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  1. 20 Jun, 2008 2 commits
    • Isaku Yamahata's avatar
      xen: Use wmb instead of rmb in xen_evtchn_do_upcall(). · 46539383
      Isaku Yamahata authored 
      This patch is ported one from 534:77db69c38249 of linux-2.6.18-xen.hg.
Use wmb instead of rmb to enforce ordering between
evtchn_upcall_pending and evtchn_pending_sel stores
in xen_evtchn_do_upcall().

Cc: Samuel Thibault <samuel.thibault@eu.citrix.com>
Signed-off-by: default avatarIsaku Yamahata <yamahata@valinux.co.jp>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: the arch/x86 maintainers <x86@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      46539383
    • Suresh Siddha's avatar
      x86: fix NULL pointer deref in __switch_to · 54481cf8
      Suresh Siddha authored 
      I am able to reproduce the oops reported by Simon in __switch_to() with
lguest.

My debug showed that there is at least one lguest specific
issue (which should be present in 2.6.25 and before aswell) and it got
exposed with a kernel oops with the recent fpu dynamic allocation patches.

In addition to the previous possible scenario (with fpu_counter), in the
presence of lguest, it is possible that the cpu's TS bit it still set and the
lguest launcher task's thread_info has TS_USEDFPU still set.

This is because of the way the lguest launcher handling the guest's TS bit.
(look at lguest_set_ts() in lguest_arch_run_guest()). This can result
in a DNA fault while doing unlazy_fpu() in __switch_to(). This will
end up causing a DNA fault in the context of new process thats
getting context switched in (as opossed to handling DNA fault in the context
of lguest launcher/helper process).

This is wrong in both pre and post 2.6.25 kernels. In the recent
2.6.26-rc series, this is showing up as NULL pointer dereferences or
sleeping function called from atomic context(__switch_to()), as
we free and dynamically allocate the FPU context for the newly
created threads. Older kernels might show some FPU corruption for processes
running inside of lguest.

With the appended patch, my test system is running for more than 50 mins
now. So atleast some of your oops (hopefully all!) should get fixed.
Please give it a try. I will spend more time with this fix tomorrow.
Reported-by: default avatarSimon Holm Thøgersen <odie@cs.aau.dk>
Reported-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      54481cf8
  3. 19 Jun, 2008 12 commits
    • Jordan Crouse's avatar
      x86, geode: add a VSA2 ID for General Software · ffe6e1da
      Jordan Crouse authored 
      General Software writes their own VSA2 module for their version
of the Geode BIOS, which returns a different ID then the standard
VSA2.  This was causing the framebuffer driver to break for most
GSW boards.
Signed-off-by: default avatarJordan Crouse <jordan.crouse@amd.com>
Cc: tglx@linutronix.de
Cc: linux-geode@lists.infradead.org
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      ffe6e1da
    • Bernhard Walle's avatar
      x86: use BOOTMEM_EXCLUSIVE on 32-bit · d3942cff
      Bernhard Walle authored 
      This patch uses the BOOTMEM_EXCLUSIVE for crashkernel reservation also for
i386 and prints a error message on failure.

The patch is still for 2.6.26 since it is only bug fixing. The unification
of reserve_crashkernel() between i386 and x86_64 should be done for 2.6.27.
Signed-off-by: default avatarBernhard Walle <bwalle@suse.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
      d3942cff
    • Mikael Pettersson's avatar
      x86, 32-bit: fix boot failure on TSC-less processors · df17b1d9
      Mikael Pettersson authored 
      Booting 2.6.26-rc6 on my 486 DX/4 fails with a "BUG: Int 6"
(invalid opcode) and a kernel halt immediately after the
kernel has been uncompressed. The BUG shows EIP pointing
to an rdtsc instruction in native_read_tsc(), invoked from
native_sched_clock().

(This error occurs so early that not even the serial console
can capture it.)

A bisection showed that this bug first occurs in 2.6.26-rc3-git7,
via commit 9ccc906c:

>x86: distangle user disabled TSC from unstable
>
>tsc_enabled is set to 0 from the command line switch "notsc" and from
>the mark_tsc_unstable code. Seperate those functionalities and replace
>tsc_enable with tsc_disable. This makes also the native_sched_clock()
>decision when to use TSC understandable.
>
>Preparatory patch to solve the sched_clock() issue on 32 bit.
>
>Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

The core reason for this bug is that native_sched_clock() gets
called before tsc_init().

Before the commit above, tsc_32.c used a "tsc_enabled" variable
which defaulted to 0 == disabled, and which only got enabled late
in tsc_init(). Thus early calls to native_sched_clock() would skip
the TSC and use jiffies instead.

After the commit above, tsc_32.c uses a "tsc_disabled" variable
which defaults to 0, meaning that the TSC is Ok to use. Early calls
to native_sched_clock() now erroneously try to use the TSC on
!cpu_has_tsc processors, leading to invalid opcode exceptions.

My proposed fix is to initialise tsc_disabled to a "soft disabled"
state distinct from the hard disabled state set up by the "notsc"
kernel option. This fixes the native_sched_clock() problem. It also
allows tsc_init() to be simplified: instead of setting tsc_disabled = 1
on every error return, we just set tsc_disabled = 0 once when all
checks have succeeded.

I've verified that this lets my 486 boot again. I've also verified
that a Core2 machine still uses the TSC as clocksource after the patch.
Signed-off-by: default avatarMikael Pettersson <mikpe@it.uu.se>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      df17b1d9
    • Suresh Siddha's avatar
      x86: fix NULL pointer deref in __switch_to · 75118a82
      Suresh Siddha authored 
      Patrick McHardy reported a crash:

> > I get this oops once a day, its apparently triggered by something
> > run by cron, but the process is a different one each time.
> >
> > Kernel is -git from yesterday shortly before the -rc6 release
> > (last commit is the usb-2.6 merge, the x86 patches are missing),
> > .config is attached.
> >
> > I'll retry with current -git, but the patches that have gone in
> > since I last updated don't look related.
> >
> > [62060.043009] BUG: unable to handle kernel NULL pointer dereference at
> > 000001ff
> > [62060.043009] IP: [<c0102a9b>] __switch_to+0x2f/0x118
> > [62060.043009] *pde = 00000000
> > [62060.043009] Oops: 0002 [#1] PREEMPT

Vegard Nossum analyzed it:

> This decodes to
>
>    0:   0f ae 00                fxsave (%eax)
>
> so it's related to the floating-point context. This is the exact
> location of the crash:
>
> $ addr2line -e arch/x86/kernel/process_32.o -i ab0
> include/asm/i387.h:232
> include/asm/i387.h:262
> arch/x86/kernel/process_32.c:595
>
> ...so it looks like prev_task->thread.xstate->fxsave has become NULL.
> Or maybe it never had any other value.

Somehow (as described below) TS_USEDFPU is set but the fpu is not
allocated or freed.

Another possible FPU pre-emption issue with the sleazy FPU optimization
which was benign before but not so anymore, with the dynamic FPU allocation
patch.

New task is getting exec'd and it is prempted at the below point.

flush_thread() {
	...
	/*
	* Forget coprocessor state..
	*/
	clear_fpu(tsk);
		<----- Preemption point
	clear_used_math();
	...
}

Now when it context switches in again, as the used_math() is still set
and fpu_counter can be > 5, we will do a math_state_restore() which sets
the task's TS_USEDFPU. After it continues from the above preemption point
it does clear_used_math() and much later free_thread_xstate().

Now, at the next context switch, it is quite possible that xstate is
null, used_math() is not set and TS_USEDFPU is still set. This will
trigger unlazy_fpu() causing kernel oops.

Fix this  by clearing tsk's fpu_counter before clearing task's fpu.
Reported-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      75118a82
    • Jeremy Fitzhardinge's avatar
      x86: set PAE PHYSICAL_MASK_SHIFT to 44 bits. · ad524d46
      Jeremy Fitzhardinge authored 
      When a 64-bit x86 processor runs in 32-bit PAE mode, a pte can
potentially have the same number of physical address bits as the
64-bit host ("Enhanced Legacy PAE Paging").  This means, in theory,
we could have up to 52 bits of physical address in a pte.

The 32-bit kernel uses a 32-bit unsigned long to represent a pfn.
This means that it can only represent physical addresses up to 32+12=44
bits wide.  Rather than widening pfns everywhere, just set 2^44 as the
Linux x86_32-PAE architectural limit for physical address size.

This is a bugfix for two cases:
1. running a 32-bit PAE kernel on a machine with
  more than 64GB RAM.
2. running a 32-bit PAE Xen guest on a host machine with
  more than 64GB RAM

In both cases, a pte could need to have more than 36 bits of physical,
and masking it to 36-bits will cause fairly severe havoc.
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      ad524d46
    • Dave Airlie's avatar
      agp: brown paper bag patch - put back two lines that got lost · 9bedbcb2
      Dave Airlie authored 
      Commit 62c96b9d ("agp/intel: cleanup
some serious whitespace badness") didn't just fix whitespace.  It also
lost two lines.

Noticed by Linus. No more whitespace diffs for me.
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9bedbcb2
    • Linus Torvalds's avatar
      Merge branch 'agp-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/agp-2.6 · 3506ba7b
      Linus Torvalds authored 
      * 'agp-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/agp-2.6:
  agp/intel: cleanup some serious whitespace badness
  [AGP] intel_agp: Add support for Intel 4 series chipsets
  [AGP] intel_agp: extra stolen mem size available for IGD_GM chipset
  agp: more boolean conversions.
  drivers/char/agp - use bool
  agp: two-stage page destruction issue
  agp/via: fixup pci ids
      3506ba7b
    • Dave Airlie's avatar
      agp/intel: cleanup some serious whitespace badness · 62c96b9d
      Dave Airlie authored 
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      62c96b9d
    • Zhenyu Wang's avatar
      [AGP] intel_agp: Add support for Intel 4 series chipsets · 25ce77ab
      Zhenyu Wang authored 
      Signed-off-by: default avatarZhenyu Wang <zhenyu.z.wang@intel.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      25ce77ab
    • Zhenyu Wang's avatar
      [AGP] intel_agp: extra stolen mem size available for IGD_GM chipset · 598d1448
      Zhenyu Wang authored 
      This adds missing stolen memory size detect for IGD_GM, be sure to
detect right size as current X intel driver (2.3.2) which has already
worked out.
Signed-off-by: default avatarZhenyu Wang <zhenyu.z.wang@intel.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      598d1448
    • Dave Airlie's avatar
      agp: more boolean conversions. · 9516b030
      Dave Airlie authored 
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      9516b030
    • Joe Perches's avatar
      drivers/char/agp - use bool · c7258012
      Joe Perches authored 
      Use boolean in AGP instead of having own TRUE/FALSE

--
Signed-off-by: default avatarJoe Perches <joe@perches.com>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      c7258012
  5. 18 Jun, 2008 26 commits
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