david/ipxe
david/ipxe
Archived
1
0
Fork 0
Code
My fork of git://git.ipxe.org/ipxe.git, it is used for my netboot environment at home.
This repository has been archived on 2020-12-06. You can view files and clone it, but cannot push or open issues or pull requests.
5,393 Commits 1 Branch 0 Tags 14 MiB
C 95.2%
Objective-C 1.7%
Assembly 1.3%
Perl 0.7%
Makefile 0.4%
Other 0.6%
cc9f31ee0c
Go to file
Michael Brown cc9f31ee0c [librm] Do not unconditionally preserve flags across virt_call() 
Commit 196f0f2 ("[librm] Convert prot_call() to a real-mode near
call") introduced a regression in which any deliberate modification to
the low 16 bits of the CPU flags (in struct i386_all_regs) would be
overwritten with the original flags value at the time of entry to
prot_call().

The regression arose because the alignment requirements of the
protected-mode stack necessitated the insertion of two bytes of
padding immediately below the prot_call() return address.  The
solution chosen was to extend the existing "pushfl / popfl" pair to
"pushfw;pushfl / popfl;popfw".  The extra "pushfw / popfw" appears at
first glance to be a no-op, but fails to take into account the fact
that the flags restored by popfl may have been deliberately modified
by the protected-mode function.

Fix by replacing "pushfw / popfw" with "pushw %ss / popw %ss".  While
%ss does appear within struct i386_all_regs, any modification to the
stored value has always been ignored by prot_call() anyway.

The most visible symptom of this regression was that SAN booting would
fail since every INT 13 call would be chained to the original INT 13
vector.

Reported-by: Vishvananda Ishaya <vishvananda@gmail.com>
Reported-by: Jamie Thompson <forum.ipxe@jamie-thompson.co.uk>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
2016-03-12 12:39:17 +00:00
contrib [errdb] Strip platform error code for non-platform-generated errors 2013-04-29 15:36:32 +01:00
src [librm] Do not unconditionally preserve flags across virt_call() 2016-03-12 12:39:17 +00:00
COPYING [legal] Update GPLv2 licence text 2015-02-26 17:59:53 +00:00
COPYING.GPLv2 [legal] Update GPLv2 licence text 2015-02-26 17:59:53 +00:00
COPYING.UBDL [legal] Add support for the Unmodified Binary Distribution Licence 2015-03-02 12:07:14 +00:00
README [doc] Re-add README file 2010-05-28 00:03:47 +01:00

README 

iPXE README File

Quick start guide:

   cd src
   make

For any more detailed instructions, see http://ipxe.org