From b2a35003dfbcc7b7a5e5c6e524e7d49ba66e0bb5 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Mon, 1 Oct 2012 00:23:55 +0200 Subject: [PATCH] ACPI: Implement physical address table override Previous patches stored ACPI tables provided via initrd in a memblock reserved area. If a table is loaded and the table type of an initrd provided one matches, the one from initrd is prefered. In case of a SSDT table, the OEM table id also has to match. ACPI tables can be loaded at boot time (static table pointers in XSDT), but also dynamically any time later via ASL commands load() or loadTable(). The override mechanism always works. Signed-off-by: Thomas Renninger Link: http://lkml.kernel.org/r/1349043837-22659-5-git-send-email-trenn@suse.de Cc: Len Brown Cc: Robert Moore Cc: Yinghai Lu Cc: Eric Piel Signed-off-by: H. Peter Anvin --- drivers/acpi/osl.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 56 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index b20b0790..007224b 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -681,12 +681,64 @@ acpi_os_table_override(struct acpi_table_header * existing_table, acpi_status acpi_os_physical_table_override(struct acpi_table_header *existing_table, - acpi_physical_address * new_address, - u32 *new_table_length) + acpi_physical_address *address, + u32 *table_length) { - return AE_SUPPORT; -} +#ifndef CONFIG_ACPI_INITRD_TABLE_OVERRIDE + *table_length = 0; + *address = 0; + return AE_OK; +#else + int table_offset = 0; + struct acpi_table_header *table; + + *table_length = 0; + *address = 0; + + if (!acpi_tables_addr) + return AE_OK; + + do { + if (table_offset + ACPI_HEADER_SIZE > all_tables_size) { + WARN_ON(1); + return AE_OK; + } + + table = acpi_os_map_memory(acpi_tables_addr + table_offset, + ACPI_HEADER_SIZE); + + if (table_offset + table->length > all_tables_size) { + acpi_os_unmap_memory(table, ACPI_HEADER_SIZE); + WARN_ON(1); + return AE_OK; + } + table_offset += table->length; + + if (memcmp(existing_table->signature, table->signature, 4)) { + acpi_os_unmap_memory(table, + ACPI_HEADER_SIZE); + continue; + } + + /* Only override tables with matching oem id */ + if (memcmp(table->oem_table_id, existing_table->oem_table_id, + ACPI_OEM_TABLE_ID_SIZE)) { + acpi_os_unmap_memory(table, + ACPI_HEADER_SIZE); + continue; + } + + table_offset -= table->length; + *table_length = table->length; + acpi_os_unmap_memory(table, ACPI_HEADER_SIZE); + *address = acpi_tables_addr + table_offset; + break; + } while (table_offset + ACPI_HEADER_SIZE < all_tables_size); + + return AE_OK; +#endif +} static irqreturn_t acpi_irq(int irq, void *dev_id) { -- 2.7.4