From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 16 Nov 2007 02:41:50 +0000 (-0500)
Subject: x86: add hpet sanity checks
X-Git-Tag: v2.6.24-rc4~114^2~4
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=f4df73c2914a49bf6a55896aaecb0563c955e167;p=linux-2.6-omap-h63xx.git

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>
---

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 289247d974c..0ca27c7b0e8 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);