Patchwork [v7,10/25] ACPI / APEI: Tell firmware the estatus queue consumed the records

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Submitter James Morse
Date Dec. 3, 2018, 6:05 p.m.
Message ID <20181203180613.228133-11-james.morse@arm.com>
Download mbox | patch
Permalink /patch/671027/
State New
Headers show

Comments

James Morse - Dec. 3, 2018, 6:05 p.m.
ACPI has a GHESv2 which is used on hardware reduced platforms to
explicitly acknowledge that the memory for CPER records has been
consumed. This lets an external agent know it can re-use this
memory for something else.

Previously notify_nmi and the estatus queue didn't do this as
they were never used on hardware reduced platforms. Once we move
notify_sea over to use the estatus queue, it may become necessary.

Add the call. This is safe for use in NMI context as the
read_ack_register is pre-mapped by ghes_new() before the
ghes can be added to an RCU list, and then found by the
notification handler.

Signed-off-by: James Morse <james.morse@arm.com>
---
 drivers/acpi/apei/ghes.c | 4 ++++
 1 file changed, 4 insertions(+)
Borislav Petkov - Dec. 11, 2018, 6:36 p.m.
On Mon, Dec 03, 2018 at 06:05:58PM +0000, James Morse wrote:
> ACPI has a GHESv2 which is used on hardware reduced platforms to
> explicitly acknowledge that the memory for CPER records has been
> consumed. This lets an external agent know it can re-use this
> memory for something else.
> 
> Previously notify_nmi and the estatus queue didn't do this as
> they were never used on hardware reduced platforms. Once we move
> notify_sea over to use the estatus queue, it may become necessary.
> 
> Add the call. This is safe for use in NMI context as the
> read_ack_register is pre-mapped by ghes_new() before the
> ghes can be added to an RCU list, and then found by the
> notification handler.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>  drivers/acpi/apei/ghes.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 366dbdd41ef3..15d94373ba72 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -926,6 +926,10 @@ static int _in_nmi_notify_one(struct ghes *ghes)
>  	__process_error(ghes);
>  	ghes_clear_estatus(ghes, buf_paddr);
>  
> +	if (is_hest_type_generic_v2(ghes) && ghes_ack_error(ghes->generic_v2))

Since ghes_ack_error() is always prepended with this check, you could
push it down into the function:

ghes_ack_error(ghes)
...

	if (!is_hest_type_generic_v2(ghes))
		return 0;

and simplify the two callsites :)

Patch

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 366dbdd41ef3..15d94373ba72 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -926,6 +926,10 @@  static int _in_nmi_notify_one(struct ghes *ghes)
 	__process_error(ghes);
 	ghes_clear_estatus(ghes, buf_paddr);
 
+	if (is_hest_type_generic_v2(ghes) && ghes_ack_error(ghes->generic_v2))
+		pr_warn_ratelimited(FW_WARN GHES_PFX
+				    "Failed to ack error status block!\n");
+
 	return 0;
 }