linux-toradex.git/arch/x86/include, branch v3.0.69

x86-32, mm: Remove reference to resume_map_numa_kva()

2013-02-28T14:32:23+00:00

commit bb112aec5ee41427e9b9726e3d57b896709598ed upstream.

Remove reference to removed function resume_map_numa_kva().

Signed-off-by: H. Peter Anvin 
Cc: Dave Hansen 
Link: http://lkml.kernel.org/r/20130131005616.1C79F411@kernel.stglabs.ibm.com
Signed-off-by: Greg Kroah-Hartman

x86/mm: Check if PUD is large when validating a kernel address

2013-02-17T18:46:20+00:00

commit 0ee364eb316348ddf3e0dfcd986f5f13f528f821 upstream.

A user reported the following oops when a backup process reads
/proc/kcore:

 BUG: unable to handle kernel paging request at ffffbb00ff33b000
 IP: [] kern_addr_valid+0xbe/0x110
 [...]

 Call Trace:
  [] read_kcore+0x17a/0x370
  [] proc_reg_read+0x77/0xc0
  [] vfs_read+0xc7/0x130
  [] sys_read+0x53/0xa0
  [] system_call_fastpath+0x16/0x1b

Investigation determined that the bug triggered when reading
system RAM at the 4G mark. On this system, that was the first
address using 1G pages for the virt->phys direct mapping so the
PUD is pointing to a physical address, not a PMD page.

The problem is that the page table walker in kern_addr_valid() is
not checking pud_large() and treats the physical address as if
it was a PMD.  If it happens to look like pmd_none then it'll
silently fail, probably returning zeros instead of real data. If
the data happens to look like a present PMD though, it will be
walked resulting in the oops above.

This patch adds the necessary pud_large() check.

Unfortunately the problem was not readily reproducible and now
they are running the backup program without accessing
/proc/kcore so the patch has not been validated but I think it
makes sense.

Signed-off-by: Mel Gorman 
Reviewed-by: Rik van Riel 
Reviewed-by: Michal Hocko 
Acked-by: Johannes Weiner 
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20130211145236.GX21389@suse.de
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86: Use enum instead of literals for trap values [PARTIAL]

2013-01-28T04:46:29+00:00

[Based on commit c94082656dac74257f63e91f78d5d458ac781fa5 upstream, only
taking the traps.h portion.]

The traps are referred to by their numbers and it can be difficult to
understand them while reading the code without context. This patch adds
enumeration of the trap numbers and replaces the numbers with the correct
enum for x86.

Signed-off-by: Kees Cook 
Link: http://lkml.kernel.org/r/20120310000710.GA32667@www.outflux.net
Signed-off-by: H. Peter Anvin 
Signed-off-by: Robin Holt 
Signed-off-by: Greg Kroah-Hartman

x86-32: Fix invalid stack address while in softirq

2012-12-03T20:59:13+00:00

commit 1022623842cb72ee4d0dbf02f6937f38c92c3f41 upstream.

In 32 bit the stack address provided by kernel_stack_pointer() may
point to an invalid range causing NULL pointer access or page faults
while in NMI (see trace below). This happens if called in softirq
context and if the stack is empty. The address at ®s->sp is then
out of range.

Fixing this by checking if regs and ®s->sp are in the same stack
context. Otherwise return the previous stack pointer stored in struct
thread_info. If that address is invalid too, return address of regs.

 BUG: unable to handle kernel NULL pointer dereference at 0000000a
 IP: [] print_context_stack+0x6e/0x8d
 *pde = 00000000
 Oops: 0000 [#1] SMP
 Modules linked in:
 Pid: 4434, comm: perl Not tainted 3.6.0-rc3-oprofile-i386-standard-g4411a05 #4 Hewlett-Packard HP xw9400 Workstation/0A1Ch
 EIP: 0060:[] EFLAGS: 00010093 CPU: 0
 EIP is at print_context_stack+0x6e/0x8d
 EAX: ffffe000 EBX: 0000000a ECX: f4435f94 EDX: 0000000a
 ESI: f4435f94 EDI: f4435f94 EBP: f5409ec0 ESP: f5409ea0
  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
 CR0: 8005003b CR2: 0000000a CR3: 34ac9000 CR4: 000007d0
 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
 DR6: ffff0ff0 DR7: 00000400
 Process perl (pid: 4434, ti=f5408000 task=f5637850 task.ti=f4434000)
 Stack:
  000003e8 ffffe000 00001ffc f4e39b00 00000000 0000000a f4435f94 c155198c
  f5409ef0 c1003723 c155198c f5409f04 00000000 f5409edc 00000000 00000000
  f5409ee8 f4435f94 f5409fc4 00000001 f5409f1c c12dce1c 00000000 c155198c
 Call Trace:
  [] dump_trace+0x7b/0xa1
  [] x86_backtrace+0x40/0x88
  [] ? oprofile_add_sample+0x56/0x84
  [] oprofile_add_sample+0x75/0x84
  [] op_amd_check_ctrs+0x46/0x260
  [] profile_exceptions_notify+0x23/0x4c
  [] nmi_handle+0x31/0x4a
  [] ? ftrace_define_fields_irq_handler_entry+0x45/0x45
  [] do_nmi+0xa0/0x2ff
  [] ? ftrace_define_fields_irq_handler_entry+0x45/0x45
  [] nmi_stack_correct+0x28/0x2d
  [] ? ftrace_define_fields_irq_handler_entry+0x45/0x45
  [] ? do_softirq+0x4b/0x7f
  
  [] irq_exit+0x35/0x5b
  [] smp_apic_timer_interrupt+0x6c/0x7a
  [] apic_timer_interrupt+0x2a/0x30
 Code: 89 fe eb 08 31 c9 8b 45 0c ff 55 ec 83 c3 04 83 7d 10 00 74 0c 3b 5d 10 73 26 3b 5d e4 73 0c eb 1f 3b 5d f0 76 1a 3b 5d e8 73 15 <8b> 13 89 d0 89 55 e0 e8 ad 42 03 00 85 c0 8b 55 e0 75 a6 eb cc
 EIP: [] print_context_stack+0x6e/0x8d SS:ESP 0068:f5409ea0
 CR2: 000000000000000a
 ---[ end trace 62afee3481b00012 ]---
 Kernel panic - not syncing: Fatal exception in interrupt

V2:
* add comments to kernel_stack_pointer()
* always return a valid stack address by falling back to the address
  of regs

Reported-by: Yang Wei 
Signed-off-by: Robert Richter 
Link: http://lkml.kernel.org/r/20120912135059.GZ8285@erda.amd.com
Signed-off-by: H. Peter Anvin 
Cc: Jun Zhang 
Signed-off-by: Greg Kroah-Hartman

x86: Remove the ancient and deprecated disable_hlt() and enable_hlt() facility

2012-11-05T08:44:26+00:00

commit f6365201d8a21fb347260f89d6e9b3e718d63c70 upstream.

The X86_32-only disable_hlt/enable_hlt mechanism was used by the
32-bit floppy driver. Its effect was to replace the use of the
HLT instruction inside default_idle() with cpu_relax() - essentially
it turned off the use of HLT.

This workaround was commented in the code as:

 "disable hlt during certain critical i/o operations"

 "This halt magic was a workaround for ancient floppy DMA
  wreckage. It should be safe to remove."

H. Peter Anvin additionally adds:

 "To the best of my knowledge, no-hlt only existed because of
  flaky power distributions on 386/486 systems which were sold to
  run DOS.  Since DOS did no power management of any kind,
  including HLT, the power draw was fairly uniform; when exposed
  to the much hhigher noise levels you got when Linux used HLT
  caused some of these systems to fail.

  They were by far in the minority even back then."

Alan Cox further says:

 "Also for the Cyrix 5510 which tended to go castors up if a HLT
  occurred during a DMA cycle and on a few other boxes HLT during
  DMA tended to go astray.

  Do we care ? I doubt it. The 5510 was pretty obscure, the 5520
  fixed it, the 5530 is probably the oldest still in any kind of
  use."

So, let's finally drop this.

Signed-off-by: Len Brown 
Signed-off-by: Josh Boyer 
Signed-off-by: Andrew Morton 
Acked-by: "H. Peter Anvin" 
Acked-by: Alan Cox 
Cc: Stephen Hemminger 
Link: http://lkml.kernel.org/n/tip-3rhk9bzf0x9rljkv488tloib@git.kernel.org
[ If anyone cares then alternative instruction patching could be
  used to replace HLT with a one-byte NOP instruction. Much simpler. ]
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86, random: Verify RDRAND functionality and allow it to be disabled

2012-10-21T16:17:12+00:00

commit 49d859d78c5aeb998b6936fcb5f288f78d713489 upstream.

If the CPU declares that RDRAND is available, go through a guranteed
reseed sequence, and make sure that it is actually working (producing
data.)   If it does not, disable the CPU feature flag.

Allow RDRAND to be disabled on the command line (as opposed to at
compile time) for a user who has special requirements with regards to
random numbers.

Signed-off-by: H. Peter Anvin 
Cc: Matt Mackall 
Cc: Herbert Xu 
Cc: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

x86, random: Architectural inlines to get random integers with RDRAND

2012-10-21T16:17:12+00:00

commit 628c6246d47b85f5357298601df2444d7f4dd3fd upstream.

Architectural inlines to get random ints and longs using the RDRAND
instruction.

Intel has introduced a new RDRAND instruction, a Digital Random Number
Generator (DRNG), which is functionally an high bandwidth entropy
source, cryptographic whitener, and integrity monitor all built into
hardware.  This enables RDRAND to be used directly, bypassing the
kernel random number pool.

For technical documentation, see:

http://software.intel.com/en-us/articles/download-the-latest-bull-mountain-software-implementation-guide/

In this patch, this is *only* used for the nonblocking random number
pool.  RDRAND is a nonblocking source, similar to our /dev/urandom,
and is therefore not a direct replacement for /dev/random.  The
architectural hooks presented in the previous patch only feed the
kernel internal users, which only use the nonblocking pool, and so
this is not a problem.

Since this instruction is available in userspace, there is no reason
to have a /dev/hw_rng device driver for the purpose of feeding rngd.
This is especially so since RDRAND is a nonblocking source, and needs
additional whitening and reduction (see the above technical
documentation for details) in order to be of "pure entropy source"
quality.

The CONFIG_EXPERT compile-time option can be used to disable this use
of RDRAND.

Signed-off-by: H. Peter Anvin 
Originally-by: Fenghua Yu 
Cc: Matt Mackall 
Cc: Herbert Xu 
Cc: "Theodore Ts'o" 
Signed-off-by: Greg Kroah-Hartman

mm: thp: fix pmd_present for split_huge_page and PROT_NONE with THP

2012-10-12T20:28:10+00:00

commit 027ef6c87853b0a9df53175063028edb4950d476 upstream.

In many places !pmd_present has been converted to pmd_none.  For pmds
that's equivalent and pmd_none is quicker so using pmd_none is better.

However (unless we delete pmd_present) we should provide an accurate
pmd_present too.  This will avoid the risk of code thinking the pmd is non
present because it's under __split_huge_page_map, see the pmd_mknotpresent
there and the comment above it.

If the page has been mprotected as PROT_NONE, it would also lead to a
pmd_present false negative in the same way as the race with
split_huge_page.

Because the PSE bit stays on at all times (both during split_huge_page and
when the _PAGE_PROTNONE bit get set), we could only check for the PSE bit,
but checking the PROTNONE bit too is still good to remember pmd_present
must always keep PROT_NONE into account.

This explains a not reproducible BUG_ON that was seldom reported on the
lists.

The same issue is in pmd_large, it would go wrong with both PROT_NONE and
if it races with split_huge_page.

Signed-off-by: Andrea Arcangeli 
Acked-by: Rik van Riel 
Cc: Johannes Weiner 
Cc: Hugh Dickins 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

x86: Simplify code by removing a !SMP #ifdefs from 'struct cpuinfo_x86'

2012-08-15T19:04:09+00:00

commit 141168c36cdee3ff23d9c7700b0edc47cb65479f and
commit 3f806e50981825fa56a7f1938f24c0680816be45 upstream.

Several fields in struct cpuinfo_x86 were not defined for the
!SMP case, likely to save space.  However, those fields still
have some meaning for UP, and keeping them allows some #ifdef
removal from other files.  The additional size of the UP kernel
from this change is not significant enough to worry about
keeping up the distinction:

	   text    data     bss     dec     hex filename
	4737168	 506459	 972040	6215667	 5ed7f3	vmlinux.o.before
	4737444	 506459	 972040	6215943	 5ed907	vmlinux.o.after

for a difference of 276 bytes for an example UP config.

If someone wants those 276 bytes back badly then it should
be implemented in a cleaner way.

Signed-off-by: Kevin Winchester 
Cc: Steffen Persvold 
Link: http://lkml.kernel.org/r/1324428742-12498-1-git-send-email-kjwinchester@gmail.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Borislav Petkov 
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman

x86, cpufeature: Rename X86_FEATURE_DTS to X86_FEATURE_DTHERM

2012-07-16T15:47:51+00:00

commit 4ad33411308596f2f918603509729922a1ec4411 upstream.

It makes sense to label "Digital Thermal Sensor" as "DTS", but
unfortunately the string "dts" was already used for "Debug Store", and
/proc/cpuinfo is a user space ABI.

Therefore, rename this to "dtherm".

This conflict went into mainline via the hwmon tree without any x86
maintainer ack, and without any kind of hint in the subject.

    a4659053 x86/hwmon: fix initialization of coretemp

Reported-by: Jean Delvare 
Link: http://lkml.kernel.org/r/4FE34BCB.5050305@linux.intel.com
Cc: Jan Beulich 
Signed-off-by: H. Peter Anvin 
[bwh: Backported to 3.2: drop the coretemp device table change]
Signed-off-by: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman