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Commit d701fda8 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86: fix early_ioremap()/btmap 



fix a long-standing weakness of the early-ioremap allocator: it
uses a single pgd entry for the boot mappings, and was not properly
protecting itself against crossing a 2MB (4MB) boundary.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent d690b2af

include/asm-x86/fixmap_32.h

+10 −2
Original line number Original line Diff line number Diff line
@@ -90,10 +90,18 @@ enum fixed_addresses { 
	FIX_PARAVIRT_BOOTMAP,

	FIX_PARAVIRT_BOOTMAP,

#endif

#endif

	__end_of_permanent_fixed_addresses,

	__end_of_permanent_fixed_addresses,

	/* temporary boot-time mappings, used before ioremap() is functional */

	/*

	 * 256 temporary boot-time mappings, used by early_ioremap(),

	 * before ioremap() is functional.

	 *

	 * We round it up to the next 512 pages boundary so that we

	 * can have a single pgd entry and a single pte table:

	 */

#define NR_FIX_BTMAPS		64

#define NR_FIX_BTMAPS		64

#define FIX_BTMAPS_NESTING	4

#define FIX_BTMAPS_NESTING	4

	FIX_BTMAP_END = __end_of_permanent_fixed_addresses,

	FIX_BTMAP_END =

		__end_of_permanent_fixed_addresses + 512 -

			(__end_of_permanent_fixed_addresses & 511),

	FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS*FIX_BTMAPS_NESTING - 1,

	FIX_BTMAP_BEGIN = FIX_BTMAP_END + NR_FIX_BTMAPS*FIX_BTMAPS_NESTING - 1,

	FIX_WP_TEST,

	FIX_WP_TEST,

	__end_of_fixed_addresses

	__end_of_fixed_addresses