From: Ingo Molnar Date: Wed, 30 Jan 2008 12:33:48 +0000 (+0100) Subject: x86: fix early_ioremap()/btmap X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d701fda8601fe267fbd3648f108f0e751305101b;p=linux-beck.git 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: Ingo Molnar Signed-off-by: Thomas Gleixner --- diff --git a/include/asm-x86/fixmap_32.h b/include/asm-x86/fixmap_32.h index 46bedb7b5426..fde140fd6d95 100644 --- a/include/asm-x86/fixmap_32.h +++ b/include/asm-x86/fixmap_32.h @@ -90,10 +90,18 @@ enum fixed_addresses { FIX_PARAVIRT_BOOTMAP, #endif __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 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_WP_TEST, __end_of_fixed_addresses