Re: [PATCH 2/3] ACPI: APEI: GHES: Extract helper functions for error status handling

[Hanjun Guo <guohanjun@huawei.com>]

On 2025/12/3 21:02, Shuai Xue wrote:
> Refactors the GHES driver by extracting common functionality into
> reusable helper functions:
> 
> 1. ghes_has_active_errors() - Checks if any error sources in a given list
>     have active errors
> 2. ghes_map_error_status() - Maps error status address to virtual address
> 3. ghes_unmap_error_status() - Unmaps error status virtual address
> 
> These helpers eliminate code duplication in the NMI path and prepare for
> similar usage in the SEA path in a subsequent patch.
> 
> No functional change intended.
> 
> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
> ---
>   drivers/acpi/apei/ghes.c | 92 +++++++++++++++++++++++++++++++---------
>   1 file changed, 72 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 62713b612865..2c7f3ca6ce50 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -1375,6 +1375,74 @@ static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list,
>   	return ret;
>   }
>   
> +/**
> + * ghes_has_active_errors - Check if there are active errors in error sources
> + * @ghes_list: List of GHES entries to check for active errors
> + *
> + * This function iterates through all GHES entries in the given list and
> + * checks if any of them has active error status by reading the error
> + * status register.
> + *
> + * Return: true if at least one source has active error, false otherwise.
> + */
> +static bool __maybe_unused ghes_has_active_errors(struct list_head *ghes_list)
> +{
> +	bool active_error = false;
> +	struct ghes *ghes;
> +
> +	rcu_read_lock();
> +	list_for_each_entry_rcu(ghes, ghes_list, list) {
> +		if (ghes->error_status_vaddr &&
> +		    readl(ghes->error_status_vaddr)) {
> +			active_error = true;
> +			break;
> +		}
> +	}
> +	rcu_read_unlock();
> +
> +	return active_error;
> +}
> +
> +/**
> + * ghes_map_error_status - Map error status address to virtual address
> + * @ghes: pointer to GHES structure
> + *
> + * Reads the error status address from ACPI HEST table and maps it to a virtual
> + * address that can be accessed by the kernel.
> + *
> + * Return: 0 on success, error code on failure.
> + */
> +static int __maybe_unused ghes_map_error_status(struct ghes *ghes)
> +{
> +	struct acpi_hest_generic *g = ghes->generic;
> +	u64 paddr;
> +	int rc;
> +
> +	rc = apei_read(&paddr, &g->error_status_address);
> +	if (rc)
> +		return rc;
> +	ghes->error_status_vaddr =
> +		acpi_os_ioremap(paddr, sizeof(ghes->estatus->block_status));
> +	if (!ghes->error_status_vaddr)
> +		return AE_BAD_ADDRESS;

Same update here.

> +
> +	return 0;
> +}
> +
> +/**
> + * ghes_unmap_error_status - Unmap error status virtual address
> + * @ghes: pointer to GHES structure
> + *
> + * Unmaps the error status address if it was previously mapped.
> + */
> +static void __maybe_unused ghes_unmap_error_status(struct ghes *ghes)
> +{
> +	if (ghes->error_status_vaddr) {
> +		iounmap(ghes->error_status_vaddr);
> +		ghes->error_status_vaddr = NULL;
> +	}
> +}
> +
>   #ifdef CONFIG_ACPI_APEI_SEA
>   static LIST_HEAD(ghes_sea);
>   
> @@ -1425,20 +1493,9 @@ static LIST_HEAD(ghes_nmi);
>   static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
>   {
>   	static DEFINE_RAW_SPINLOCK(ghes_notify_lock_nmi);
> -	bool active_error = false;
>   	int ret = NMI_DONE;
> -	struct ghes *ghes;
>   
> -	rcu_read_lock();
> -	list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
> -		if (ghes->error_status_vaddr && readl(ghes->error_status_vaddr)) {
> -			active_error = true;
> -			break;
> -		}
> -	}
> -	rcu_read_unlock();
> -
> -	if (!active_error)
> +	if (!ghes_has_active_errors(&ghes_nmi))
>   		return ret;
>   
>   	if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
> @@ -1455,16 +1512,11 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
>   
>   static int ghes_nmi_add(struct ghes *ghes)
>   {
> -	struct acpi_hest_generic *g = ghes->generic;
> -	u64 paddr;
>   	int rc;
>   
> -	rc = apei_read(&paddr, &g->error_status_address);
> +	rc = ghes_map_error_status(ghes);
>   	if (rc)
>   		return rc;
> -	ghes->error_status_vaddr = acpi_os_ioremap(paddr, sizeof(ghes->estatus->block_status));
> -	if (!ghes->error_status_vaddr)
> -		return AE_BAD_ADDRESS;
>   
>   	mutex_lock(&ghes_list_mutex);
>   	if (list_empty(&ghes_nmi))
> @@ -1483,8 +1535,7 @@ static void ghes_nmi_remove(struct ghes *ghes)
>   		unregister_nmi_handler(NMI_LOCAL, "ghes");
>   	mutex_unlock(&ghes_list_mutex);
>   
> -	if (ghes->error_status_vaddr)
> -		iounmap(ghes->error_status_vaddr);
> +	ghes_unmap_error_status(ghes);
>   
>   	/*
>   	 * To synchronize with NMI handler, ghes can only be
> @@ -1492,6 +1543,7 @@ static void ghes_nmi_remove(struct ghes *ghes)
>   	 */
>   	synchronize_rcu();
>   }
> +

I think it's not belong to this patch.

Thanks
Hanjun

>   #else /* CONFIG_HAVE_ACPI_APEI_NMI */
>   static inline int ghes_nmi_add(struct ghes *ghes) { return -EINVAL; }
>   static inline void ghes_nmi_remove(struct ghes *ghes) { }
>