Since 2.6.26 the CONFIG_NONPROMISC_DEVMEM options limits the physical addresses which can be accessed through /dev/mem. Sources: - Changelog: http://kernelnewbies.org/Linux_2_6_26 - Initial commit: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ae531c26c5c2a28ca1b35a75b39b3b256850f2c8 - Rename of name: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d092633bff3b19faffc480fe9810805e7792a029 Signed-off-by: Elie De Brauwer <eliedebrauwer@xxxxxxxxx> --- man4/mem.4 | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/man4/mem.4 b/man4/mem.4 index 6688345..372d4fa 100644 --- a/man4/mem.4 +++ b/man4/mem.4 @@ -23,7 +23,7 @@ .\" %%%LICENSE_END .\" .\" Modified Sat Jul 24 16:59:10 1993 by Rik Faith (faith@xxxxxxxxxx) -.TH MEM 4 1992-11-21 "Linux" "Linux Programmer's Manual" +.TH MEM 4 2015-01-02 "Linux" "Linux Programmer's Manual" .SH NAME mem, kmem, port \- system memory, kernel memory and system ports .SH DESCRIPTION @@ -40,6 +40,13 @@ References to nonexistent locations cause errors to be returned. Examining and patching is likely to lead to unexpected results when read-only or write-only bits are present. .LP +Since 2.6.26, and depending on the architecture, the +.B CONFIG_STRICT_DEVMEM +kernel configuration option limits the areas +which can be accessed through this file. +For example: on x86, RAM access is not allowed but accessing +memory-mapped PCI regions is. +.LP It is typically created by: .RS .sp -- 2.1.3 -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
