Re: [PATCH] acpi: Fix ACPI GPE mask kernel parameter

Rafael J. Wysocki
2017-12-16T01:57:06Z

On Thursday, November 30, 2017 9:05:59 PM CET Prarit Bhargava wrote:
> The acpi_mask_gpe= kernel parameter documentation states that the range
> of mask is 128 GPEs (0x00 to 0x7F). The acpi_masked_gpes mask is a u64 so
> only 64 GPEs (0x00 to 0x3F) can really be masked.
>
> Use a bitmap of size 0xFF instead of a u64 for the GPE mask so 256
> GPEs can be masked.
>
> Fixes: 9c4aa1eecb48 ("ACPI / sysfs: Provide quirk mechanism to prevent GPE flooding")
> Signed-off-by: Prarit Bharava <prarit@redhat.com>
> Cc: Lv Zheng <lv.zheng@intel.com>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: linux-doc@vger.kernel.org
> ---
> Documentation/admin-guide/kernel-parameters.txt | 1 -
> drivers/acpi/sysfs.c | 26 ++++++++-----------------
> 2 files changed, 8 insertions(+), 19 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6571fbfdb2a1..89ba74761180 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -114,7 +114,6 @@
> This facility can be used to prevent such uncontrolled
> GPE floodings.
> Format: <int>
> - Support masking of GPEs numbered from 0x00 to 0x7f.
>
> acpi_no_auto_serialize [HW,ACPI]
> Disable auto-serialization of AML methods
> diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c
> index 06a150bb35bf..4fc59c3bc673 100644
> --- a/drivers/acpi/sysfs.c
> +++ b/drivers/acpi/sysfs.c
> @@ -816,14 +816,8 @@ static ssize_t counter_set(struct kobject *kobj,
> * interface:
> * echo unmask > /sys/firmware/acpi/interrupts/gpe00
> */
> -
> -/*
> - * Currently, the GPE flooding prevention only supports to mask the GPEs
> - * numbered from 00 to 7f.
> - */
> -#define ACPI_MASKABLE_GPE_MAX 0x80
> -
> -static u64 __initdata acpi_masked_gpes;
> +#define ACPI_MASKABLE_GPE_MAX 0xFF
> +static DECLARE_BITMAP(acpi_masked_gpes_map, ACPI_MASKABLE_GPE_MAX) __initdata;
>
> static int __init acpi_gpe_set_masked_gpes(char *val)
> {
> @@ -831,7 +825,7 @@ static int __init acpi_gpe_set_masked_gpes(char *val)
>
> if (kstrtou8(val, 0, &gpe) || gpe > ACPI_MASKABLE_GPE_MAX)
> return -EINVAL;
> - acpi_masked_gpes |= ((u64)1<<gpe);
> + set_bit(gpe, acpi_masked_gpes_map);
>
> return 1;
> }
> @@ -843,15 +837,11 @@ void __init acpi_gpe_apply_masked_gpes(void)
> acpi_status status;
> u8 gpe;
>
> - for (gpe = 0;
> - gpe < min_t(u8, ACPI_MASKABLE_GPE_MAX, acpi_current_gpe_count);
> - gpe++) {
> - if (acpi_masked_gpes & ((u64)1<<gpe)) {
> - status = acpi_get_gpe_device(gpe, &handle);
> - if (ACPI_SUCCESS(status)) {
> - pr_info("Masking GPE 0x%x.\n", gpe);
> - (void)acpi_mask_gpe(handle, gpe, TRUE);
> - }
> + for_each_set_bit(gpe, acpi_masked_gpes_map, ACPI_MASKABLE_GPE_MAX) {
> + status = acpi_get_gpe_device(gpe, &handle);
> + if (ACPI_SUCCESS(status)) {
> + pr_info("Masking GPE 0x%x.\n", gpe);
> + (void)acpi_mask_gpe(handle, gpe, TRUE);
> }
> }
> }
>

Applied, thanks!