]> git.openfabrics.org - ~shefty/rdma-dev.git/commit
x86: avoid high BIOS area when allocating address space
authorBjorn Helgaas <bjorn.helgaas@hp.com>
Thu, 16 Dec 2010 17:39:02 +0000 (10:39 -0700)
committerJesse Barnes <jbarnes@virtuousgeek.org>
Fri, 17 Dec 2010 18:01:30 +0000 (10:01 -0800)
commita2c606d53ab71dee6410f10ef0adf67321d60e06
tree7a4cf519cbfc01fd1c4273c1481f40f4cd7d00bc
parent4dc2287c1805e7fe8a7cb90bbcd44abee8cdb914
x86: avoid high BIOS area when allocating address space

This prevents allocation of the last 2MB before 4GB.

The experiment described here shows Windows 7 ignoring the last 1MB:
https://bugzilla.kernel.org/show_bug.cgi?id=23542#c27

This patch ignores the top 2MB instead of just 1MB because H. Peter Anvin
says "There will be ROM at the top of the 32-bit address space; it's a fact
of the architecture, and on at least older systems it was common to have a
shadow 1 MiB below."

Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
arch/x86/include/asm/e820.h
arch/x86/kernel/resource.c