[PATCH v5 02/10] ACPI: APEI: GHES: move CPER read helpers

[Jonathan Cameron]

On Fri, 29 May 2026 10:50:42 +0100
Ahmed Tiba <ahmed.tiba at arm.com> wrote:

> Relocate the CPER buffer mapping, peek, and clear helpers from ghes.c into
> ghes_cper.c so they can be shared with other firmware-first providers.
> This commit only shuffles code; behavior stays the same.
> 
> Signed-off-by: Ahmed Tiba <ahmed.tiba at arm.com>

A couple of things I noticed whilst quickly scan through what was moved inline.

Move itself looks fine to me.
Reviewed-by: Jonathan Cameron <jic23 at kernel.org>

> diff --git a/drivers/acpi/apei/ghes_cper.c b/drivers/acpi/apei/ghes_cper.c
> new file mode 100644
> index 000000000000..7bb72fe57838
> --- /dev/null
> +++ b/drivers/acpi/apei/ghes_cper.c
> @@ -0,0 +1,195 @@

> +
> +/* Check the top-level record header has an appropriate size. */
> +int __ghes_check_estatus(struct ghes *ghes,
> +			 struct acpi_hest_generic_status *estatus)
> +{
> +	u32 len = cper_estatus_len(estatus);
> +	u32 max_len = min(ghes->generic->error_block_length,
> +			  ghes->estatus_length);
> +
> +	if (len < sizeof(*estatus)) {
> +		pr_warn_ratelimited(FW_WARN GHES_PFX "Truncated error status block!\n");
> +		return -EIO;
> +	}
> +
> +	if (!len || len > max_len) {

Obviously this is just a move, but that if !len is silly given that will have failed
the previous check as 0 is definitely less than sizeof(*estatus)

Maybe add a trivial patch to tidy this up and any similar oddities.


> +		pr_warn_ratelimited(FW_WARN GHES_PFX "Invalid error status block length!\n");
> +		return -EIO;
> +	}
> +
> +	if (cper_estatus_check_header(estatus)) {
> +		pr_warn_ratelimited(FW_WARN GHES_PFX "Invalid CPER header!\n");
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Read the CPER block, returning its address, and header in estatus. */
> +int __ghes_peek_estatus(struct ghes *ghes,
> +			struct acpi_hest_generic_status *estatus,
> +			u64 *buf_paddr, enum fixed_addresses fixmap_idx)
> +{
> +	struct acpi_hest_generic *g = ghes->generic;
> +	int rc;
> +
> +	rc = apei_read(buf_paddr, &g->error_status_address);
> +	if (rc) {
> +		*buf_paddr = 0;
> +		pr_warn_ratelimited(FW_WARN GHES_PFX
> +				    "Failed to read error status block address for hardware error source: %d.\n",
> +				   g->header.source_id);

Whilst you are here I don't think anyone would mind if you fix the alignment.
Looks like it's one space short.

> +		return -EIO;
> +	}
> +	if (!*buf_paddr)
> +		return -ENOENT;
> +
> +	ghes_copy_tofrom_phys(estatus, *buf_paddr, sizeof(*estatus), 1,
> +			      fixmap_idx);
> +	if (!estatus->block_status) {
> +		*buf_paddr = 0;
> +		return -ENOENT;
> +	}
> +
> +	return 0;
> +}