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Commit f4df73c2 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Thomas Gleixner
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
parent bbbd9995

arch/x86/kernel/acpi/boot.c

+32 −0
Original line number Diff line number Diff line
@@ -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);