Re: [PATCH v6] ACPI: explicit init HEST, SDEI and GHES in apci_init

From: Shuai Xue <xueshuai@linux.alibaba.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: rafael@kernel.org, bp@alien8.de, tony.luck@intel.com,
	james.morse@arm.com, lenb@kernel.org, rjw@rjwysocki.net,
	bhelgaas@google.com, zhangliguang@linux.alibaba.com,
	zhuo.song@linux.alibaba.com, linux-kernel@vger.kernel.org,
	linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-pci@vger.kernel.org
Subject: Re: [PATCH v6] ACPI: explicit init HEST, SDEI and GHES in apci_init
Date: Fri, 21 Jan 2022 11:43:25 +0800	[thread overview]
Message-ID: <4c34906a-244e-3956-0ca7-7131b268cf60@linux.alibaba.com> (raw)
In-Reply-To: <20220120162241.GA1047212@bhelgaas>

Hi, Bjorn,

Thank you for your comments.

在 2022/1/21 AM12:22, Bjorn Helgaas 写道:
> On Thu, Jan 20, 2022 at 01:05:22PM +0800, Shuai Xue wrote:
>> From commit e147133a42cb ("ACPI / APEI: Make hest.c manage the estatus
>> memory pool") was merged, ghes_init() relies on acpi_hest_init() to manage
>> the estatus memory pool. On the other hand, ghes_init() relies on
>> sdei_init() to detect the SDEI version and (un)register events. The
>> dependencies are as follows:
>>
>>     ghes_init() => acpi_hest_init() => acpi_bus_init() => acpi_init()
>>     ghes_init() => sdei_init()
>>
>> HEST is not PCI-specific and initcall ordering is implicit and not
>> well-defined within a level.
>>
>> Based on above, remove acpi_hest_init() from acpi_pci_root_init() and
>> convert ghes_init() and sdei_init() from initcalls to explicit calls in the
>> following order:
>>
>>     acpi_hest_init()
>>     sdei_init()
>>     ghes_init()
>>
>> Suggested-by: Bjorn Helgaas <helgaas@kernel.org>
> 
> I didn't suggest the approach; I just reviewed the patch and the
> commit log and proposed moving it out of acpi_pci_root_init().  That
> doesn't need to be acknowledged.

I will delete it in next version :)

>> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
> 
> Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>

Will add this in next version.

> Minor extra "return" below. 
>> ---
>>  drivers/acpi/apei/ghes.c    | 17 +++++++----------
>>  drivers/acpi/bus.c          |  4 ++++
>>  drivers/acpi/pci_root.c     |  3 ---
>>  drivers/firmware/arm_sdei.c | 13 ++-----------
>>  include/acpi/apei.h         |  4 +++-
>>  include/linux/arm_sdei.h    |  2 ++
>>  6 files changed, 18 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
>> index 0c5c9acc6254..bed4f10cfcb8 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -1457,33 +1457,33 @@ static struct platform_driver ghes_platform_driver = {
>>  	.remove		= ghes_remove,
>>  };
>>  
>> -static int __init ghes_init(void)
>> +void __init ghes_init(void)
>>  {
>>  	int rc;
>>  
>>  	if (acpi_disabled)
>> -		return -ENODEV;
>> +		return;
>>  
>>  	switch (hest_disable) {
>>  	case HEST_NOT_FOUND:
>> -		return -ENODEV;
>> +		return;
>>  	case HEST_DISABLED:
>>  		pr_info(GHES_PFX "HEST is not enabled!\n");
>> -		return -EINVAL;
>> +		return;
>>  	default:
>>  		break;
>>  	}
>>  
>>  	if (ghes_disable) {
>>  		pr_info(GHES_PFX "GHES is not enabled!\n");
>> -		return -EINVAL;
>> +		return;
>>  	}
>>  
>>  	ghes_nmi_init_cxt();
>>  
>>  	rc = platform_driver_register(&ghes_platform_driver);
>>  	if (rc)
>> -		goto err;
>> +		return;
>>  
>>  	rc = apei_osc_setup();
>>  	if (rc == 0 && osc_sb_apei_support_acked)
>> @@ -1495,8 +1495,5 @@ static int __init ghes_init(void)
>>  	else
>>  		pr_info(GHES_PFX "Failed to enable APEI firmware first mode.\n");
>>  
>> -	return 0;
>> -err:
>> -	return rc;
>> +	return;
> 
> Unnecessary "return".

Will fix it in next version.

> 
>>  }
>> -device_initcall(ghes_init);
>> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
>> index 07f604832fd6..1dcd71df2cd5 100644
>> --- a/drivers/acpi/bus.c
>> +++ b/drivers/acpi/bus.c
>> @@ -30,6 +30,7 @@
>>  #include <linux/acpi_viot.h>
>>  #include <linux/pci.h>
>>  #include <acpi/apei.h>
>> +#include <linux/arm_sdei.h>
> 
> This "arm" looks a little out of place in this supposedly arch-generic
> code.  Not really a new thing with this patch, since this #include
> already appears in drivers/acpi/apei/ghes.c.  Maybe it's unavoidable.

Yep, should we move sdei_init() into the beginning of ghes_init()?

> sdei_init() and ghes_init() stick out here because they're the only
> functions without an "acpi_" prefix.  Maybe a separate patch to rename
> them?

Sorry, I forgot to send a patch to rename them. I have a question about this.

> Software Delegated Exception Interface (|SDEI|) is an Arm specification for
> Non-secure world to register handlers with firmware to receive notifications
> about system events.
> LINK: https://github.com/ARM-software/arm-trusted-firmware/blob/master/docs/components/sdei.rst

I think SDEI is not a ACPI Specification but Arm specification so we should
not rename sdei_init() with an "acpi_" prefix.  If we move sdei_init() into
ghes_init(), and rename ghes_init() to acpi_ghes_init(), then all looks
fine? What's your opinion, Bjorn?

Best Regards.

Shuai

> 
>>  #include <linux/suspend.h>
>>  #include <linux/prmt.h>
>>  
>> @@ -1331,6 +1332,9 @@ static int __init acpi_init(void)
>>  
>>  	pci_mmcfg_late_init();
>>  	acpi_iort_init();
>> +	acpi_hest_init();
>> +	sdei_init();
>> +	ghes_init();
>>  	acpi_scan_init();
>>  	acpi_ec_init();
>>  	acpi_debugfs_init();
>> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
>> index b76db99cced3..6f9e75d14808 100644
>> --- a/drivers/acpi/pci_root.c
>> +++ b/drivers/acpi/pci_root.c
>> @@ -22,8 +22,6 @@
>>  #include <linux/slab.h>
>>  #include <linux/dmi.h>
>>  #include <linux/platform_data/x86/apple.h>
>> -#include <acpi/apei.h>	/* for acpi_hest_init() */
>> -
>>  #include "internal.h"
>>  
>>  #define ACPI_PCI_ROOT_CLASS		"pci_bridge"
>> @@ -943,7 +941,6 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>>  
>>  void __init acpi_pci_root_init(void)
>>  {
>> -	acpi_hest_init();
>>  	if (acpi_pci_disabled)
>>  		return;
>>  
>> diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c
>> index a7e762c352f9..1e1a51510e83 100644
>> --- a/drivers/firmware/arm_sdei.c
>> +++ b/drivers/firmware/arm_sdei.c
>> @@ -1059,14 +1059,14 @@ static bool __init sdei_present_acpi(void)
>>  	return true;
>>  }
>>  
>> -static int __init sdei_init(void)
>> +void __init sdei_init(void)
>>  {
>>  	struct platform_device *pdev;
>>  	int ret;
>>  
>>  	ret = platform_driver_register(&sdei_driver);
>>  	if (ret || !sdei_present_acpi())
>> -		return ret;
>> +		return;
>>  
>>  	pdev = platform_device_register_simple(sdei_driver.driver.name,
>>  					       0, NULL, 0);
>> @@ -1076,17 +1076,8 @@ static int __init sdei_init(void)
>>  		pr_info("Failed to register ACPI:SDEI platform device %d\n",
>>  			ret);
>>  	}
>> -
>> -	return ret;
>>  }
>>  
>> -/*
>> - * On an ACPI system SDEI needs to be ready before HEST:GHES tries to register
>> - * its events. ACPI is initialised from a subsys_initcall(), GHES is initialised
>> - * by device_initcall(). We want to be called in the middle.
>> - */
>> -subsys_initcall_sync(sdei_init);
>> -
>>  int sdei_event_handler(struct pt_regs *regs,
>>  		       struct sdei_registered_event *arg)
>>  {
>> diff --git a/include/acpi/apei.h b/include/acpi/apei.h
>> index ece0a8af2bae..4e60dd73c3bb 100644
>> --- a/include/acpi/apei.h
>> +++ b/include/acpi/apei.h
>> @@ -27,14 +27,16 @@ extern int hest_disable;
>>  extern int erst_disable;
>>  #ifdef CONFIG_ACPI_APEI_GHES
>>  extern bool ghes_disable;
>> +void __init ghes_init(void);
>>  #else
>>  #define ghes_disable 1
>> +static inline void ghes_init(void) { }
>>  #endif
>>  
>>  #ifdef CONFIG_ACPI_APEI
>>  void __init acpi_hest_init(void);
>>  #else
>> -static inline void acpi_hest_init(void) { return; }
>> +static inline void acpi_hest_init(void) { }
>>  #endif
>>  
>>  int erst_write(const struct cper_record_header *record);
>> diff --git a/include/linux/arm_sdei.h b/include/linux/arm_sdei.h
>> index 0a241c5c911d..14dc461b0e82 100644
>> --- a/include/linux/arm_sdei.h
>> +++ b/include/linux/arm_sdei.h
>> @@ -46,9 +46,11 @@ int sdei_unregister_ghes(struct ghes *ghes);
>>  /* For use by arch code when CPU hotplug notifiers are not appropriate. */
>>  int sdei_mask_local_cpu(void);
>>  int sdei_unmask_local_cpu(void);
>> +void __init sdei_init(void);
>>  #else
>>  static inline int sdei_mask_local_cpu(void) { return 0; }
>>  static inline int sdei_unmask_local_cpu(void) { return 0; }
>> +static inline void sdei_init(void) { }
>>  #endif /* CONFIG_ARM_SDE_INTERFACE */
>>  
>>  
>> -- 
>> 2.20.1.12.g72788fdb
>>
>>
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