From 540aca06b737cc38965b52eeceefba3d24376461 Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Wed, 4 Mar 2009 11:46:40 +0200 Subject: x86: move devmem_is_allowed() to common mm/init.c Impact: cleanup The function is identical on 32-bit and 64-bit configurations so move it to the common mm/init.c file. Signed-off-by: Pekka Enberg LKML-Reference: <1236160001.29024.29.camel@penberg-laptop> Signed-off-by: Ingo Molnar --- arch/x86/mm/init.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'arch/x86/mm/init.c') diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index ce6a722587d8..f89df52683c5 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -1,9 +1,33 @@ +#include #include + #include #include +#include #include #include +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain address + * is valid. The argument is a physical page number. + * + * + * On x86, access has to be given to the first megabyte of ram because that area + * contains bios code and data regions used by X and dosemu and similar apps. + * Access has to be given to non-kernel-ram areas as well, these contain the PCI + * mmio resources as well as potential bios/acpi data regions. + */ +int devmem_is_allowed(unsigned long pagenr) +{ + if (pagenr <= 256) + return 1; + if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) + return 0; + if (!page_is_ram(pagenr)) + return 1; + return 0; +} + void free_init_pages(char *what, unsigned long begin, unsigned long end) { unsigned long addr = begin; -- cgit v1.2.3