linux-kernel - [PATCH AUTOSEL 4.9 08/98] ACPI: sysfs: Make ACPI GPE mask kernel parameter cover all GPEs

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Message-Id: <20181025141423.213774-8-sashal@kernel.org>
Date:   Thu, 25 Oct 2018 10:12:53 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     stable@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Prarit Bhargava <prarit@...hat.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH AUTOSEL 4.9 08/98] ACPI: sysfs: Make ACPI GPE mask kernel parameter cover all GPEs

From: Prarit Bhargava <prarit@...hat.com>

[ Upstream commit 0f27cff8597d86f881ea8274b49b63b678c14a3c ]

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@...hat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 Documentation/kernel-parameters.txt |  1 -
 drivers/acpi/sysfs.c                | 26 ++++++++------------------
 2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f9f67be8d3c3..c708a50b060e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -313,7 +313,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			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 cf05ae973381..a36d0739dbfe 100644
--- a/drivers/acpi/sysfs.c
+++ b/drivers/acpi/sysfs.c
@@ -724,14 +724,8 @@ 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)
 {
@@ -739,7 +733,7 @@ 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;
 }
@@ -751,15 +745,11 @@ 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);
 		}
 	}
 }
-- 
2.17.1