Re: [PATCH V11 05/10] acpi: apei: handle SEA notification type for ARMv8

["Baicar, Tyler" <tbaicar@codeaurora.org>]

Hello Xie XiuQi,


On 3/1/2017 12:42 AM, Xie XiuQi wrote:
> Hi Tyler,
>
> On 2017/2/22 5:21, Tyler Baicar wrote:
>> ARM APEI extension proposal added SEA (Synchronous External Abort)
>> notification type for ARMv8.
>> Add a new GHES error source handling function for SEA. If an error
>> source's notification type is SEA, then this function can be registered
>> into the SEA exception handler. That way GHES will parse and report
>> SEA exceptions when they occur.
> I have a question about ghes_proc. In ghes_proc, we just parse and report
> the error information, but no one use it for error recovery now.
>
> Take the SEA case for example, we get the physical address from parsing
> the GHES table. But the memory management system or other drivers/modules
> know what the really meaning of the error address/page. There is no way to
> notify them to do the recovery now.
>
> So, could we add a notify at appropriate position. All drivers or modules
> which are interested in this error could receive and take the corresponding
> action.
Error recovery is outside the scope of these patches. These patches are 
supposed to setup the infrastructure to parse/report the SEAs. Error 
recovery can be added after the fact which is what has been done for 
platform memory errors; the page off-lining support was added after the 
error parsing/reporting code was in.

Thanks,
Tyler
>
>> An SEA can interrupt code that had interrupts masked and is treated as
>> an NMI. To aid this the page of address space for mapping APEI buffers
>> while in_nmi() is always reserved, and ghes_ioremap_pfn_nmi() is
>> changed to use the helper methods to find the prot_t to map with in
>> the same way as ghes_ioremap_pfn_irq().
>>
>> Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org>
>> CC: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org>
>> ---
>>   arch/arm64/Kconfig        |  1 +
>>   arch/arm64/mm/fault.c     | 13 ++++++++
>>   drivers/acpi/apei/Kconfig | 15 +++++++++
>>   drivers/acpi/apei/ghes.c  | 77 +++++++++++++++++++++++++++++++++++++++++++----
>>   include/acpi/ghes.h       |  7 +++++
>>   5 files changed, 107 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 1117421..fca4dc1 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -88,6 +88,7 @@ config ARM64
>>   	select HAVE_IRQ_TIME_ACCOUNTING
>>   	select HAVE_MEMBLOCK
>>   	select HAVE_MEMBLOCK_NODE_MAP if NUMA
>> +	select HAVE_NMI if ACPI_APEI_SEA
>>   	select HAVE_PATA_PLATFORM
>>   	select HAVE_PERF_EVENTS
>>   	select HAVE_PERF_REGS
>> diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
>> index d178dc0..b2d57fc 100644
>> --- a/arch/arm64/mm/fault.c
>> +++ b/arch/arm64/mm/fault.c
>> @@ -41,6 +41,8 @@
>>   #include <asm/pgtable.h>
>>   #include <asm/tlbflush.h>
>>   
>> +#include <acpi/ghes.h>
>> +
>>   static const char *fault_name(unsigned int esr);
>>   
>>   #ifdef CONFIG_KPROBES
>> @@ -498,6 +500,17 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs)
>>   	pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n",
>>   		 fault_name(esr), esr, addr);
>>   
>> +	/*
>> +	 * Synchronous aborts may interrupt code which had interrupts masked.
>> +	 * Before calling out into the wider kernel tell the interested
>> +	 * subsystems.
>> +	 */
>> +	if (IS_ENABLED(ACPI_APEI_SEA)) {
>> +		nmi_enter();
>> +		ghes_notify_sea();
>> +		nmi_exit();
>> +	}
>> +
>>   	info.si_signo = SIGBUS;
>>   	info.si_errno = 0;
>>   	info.si_code  = 0;
>> diff --git a/drivers/acpi/apei/Kconfig b/drivers/acpi/apei/Kconfig
>> index b0140c8..c545dd1 100644
>> --- a/drivers/acpi/apei/Kconfig
>> +++ b/drivers/acpi/apei/Kconfig
>> @@ -39,6 +39,21 @@ config ACPI_APEI_PCIEAER
>>   	  PCIe AER errors may be reported via APEI firmware first mode.
>>   	  Turn on this option to enable the corresponding support.
>>   
>> +config ACPI_APEI_SEA
>> +	bool "APEI Synchronous External Abort logging/recovering support"
>> +	depends on ARM64 && ACPI_APEI && ACPI_APEI_GHES
>> +	default y
>> +	help
>> +	  This option should be enabled if the system supports
>> +	  firmware first handling of SEA (Synchronous External Abort).
>> +	  SEA happens with certain faults of data abort or instruction
>> +	  abort synchronous exceptions on ARMv8 systems. If a system
>> +	  supports firmware first handling of SEA, the platform analyzes
>> +	  and handles hardware error notifications from SEA, and it may then
>> +	  form a HW error record for the OS to parse and handle. This
>> +	  option allows the OS to look for such hardware error record, and
>> +	  take appropriate action.
>> +
>>   config ACPI_APEI_MEMORY_FAILURE
>>   	bool "APEI memory error recovering support"
>>   	depends on ACPI_APEI && MEMORY_FAILURE
>> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
>> index b25e7cf..b0596ba 100644
>> --- a/drivers/acpi/apei/ghes.c
>> +++ b/drivers/acpi/apei/ghes.c
>> @@ -114,11 +114,7 @@
>>    * Two virtual pages are used, one for IRQ/PROCESS context, the other for
>>    * NMI context (optionally).
>>    */
>> -#ifdef CONFIG_HAVE_ACPI_APEI_NMI
>>   #define GHES_IOREMAP_PAGES           2
>> -#else
>> -#define GHES_IOREMAP_PAGES           1
>> -#endif
>>   #define GHES_IOREMAP_IRQ_PAGE(base)	(base)
>>   #define GHES_IOREMAP_NMI_PAGE(base)	((base) + PAGE_SIZE)
>>   
>> @@ -157,10 +153,14 @@ static void ghes_ioremap_exit(void)
>>   static void __iomem *ghes_ioremap_pfn_nmi(u64 pfn)
>>   {
>>   	unsigned long vaddr;
>> +	phys_addr_t paddr;
>> +	pgprot_t prot;
>>   
>>   	vaddr = (unsigned long)GHES_IOREMAP_NMI_PAGE(ghes_ioremap_area->addr);
>> -	ioremap_page_range(vaddr, vaddr + PAGE_SIZE,
>> -			   pfn << PAGE_SHIFT, PAGE_KERNEL);
>> +
>> +	paddr = pfn << PAGE_SHIFT;
>> +	prot = arch_apei_get_mem_attribute(paddr);
>> +	ioremap_page_range(vaddr, vaddr + PAGE_SIZE, paddr, prot);
>>   
>>   	return (void __iomem *)vaddr;
>>   }
>> @@ -767,6 +767,50 @@ static int ghes_notify_sci(struct notifier_block *this,
>>   	.notifier_call = ghes_notify_sci,
>>   };
>>   
>> +#ifdef CONFIG_ACPI_APEI_SEA
>> +static LIST_HEAD(ghes_sea);
>> +
>> +void ghes_notify_sea(void)
>> +{
>> +	struct ghes *ghes;
>> +
>> +	/*
>> +	 * synchronize_rcu() will wait for nmi_exit(), so no need to
>> +	 * rcu_read_lock().
>> +	 */
>> +	list_for_each_entry_rcu(ghes, &ghes_sea, list) {
>> +		ghes_proc(ghes);
>> +	}
>> +}
>> +
>> +static void ghes_sea_add(struct ghes *ghes)
>> +{
>> +	mutex_lock(&ghes_list_mutex);
>> +	list_add_rcu(&ghes->list, &ghes_sea);
>> +	mutex_unlock(&ghes_list_mutex);
>> +}
>> +
>> +static void ghes_sea_remove(struct ghes *ghes)
>> +{
>> +	mutex_lock(&ghes_list_mutex);
>> +	list_del_rcu(&ghes->list);
>> +	mutex_unlock(&ghes_list_mutex);
>> +	synchronize_rcu();
>> +}
>> +#else /* CONFIG_ACPI_APEI_SEA */
>> +static inline void ghes_sea_add(struct ghes *ghes)
>> +{
>> +	pr_err(GHES_PFX "ID: %d, trying to add SEA notification which is not supported\n",
>> +	       ghes->generic->header.source_id);
>> +}
>> +
>> +static inline void ghes_sea_remove(struct ghes *ghes)
>> +{
>> +	pr_err(GHES_PFX "ID: %d, trying to remove SEA notification which is not supported\n",
>> +	       ghes->generic->header.source_id);
>> +}
>> +#endif /* CONFIG_ACPI_APEI_SEA */
>> +
>>   #ifdef CONFIG_HAVE_ACPI_APEI_NMI
>>   /*
>>    * printk is not safe in NMI context.  So in NMI handler, we allocate
>> @@ -1012,6 +1056,14 @@ static int ghes_probe(struct platform_device *ghes_dev)
>>   	case ACPI_HEST_NOTIFY_EXTERNAL:
>>   	case ACPI_HEST_NOTIFY_SCI:
>>   		break;
>> +	case ACPI_HEST_NOTIFY_SEA:
>> +		if (!IS_ENABLED(CONFIG_ACPI_APEI_SEA)) {
>> +			pr_warn(GHES_PFX "Generic hardware error source: %d notified via SEA is not supported\n",
>> +				generic->header.source_id);
>> +			rc = -ENOTSUPP;
>> +			goto err;
>> +		}
>> +		break;
>>   	case ACPI_HEST_NOTIFY_NMI:
>>   		if (!IS_ENABLED(CONFIG_HAVE_ACPI_APEI_NMI)) {
>>   			pr_warn(GHES_PFX "Generic hardware error source: %d notified via NMI interrupt is not supported!\n",
>> @@ -1023,6 +1075,13 @@ static int ghes_probe(struct platform_device *ghes_dev)
>>   		pr_warning(GHES_PFX "Generic hardware error source: %d notified via local interrupt is not supported!\n",
>>   			   generic->header.source_id);
>>   		goto err;
>> +	case ACPI_HEST_NOTIFY_GPIO:
>> +	case ACPI_HEST_NOTIFY_SEI:
>> +	case ACPI_HEST_NOTIFY_GSIV:
>> +		pr_warn(GHES_PFX "Generic hardware error source: %d notified via notification type %u is not supported\n",
>> +			generic->header.source_id, generic->header.source_id);
>> +		rc = -ENOTSUPP;
>> +		goto err;
>>   	default:
>>   		pr_warning(FW_WARN GHES_PFX "Unknown notification type: %u for generic hardware error source: %d\n",
>>   			   generic->notify.type, generic->header.source_id);
>> @@ -1077,6 +1136,9 @@ static int ghes_probe(struct platform_device *ghes_dev)
>>   		list_add_rcu(&ghes->list, &ghes_sci);
>>   		mutex_unlock(&ghes_list_mutex);
>>   		break;
>> +	case ACPI_HEST_NOTIFY_SEA:
>> +		ghes_sea_add(ghes);
>> +		break;
>>   	case ACPI_HEST_NOTIFY_NMI:
>>   		ghes_nmi_add(ghes);
>>   		break;
>> @@ -1119,6 +1181,9 @@ static int ghes_remove(struct platform_device *ghes_dev)
>>   			unregister_acpi_hed_notifier(&ghes_notifier_sci);
>>   		mutex_unlock(&ghes_list_mutex);
>>   		break;
>> +	case ACPI_HEST_NOTIFY_SEA:
>> +		ghes_sea_remove(ghes);
>> +		break;
>>   	case ACPI_HEST_NOTIFY_NMI:
>>   		ghes_nmi_remove(ghes);
>>   		break;
>> diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h
>> index 6ae318b..18bc935 100644
>> --- a/include/acpi/ghes.h
>> +++ b/include/acpi/ghes.h
>> @@ -1,3 +1,6 @@
>> +#ifndef GHES_H
>> +#define GHES_H
>> +
>>   #include <acpi/apei.h>
>>   #include <acpi/hed.h>
>>   
>> @@ -95,3 +98,7 @@ static inline void *acpi_hest_generic_data_payload(struct acpi_hest_generic_data
>>   		(void *)(((struct acpi_hest_generic_data_v300 *)(gdata)) + 1) :
>>   		gdata + 1;
>>   }
>> +
>> +void ghes_notify_sea(void);
>> +
>> +#endif /* GHES_H */
>>

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