eb7de0fb648@huawei.com> (raw)
In-Reply-To: <20240423093501.3460764-1-liwei391@huawei.com>


在 2024/4/23 17:35, Wei Li 写道:
> The function run_all_insn_set_hw_mode() is registered as startup callback
> of 'CPUHP_AP_ARM64_ISNDEP_STARTING', it invokes set_hw_mode() methods of
> all emulated instructions.
>
> As the STARTING callbacks are not expected to fail, if one of the
> set_hw_mode() fails, e.g. due to el0 mixed-endian is not supported for
> 'setend', it will report a warning:
>
> ```
> CPU[2] cannot support the emulation of setend
> CPU 2 UP state arm64/isndep:starting (136) failed (-22)
> CPU2: Booted secondary processor 0x0000000002 [0x414fd0c1]
> ```
>
> To fix it, add a check for INSN_UNAVAILABLE status and skip the process.
>
> Signed-off-by: Wei Li <liwei391@huawei.com>
> ---
>   arch/arm64/kernel/armv8_deprecated.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
> index dd6ce86d4332..b776e7424fe9 100644
> --- a/arch/arm64/kernel/armv8_deprecated.c
> +++ b/arch/arm64/kernel/armv8_deprecated.c
> @@ -462,6 +462,9 @@ static int run_all_insn_set_hw_mode(unsigned int cpu)
>   	for (int i = 0; i < ARRAY_SIZE(insn_emulations); i++) {
>   		struct insn_emulation *insn = insn_emulations[i];
>   		bool enable = READ_ONCE(insn->current_mode) == INSN_HW;
> +		if (insn->status == INSN_UNAVAILABLE)
> +			continue;
> +
I happen to have this problem too. Thanks.
Tested-by: Huisong Li <lihuisong@huawei.com>
>   		if (insn->set_hw_mode && insn->set_hw_mode(enable)) {
>   			pr_warn("CPU[%u] cannot support the emulation of %s",
>   				cpu, insn->name);

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