[PATCH v4 08/22] x86, ACPI: Make acpi_initrd_override_find work with 32bit flat mode

[Yinghai Lu]

For finding with 32bit, it would be easy to access initrd in 32bit
flat mode, as we don't need to set page table.

That is from head_32.S, and microcode updating already use this trick.

Need to change acpi_initrd_override_find to use phys to access global
variables.

Pass is_phys in the function, as we can not use address to decide if it
is phys or virtual address on 32 bit. Boot loader could load initrd above
max_low_pfn.

Don't call printk as it uses global variables, so delay print later
during copying.

Change table_sigs to use stack instead, otherwise it is too messy to change
string array to phys and still keep offset calculating correct.
That size is about 36x4 bytes, and it is small to settle in stack.

Also remove "continue" in MARCO to make code more readable.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Jacob Shin <jacob.shin@xxxxxxx>
Cc: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: linux-acpi@xxxxxxxxxxxxxxx
Tested-by: Thomas Renninger <trenn@xxxxxxx>
---
 arch/x86/kernel/setup.c |  2 +-
 drivers/acpi/osl.c      | 85 ++++++++++++++++++++++++++++++++++---------------
 include/linux/acpi.h    |  5 +--
 3 files changed, 63 insertions(+), 29 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index d0cc176..16a703f 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1093,7 +1093,7 @@ void __init setup_arch(char **cmdline_p)
 	reserve_initrd();
 
 	acpi_initrd_override_find((void *)initrd_start,
-					initrd_end - initrd_start);
+					initrd_end - initrd_start, false);
 	acpi_initrd_override_copy();
 
 	reserve_crashkernel();
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index ee5c531..cce92a5 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -551,21 +551,9 @@ u8 __init acpi_table_checksum(u8 *buffer, u32 length)
 	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 };
-
 /* Non-fatal errors: Affected tables/files are ignored */
 #define INVALID_TABLE(x, path, name)					\
-	{ pr_err("ACPI OVERRIDE: " x " [%s%s]\n", path, name); continue; }
+	do { pr_err("ACPI OVERRIDE: " x " [%s%s]\n", path, name); } while (0)
 
 #define ACPI_HEADER_SIZE sizeof(struct acpi_table_header)
 
@@ -576,17 +564,45 @@ struct file_pos {
 };
 static struct file_pos __initdata acpi_initrd_files[ACPI_OVERRIDE_TABLES];
 
-void __init acpi_initrd_override_find(void *data, size_t size)
+/*
+ * acpi_initrd_override_find() is called from head_32.S and head64.c.
+ * head_32.S calling path is with 32bit flat mode, so we can access
+ * initrd early without setting pagetable or relocating initrd. For
+ * global variables accessing, we need to use phys address instead of
+ * kernel virtual address, try to put table_sigs string array in stack,
+ * so avoid switching for it.
+ * Also don't call printk as it uses global variables.
+ */
+void __init acpi_initrd_override_find(void *data, size_t size, bool is_phys)
 {
 	int sig, no, table_nr = 0;
 	long offset = 0;
 	struct acpi_table_header *table;
 	char cpio_path[32] = "kernel/firmware/acpi/";
 	struct cpio_data file;
+	struct file_pos *files = acpi_initrd_files;
+	int *all_tables_size_p = &all_tables_size;
+
+	/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */
+	char *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 };
 
 	if (data == NULL || size == 0)
 		return;
 
+	if (is_phys) {
+		files = (struct file_pos *)__pa_symbol(acpi_initrd_files);
+		all_tables_size_p = (int *)__pa_symbol(&all_tables_size);
+	}
+
 	for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) {
 		file = find_cpio_data(cpio_path, data, size, &offset);
 		if (!file.data)
@@ -595,9 +611,12 @@ void __init acpi_initrd_override_find(void *data, size_t size)
 		data += offset;
 		size -= offset;
 
-		if (file.size < sizeof(struct acpi_table_header))
-			INVALID_TABLE("Table smaller than ACPI header",
+		if (file.size < sizeof(struct acpi_table_header)) {
+			if (!is_phys)
+				INVALID_TABLE("Table smaller than ACPI header",
 				      cpio_path, file.name);
+			continue;
+		}
 
 		table = file.data;
 
@@ -605,22 +624,33 @@ void __init acpi_initrd_override_find(void *data, size_t size)
 			if (!memcmp(table->signature, table_sigs[sig], 4))
 				break;
 
-		if (!table_sigs[sig])
-			INVALID_TABLE("Unknown signature",
+		if (!table_sigs[sig]) {
+			if (!is_phys)
+				 INVALID_TABLE("Unknown signature",
 				      cpio_path, file.name);
-		if (file.size != table->length)
-			INVALID_TABLE("File length does not match table length",
+			continue;
+		}
+		if (file.size != table->length) {
+			if (!is_phys)
+				INVALID_TABLE("File length does not match table length",
 				      cpio_path, file.name);
-		if (acpi_table_checksum(file.data, table->length))
-			INVALID_TABLE("Bad table checksum",
+			continue;
+		}
+		if (acpi_table_checksum(file.data, table->length)) {
+			if (!is_phys)
+				INVALID_TABLE("Bad table checksum",
 				      cpio_path, file.name);
+			continue;
+		}
 
-		pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n",
+		if (!is_phys)
+			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 = __pa_nodebug(file.data);
-		acpi_initrd_files[table_nr].size = file.size;
+		(*all_tables_size_p) += table->length;
+		files[table_nr].data = is_phys ? (phys_addr_t)file.data :
+						  __pa_nodebug(file.data);
+		files[table_nr].size = file.size;
 		table_nr++;
 	}
 }
@@ -670,6 +700,9 @@ void __init acpi_initrd_override_copy(void)
 			break;
 		q = early_ioremap(addr, size);
 		p = early_ioremap(acpi_tables_addr + total_offset, size);
+		pr_info("%4.4s ACPI table found in initrd [%#010llx-%#010llx]\n",
+				((struct acpi_table_header *)q)->signature,
+				(u64)addr, (u64)(addr + size - 1));
 		memcpy(p, q, size);
 		early_iounmap(q, size);
 		early_iounmap(p, size);
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 1654a241..4b943e6 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -478,10 +478,11 @@ static inline bool acpi_driver_match_device(struct device *dev,
 #endif	/* !CONFIG_ACPI */
 
 #ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE
-void acpi_initrd_override_find(void *data, size_t size);
+void acpi_initrd_override_find(void *data, size_t size, bool is_phys);
 void acpi_initrd_override_copy(void);
 #else
-static inline void acpi_initrd_override_find(void *data, size_t size) { }
+static inline void acpi_initrd_override_find(void *data, size_t size,
+						 bool is_phys) { }
 static inline void acpi_initrd_override_copy(void) { }
 #endif
 
-- 
1.8.1.4

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