From 9c4aa1eecb48cfac18ed5e3aca9d9ae58fbafc11 Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Fri, 16 Dec 2016 12:07:57 +0800 Subject: [PATCH] ACPI / sysfs: Provide quirk mechanism to prevent GPE flooding Sometimes, the users may require a quirk to be provided from ACPI subsystem core to prevent a GPE from flooding. Normally, if a GPE cannot be dispatched, ACPICA core automatically prevents the GPE from firing. But there are cases the GPE is dispatched by _Lxx/_Exx provided via AML table, and OSPM is lacking of the knowledge to get _Lxx/_Exx correctly executed to handle the GPE, thus the GPE flooding may still occur. The existing quirk mechanism can be enabled/disabled using the following commands to prevent such kind of GPE flooding during runtime: # echo mask > /sys/firmware/acpi/interrupts/gpe00 # echo unmask > /sys/firmware/acpi/interrupts/gpe00 To avoid GPE flooding during boot, we need a boot stage mechanism. This patch provides such a boot stage quirk mechanism to stop this kind of GPE flooding. This patch doesn't fix any feature gap but since the new feature gaps could be found in the future endlessly, and can disappear if the feature gaps are filled, providing a boot parameter rather than a DMI table should suffice. Link: https://bugzilla.kernel.org/show_bug.cgi?id=53071 Link: https://bugzilla.kernel.org/show_bug.cgi?id=117481 Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/887793 Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki --- .../admin-guide/kernel-parameters.txt | 10 ++++ drivers/acpi/internal.h | 1 + drivers/acpi/scan.c | 1 + drivers/acpi/sysfs.c | 56 +++++++++++++++++++ 4 files changed, 68 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 21e2d8863705..d1eec5ed1134 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -106,6 +106,16 @@ use by PCI Format: ,... + acpi_mask_gpe= [HW,ACPI] + Due to the existence of _Lxx/_Exx, some GPEs triggered + by unsupported hardware/firmware features can result in + GPE floodings that cannot be automatically disabled by + the GPE dispatcher. + This facility can be used to prevent such uncontrolled + GPE floodings. + Format: + Support masking of GPEs numbered from 0x00 to 0x7f. + acpi_no_auto_serialize [HW,ACPI] Disable auto-serialization of AML methods AML control methods that contain the opcodes to create diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 1b41a2739dac..0c452265c111 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -37,6 +37,7 @@ void acpi_amba_init(void); static inline void acpi_amba_init(void) {} #endif int acpi_sysfs_init(void); +void acpi_gpe_apply_masked_gpes(void); void acpi_container_init(void); void acpi_memory_hotplug_init(void); #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 45dec874ea55..192691880d55 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -2074,6 +2074,7 @@ int __init acpi_scan_init(void) } } + acpi_gpe_apply_masked_gpes(); acpi_update_all_gpes(); acpi_ec_ecdt_start(); diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index 703c26e7022c..cf05ae973381 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -708,6 +708,62 @@ static ssize_t counter_set(struct kobject *kobj, return result ? result : size; } +/* + * A Quirk Mechanism for GPE Flooding Prevention: + * + * Quirks may be needed to prevent GPE flooding on a specific GPE. The + * flooding typically cannot be detected and automatically prevented by + * ACPI_GPE_DISPATCH_NONE check because there is a _Lxx/_Exx prepared in + * the AML tables. This normally indicates a feature gap in Linux, thus + * instead of providing endless quirk tables, we provide a boot parameter + * for those who want this quirk. For example, if the users want to prevent + * the GPE flooding for GPE 00, they need to specify the following boot + * parameter: + * acpi_mask_gpe=0x00 + * The masking status can be modified by the following runtime controlling + * 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; + +static int __init acpi_gpe_set_masked_gpes(char *val) +{ + u8 gpe; + + if (kstrtou8(val, 0, &gpe) || gpe > ACPI_MASKABLE_GPE_MAX) + return -EINVAL; + acpi_masked_gpes |= ((u64)1<