[PATCH] acpi: Fix ACPI GPE mask kernel parameter

[Prarit Bhargava <prarit@redhat.com>]

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);
 		}
 	}
 }
-- 
2.15.0.rc0.39.g2f0e14e64