x86: add hpet sanity checks

Some BIOSes advertise HPET at 0x0. We really do no want to 
allocate a resource there. Check for it and leave early.

Other BIOSes tell us the HPET is at 0xfed0000000000000 
instead of 0xfed00000. Add a check and fix it up with a warning
on user request.


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 32 insertions, 0 deletions

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 289247d974c6..0ca27c7b0e8d 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -637,6 +637,38 @@ static int __init acpi_parse_hpet(struct acpi_table_header *table)
         }
 
         hpet_address = hpet_tbl->address.address;
+
+        /*
+         * Some broken BIOSes advertise HPET at 0x0. We really do not
+         * want to allocate a resource there.
+         */
+        if (!hpet_address) {
+                printk(KERN_WARNING PREFIX
+                       "HPET id: %#x base: %#lx is invalid\n",
+                       hpet_tbl->id, hpet_address);
+                return 0;
+        }
+#ifdef CONFIG_X86_64
+        /*
+         * Some even more broken BIOSes advertise HPET at
+         * 0xfed0000000000000 instead of 0xfed00000. Fix it up and add
+         * some noise:
+         */
+        if (hpet_address == 0xfed0000000000000UL) {
+                if (!hpet_force_user) {
+                        printk(KERN_WARNING PREFIX "HPET id: %#x "
+                               "base: 0xfed0000000000000 is bogus\n "
+                               "try hpet=force on the kernel command line to "
+                               "fix it up to 0xfed00000.\n", hpet_tbl->id);
+                        hpet_address = 0;
+                        return 0;
+                }
+                printk(KERN_WARNING PREFIX
+                       "HPET id: %#x base: 0xfed0000000000000 fixed up "
+                       "to 0xfed00000.\n", hpet_tbl->id);
+                hpet_address >>= 32;
+        }
+#endif
         printk(KERN_INFO PREFIX "HPET id: %#x base: %#lx\n",
                hpet_tbl->id, hpet_address);