ACPI: tables: complete searching upon RSDP w/ bad checksum.
ACPI tables follow a tree structure in memory.
The root of the tree is the RSDP (Root System Description Pointer).
To find the RSDP, the OS searches for the signature "RSD PTR "
in well known physical memory locations. Then the OS computes
a table checksum to verify that the signature is really part
of a valid table header.
Some systems have a proper signature but an invalid checksum;
followed elsewhere by a proper signature with valid checksum.
http://bugzilla.kernel.org/show_bug.cgi?id=9444
The Linux RSDP scanning code bailed out on those systems
and as a result they booted with ACPI disabled.
Fix this by deleting the Linux RSDP scanning code and
plugging in the ACPICA RSDP scanning code.
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 0ca27c7..719c74b 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -581,25 +581,6 @@
EXPORT_SYMBOL(acpi_unregister_ioapic);
-static unsigned long __init
-acpi_scan_rsdp(unsigned long start, unsigned long length)
-{
- unsigned long offset = 0;
- unsigned long sig_len = sizeof("RSD PTR ") - 1;
-
- /*
- * Scan all 16-byte boundaries of the physical memory region for the
- * RSDP signature.
- */
- for (offset = 0; offset < length; offset += 16) {
- if (strncmp((char *)(phys_to_virt(start) + offset), "RSD PTR ", sig_len))
- continue;
- return (start + offset);
- }
-
- return 0;
-}
-
static int __init acpi_parse_sbf(struct acpi_table_header *table)
{
struct acpi_table_boot *sb;
@@ -742,27 +723,6 @@
return 0;
}
-unsigned long __init acpi_find_rsdp(void)
-{
- unsigned long rsdp_phys = 0;
-
- if (efi_enabled) {
- if (efi.acpi20 != EFI_INVALID_TABLE_ADDR)
- return efi.acpi20;
- else if (efi.acpi != EFI_INVALID_TABLE_ADDR)
- return efi.acpi;
- }
- /*
- * Scan memory looking for the RSDP signature. First search EBDA (low
- * memory) paragraphs and then search upper memory (E0000-FFFFF).
- */
- rsdp_phys = acpi_scan_rsdp(0, 0x400);
- if (!rsdp_phys)
- rsdp_phys = acpi_scan_rsdp(0xE0000, 0x20000);
-
- return rsdp_phys;
-}
-
#ifdef CONFIG_X86_LOCAL_APIC
/*
* Parse LAPIC entries in MADT
diff --git a/arch/x86/kernel/srat_32.c b/arch/x86/kernel/srat_32.c
index 2a8713e..b3b2c95 100644
--- a/arch/x86/kernel/srat_32.c
+++ b/arch/x86/kernel/srat_32.c
@@ -276,7 +276,7 @@
int tables = 0;
int i = 0;
- rsdp_address = acpi_find_rsdp();
+ rsdp_address = acpi_os_get_root_pointer();
if (!rsdp_address) {
printk("%s: System description tables not found\n",
__FUNCTION__);