linux-kernel - Re: [PATCH 1/3] acpi/processor: fix evaluating

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Message-ID: <06e6cefb-c773-d959-d569-84dd63e240e1@oderland.se>
Date:   Fri, 3 Feb 2023 14:58:00 +0100
From:   Josef Johansson <josef@...rland.se>
To:     Jan Beulich <jbeulich@...e.com>
Cc:     xen-devel@...ts.xenproject.org, x86@...nel.org,
        linux-acpi@...r.kernel.org, Roger Pau Monne <roger.pau@...rix.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] acpi/processor: fix evaluating _PDC method when
 running as Xen dom0


On 2/3/23 08:05, Jan Beulich wrote:
> On 30.01.2023 10:21, Josef Johansson wrote:
>> On 11/21/22 11:21, Roger Pau Monne wrote:
>>> --- a/arch/x86/xen/enlighten.c
>>> +++ b/arch/x86/xen/enlighten.c
>>> @@ -346,3 +346,30 @@ void xen_arch_unregister_cpu(int num)
>>>    }
>>>    EXPORT_SYMBOL(xen_arch_unregister_cpu);
>>>    #endif
>>> +
>>> +#ifdef CONFIG_XEN_DOM0
>>> +bool __init xen_processor_present(uint32_t acpi_id)
>>> +{
>>> +	unsigned int i, maxid;
>>> +	struct xen_platform_op op = {
>>> +		.cmd = XENPF_get_cpuinfo,
>>> +		.interface_version = XENPF_INTERFACE_VERSION,
>>> +	};
>>> +	int ret = HYPERVISOR_platform_op(&op);
>>> +
>>> +	if (ret)
>>> +		return false;
>>> +
>>> +	maxid = op.u.pcpu_info.max_present;
>>> +	for (i = 0; i <= maxid; i++) {
>>> +		op.u.pcpu_info.xen_cpuid = i;
>>> +		ret = HYPERVISOR_platform_op(&op);
>>> +		if (ret)
>>> +			continue;
>>> +		if (op.u.pcpu_info.acpi_id == acpi_id)
>>> +			return op.u.pcpu_info.flags & XEN_PCPU_FLAGS_ONLINE;
>>> +	}
>>> +
>>> +	return false;
>>> +}
>> My compiler (Default GCC on Fedora 32, compiling for Qubes) complain
>> loudly that the below was missing.
>>
>> +}
>> +EXPORT_SYMBOL(xen_processor_present);
>>
>> `ERROR: MODPOST xen_processor_present
>> [drivers/xen/xen-acpi-processor.ko] undefined!`
>>
>> Same thing with xen_sanitize_pdc in the next patch.
>>
>> +}
>> +EXPORT_SYMBOL(xen_sanitize_pdc);
>>
>> Everything compiled fine after those changes.
> Except that you may not export __init symbols. The section mismatch checker
> should actually complain about that.
>
> Jan

That makes sense. Patch 3 does change it from an __init though.

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 394dd6675113..a7b41103d3e5 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -348,7 +348,7 @@ EXPORT_SYMBOL(xen_arch_unregister_cpu);
  #endif

  #ifdef CONFIG_XEN_DOM0
-bool __init xen_processor_present(uint32_t acpi_id)
+bool xen_processor_present(uint32_t acpi_id)
  {


So the change should be in Patch 3 I guess.

Regards
- Josef