From 307ecb0aa3a24528efd1cfcea8215b2d82df6e10 Mon Sep 17 00:00:00 2001 From: Lv Zheng Date: Tue, 13 Sep 2016 17:48:27 +0800 Subject: [PATCH] ACPI / sysfs: Fix an issue for LoadTable opcode OEM tables can be installed via RSDT/XSDT, in this case, they have already been created under /sys/firmware/acpi/tables. For this kind of tables, normally LoadTable opcode will be executed to load them. If LoadTable opcode is executed after acpi_sysfs_init(), acpi_sysfs_table_handler() will be invoked, thus a redundant table file will be created under /sys/firmware/acpi/tables/dynamic. Then running "acpidump" on such platform results in an error, complaining blank empty table (see Link 1 below). The bug can be reproduced by customizing an OEM1 table, allowing it to be overridden via 'table_sigs' (drivers/acpi/tables.c), adding the following code to the customized DSDT to load it: Name (OEMH, Zero) Name (OEMF, One) If (LEqual (OEMF, One)) { Store (LoadTable ("OEM1", "Intel", "Test"), OEMH) Store (Zero, OEMF) } In order to make sure that the OEM1 table is installed after acpi_sysfs_init(), acpi_sysfs_init() can be moved before invoking acpi_load_tables(). Then the following command execution result can be seen: # acpidump > acpidump.txt Could not read table header: /sysfs/firmware/acpi/tables/dynamic/OEM12 Could not get ACPI table at index 17, AE_BAD_HEADER Link: https://bugzilla.kernel.org/show_bug.cgi?id=150841 # [1] Link: https://github.com/acpica/acpica/commit/ed6a5fbc Reported-by: Jason Voelz Reported-by: Francisco Leoner Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki --- drivers/acpi/sysfs.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index 703c993888b2..c88d4bdf2165 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -383,7 +383,7 @@ acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context) struct acpi_table_attr *table_attr; switch (event) { - case ACPI_TABLE_EVENT_LOAD: + case ACPI_TABLE_EVENT_INSTALL: table_attr = kzalloc(sizeof(struct acpi_table_attr), GFP_KERNEL); if (!table_attr) @@ -397,7 +397,9 @@ acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context) } else list_add_tail(&table_attr->node, &acpi_table_attr_list); break; + case ACPI_TABLE_EVENT_LOAD: case ACPI_TABLE_EVENT_UNLOAD: + case ACPI_TABLE_EVENT_UNINSTALL: /* * we do not need to do anything right now * because the table is not deleted from the