From e2c59e7b301efa7a5473d28d5f840dcf53fb431d Mon Sep 17 00:00:00 2001
From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Date: Fri, 4 Mar 2022 21:20:39 +0000
Subject: [PATCH 01/21] ACPICA: Limit error message flood caused by firmware
 bug

The following error messages are generated because of an infinite
recursion in the latest production BIOS:

ACPI Error: Method reached maximum reentrancy limit (255) (20210331/dsmethod-309)
ACPI Error: Aborting method \_SB.PCI0.LPC0.EC0.VFCD.PDVL due to previous error (AE_AML_METHOD_LIMIT) (20210331/psparse-529)
[...]
ACPI Error: Aborting method \_SB.PCI0.LPC0.EC0.VFCD.PDVL due to previous error (AE_AML_METHOD_LIMIT) (20210331/psparse-529)

Let's detect this and limit the amount of errors generated.

Additionally, add a kernel parameter 'acpi_no_msg_flood_detect' to
disable the detection for debugging purposes.

https://gitlab.steamos.cloud/jupiter/linux-integration/-/issues/11

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/acpi/acpica/dsmethod.c |  5 ++--
 drivers/acpi/acpica/uterror.c  | 53 ++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpica/dsmethod.c b/drivers/acpi/acpica/dsmethod.c
index e809c2aed78a..66267b1a3170 100644
--- a/drivers/acpi/acpica/dsmethod.c
+++ b/drivers/acpi/acpica/dsmethod.c
@@ -306,8 +306,9 @@ acpi_ds_begin_method_execution(struct acpi_namespace_node *method_node,
 	/* Prevent wraparound of thread count */
 
 	if (obj_desc->method.thread_count == ACPI_UINT8_MAX) {
-		ACPI_ERROR((AE_INFO,
-			    "Method reached maximum reentrancy limit (255)"));
+		/* Suppressing this due to firmware bug flooding the logs */
+		/*ACPI_ERROR((AE_INFO,
+			    "Method reached maximum reentrancy limit (255)"));*/
 		return_ACPI_STATUS(AE_AML_METHOD_LIMIT);
 	}
 
diff --git a/drivers/acpi/acpica/uterror.c b/drivers/acpi/acpica/uterror.c
index 918aca7c4db4..4a482de2e55d 100644
--- a/drivers/acpi/acpica/uterror.c
+++ b/drivers/acpi/acpica/uterror.c
@@ -278,6 +278,56 @@ acpi_ut_namespace_error(const char *module_name,
 }
 #endif
 
+/*******************************************************************************
+ *
+ * Limit the error message flood caused by a firmware bug:
+ *
+ * ACPI Error: Method reached maximum reentrancy limit (255) (20210331/dsmethod-309)
+ * ACPI Error: Aborting method \_SB.PCI0.LPC0.EC0.VFCD.PDVL due to previous error (AE_AML_METHOD_LIMIT) (20210331/psparse-529)
+ * [...]
+ * ACPI Error: Aborting method \_SB.PCI0.LPC0.EC0.VFCD.PDVL due to previous error (AE_AML_METHOD_LIMIT) (20210331/psparse-529)
+ *
+ ******************************************************************************/
+
+static bool acpi_disable_msg_flood_detect;
+
+static int __init acpi_no_msg_flood_detect_setup(char *s)
+{
+	acpi_disable_msg_flood_detect = true;
+	pr_info("ACPI error message flood detection disabled\n");
+
+	return 0;
+}
+
+early_param("acpi_no_msg_flood_detect", acpi_no_msg_flood_detect_setup);
+
+static bool acpi_skip_print_node(struct acpi_namespace_node *node)
+{
+	static bool skip_print = false;
+	struct acpi_buffer buffer;
+	acpi_status status;
+
+	if (acpi_disable_msg_flood_detect || !node)
+		return false;
+
+	if (!skip_print) {
+		/* Convert handle to full pathname */
+		buffer.length = ACPI_ALLOCATE_LOCAL_BUFFER;
+
+		status = acpi_ns_handle_to_pathname(node, &buffer, TRUE);
+		if (ACPI_SUCCESS(status)) {
+			skip_print = !strcmp((const char *)buffer.pointer,
+					     "\\_SB.PCI0.LPC0.EC0.VFCD.PDVL");
+			ACPI_FREE(buffer.pointer);
+
+			if (skip_print)
+				return false; /* print once */
+		}
+	}
+
+	return skip_print;
+}
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_ut_method_error
@@ -305,6 +355,9 @@ acpi_ut_method_error(const char *module_name,
 	acpi_status status;
 	struct acpi_namespace_node *node = prefix_node;
 
+	if (acpi_skip_print_node(node))
+		return;
+
 	ACPI_MSG_REDIRECT_BEGIN;
 	acpi_os_printf(ACPI_MSG_ERROR);
 
-- 
2.45.2

