For relocatable 32bit kernels, boot/compressed/relocs.c processes
relocation entries in the kernel image and appends it to the kernel
image such that boot/compressed/head_32.S can relocate the kernel.
The kernel image is one statically linked object and only uses two
relocation types - R_386_PC32 and R_386_32, of the two only the latter
needs massaging during kernel relocation and thus handled by relocs.
R_386_PC32 is ignored and all other relocation types are considered
error.

When the target of a relocation resides in a discarded section,
binutils doesn't throw away the relocation record but nullifies it by
changing it to R_386_NONE, which unfortunately makes relocs fail.

The problem was triggered by yet out-of-tree x86 stack unwind patches
but given the binutils behavior, ignoring R_386_NONE is the right
thing to do.

The problem has been tracked down to binutils behavior by Jan Beulich.

[ Impact: fix build with certain binutils by ignoring R_386_NONE ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <4A1B8150.40702@kernel.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Remove ACPI 3 E820 extended memory attributes support.  At least one
vendor actively set all the flags to zero, but left ECX on return at
24.  This bug may be present in other BIOSes.

The breakage functionally means the ACPI 3 flags are probably
completely useless, and that no OS any time soon is going to rely on
their existence.  Therefore, drop support completely.  We may want to
revisit this question in the future, if we find ourselves actually
needing the flags.

This reverts all or part of the following checkins:

     cd670599
     c549e71d

However, retain the part from the latter commit that copies e820 into
a temporary buffer; that is an unrelated BIOS workaround.  Put in a
comment to explain that part.

See https://bugzilla.redhat.com/show_bug.cgi?id=499396 for some
additional information.

[ Impact: detect all memory on affected machines ]
Reported-by: NThomas J. Baker <tjb@unh.edu>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Acked-by: NLen Brown <len.brown@intel.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: Kyle McMartin <kmcmartin@redhat.com>
Cc: Matt Domsch <matt_domsch@dell.com>

Impact: Fixes these modes on at least one system

The rewrite of the setup code into C resequenced the font setting and
register reprogramming phases of configuring nonstandard VGA modes
which use 480 scan lines in text mode.  However, there exists at least
one board (Micro-Star MS-7383 version 2.0) on which this resequencing
causes an unusable display.

Revert to the original sequencing: set up 480-line mode, install the
font, and then adjust the vertical end register appropriately.

This failure was masked by the fact that the 480-line setup was broken
until checkin 5f641356 (therefore this
is not a -stable candidate bug fix.)
Reported-by: NAndi Kleen <andi@firstfloor.org>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: code size reduction (possibly critical)

The x86 boot and decompression code has no use of the branch profiling
constructs, so disable them.  This would bloat the setup code by as
much as 14K, eating up a fairly large chunk of the 32K area we are
guaranteed to have.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: BIOS bug safety

For pre-ACPI 3 BIOSes, pre-initialize the end of the e820 buffer just
in case the BIOS returns an unchanged %ecx but without actually
touching the ACPI 3 extended flags field.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: ACPI 3 spec compliance, BIOS bug workaround

The ACPI 3 spec added another field to the E820 buffer -- which is
backwards incompatible, since it contains a validity bit.
Furthermore, there has been at least one report of a BIOS which
assumes that the buffer it is pointed at is the same buffer as for the
previous E820 call.  Therefore, read the data into a temporary buffer
and copy the standard part of it if and only if the valid bit is set.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: BIOS bugproofing

Since there are BIOSes known to clobber %ebx and %esi for INT 15 E820,
assume there is something out there clobbering %edi and/or %ebp too,
and don't wait for it to fail.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Jordan Hargrave diagnosed a BIOS clobbering %esi in the E820 call.
That particular BIOS has been fixed, but there is a possibility that
this is responsible for other occasional reports of early boot
failure, and it does not hurt to add %esi to the clobbers.

-stable candidate patch.

Cc: Justin Forbes <jmforbes@linuxtx.org>
Signed-off-by: NMichael K Johnson <johnsonm@rpath.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: stable@kernel.org

Impact: fix rarely-used feature

The VGA Miscellaneous Output Register is read from address 0x3CC but
written to address 0x3C2.  This was missed when this code was
converted from assembly to C.  While we're at it, clean up the code by
making the overflow bits and the math used to set the bits explicit.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: cleanup

The setup code is mostly 16-bit code, but there is a small stub of
32-bit code at the end.  Move the 32-bit code to a separate segment,
.text32, to avoid scrambling the disassembly.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: cleanup

Instead of using CLEAN_FILES in arch/x86/Makefile, add generated files
to targets in arch/x86/boot/Makefile, so they will get naturally
cleaned up by "make clean".

Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: cleanup

Remove targets that were used for zImage only, and Makefile
infrastructure that was there to support the zImage/bzImage split.
Reported-by: NPaul Bolle <pebolle@tiscali.nl>
LKML-Reference: <1236879901.24144.26.camel@test.thuisdomein>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: obsolete feature removal

The zImage kernel format has been functionally unused for a very long
time.  It is just barely possible to build a modern kernel that still
fits within the zImage size limit, but it is highly unlikely that
anyone ever uses it.  Furthermore, although it is still supported by
most bootloaders, it has been at best poorly tested (or not tested at
all); some bootloaders are even known to not support zImage at all and
not having even noticed.

Also remove some really obsolete constants that no longer have any
meaning.

LKML-Reference: <49B703D4.1000008@zytor.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: remove unused/broken code

The Voyager subarch last built successfully on the v2.6.26 kernel
and has been stale since then and does not build on the v2.6.27,
v2.6.28 and v2.6.29-rc5 kernels.

No actual users beyond the maintainer reported this breakage.
Patches were sent and most of the fixes were accepted but the
discussion around how to do a few remaining issues cleanly
fizzled out with no resolution and the code remained broken.

In the v2.6.30 x86 tree development cycle 32-bit subarch support
has been reworked and removed - and the Voyager code, beyond the
build problems already known, needs serious and significant
changes and probably a rewrite to support it.

CONFIG_X86_VOYAGER has been marked BROKEN then. The maintainer has
been notified but no patches have been sent so far to fix it.

While all other subarchs have been converted to the new scheme,
voyager is still broken. We'd prefer to receive patches which
clean up the current situation in a constructive way, but even in
case of removal there is no obstacle to add that support back
after the issues have been sorted out in a mutually acceptable
fashion.

So remove this inactive code for now.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: clenaup

Linker script will put startup_32 at predefined
address so using startup_32 will not bloat the
code size.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: clenaup

Linker script will put startup_32 at predefined
address so using ENTRY will not bloat the code
size.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

We are in setup stage so we use GLOBAL
instead of ENTRY and do not increase code
size.
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup
Signed-off-by: NCyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

In general, the only definitions that assembly files can use
are in _types.S headers (where available), so convert them.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

When probing the keyboard controller to enable A20, if we get FF back
(which is *possible* as a valid status word, but is extremely
unlikely) then bail after much fewer iterations than we otherwise
would, and abort the attempt to access the KBC.

This hopefully should make it work a lot better for embedded platforms
which don't have a KBC and where the BIOS doesn't implement
INT 15h AX=2401h (and doesn't boot with A20 already enabled.)

If this works, it will be the one remaining use of CONFIG_X86_ELAN as
anything other than a processor type optimization option.
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: fix potential miscompile (currently believed non-manifest)

As the comment explains, the VBE DDC call can clobber any register.
Tell the compiler about that fact.
Signed-off-by: NAndreas Schwab <schwab@suse.de>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: fix potential miscompile (currently believed non-manifest)

As the comment explains, the VBE DDC call can clobber any register.
Tell the compiler about that fact.
Signed-off-by: NAndreas Schwab <schwab@suse.de>
Signed-off-by: NH. Peter Anvin <hpa@linux.intel.com>

Impact: Replaces x86 kernel decompressor with new code

This is the third part of the bzip2/lzma patch

The bzip patch is based on an idea by Christian Ludwig, includes support for
compressing the kernel with bzip2 or lzma rather than gzip. Both
compressors give smaller sizes than gzip.  Lzma's decompresses faster
than bzip2.

It also supports ramdisks and initramfs' compressed using these two
compressors.

The functionality has been successfully used for a couple of years by
the udpcast project

This version applies to "tip" kernel 2.6.28

This part contains:
- support for new bzip2 and lzma kernel compression for x86
Signed-off-by: NAlain Knaff <alain@knaff.lu>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: build fix with certain compilers

GCC can decide to use %dil when "r" is used, which is not valid for
setnz.

This bug was brought out by Stephen Rothwell's merging of the
branch tracer into linux-next.

[ Thanks to Uros Bizjak for recommending 'q' over 'Q' ]
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: make global variables static

Fix these sparse warnings:

 arch/x86/boot/video.c:233:3: warning: symbol 'saved' was not declared. Should it be static?
 arch/x86/boot/video-vga.c:37:13: warning: symbol 'video_vga' was not declared. Should it be static?
Signed-off-by: NHannes Eder <hannes@hanneseder.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

These variables are only used in their source files, so make them static.
Signed-off-by: NRoel Kluin <roel.kluin@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Currently, it is possible to set a graphics VESA mode at boot time via the
vga= parameter even when no framebuffer driver supporting this is
configured.  This could lead to the system booting with a black screen,
without a usable console.

Fix this problem by only allowing to set graphics modes at boot time if a
supporting framebuffer driver is configured.
Signed-off-by: NMichal Januszewski <spock@gentoo.org>
Acked-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace a magic number with a named constant in the VESA boot code.
Signed-off-by: NMichal Januszewski <spock@gentoo.org>
Cc: linux-fbdev-devel@lists.sourceforge.net
Signed-off-by: NIngo Molnar <mingo@elte.hu>

After commit 968de4f0 ("i386: Relocatable kernel support") IMAGE_OFFSET wasn't
actually used anymore in the (current) X86 build system. Now remove its last
traces.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: segfault on build of a 32-bit relocatable kernel

When converting arch/x86/boot/compressed/relocs.c to support unlimited
sections, the computation of sym_strtab in walk_relocs() was done
incorrectly.  This causes a segfault for some people when building the
relocatable 32-bit kernel.

Pointed out by Anonymous <pageexec@freemail.hu>.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This reverts commit 464f04c9.
Obsoleted by commit 6cdcdb99.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Some BIOSes do not indicate error when trying to read from non-
existing device. Zero buffer before reading and check that we
possibly have valid MBR by looking for MBR magic.

This was fixed in different way for edd.S in
http://marc.info/?l=linux-kernel&m=114087765422490&w=2, but lost
again when edd.S was rewritten in C.

Signed-off-by: Andrey Borzenkov < arvidjaar@mail.ru>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Checkin e38e05a8 added a 9th CPU flag
word, but didn't adjust the boot code to match.  This patch adds the
necessary boot code support.

Note: due to a typo in an #if statement, it didn't trigger the #error
this was supposed to do.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

Impact: None (cleanup)

SWAP_DEV is unused since 2.6.23-rc1. The comment was already incorrect
since (at least) 2.6.12.
Signed-off-by: NPaul Bolle <pebolle@tiscali.nl>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

> This is regression but old enough. Apparently I had for whatever reasons
> EDD turned off till recently. This is 2.6.27-rc5 just in case.
>
> In 2006 I fixed ghost devices due to buggy BIOS:
>
> http://marc.info/?l=linux-kernel&m=114087765422490&w=2
>
> Later edd.S has been rewritten in C, and apparently this patch has been
> lost:
>
> {pts/1}% ls /sys/firmware/edd
> int13_dev80/  int13_dev84/  int13_dev88/  int13_dev8c/
> int13_dev81/  int13_dev85/  int13_dev89/  int13_dev8d/
> int13_dev82/  int13_dev86/  int13_dev8a/  int13_dev8e/
> int13_dev83/  int13_dev87/  int13_dev8b/  int13_dev8f/
>
> But I have just a single disk. This is the same system BTW.

Some BIOSes do not always set CF on error before return from int13.
The patch adds additional check for status being zero (AH == 0).

This was fixed for edd.S in
http://marc.info/?l=linux-kernel&m=114087765422490&w=2, but lost
again when edd.S was rewritten in C.
Signed-off-by: NAndrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When building image.iso (make isoimage), use the isohybrid tool if it
exists.  isohybrid is a script included with Syslinux 3.72 and higher,
which creates an image that can be booted either as a hard disk
(including removable, e.g. USB disk) or as a CD-ROM.

If isohybrid doesn't exist, then this has no effect.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The CPU feature detection code in the boot code is somewhat minimal,
and doesn't include all possible CPUID words.  In particular, it
doesn't contain the code for CPU feature words 2 (Transmeta),
3 (Linux-specific), 5 (VIA), or 7 (scattered).  Zero them out, so we
can still set those bits as known at compile time; in particular, this
allows creating a Linux-specific NOPL flag and have it required (and
therefore resolvable at compile time) in 64-bit mode.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

The Kbuild variable "targets" is supposed to be
configuration-independent and reflect "all possible targets".  This is
required to make "make clean" work properly.

Therefore, move all manipulation of "targets" as well as custom rules
out of the x86-32 ifdef statement.  Only leave inside the ifdefs the
things that are genuinely configuration-dependent.
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>