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author | Rafael J. Wysocki | 2014-12-01 23:50:16 +0100 |
---|---|---|
committer | Rafael J. Wysocki | 2014-12-01 23:50:16 +0100 |
commit | c50f13c672df758b59e026c15b9118f3ed46edc4 (patch) | |
tree | 994eb40c3da799b01988effd5f68039bfafacdfb /drivers/acpi/acpica/evgpe.c | |
parent | e5874591d67f6f4ee10df88d321692aeccb4bcf4 (diff) |
ACPICA: Save current masks of enabled GPEs after enable register writes
There is a race condition between acpi_hw_disable_all_gpes() or
acpi_enable_all_wakeup_gpes() and acpi_ev_asynch_enable_gpe() such
that if the latter wins the race, it may mistakenly enable a GPE
disabled by the former. This may lead to premature system wakeups
during system suspend and potentially to more serious consequences.
The source of the problem is how acpi_hw_low_set_gpe() works when
passed ACPI_GPE_CONDITIONAL_ENABLE as the second argument. In that
case, the GPE will be enabled if the corresponding bit is set in the
enable_for_run mask of the GPE enable register containing that bit.
However, acpi_hw_disable_all_gpes() and acpi_enable_all_wakeup_gpes()
don't modify the enable_for_run masks of GPE registers when writing
to them. In consequence, if acpi_ev_asynch_enable_gpe(), which
eventually calls acpi_hw_low_set_gpe() with the second argument
equal to ACPI_GPE_CONDITIONAL_ENABLE, is executed in parallel with
one of these functions, it may reverse changes made by them.
To fix the problem, introduce a new enable_mask field in struct
acpi_gpe_register_info in which to store the current mask of
enabled GPEs and modify acpi_hw_low_set_gpe() to take this
mask into account instead of enable_for_run when its second
argument is equal to ACPI_GPE_CONDITIONAL_ENABLE. Also modify
the low-level routines called by acpi_hw_disable_all_gpes(),
acpi_enable_all_wakeup_gpes() and acpi_enable_all_runtime_gpes()
to update the enable_mask masks of GPE registers after all
(successful) writes to those registers.
Acked-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/acpica/evgpe.c')
-rw-r--r-- | drivers/acpi/acpica/evgpe.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c index 2095dfb72bcb..81db932b15ee 100644 --- a/drivers/acpi/acpica/evgpe.c +++ b/drivers/acpi/acpica/evgpe.c @@ -134,7 +134,7 @@ acpi_status acpi_ev_enable_gpe(struct acpi_gpe_event_info *gpe_event_info) /* Enable the requested GPE */ - status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE); + status = acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_ENABLE_SAVE); return_ACPI_STATUS(status); } @@ -213,7 +213,7 @@ acpi_ev_remove_gpe_reference(struct acpi_gpe_event_info *gpe_event_info) if (ACPI_SUCCESS(status)) { status = acpi_hw_low_set_gpe(gpe_event_info, - ACPI_GPE_DISABLE); + ACPI_GPE_DISABLE_SAVE); } if (ACPI_FAILURE(status)) { @@ -655,7 +655,7 @@ acpi_status acpi_ev_finish_gpe(struct acpi_gpe_event_info * gpe_event_info) /* * Enable this GPE, conditionally. This means that the GPE will - * only be physically enabled if the enable_for_run bit is set + * only be physically enabled if the enable_mask bit is set * in the event_info. */ (void)acpi_hw_low_set_gpe(gpe_event_info, ACPI_GPE_CONDITIONAL_ENABLE); |