Commit 0ad5bce7 authored Sep 11, 2008 by Jeremy Fitzhardinge Committed by Ingo Molnar Sep 12, 2008

x86: fix possible x86_64 and EFI regression



Russ Anderson reported a boot crash with EFI and latest mainline:

 BIOS-e820: 00000000fffa0000 - 00000000fffac000 (reserved)
Pid: 0, comm: swapper Not tainted 2.6.27-rc5-00100-gec0c15a-dirty #5

Call Trace:
 [<ffffffff80849195>] early_idt_handler+0x55/0x69
 [<ffffffff80313e52>] __memcpy+0x12/0xa4
 [<ffffffff80859015>] efi_init+0xce/0x932
 [<ffffffff80869c83>] setup_early_serial8250_console+0x2d/0x36a
 [<ffffffff80238688>] __insert_resource+0x18/0xc8
 [<ffffffff8084f6de>] setup_arch+0x3a7/0x632
 [<ffffffff808499ed>] start_kernel+0x91/0x367
 [<ffffffff80849393>] x86_64_start_kernel+0xe3/0xe7
 [<ffffffff808492b0>] x86_64_start_kernel+0x0/0xe7

 RIP 0x10

Such a crash is possible if the CPU in this system is a 64-bit
processor which doesn't support NX (ie, old Intel P4 -based64-bit
processors).

Certainly, if we support such processors, then we should start with
_PAGE_NX initially clear in __supported_pte_flags, and then set it once
we've established that the processor does indeed support NX.  That will
prevent early_ioremap - or anything else - from trying to set it.

The simple fix is to simply call check_efer() earlier.

Reported-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent f461a1d8

arch/x86/kernel/setup.c

+4 −1

Original line number	Original line	Diff line number	Diff line
	@@ -670,6 +670,10 @@ void __init setup_arch(char **cmdline_p)

	parse_early_param();		parse_early_param();

			#ifdef CONFIG_X86_64
			check_efer();
			#endif

	#if defined(CONFIG_VMI) && defined(CONFIG_X86_32)		#if defined(CONFIG_VMI) && defined(CONFIG_X86_32)
	/*		/*
	* Must be before kernel pagetables are setup		* Must be before kernel pagetables are setup
	@@ -738,7 +742,6 @@ void __init setup_arch(char **cmdline_p)
	#else		#else
	num_physpages = max_pfn;		num_physpages = max_pfn;

	check_efer();

	/* How many end-of-memory variables you have, grandma! */		/* How many end-of-memory variables you have, grandma! */
	/* need this before calling reserve_initrd */		/* need this before calling reserve_initrd */

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