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Message-ID: <CAErzpmvQqv6S-XkTf46bzTRQuv3h1LGXFixX-D_bCho-bD+upg@mail.gmail.com>
Date: Mon, 5 Jan 2026 13:12:01 +0800
From: Donglin Peng <dolinux.peng@...il.com>
To: Shuai Xue <xueshuai@...ux.alibaba.com>
Cc: tony.luck@...el.com, guohanjun@...wei.com, mchehab@...nel.org,
yazen.ghannam@....com, dave.jiang@...el.com,
Smita.KoralahalliChannabasappa@....com, leitao@...ian.org,
pengdonglin@...omi.com, baolin.wang@...ux.alibaba.com,
benjamin.cheatham@....com, bp@...en8.de, dan.j.williams@...el.com,
james.morse@....com, lenb@...nel.org, linux-acpi@...r.kernel.org,
linux-kernel@...r.kernel.org, rafael@...nel.org, zhuo.song@...ux.alibaba.com
Subject: Re: [PATCH v2 2/3] ACPI: APEI: GHES: Extract helper functions for
error status handling
On Sun, Jan 4, 2026 at 8:05 PM Shuai Xue <xueshuai@...ux.alibaba.com> 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.
>
> Tested-by: Tony Luck <tony.luck@...el.com>
> Reviewed-by: Tony Luck <tony.luck@...el.com>
> Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
> ---
> drivers/acpi/apei/ghes.c | 93 +++++++++++++++++++++++++++++++---------
> 1 file changed, 72 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 0e97d50b0240..7600063fe263 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -1406,6 +1406,75 @@ 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();
Nit: Use `guard(rcu)()` instead of explicit
`rcu_read_lock()`/`rcu_read_unlock()`.
Thanks,
Donglin
> + 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 -EINVAL;
> +
> + 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);
>
> @@ -1456,20 +1525,9 @@ 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))
> @@ -1486,18 +1544,12 @@ 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 -EINVAL;
> -
> mutex_lock(&ghes_list_mutex);
> if (list_empty(&ghes_nmi))
> register_nmi_handler(NMI_LOCAL, ghes_notify_nmi, 0, "ghes");
> @@ -1515,8 +1567,7 @@ 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
> --
> 2.39.3
>
>
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