From c613ec1a7ff3714da11c7c48a13bab03beb5c376 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Fri, 10 Oct 2008 10:46:45 +0100 Subject: [PATCH] x86, early_ioremap: fix fencepost error The x86 implementation of early_ioremap has an off by one error. If we get an object which ends on the first byte of a page we undermap by one page and this causes a crash on boot with the ASUS P5QL whose DMI table happens to fit this alignment. The size computation is currently last_addr = phys_addr + size - 1; npages = (PAGE_ALIGN(last_addr) - phys_addr) (Consider a request for 1 byte at alignment 0...) Closes #11693 Debugging work by Ian Campbell/Felix Geyer Signed-off-by: Alan Cox Cc: Signed-off-by: Ingo Molnar --- arch/x86/mm/ioremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 6ab3196d12b4..10b52309aefd 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -614,7 +614,7 @@ void __init *early_ioremap(unsigned long phys_addr, unsigned long size) */ offset = phys_addr & ~PAGE_MASK; phys_addr &= PAGE_MASK; - size = PAGE_ALIGN(last_addr) - phys_addr; + size = PAGE_ALIGN(last_addr + 1) - phys_addr; /* * Mappings have to fit in the FIX_BTMAP area. -- 2.20.1