[PATCH 0/3] ACPI / tables: Add table upgrade mechanism

[PATCH 0/3] ACPI / tables: Add table upgrade mechanism

[Lv Zheng]

This patch introduces a table upgrade mechanism based on the existing
initrd table override mechanism.

Lv Zheng (3):
  ACPI / tables: Move table override mechanisms to tables.c
  ACPI / x86: Cleanup initrd related code
  ACPI / tables: Convert the initrd table override mechanisms to the
    table upgrade mechanism

 Documentation/acpi/initrd_table_override.txt |   65 +++---
 arch/x86/kernel/setup.c                      |   12 +-
 drivers/acpi/Kconfig                         |    8 +-
 drivers/acpi/internal.h                      |    1 -
 drivers/acpi/osl.c                           |  274 ----------------------
 drivers/acpi/tables.c                        |  312 +++++++++++++++++++++++++-
 include/linux/acpi.h                         |    6 +-
 7 files changed, 366 insertions(+), 312 deletions(-)

-- 
1.7.10

[PATCH 1/3] ACPI / tables: Move table override mechanisms to tables.c

[Lv Zheng]

This patch moves acpi_os_table_override() and
acpi_os_physical_table_override() to tables.c.

Along with the mechanisms, acpi_initrd_initialize_tables() is also moved to
tables.c to form a static function. The following functions are renamed
according to this change:
1. acpi_initrd_override() -> renamed to early_acpi_table_init(), which
   invokes acpi_table_initrd_init()
2. acpi_os_physical_table_override() -> which invokes
   acpi_table_initrd_override()
3. acpi_initialize_initrd_tables() -> renamed to acpi_table_initrd_scan()

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
---
 arch/x86/kernel/setup.c |    2 +-
 drivers/acpi/internal.h |    1 -
 drivers/acpi/osl.c      |  274 --------------------------------------------
 drivers/acpi/tables.c   |  292 ++++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/acpi.h    |    4 +-
 5 files changed, 294 insertions(+), 279 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 2367ae0..902a6f7 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1139,7 +1139,7 @@ void __init setup_arch(char **cmdline_p)
 	reserve_initrd();
 
 #if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD)
-	acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start);
+	early_acpi_table_init((void *)initrd_start, initrd_end - initrd_start);
 #endif
 
 	vsmp_init();
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 7c18847..1b0e6fd 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -20,7 +20,6 @@
 
 #define PREFIX "ACPI: "
 
-void acpi_initrd_initialize_tables(void);
 acpi_status acpi_os_initialize1(void);
 void init_acpi_device_notify(void);
 int acpi_scan_init(void);
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index bef06c9..00d2a22 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -602,280 +602,6 @@ acpi_os_predefined_override(const struct acpi_predefined_names *init_val,
 	return AE_OK;
 }
 
-static void acpi_table_taint(struct acpi_table_header *table)
-{
-	pr_warn(PREFIX
-		"Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
-		table->signature, table->oem_table_id);
-	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
-}
-
-#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
-#include <linux/earlycpio.h>
-#include <linux/memblock.h>
-
-static u64 acpi_tables_addr;
-static int all_tables_size;
-
-/* Copied from acpica/tbutils.c:acpi_tb_checksum() */
-static u8 __init acpi_table_checksum(u8 *buffer, u32 length)
-{
-	u8 sum = 0;
-	u8 *end = buffer + length;
-
-	while (buffer < end)
-		sum = (u8) (sum + *(buffer++));
-	return sum;
-}
-
-/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
-static const char * const table_sigs[] = {
-	ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ,
-	ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT,
-	ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF,
-	ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET,
-	ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI,
-	ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA,
-	ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT,
-	ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT,
-	ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL };
-
-#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
-
-#define ACPI_OVERRIDE_TABLES 64
-static struct cpio_data __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
-static DECLARE_BITMAP(acpi_initrd_installed, ACPI_OVERRIDE_TABLES);
-
-#define MAP_CHUNK_SIZE   (NR_FIX_BTMAPS << PAGE_SHIFT)
-
-void __init acpi_initrd_override(void *data, size_t size)
-{
-	int sig, no, table_nr = 0, total_offset = 0;
-	long offset = 0;
-	struct acpi_table_header *table;
-	char cpio_path[32] = "kernel/firmware/acpi/";
-	struct cpio_data file;
-
-	if (data == NULL || size == 0)
-		return;
-
-	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
-		file = find_cpio_data(cpio_path, data, size, &offset);
-		if (!file.data)
-			break;
-
-		data += offset;
-		size -= offset;
-
-		if (file.size < sizeof(struct acpi_table_header)) {
-			pr_err("ACPI OVERRIDE: Table smaller than ACPI header [%s%s]\n",
-				cpio_path, file.name);
-			continue;
-		}
-
-		table = file.data;
-
-		for (sig = 0; table_sigs[sig]; sig++)
-			if (!memcmp(table->signature, table_sigs[sig], 4))
-				break;
-
-		if (!table_sigs[sig]) {
-			pr_err("ACPI OVERRIDE: Unknown signature [%s%s]\n",
-				cpio_path, file.name);
-			continue;
-		}
-		if (file.size != table->length) {
-			pr_err("ACPI OVERRIDE: File length does not match table length [%s%s]\n",
-				cpio_path, file.name);
-			continue;
-		}
-		if (acpi_table_checksum(file.data, table->length)) {
-			pr_err("ACPI OVERRIDE: Bad table checksum [%s%s]\n",
-				cpio_path, file.name);
-			continue;
-		}
-
-		pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
-			table->signature, cpio_path, file.name, table->length);
-
-		all_tables_size += table->length;
-		acpi_initrd_files[table_nr].data = file.data;
-		acpi_initrd_files[table_nr].size = file.size;
-		table_nr++;
-	}
-	if (table_nr == 0)
-		return;
-
-	acpi_tables_addr =
-		memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
-				       all_tables_size, PAGE_SIZE);
-	if (!acpi_tables_addr) {
-		WARN_ON(1);
-		return;
-	}
-	/*
-	 * Only calling e820_add_reserve does not work and the
-	 * tables are invalid (memory got used) later.
-	 * memblock_reserve works as expected and the tables won't get modified.
-	 * But it's not enough on X86 because ioremap will
-	 * complain later (used by acpi_os_map_memory) that the pages
-	 * that should get mapped are not marked "reserved".
-	 * Both memblock_reserve and e820_add_region (via arch_reserve_mem_area)
-	 * works fine.
-	 */
-	memblock_reserve(acpi_tables_addr, all_tables_size);
-	arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
-
-	/*
-	 * early_ioremap only can remap 256k one time. If we map all
-	 * tables one time, we will hit the limit. Need to map chunks
-	 * one by one during copying the same as that in relocate_initrd().
-	 */
-	for (no = 0; no < table_nr; no++) {
-		unsigned char *src_p = acpi_initrd_files[no].data;
-		phys_addr_t size = acpi_initrd_files[no].size;
-		phys_addr_t dest_addr = acpi_tables_addr + total_offset;
-		phys_addr_t slop, clen;
-		char *dest_p;
-
-		total_offset += size;
-
-		while (size) {
-			slop = dest_addr & ~PAGE_MASK;
-			clen = size;
-			if (clen > MAP_CHUNK_SIZE - slop)
-				clen = MAP_CHUNK_SIZE - slop;
-			dest_p = early_ioremap(dest_addr & PAGE_MASK,
-						 clen + slop);
-			memcpy(dest_p + slop, src_p, clen);
-			early_iounmap(dest_p, clen + slop);
-			src_p += clen;
-			dest_addr += clen;
-			size -= clen;
-		}
-	}
-}
-
-acpi_status
-acpi_os_physical_table_override(struct acpi_table_header *existing_table,
-				acpi_physical_address *address, u32 *length)
-{
-	int table_offset = 0;
-	int table_index = 0;
-	struct acpi_table_header *table;
-	u32 table_length;
-
-	*length = 0;
-	*address = 0;
-	if (!acpi_tables_addr)
-		return AE_OK;
-
-	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
-		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_length = table->length;
-
-		/* Only override tables matched */
-		if (test_bit(table_index, acpi_initrd_installed) ||
-		    memcmp(existing_table->signature, table->signature, 4) ||
-		    memcmp(table->oem_table_id, existing_table->oem_table_id,
-			   ACPI_OEM_TABLE_ID_SIZE)) {
-			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
-			goto next_table;
-		}
-
-		*length = table_length;
-		*address = acpi_tables_addr + table_offset;
-		acpi_table_taint(existing_table);
-		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
-		set_bit(table_index, acpi_initrd_installed);
-		break;
-
-next_table:
-		table_offset += table_length;
-		table_index++;
-	}
-	return AE_OK;
-}
-
-void __init acpi_initrd_initialize_tables(void)
-{
-	int table_offset = 0;
-	int table_index = 0;
-	u32 table_length;
-	struct acpi_table_header *table;
-
-	if (!acpi_tables_addr)
-		return;
-
-	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
-		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;
-		}
-
-		table_length = table->length;
-
-		/* Skip RSDT/XSDT which should only be used for override */
-		if (test_bit(table_index, acpi_initrd_installed) ||
-		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_RSDT) ||
-		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_XSDT)) {
-			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
-			goto next_table;
-		}
-
-		acpi_table_taint(table);
-		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
-		acpi_install_table(acpi_tables_addr + table_offset, TRUE);
-		set_bit(table_index, acpi_initrd_installed);
-next_table:
-		table_offset += table_length;
-		table_index++;
-	}
-}
-#else
-acpi_status
-acpi_os_physical_table_override(struct acpi_table_header *existing_table,
-				acpi_physical_address *address,
-				u32 *table_length)
-{
-	*table_length = 0;
-	*address = 0;
-	return AE_OK;
-}
-
-void __init acpi_initrd_initialize_tables(void)
-{
-}
-#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
-
-acpi_status
-acpi_os_table_override(struct acpi_table_header *existing_table,
-		       struct acpi_table_header **new_table)
-{
-	if (!existing_table || !new_table)
-		return AE_BAD_PARAMETER;
-
-	*new_table = NULL;
-
-#ifdef CONFIG_ACPI_CUSTOM_DSDT
-	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
-		*new_table = (struct acpi_table_header *)AmlCode;
-#endif
-	if (*new_table != NULL)
-		acpi_table_taint(existing_table);
-	return AE_OK;
-}
-
 static irqreturn_t acpi_irq(int irq, void *dev_id)
 {
 	u32 handled;
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index f49c024..2e74dbf 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -32,6 +32,8 @@
 #include <linux/errno.h>
 #include <linux/acpi.h>
 #include <linux/bootmem.h>
+#include <linux/earlycpio.h>
+#include <linux/memblock.h>
 #include "internal.h"
 
 #define ACPI_MAX_TABLES		128
@@ -433,6 +435,294 @@ static void __init check_multiple_madt(void)
 	return;
 }
 
+static void acpi_table_taint(struct acpi_table_header *table)
+{
+	pr_warn("Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
+		table->signature, table->oem_table_id);
+	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
+}
+
+#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+static u64 acpi_tables_addr;
+static int all_tables_size;
+
+/* Copied from acpica/tbutils.c:acpi_tb_checksum() */
+static u8 __init acpi_table_checksum(u8 *buffer, u32 length)
+{
+	u8 sum = 0;
+	u8 *end = buffer + length;
+
+	while (buffer < end)
+		sum = (u8) (sum + *(buffer++));
+	return sum;
+}
+
+/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
+static const char * const table_sigs[] = {
+	ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ,
+	ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT,
+	ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF,
+	ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET,
+	ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI,
+	ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA,
+	ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT,
+	ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT,
+	ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL };
+
+#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
+
+#define ACPI_OVERRIDE_TABLES 64
+static struct cpio_data __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
+static DECLARE_BITMAP(acpi_initrd_installed, ACPI_OVERRIDE_TABLES);
+
+#define MAP_CHUNK_SIZE   (NR_FIX_BTMAPS << PAGE_SHIFT)
+
+static void __init acpi_table_initrd_init(void *data, size_t size)
+{
+	int sig, no, table_nr = 0, total_offset = 0;
+	long offset = 0;
+	struct acpi_table_header *table;
+	char cpio_path[32] = "kernel/firmware/acpi/";
+	struct cpio_data file;
+
+	if (data == NULL || size == 0)
+		return;
+
+	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
+		file = find_cpio_data(cpio_path, data, size, &offset);
+		if (!file.data)
+			break;
+
+		data += offset;
+		size -= offset;
+
+		if (file.size < sizeof(struct acpi_table_header)) {
+			pr_err("ACPI OVERRIDE: Table smaller than ACPI header [%s%s]\n",
+				cpio_path, file.name);
+			continue;
+		}
+
+		table = file.data;
+
+		for (sig = 0; table_sigs[sig]; sig++)
+			if (!memcmp(table->signature, table_sigs[sig], 4))
+				break;
+
+		if (!table_sigs[sig]) {
+			pr_err("ACPI OVERRIDE: Unknown signature [%s%s]\n",
+				cpio_path, file.name);
+			continue;
+		}
+		if (file.size != table->length) {
+			pr_err("ACPI OVERRIDE: File length does not match table length [%s%s]\n",
+				cpio_path, file.name);
+			continue;
+		}
+		if (acpi_table_checksum(file.data, table->length)) {
+			pr_err("ACPI OVERRIDE: Bad table checksum [%s%s]\n",
+				cpio_path, file.name);
+			continue;
+		}
+
+		pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
+			table->signature, cpio_path, file.name, table->length);
+
+		all_tables_size += table->length;
+		acpi_initrd_files[table_nr].data = file.data;
+		acpi_initrd_files[table_nr].size = file.size;
+		table_nr++;
+	}
+	if (table_nr == 0)
+		return;
+
+	acpi_tables_addr =
+		memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT,
+				       all_tables_size, PAGE_SIZE);
+	if (!acpi_tables_addr) {
+		WARN_ON(1);
+		return;
+	}
+	/*
+	 * Only calling e820_add_reserve does not work and the
+	 * tables are invalid (memory got used) later.
+	 * memblock_reserve works as expected and the tables won't get modified.
+	 * But it's not enough on X86 because ioremap will
+	 * complain later (used by acpi_os_map_memory) that the pages
+	 * that should get mapped are not marked "reserved".
+	 * Both memblock_reserve and e820_add_region (via arch_reserve_mem_area)
+	 * works fine.
+	 */
+	memblock_reserve(acpi_tables_addr, all_tables_size);
+	arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
+
+	/*
+	 * early_ioremap only can remap 256k one time. If we map all
+	 * tables one time, we will hit the limit. Need to map chunks
+	 * one by one during copying the same as that in relocate_initrd().
+	 */
+	for (no = 0; no < table_nr; no++) {
+		unsigned char *src_p = acpi_initrd_files[no].data;
+		phys_addr_t size = acpi_initrd_files[no].size;
+		phys_addr_t dest_addr = acpi_tables_addr + total_offset;
+		phys_addr_t slop, clen;
+		char *dest_p;
+
+		total_offset += size;
+
+		while (size) {
+			slop = dest_addr & ~PAGE_MASK;
+			clen = size;
+			if (clen > MAP_CHUNK_SIZE - slop)
+				clen = MAP_CHUNK_SIZE - slop;
+			dest_p = early_ioremap(dest_addr & PAGE_MASK,
+						 clen + slop);
+			memcpy(dest_p + slop, src_p, clen);
+			early_iounmap(dest_p, clen + slop);
+			src_p += clen;
+			dest_addr += clen;
+			size -= clen;
+		}
+	}
+}
+
+static acpi_status
+acpi_table_initrd_override(struct acpi_table_header *existing_table,
+			   acpi_physical_address *address, u32 *length)
+{
+	int table_offset = 0;
+	int table_index = 0;
+	struct acpi_table_header *table;
+	u32 table_length;
+
+	*length = 0;
+	*address = 0;
+	if (!acpi_tables_addr)
+		return AE_OK;
+
+	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
+		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_length = table->length;
+
+		/* Only override tables matched */
+		if (test_bit(table_index, acpi_initrd_installed) ||
+		    memcmp(existing_table->signature, table->signature, 4) ||
+		    memcmp(table->oem_table_id, existing_table->oem_table_id,
+			   ACPI_OEM_TABLE_ID_SIZE)) {
+			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+			goto next_table;
+		}
+
+		*length = table_length;
+		*address = acpi_tables_addr + table_offset;
+		acpi_table_taint(existing_table);
+		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+		set_bit(table_index, acpi_initrd_installed);
+		break;
+
+next_table:
+		table_offset += table_length;
+		table_index++;
+	}
+	return AE_OK;
+}
+
+static void __init acpi_table_initrd_scan(void)
+{
+	int table_offset = 0;
+	int table_index = 0;
+	u32 table_length;
+	struct acpi_table_header *table;
+
+	if (!acpi_tables_addr)
+		return;
+
+	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
+		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;
+		}
+
+		table_length = table->length;
+
+		/* Skip RSDT/XSDT which should only be used for override */
+		if (test_bit(table_index, acpi_initrd_installed) ||
+		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_RSDT) ||
+		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_XSDT)) {
+			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+			goto next_table;
+		}
+
+		acpi_table_taint(table);
+		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+		acpi_install_table(acpi_tables_addr + table_offset, TRUE);
+		set_bit(table_index, acpi_initrd_installed);
+next_table:
+		table_offset += table_length;
+		table_index++;
+	}
+}
+#else
+static void __init acpi_table_initrd_init(void *data, size_t size)
+{
+}
+
+static acpi_status
+acpi_table_initrd_override(struct acpi_table_header *existing_table,
+			   acpi_physical_address *address,
+			   u32 *table_length)
+{
+	*table_length = 0;
+	*address = 0;
+	return AE_OK;
+}
+
+static void __init acpi_table_initrd_scan(void)
+{
+}
+#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
+
+acpi_status
+acpi_os_physical_table_override(struct acpi_table_header *existing_table,
+				acpi_physical_address *address,
+				u32 *table_length)
+{
+	return acpi_table_initrd_override(existing_table, address,
+					  table_length);
+}
+
+acpi_status
+acpi_os_table_override(struct acpi_table_header *existing_table,
+		       struct acpi_table_header **new_table)
+{
+	if (!existing_table || !new_table)
+		return AE_BAD_PARAMETER;
+
+	*new_table = NULL;
+
+#ifdef CONFIG_ACPI_CUSTOM_DSDT
+	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
+		*new_table = (struct acpi_table_header *)AmlCode;
+#endif
+	if (*new_table != NULL)
+		acpi_table_taint(existing_table);
+	return AE_OK;
+}
+
+void __init early_acpi_table_init(void *data, size_t size)
+{
+	acpi_table_initrd_init(data, size);
+}
+
 /*
  * acpi_table_init()
  *
@@ -457,7 +747,7 @@ int __init acpi_table_init(void)
 	status = acpi_initialize_tables(initial_tables, ACPI_MAX_TABLES, 0);
 	if (ACPI_FAILURE(status))
 		return -EINVAL;
-	acpi_initrd_initialize_tables();
+	acpi_table_initrd_scan();
 
 	check_multiple_madt();
 	return 0;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 06ed7e5..86ac608 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -191,9 +191,9 @@ static inline int acpi_debugger_notify_command_complete(void)
 #endif
 
 #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
-void acpi_initrd_override(void *data, size_t size);
+void early_acpi_table_init(void *data, size_t size);
 #else
-static inline void acpi_initrd_override(void *data, size_t size)
+static inline void early_acpi_table_init(void *data, size_t size)
 {
 }
 #endif
-- 
1.7.10

RE: [PATCH 1/3] ACPI / tables: Move table override mechanisms to tables.c

[Zheng, Lv]

Hi, Rafael

> From: Zheng, Lv
> Subject: [PATCH 1/3] ACPI / tables: Move table override mechanisms to
> tables.c
> 
> This patch moves acpi_os_table_override() and
> acpi_os_physical_table_override() to tables.c.
> 
> Along with the mechanisms, acpi_initrd_initialize_tables() is also moved to
> tables.c to form a static function. The following functions are renamed
> according to this change:
> 1. acpi_initrd_override() -> renamed to early_acpi_table_init(), which
>    invokes acpi_table_initrd_init()
> 2. acpi_os_physical_table_override() -> which invokes
>    acpi_table_initrd_override()
> 3. acpi_initialize_initrd_tables() -> renamed to acpi_table_initrd_scan()
> 
> Signed-off-by: Lv Zheng <lv.zheng@intel.com>
> ---
>  arch/x86/kernel/setup.c |    2 +-
>  drivers/acpi/internal.h |    1 -
>  drivers/acpi/osl.c      |  274 --------------------------------------------
>  drivers/acpi/tables.c   |  292
> ++++++++++++++++++++++++++++++++++++++++++++++-
>  include/linux/acpi.h    |    4 +-
>  5 files changed, 294 insertions(+), 279 deletions(-)
> 
> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
> index 2367ae0..902a6f7 100644
> --- a/arch/x86/kernel/setup.c
> +++ b/arch/x86/kernel/setup.c
> @@ -1139,7 +1139,7 @@ void __init setup_arch(char **cmdline_p)
>  	reserve_initrd();
> 
>  #if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD)
> -	acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start);
> +	early_acpi_table_init((void *)initrd_start, initrd_end - initrd_start);
>  #endif
> 
>  	vsmp_init();
> diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> index 7c18847..1b0e6fd 100644
> --- a/drivers/acpi/internal.h
> +++ b/drivers/acpi/internal.h
> @@ -20,7 +20,6 @@
> 
>  #define PREFIX "ACPI: "
> 
> -void acpi_initrd_initialize_tables(void);
>  acpi_status acpi_os_initialize1(void);
>  void init_acpi_device_notify(void);
>  int acpi_scan_init(void);
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index bef06c9..00d2a22 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -602,280 +602,6 @@ acpi_os_predefined_override(const struct
> acpi_predefined_names *init_val,
>  	return AE_OK;
>  }
> 
> -static void acpi_table_taint(struct acpi_table_header *table)
> -{
> -	pr_warn(PREFIX
> -		"Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
> -		table->signature, table->oem_table_id);
> -	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE,
> LOCKDEP_NOW_UNRELIABLE);
> -}
> -
> -#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
> -#include <linux/earlycpio.h>
> -#include <linux/memblock.h>
> -
> -static u64 acpi_tables_addr;
> -static int all_tables_size;
> -
> -/* Copied from acpica/tbutils.c:acpi_tb_checksum() */
> -static u8 __init acpi_table_checksum(u8 *buffer, u32 length)
> -{
> -	u8 sum = 0;
> -	u8 *end = buffer + length;
> -
> -	while (buffer < end)
> -		sum = (u8) (sum + *(buffer++));
> -	return sum;
> -}
> -
> -/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
> -static const char * const table_sigs[] = {
> -	ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ,
> -	ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT,
> -	ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF,
> -	ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET,
> -	ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI,
> -	ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA,
> -	ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT,
> -	ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT,
> -	ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL };
> -
> -#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
> -
> -#define ACPI_OVERRIDE_TABLES 64
> -static struct cpio_data __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
> -static DECLARE_BITMAP(acpi_initrd_installed, ACPI_OVERRIDE_TABLES);
> -
> -#define MAP_CHUNK_SIZE   (NR_FIX_BTMAPS << PAGE_SHIFT)
> -
> -void __init acpi_initrd_override(void *data, size_t size)
> -{
> -	int sig, no, table_nr = 0, total_offset = 0;
> -	long offset = 0;
> -	struct acpi_table_header *table;
> -	char cpio_path[32] = "kernel/firmware/acpi/";
> -	struct cpio_data file;
> -
> -	if (data == NULL || size == 0)
> -		return;
> -
> -	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
> -		file = find_cpio_data(cpio_path, data, size, &offset);
> -		if (!file.data)
> -			break;
> -
> -		data += offset;
> -		size -= offset;
> -
> -		if (file.size < sizeof(struct acpi_table_header)) {
> -			pr_err("ACPI OVERRIDE: Table smaller than ACPI
> header [%s%s]\n",
> -				cpio_path, file.name);
> -			continue;
> -		}
> -
> -		table = file.data;
> -
> -		for (sig = 0; table_sigs[sig]; sig++)
> -			if (!memcmp(table->signature, table_sigs[sig], 4))
> -				break;
> -
> -		if (!table_sigs[sig]) {
> -			pr_err("ACPI OVERRIDE: Unknown signature
> [%s%s]\n",
> -				cpio_path, file.name);
> -			continue;
> -		}
> -		if (file.size != table->length) {
> -			pr_err("ACPI OVERRIDE: File length does not match
> table length [%s%s]\n",
> -				cpio_path, file.name);
> -			continue;
> -		}
> -		if (acpi_table_checksum(file.data, table->length)) {
> -			pr_err("ACPI OVERRIDE: Bad table checksum
> [%s%s]\n",
> -				cpio_path, file.name);
> -			continue;
> -		}
> -
> -		pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
> -			table->signature, cpio_path, file.name, table->length);
> -
> -		all_tables_size += table->length;
> -		acpi_initrd_files[table_nr].data = file.data;
> -		acpi_initrd_files[table_nr].size = file.size;
> -		table_nr++;
> -	}
> -	if (table_nr == 0)
> -		return;
> -
> -	acpi_tables_addr =
> -		memblock_find_in_range(0, max_low_pfn_mapped <<
> PAGE_SHIFT,
> -				       all_tables_size, PAGE_SIZE);
> -	if (!acpi_tables_addr) {
> -		WARN_ON(1);
> -		return;
> -	}
> -	/*
> -	 * Only calling e820_add_reserve does not work and the
> -	 * tables are invalid (memory got used) later.
> -	 * memblock_reserve works as expected and the tables won't get
> modified.
> -	 * But it's not enough on X86 because ioremap will
> -	 * complain later (used by acpi_os_map_memory) that the pages
> -	 * that should get mapped are not marked "reserved".
> -	 * Both memblock_reserve and e820_add_region (via
> arch_reserve_mem_area)
> -	 * works fine.
> -	 */
> -	memblock_reserve(acpi_tables_addr, all_tables_size);
> -	arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
> -
> -	/*
> -	 * early_ioremap only can remap 256k one time. If we map all
> -	 * tables one time, we will hit the limit. Need to map chunks
> -	 * one by one during copying the same as that in relocate_initrd().
> -	 */
> -	for (no = 0; no < table_nr; no++) {
> -		unsigned char *src_p = acpi_initrd_files[no].data;
> -		phys_addr_t size = acpi_initrd_files[no].size;
> -		phys_addr_t dest_addr = acpi_tables_addr + total_offset;
> -		phys_addr_t slop, clen;
> -		char *dest_p;
> -
> -		total_offset += size;
> -
> -		while (size) {
> -			slop = dest_addr & ~PAGE_MASK;
> -			clen = size;
> -			if (clen > MAP_CHUNK_SIZE - slop)
> -				clen = MAP_CHUNK_SIZE - slop;
> -			dest_p = early_ioremap(dest_addr & PAGE_MASK,
> -						 clen + slop);
> -			memcpy(dest_p + slop, src_p, clen);
> -			early_iounmap(dest_p, clen + slop);
> -			src_p += clen;
> -			dest_addr += clen;
> -			size -= clen;
> -		}
> -	}
> -}
> -
> -acpi_status
> -acpi_os_physical_table_override(struct acpi_table_header *existing_table,
> -				acpi_physical_address *address, u32 *length)
> -{
> -	int table_offset = 0;
> -	int table_index = 0;
> -	struct acpi_table_header *table;
> -	u32 table_length;
> -
> -	*length = 0;
> -	*address = 0;
> -	if (!acpi_tables_addr)
> -		return AE_OK;
> -
> -	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
> -		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_length = table->length;
> -
> -		/* Only override tables matched */
> -		if (test_bit(table_index, acpi_initrd_installed) ||
> -		    memcmp(existing_table->signature, table->signature, 4) ||
> -		    memcmp(table->oem_table_id, existing_table-
> >oem_table_id,
> -			   ACPI_OEM_TABLE_ID_SIZE)) {
> -			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> -			goto next_table;
> -		}
> -
> -		*length = table_length;
> -		*address = acpi_tables_addr + table_offset;
> -		acpi_table_taint(existing_table);
> -		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> -		set_bit(table_index, acpi_initrd_installed);
> -		break;
> -
> -next_table:
> -		table_offset += table_length;
> -		table_index++;
> -	}
> -	return AE_OK;
> -}
> -
> -void __init acpi_initrd_initialize_tables(void)
> -{
> -	int table_offset = 0;
> -	int table_index = 0;
> -	u32 table_length;
> -	struct acpi_table_header *table;
> -
> -	if (!acpi_tables_addr)
> -		return;
> -
> -	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
> -		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;
> -		}
> -
> -		table_length = table->length;
> -
> -		/* Skip RSDT/XSDT which should only be used for override */
> -		if (test_bit(table_index, acpi_initrd_installed) ||
> -		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_RSDT)
> ||
> -		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_XSDT)) {
> -			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> -			goto next_table;
> -		}
> -
> -		acpi_table_taint(table);
> -		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> -		acpi_install_table(acpi_tables_addr + table_offset, TRUE);
> -		set_bit(table_index, acpi_initrd_installed);
> -next_table:
> -		table_offset += table_length;
> -		table_index++;
> -	}
> -}
> -#else
> -acpi_status
> -acpi_os_physical_table_override(struct acpi_table_header *existing_table,
> -				acpi_physical_address *address,
> -				u32 *table_length)
> -{
> -	*table_length = 0;
> -	*address = 0;
> -	return AE_OK;
> -}
> -
> -void __init acpi_initrd_initialize_tables(void)
> -{
> -}
> -#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
> -
> -acpi_status
> -acpi_os_table_override(struct acpi_table_header *existing_table,
> -		       struct acpi_table_header **new_table)
> -{
> -	if (!existing_table || !new_table)
> -		return AE_BAD_PARAMETER;
> -
> -	*new_table = NULL;
> -
> -#ifdef CONFIG_ACPI_CUSTOM_DSDT
> -	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
> -		*new_table = (struct acpi_table_header *)AmlCode;
> -#endif
> -	if (*new_table != NULL)
> -		acpi_table_taint(existing_table);
> -	return AE_OK;
> -}
> -
>  static irqreturn_t acpi_irq(int irq, void *dev_id)
>  {
>  	u32 handled;
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index f49c024..2e74dbf 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -32,6 +32,8 @@
>  #include <linux/errno.h>
>  #include <linux/acpi.h>
>  #include <linux/bootmem.h>
> +#include <linux/earlycpio.h>
> +#include <linux/memblock.h>
>  #include "internal.h"
> 
>  #define ACPI_MAX_TABLES		128
> @@ -433,6 +435,294 @@ static void __init check_multiple_madt(void)
>  	return;
>  }
> 
> +static void acpi_table_taint(struct acpi_table_header *table)
> +{
> +	pr_warn("Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n",
> +		table->signature, table->oem_table_id);
> +	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE,
> LOCKDEP_NOW_UNRELIABLE);
> +}
> +
> +#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
> +static u64 acpi_tables_addr;
> +static int all_tables_size;
> +
> +/* Copied from acpica/tbutils.c:acpi_tb_checksum() */
> +static u8 __init acpi_table_checksum(u8 *buffer, u32 length)
> +{
> +	u8 sum = 0;
> +	u8 *end = buffer + length;
> +
> +	while (buffer < end)
> +		sum = (u8) (sum + *(buffer++));
> +	return sum;
> +}
> +
> +/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
> +static const char * const table_sigs[] = {
> +	ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ,
> +	ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT,
> +	ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF,
> +	ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET,
> +	ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI,
> +	ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA,
> +	ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT,
> +	ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT,
> +	ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL };
> +
> +#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
> +
> +#define ACPI_OVERRIDE_TABLES 64
> +static struct cpio_data __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
> +static DECLARE_BITMAP(acpi_initrd_installed, ACPI_OVERRIDE_TABLES);
> +
> +#define MAP_CHUNK_SIZE   (NR_FIX_BTMAPS << PAGE_SHIFT)
> +
> +static void __init acpi_table_initrd_init(void *data, size_t size)
> +{
> +	int sig, no, table_nr = 0, total_offset = 0;
> +	long offset = 0;
> +	struct acpi_table_header *table;
> +	char cpio_path[32] = "kernel/firmware/acpi/";
> +	struct cpio_data file;
> +
> +	if (data == NULL || size == 0)
> +		return;
> +
> +	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
> +		file = find_cpio_data(cpio_path, data, size, &offset);
> +		if (!file.data)
> +			break;
> +
> +		data += offset;
> +		size -= offset;
> +
> +		if (file.size < sizeof(struct acpi_table_header)) {
> +			pr_err("ACPI OVERRIDE: Table smaller than ACPI
> header [%s%s]\n",
> +				cpio_path, file.name);
> +			continue;
> +		}
> +
> +		table = file.data;
> +
> +		for (sig = 0; table_sigs[sig]; sig++)
> +			if (!memcmp(table->signature, table_sigs[sig], 4))
> +				break;
> +
> +		if (!table_sigs[sig]) {
> +			pr_err("ACPI OVERRIDE: Unknown signature
> [%s%s]\n",
> +				cpio_path, file.name);
> +			continue;
> +		}
> +		if (file.size != table->length) {
> +			pr_err("ACPI OVERRIDE: File length does not match
> table length [%s%s]\n",
> +				cpio_path, file.name);
> +			continue;
> +		}
> +		if (acpi_table_checksum(file.data, table->length)) {
> +			pr_err("ACPI OVERRIDE: Bad table checksum
> [%s%s]\n",
> +				cpio_path, file.name);
> +			continue;
> +		}
> +
> +		pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
> +			table->signature, cpio_path, file.name, table->length);
> +
> +		all_tables_size += table->length;
> +		acpi_initrd_files[table_nr].data = file.data;
> +		acpi_initrd_files[table_nr].size = file.size;
> +		table_nr++;
> +	}
> +	if (table_nr == 0)
> +		return;
> +
> +	acpi_tables_addr =
> +		memblock_find_in_range(0, max_low_pfn_mapped <<
> PAGE_SHIFT,
> +				       all_tables_size, PAGE_SIZE);
> +	if (!acpi_tables_addr) {
> +		WARN_ON(1);
> +		return;
> +	}
> +	/*
> +	 * Only calling e820_add_reserve does not work and the
> +	 * tables are invalid (memory got used) later.
> +	 * memblock_reserve works as expected and the tables won't get
> modified.
> +	 * But it's not enough on X86 because ioremap will
> +	 * complain later (used by acpi_os_map_memory) that the pages
> +	 * that should get mapped are not marked "reserved".
> +	 * Both memblock_reserve and e820_add_region (via
> arch_reserve_mem_area)
> +	 * works fine.
> +	 */
> +	memblock_reserve(acpi_tables_addr, all_tables_size);
> +	arch_reserve_mem_area(acpi_tables_addr, all_tables_size);
> +
> +	/*
> +	 * early_ioremap only can remap 256k one time. If we map all
> +	 * tables one time, we will hit the limit. Need to map chunks
> +	 * one by one during copying the same as that in relocate_initrd().
> +	 */
> +	for (no = 0; no < table_nr; no++) {
> +		unsigned char *src_p = acpi_initrd_files[no].data;
> +		phys_addr_t size = acpi_initrd_files[no].size;
> +		phys_addr_t dest_addr = acpi_tables_addr + total_offset;
> +		phys_addr_t slop, clen;
> +		char *dest_p;
> +
> +		total_offset += size;
> +
> +		while (size) {
> +			slop = dest_addr & ~PAGE_MASK;
> +			clen = size;
> +			if (clen > MAP_CHUNK_SIZE - slop)
> +				clen = MAP_CHUNK_SIZE - slop;
> +			dest_p = early_ioremap(dest_addr & PAGE_MASK,
> +						 clen + slop);
> +			memcpy(dest_p + slop, src_p, clen);
> +			early_iounmap(dest_p, clen + slop);
> +			src_p += clen;
> +			dest_addr += clen;
> +			size -= clen;
> +		}
> +	}
> +}
> +
> +static acpi_status
> +acpi_table_initrd_override(struct acpi_table_header *existing_table,
> +			   acpi_physical_address *address, u32 *length)
> +{
> +	int table_offset = 0;
> +	int table_index = 0;
> +	struct acpi_table_header *table;
> +	u32 table_length;
> +
> +	*length = 0;
> +	*address = 0;
> +	if (!acpi_tables_addr)
> +		return AE_OK;
> +
> +	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
> +		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_length = table->length;
> +
> +		/* Only override tables matched */
> +		if (test_bit(table_index, acpi_initrd_installed) ||
> +		    memcmp(existing_table->signature, table->signature, 4) ||
> +		    memcmp(table->oem_table_id, existing_table-
> >oem_table_id,
> +			   ACPI_OEM_TABLE_ID_SIZE)) {
> +			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> +			goto next_table;
> +		}
> +
> +		*length = table_length;
> +		*address = acpi_tables_addr + table_offset;
> +		acpi_table_taint(existing_table);
> +		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> +		set_bit(table_index, acpi_initrd_installed);
> +		break;
> +
> +next_table:
> +		table_offset += table_length;
> +		table_index++;
> +	}
> +	return AE_OK;
> +}
> +
> +static void __init acpi_table_initrd_scan(void)
> +{
> +	int table_offset = 0;
> +	int table_index = 0;
> +	u32 table_length;
> +	struct acpi_table_header *table;
> +
> +	if (!acpi_tables_addr)
> +		return;
> +
> +	while (table_offset + ACPI_HEADER_SIZE <= all_tables_size) {
> +		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;
> +		}
> +
> +		table_length = table->length;
> +
> +		/* Skip RSDT/XSDT which should only be used for override */
> +		if (test_bit(table_index, acpi_initrd_installed) ||
> +		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_RSDT)
> ||
> +		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_XSDT)) {
> +			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> +			goto next_table;
> +		}
> +
> +		acpi_table_taint(table);
> +		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
> +		acpi_install_table(acpi_tables_addr + table_offset, TRUE);
> +		set_bit(table_index, acpi_initrd_installed);
> +next_table:
> +		table_offset += table_length;
> +		table_index++;
> +	}
> +}
> +#else
> +static void __init acpi_table_initrd_init(void *data, size_t size)
> +{
> +}
> +
> +static acpi_status
> +acpi_table_initrd_override(struct acpi_table_header *existing_table,
> +			   acpi_physical_address *address,
> +			   u32 *table_length)
> +{
> +	*table_length = 0;
> +	*address = 0;
> +	return AE_OK;
> +}
> +
> +static void __init acpi_table_initrd_scan(void)
> +{
> +}
> +#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
> +
> +acpi_status
> +acpi_os_physical_table_override(struct acpi_table_header *existing_table,
> +				acpi_physical_address *address,
> +				u32 *table_length)
> +{
> +	return acpi_table_initrd_override(existing_table, address,
> +					  table_length);
> +}
> +
> +acpi_status
> +acpi_os_table_override(struct acpi_table_header *existing_table,
> +		       struct acpi_table_header **new_table)
> +{
> +	if (!existing_table || !new_table)
> +		return AE_BAD_PARAMETER;
> +
> +	*new_table = NULL;
> +
> +#ifdef CONFIG_ACPI_CUSTOM_DSDT
> +	if (strncmp(existing_table->signature, "DSDT", 4) == 0)
> +		*new_table = (struct acpi_table_header *)AmlCode;
> +#endif
> +	if (*new_table != NULL)
> +		acpi_table_taint(existing_table);
> +	return AE_OK;
> +}
> +
> +void __init early_acpi_table_init(void *data, size_t size)
> +{
> +	acpi_table_initrd_init(data, size);
> +}
> +
>  /*
>   * acpi_table_init()
>   *
> @@ -457,7 +747,7 @@ int __init acpi_table_init(void)
>  	status = acpi_initialize_tables(initial_tables, ACPI_MAX_TABLES, 0);
>  	if (ACPI_FAILURE(status))
>  		return -EINVAL;
> -	acpi_initrd_initialize_tables();
> +	acpi_table_initrd_scan();
> 
>  	check_multiple_madt();
>  	return 0;
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 06ed7e5..86ac608 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -191,9 +191,9 @@ static inline int
> acpi_debugger_notify_command_complete(void)
>  #endif
> 
>  #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
> -void acpi_initrd_override(void *data, size_t size);
> +void early_acpi_table_init(void *data, size_t size);
>  #else
> -static inline void acpi_initrd_override(void *data, size_t size)
> +static inline void early_acpi_table_init(void *data, size_t size)
>  {
>  }
>  #endif
[Lv Zheng] 
This block was wrong.
early_acpi_table_init() is no longer dependent on CONFIG_ACPI_INITRD_TABLE_OVERRIDE but dependent on CONFIG_ACPI.
Updated v2 patches are sent to the mailing list.

Thanks
-Lv

> --
> 1.7.10

Re: [PATCH 1/3] ACPI / tables: Move table override mechanisms to tables.c

[Rafael J. Wysocki]

On Mon, Apr 11, 2016 at 4:16 AM, Zheng, Lv <lv.zheng@intel.com> wrote:
> Hi, Rafael

Hi,

>> From: Zheng, Lv
>> Subject: [PATCH 1/3] ACPI / tables: Move table override mechanisms to
>> tables.c
>>
>> This patch moves acpi_os_table_override() and
>> acpi_os_physical_table_override() to tables.c.
>>

[cut]

>>  #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
>> -void acpi_initrd_override(void *data, size_t size);
>> +void early_acpi_table_init(void *data, size_t size);
>>  #else
>> -static inline void acpi_initrd_override(void *data, size_t size)
>> +static inline void early_acpi_table_init(void *data, size_t size)
>>  {
>>  }
>>  #endif
> [Lv Zheng]
> This block was wrong.
> early_acpi_table_init() is no longer dependent on CONFIG_ACPI_INITRD_TABLE_OVERRIDE but dependent on CONFIG_ACPI.

I see.

> Updated v2 patches are sent to the mailing list.

Is this the only difference between v1 and v2?

Thanks,
Rafael

RE: [PATCH 1/3] ACPI / tables: Move table override mechanisms to tables.c

[Zheng, Lv]

Hi,

> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
> Rafael J. Wysocki
> Sent: Monday, April 11, 2016 9:31 PM
> Subject: Re: [PATCH 1/3] ACPI / tables: Move table override mechanisms to
> tables.c
> 
> On Mon, Apr 11, 2016 at 4:16 AM, Zheng, Lv <lv.zheng@intel.com> wrote:
> > Hi, Rafael
> 
> Hi,
> 
> >> From: Zheng, Lv
> >> Subject: [PATCH 1/3] ACPI / tables: Move table override mechanisms to
> >> tables.c
> >>
> >> This patch moves acpi_os_table_override() and
> >> acpi_os_physical_table_override() to tables.c.
> >>
> 
> [cut]
> 
> >>  #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
> >> -void acpi_initrd_override(void *data, size_t size);
> >> +void early_acpi_table_init(void *data, size_t size);
> >>  #else
> >> -static inline void acpi_initrd_override(void *data, size_t size)
> >> +static inline void early_acpi_table_init(void *data, size_t size)
> >>  {
> >>  }
> >>  #endif
> > [Lv Zheng]
> > This block was wrong.
> > early_acpi_table_init() is no longer dependent on
> CONFIG_ACPI_INITRD_TABLE_OVERRIDE but dependent on CONFIG_ACPI.
> 
> I see.
> 
> > Updated v2 patches are sent to the mailing list.
> 
> Is this the only difference between v1 and v2?

[Lv Zheng] 
One of the follow-up patches (PATCH 3) in this series is updated accordingly.

Thanks and best regards
-Lv

Re: [PATCH 1/3] ACPI / tables: Move table override mechanisms to tables.c

[Rafael J. Wysocki]

On Tue, Apr 12, 2016 at 1:27 AM, Zheng, Lv <lv.zheng@intel.com> wrote:
> Hi,
>
>> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
>> Rafael J. Wysocki
>> Sent: Monday, April 11, 2016 9:31 PM
>> Subject: Re: [PATCH 1/3] ACPI / tables: Move table override mechanisms to
>> tables.c
>>
>> On Mon, Apr 11, 2016 at 4:16 AM, Zheng, Lv <lv.zheng@intel.com> wrote:
>> > Hi, Rafael
>>
>> Hi,
>>
>> >> From: Zheng, Lv
>> >> Subject: [PATCH 1/3] ACPI / tables: Move table override mechanisms to
>> >> tables.c
>> >>
>> >> This patch moves acpi_os_table_override() and
>> >> acpi_os_physical_table_override() to tables.c.
>> >>
>>
>> [cut]
>>
>> >>  #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
>> >> -void acpi_initrd_override(void *data, size_t size);
>> >> +void early_acpi_table_init(void *data, size_t size);
>> >>  #else
>> >> -static inline void acpi_initrd_override(void *data, size_t size)
>> >> +static inline void early_acpi_table_init(void *data, size_t size)
>> >>  {
>> >>  }
>> >>  #endif
>> > [Lv Zheng]
>> > This block was wrong.
>> > early_acpi_table_init() is no longer dependent on
>> CONFIG_ACPI_INITRD_TABLE_OVERRIDE but dependent on CONFIG_ACPI.
>>
>> I see.
>>
>> > Updated v2 patches are sent to the mailing list.
>>
>> Is this the only difference between v1 and v2?
>
> [Lv Zheng]
> One of the follow-up patches (PATCH 3) in this series is updated accordingly.

OK, thanks.

It generally is good to add that type of information to the patches in
the new version (in an additional section below the sign-off tag).

Thanks,
Rafael

[PATCH 2/3] ACPI / x86: Cleanup initrd related code

[Lv Zheng]

In arch/x86/kernel/setup.c, the #ifdef kept for CONFIG_ACPI actually is
related to the accessibility of initrd_start/initrd_end, so the stub should
be provided from this source file and should only be dependent on
CONFIG_BLK_DEV_INITRD.
Note that when ACPI=n and BLK_DEV_INITRD=y, early_initrd_acpi_init() is
still a stub because of the stub prepared for early_acpi_table_init().

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
---
 arch/x86/kernel/setup.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 902a6f7..c4e7b39 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -398,6 +398,11 @@ static void __init reserve_initrd(void)
 
 	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
 }
+
+static void __init early_initrd_acpi_init(void)
+{
+	early_acpi_table_init((void *)initrd_start, initrd_end - initrd_start);
+}
 #else
 static void __init early_reserve_initrd(void)
 {
@@ -405,6 +410,9 @@ static void __init early_reserve_initrd(void)
 static void __init reserve_initrd(void)
 {
 }
+static void __init early_initrd_acpi_init(void)
+{
+}
 #endif /* CONFIG_BLK_DEV_INITRD */
 
 static void __init parse_setup_data(void)
@@ -1138,9 +1146,7 @@ void __init setup_arch(char **cmdline_p)
 
 	reserve_initrd();
 
-#if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD)
-	early_acpi_table_init((void *)initrd_start, initrd_end - initrd_start);
-#endif
+	early_initrd_acpi_init();
 
 	vsmp_init();
 
-- 
1.7.10

[PATCH 3/3] ACPI / tables: Convert the initrd table override mechanisms to the table upgrade mechanism

[Lv Zheng]

This patch converts the initrd table override mechanism to the table
upgrade mechanism by restricting its usage to the tables released with
compatibility and more recent revision.

This use case has been encouraged by the ACPI specification:
1. OEMID:
   An OEM-supplied string that identifies the OEM.
2. OEM Table ID:
   An OEM-supplied string that the OEM uses to identify the particular data
   table. This field is particularly useful when defining a definition
   block to distinguish definition block functions. OEM assigns each
   dissimilar table a new OEM Table Id.
3. OEM Revision:
   An OEM-supplied revision number. Larger numbers are assumed to be newer
   revisions.
For OEMs, good practices will ensure consistency when assigning OEMID and
OEM Table ID fields in any table. The intent of these fields is to allow
for a binary control system that support services can use. Because many
support function can be automated, it is useful when a tool can
programatically determine which table release is a compatible and more
recent revision of a prior table on the same OEMID and OEM Table ID.

The facility can now be used by the vendors to upgrade wrong tables for bug
fixing purpose, thus lockdep disabling taint is not suitable for it and it
should be a default 'y' option to implement the spec encouraged use case.

Note that, by implementing table upgrade inside of ACPICA itself, it is
possible to remove acpi_table_initrd_override() and tables can be upgraded
by acpi_install_table() automatically. Though current ACPICA impelentation
hasn't implemented this, this patched changes the table flag setting timing
to allow this to be implemented in ACPICA without changing the code here.

Documentation of initrd override mechanism is upgraded accordingly.

Original-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
---
 Documentation/acpi/initrd_table_override.txt |   65 +++++++++++++++-----------
 drivers/acpi/Kconfig                         |    8 ++--
 drivers/acpi/tables.c                        |   48 +++++++++++++------
 include/linux/acpi.h                         |    2 +-
 4 files changed, 78 insertions(+), 45 deletions(-)

diff --git a/Documentation/acpi/initrd_table_override.txt b/Documentation/acpi/initrd_table_override.txt
index 35c3f54..eb651a6 100644
--- a/Documentation/acpi/initrd_table_override.txt
+++ b/Documentation/acpi/initrd_table_override.txt
@@ -1,5 +1,5 @@
-Overriding ACPI tables via initrd
-=================================
+Upgrading ACPI tables via initrd
+================================
 
 1) Introduction (What is this about)
 2) What is this for
@@ -9,12 +9,14 @@ Overriding ACPI tables via initrd
 1) What is this about
 ---------------------
 
-If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to
-override nearly any ACPI table provided by the BIOS with an instrumented,
-modified one.
+If the ACPI_TABLE_UPGRADE compile option is true, it is possible to
+upgrade the ACPI execution environment that is defined by the ACPI tables
+via upgrading the ACPI tables provided by the BIOS with an instrumented,
+modified, more recent version one, or installing brand new ACPI tables.
 
-For a full list of ACPI tables that can be overridden, take a look at
-the char *table_sigs[MAX_ACPI_SIGNATURE]; definition in drivers/acpi/osl.c
+For a full list of ACPI tables that can be upgraded/installed, take a look
+at the char *table_sigs[MAX_ACPI_SIGNATURE]; definition in
+drivers/acpi/tables.c.
 All ACPI tables iasl (Intel's ACPI compiler and disassembler) knows should
 be overridable, except:
    - ACPI_SIG_RSDP (has a signature of 6 bytes)
@@ -25,17 +27,20 @@ Both could get implemented as well.
 2) What is this for
 -------------------
 
-Please keep in mind that this is a debug option.
-ACPI tables should not get overridden for productive use.
-If BIOS ACPI tables are overridden the kernel will get tainted with the
-TAINT_OVERRIDDEN_ACPI_TABLE flag.
-Complain to your platform/BIOS vendor if you find a bug which is so sever
-that a workaround is not accepted in the Linux kernel.
+Complain to your platform/BIOS vendor if you find a bug which is so severe
+that a workaround is not accepted in the Linux kernel. And this facility
+allows you to upgrade the buggy tables before your platform/BIOS vendor
+releases an upgraded BIOS binary.
 
-Still, it can and should be enabled in any kernel, because:
-  - There is no functional change with not instrumented initrds
-  - It provides a powerful feature to easily debug and test ACPI BIOS table
-    compatibility with the Linux kernel.
+This facility can be used by platform/BIOS vendors to provide a Linux
+compatible environment without modifying the underlying platform firmware.
+
+This facility also provides a powerful feature to easily debug and test
+ACPI BIOS table compatibility with the Linux kernel by modifying old
+platform provided ACPI tables or inserting new ACPI tables.
+
+It can and should be enabled in any kernel because there is no functional
+change with not instrumented initrds.
 
 
 3) How does it work
@@ -50,23 +55,31 @@ iasl -d *.dat
 # For example add this statement into a _PRT (PCI Routing Table) function
 # of the DSDT:
 Store("HELLO WORLD", debug)
+# And increase the OEM Revision. For example, before modification:
+DefinitionBlock ("DSDT.aml", "DSDT", 2, "INTEL ", "TEMPLATE", 0x00000000)
+# After modification:
+DefinitionBlock ("DSDT.aml", "DSDT", 2, "INTEL ", "TEMPLATE", 0x00000001)
 iasl -sa dsdt.dsl
 # Add the raw ACPI tables to an uncompressed cpio archive.
-# They must be put into a /kernel/firmware/acpi directory inside the
-# cpio archive.
-# The uncompressed cpio archive must be the first.
-# Other, typically compressed cpio archives, must be
-# concatenated on top of the uncompressed one.
+# They must be put into a /kernel/firmware/acpi directory inside the cpio
+# archive. Note that if the table put here matches a platform table
+# (similar Table Signature, and similar OEMID, and similar OEM Table ID)
+# with a more recent OEM Revision, the platform table will be upgraded by
+# this table. If the table put here doesn't match a platform table
+# (dissimilar Table Signature, or dissimilar OEMID, or dissimilar OEM Table
+# ID), this table will be appended.
 mkdir -p kernel/firmware/acpi
 cp dsdt.aml kernel/firmware/acpi
-# A maximum of: #define ACPI_OVERRIDE_TABLES 10
-# tables are  currently allowed (see osl.c):
+# A maximum of "NR_ACPI_INITRD_TABLES (64)" tables are currently allowed
+# (see osl.c):
 iasl -sa facp.dsl
 iasl -sa ssdt1.dsl
 cp facp.aml kernel/firmware/acpi
 cp ssdt1.aml kernel/firmware/acpi
-# Create the uncompressed cpio archive and concatenate the original initrd
-# on top:
+# The uncompressed cpio archive must be the first. Other, typically
+# compressed cpio archives, must be concatenated on top of the uncompressed
+# one. Following command creates the uncompressed cpio archive and
+# concatenates the original initrd on top:
 find kernel | cpio -H newc --create > /boot/instrumented_initrd
 cat /boot/initrd >>/boot/instrumented_initrd
 # reboot with increased acpi debug level, e.g. boot params:
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 82b96ee..b225c4b 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -311,12 +311,12 @@ config ACPI_CUSTOM_DSDT
 	bool
 	default ACPI_CUSTOM_DSDT_FILE != ""
 
-config ACPI_INITRD_TABLE_OVERRIDE
-	bool "ACPI tables override via initrd"
+config ACPI_TABLE_UPGRADE
+	bool "Allow upgrading ACPI tables via initrd"
 	depends on BLK_DEV_INITRD && X86
-	default n
+	default y
 	help
-	  This option provides functionality to override arbitrary ACPI tables
+	  This option provides functionality to upgrade arbitrary ACPI tables
 	  via initrd. No functional change if no ACPI tables are passed via
 	  initrd, therefore it's safe to say Y.
 	  See Documentation/acpi/initrd_table_override.txt for details
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index 2e74dbf..08795fb 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -442,7 +442,7 @@ static void acpi_table_taint(struct acpi_table_header *table)
 	add_taint(TAINT_OVERRIDDEN_ACPI_TABLE, LOCKDEP_NOW_UNRELIABLE);
 }
 
-#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+#ifdef CONFIG_ACPI_TABLE_UPGRADE
 static u64 acpi_tables_addr;
 static int all_tables_size;
 
@@ -471,9 +471,9 @@ static const char * const table_sigs[] = {
 
 #define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
 
-#define ACPI_OVERRIDE_TABLES 64
-static struct cpio_data __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
-static DECLARE_BITMAP(acpi_initrd_installed, ACPI_OVERRIDE_TABLES);
+#define NR_ACPI_INITRD_TABLES 64
+static struct cpio_data __initdata acpi_initrd_files[NR_ACPI_INITRD_TABLES];
+static DECLARE_BITMAP(acpi_initrd_installed, NR_ACPI_INITRD_TABLES);
 
 #define MAP_CHUNK_SIZE   (NR_FIX_BTMAPS << PAGE_SHIFT)
 
@@ -488,7 +488,7 @@ static void __init acpi_table_initrd_init(void *data, size_t size)
 	if (data == NULL || size == 0)
 		return;
 
-	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
+	for (no = 0; no < NR_ACPI_INITRD_TABLES; no++) {
 		file = find_cpio_data(cpio_path, data, size, &offset);
 		if (!file.data)
 			break;
@@ -611,19 +611,30 @@ acpi_table_initrd_override(struct acpi_table_header *existing_table,
 		table_length = table->length;
 
 		/* Only override tables matched */
-		if (test_bit(table_index, acpi_initrd_installed) ||
-		    memcmp(existing_table->signature, table->signature, 4) ||
+		if (memcmp(existing_table->signature, table->signature, 4) ||
+		    memcmp(table->oem_id, existing_table->oem_id,
+			   ACPI_OEM_ID_SIZE) ||
 		    memcmp(table->oem_table_id, existing_table->oem_table_id,
 			   ACPI_OEM_TABLE_ID_SIZE)) {
 			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
 			goto next_table;
 		}
+		/*
+		 * Mark the table to avoid being used in
+		 * acpi_table_initrd_scan() and check the revision.
+		 */
+		if (test_and_set_bit(table_index, acpi_initrd_installed) ||
+		    existing_table->oem_revision >= table->oem_revision) {
+			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+			goto next_table;
+		}
 
 		*length = table_length;
 		*address = acpi_tables_addr + table_offset;
-		acpi_table_taint(existing_table);
+		pr_info("Table Upgrade: override [%4.4s-%6.6s-%8.8s]\n",
+			table->signature, table->oem_id,
+			table->oem_table_id);
 		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
-		set_bit(table_index, acpi_initrd_installed);
 		break;
 
 next_table:
@@ -655,17 +666,26 @@ static void __init acpi_table_initrd_scan(void)
 		table_length = table->length;
 
 		/* Skip RSDT/XSDT which should only be used for override */
-		if (test_bit(table_index, acpi_initrd_installed) ||
-		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_RSDT) ||
+		if (ACPI_COMPARE_NAME(table->signature, ACPI_SIG_RSDT) ||
 		    ACPI_COMPARE_NAME(table->signature, ACPI_SIG_XSDT)) {
 			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
 			goto next_table;
 		}
+		/*
+		 * Mark the table to avoid being used in
+		 * acpi_table_initrd_override(). Though this is not possible
+		 * because override is disabled in acpi_install_table().
+		 */
+		if (test_and_set_bit(table_index, acpi_initrd_installed)) {
+			acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
+			goto next_table;
+		}
 
-		acpi_table_taint(table);
+		pr_info("Table Upgrade: install [%4.4s-%6.6s-%8.8s]\n",
+			table->signature, table->oem_id,
+			table->oem_table_id);
 		acpi_os_unmap_memory(table, ACPI_HEADER_SIZE);
 		acpi_install_table(acpi_tables_addr + table_offset, TRUE);
-		set_bit(table_index, acpi_initrd_installed);
 next_table:
 		table_offset += table_length;
 		table_index++;
@@ -689,7 +709,7 @@ acpi_table_initrd_override(struct acpi_table_header *existing_table,
 static void __init acpi_table_initrd_scan(void)
 {
 }
-#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */
+#endif /* CONFIG_ACPI_TABLE_UPGRADE */
 
 acpi_status
 acpi_os_physical_table_override(struct acpi_table_header *existing_table,
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 86ac608..68ff412 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -190,7 +190,7 @@ static inline int acpi_debugger_notify_command_complete(void)
 }
 #endif
 
-#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
+#ifdef CONFIG_ACPI_TABLE_UPGRADE
 void early_acpi_table_init(void *data, size_t size);
 #else
 static inline void early_acpi_table_init(void *data, size_t size)
-- 
1.7.10

Re: [PATCH 0/3] ACPI / tables: Add table upgrade mechanism

[Andy Shevchenko]

On Fri, Apr 8, 2016 at 10:35 AM, Lv Zheng <lv.zheng@intel.com> wrote:
> This patch introduces a table upgrade mechanism based on the existing
> initrd table override mechanism.
>

Mika, I think we might take advantage of this change.

> Lv Zheng (3):
>   ACPI / tables: Move table override mechanisms to tables.c
>   ACPI / x86: Cleanup initrd related code
>   ACPI / tables: Convert the initrd table override mechanisms to the
>     table upgrade mechanism
>
>  Documentation/acpi/initrd_table_override.txt |   65 +++---
>  arch/x86/kernel/setup.c                      |   12 +-
>  drivers/acpi/Kconfig                         |    8 +-
>  drivers/acpi/internal.h                      |    1 -
>  drivers/acpi/osl.c                           |  274 ----------------------
>  drivers/acpi/tables.c                        |  312 +++++++++++++++++++++++++-
>  include/linux/acpi.h                         |    6 +-
>  7 files changed, 366 insertions(+), 312 deletions(-)
>
> --
> 1.7.10
>



-- 
With Best Regards,
Andy Shevchenko