linux-toradex.git/arch/x86/entry, branch v4.4.5

x86/entry/compat: Add missing CLAC to entry_INT80_32

2016-03-03T23:07:30+00:00

commit 3d44d51bd339766f0178f0cf2e8d048b4a4872aa upstream.

This doesn't seem to fix a regression -- I don't think the CLAC was
ever there.

I double-checked in a debugger: entries through the int80 gate do
not automatically clear AC.

Stable maintainers: I can provide a backport to 4.3 and earlier if
needed.  This needs to be backported all the way to 3.10.

Reported-by: Brian Gerst 
Signed-off-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 63bcff2a307b ("x86, smap: Add STAC and CLAC instructions to control user space access")
Link: http://lkml.kernel.org/r/b02b7e71ae54074be01fc171cbd4b72517055c0e.1456345086.git.luto@kernel.org
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/entry: Restore traditional SYSENTER calling convention

2015-12-21T15:05:01+00:00

It turns out that some Android versions hardcode the SYSENTER
calling convention.  This is buggy and will cause problems no
matter what the kernel does.  Nonetheless, we should try to
support it.

Credit goes to Linus for pointing out a clean way to handle
the SYSENTER/SYSCALL clobber differences while preserving
straightforward DWARF annotations.

I believe that the original offending Android commit was:

https://android.googlesource.com/platform%2Fbionic/+/7dc3684d7a2587e43e6d2a8e0e3f39bf759bd535

Reported-by: Qiuxu Zhuo 
Signed-off-by: Andy Lutomirski 
Reviewed-and-tested-by: Borislav Petkov 
Cc: 
Cc: Su Tao 
Cc: Denys Vlasenko 
Cc: 
Cc: 
Cc: Brian Gerst 
Cc: Mingwei Shi 
Cc: Linus Torvalds 
Signed-off-by: Thomas Gleixner

x86/entry: Fix some comments

2015-12-21T15:05:01+00:00

Signed-off-by: Andy Lutomirski 
Reviewed-and-tested-by: Borislav Petkov 
Cc: 
Cc: Su Tao 
Cc: Denys Vlasenko 
Cc: 
Cc: 
Cc: 
Cc: Brian Gerst 
Cc: Mingwei Shi 
Cc: Linus Torvalds 
Signed-off-by: Thomas Gleixner

x86/xen: Avoid fast syscall path for Xen PV guests

2015-12-19T08:55:52+00:00

After 32-bit syscall rewrite, and specifically after commit:

  5f310f739b4c ("x86/entry/32: Re-implement SYSENTER using the new C path")

... the stack frame that is passed to xen_sysexit is no longer a
"standard" one (i.e. it's not pt_regs).

Since we end up calling xen_iret from xen_sysexit we don't need
to fix up the stack and instead follow entry_SYSENTER_32's IRET
path directly to xen_iret.

We can do the same thing for compat mode even though stack does
not need to be fixed. This will allow us to drop usergs_sysret32
paravirt op (in the subsequent patch)

Suggested-by: Andy Lutomirski 
Signed-off-by: Boris Ostrovsky 
Reviewed-by: Borislav Petkov 
Acked-by: Andy Lutomirski 
Cc: Andrew Morton 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: david.vrabel@citrix.com
Cc: konrad.wilk@oracle.com
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1447970147-1733-2-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Thomas Gleixner

x86/entry/64: Fix irqflag tracing wrt context tracking

2015-11-24T08:55:02+00:00

Paolo pointed out that enter_from_user_mode could be called
while irqflags were traced as though IRQs were on.

In principle, this could confuse lockdep.  It doesn't cause any
problems that I've seen in any configuration, but if I build
with CONFIG_DEBUG_LOCKDEP=y, enable a nohz_full CPU, and add
code like:

	if (irqs_disabled()) {
		spin_lock(&something);
		spin_unlock(&something);
	}

to the top of enter_from_user_mode, then lockdep will complain
without this fix.  It seems that lockdep's irqflags sanity
checks are too weak to detect this bug without forcing the
issue.

This patch adds one byte to normal kernels, and it's IMO a bit
ugly. I haven't spotted a better way to do this yet, though.
The issue is that we can't do TRACE_IRQS_OFF until after SWAPGS
(if needed), but we're also supposed to do it before calling C
code.

An alternative approach would be to call trace_hardirqs_off in
enter_from_user_mode.  That would be less code and would not
bloat normal kernels at all, but it would be harder to see how
the code worked.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Thomas Gleixner 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: Frederic Weisbecker 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/86237e362390dfa6fec12de4d75a238acb0ae787.1447361906.git.luto@kernel.org
Signed-off-by: Ingo Molnar

mm: mlock: add new mlock system call

2015-11-06T03:34:48+00:00

With the refactored mlock code, introduce a new system call for mlock.
The new call will allow the user to specify what lock states are being
added.  mlock2 is trivial at the moment, but a follow on patch will add a
new mlock state making it useful.

Signed-off-by: Eric B Munson 
Acked-by: Michal Hocko 
Acked-by: Vlastimil Babka 
Cc: Heiko Carstens 
Cc: Geert Uytterhoeven 
Cc: Catalin Marinas 
Cc: Stephen Rothwell 
Cc: Guenter Roeck 
Cc: Jonathan Corbet 
Cc: Kirill A. Shutemov 
Cc: Michael Kerrisk 
Cc: Ralf Baechle 
Cc: Shuah Khan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2015-11-04T05:23:56+00:00

Pull x86 mm changes from Ingo Molnar:
 "The main changes are: continued PAT work by Toshi Kani, plus a new
  boot time warning about insecure RWX kernel mappings, by Stephen
  Smalley.

  The new CONFIG_DEBUG_WX=y warning is marked default-y if
  CONFIG_DEBUG_RODATA=y is already eanbled, as a special exception, as
  these bugs are hard to notice and this check already found several
  live bugs"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Warn on W^X mappings
  x86/mm: Fix no-change case in try_preserve_large_page()
  x86/mm: Fix __split_large_page() to handle large PAT bit
  x86/mm: Fix try_preserve_large_page() to handle large PAT bit
  x86/mm: Fix gup_huge_p?d() to handle large PAT bit
  x86/mm: Fix slow_virt_to_phys() to handle large PAT bit
  x86/mm: Fix page table dump to show PAT bit
  x86/asm: Add pud_pgprot() and pmd_pgprot()
  x86/asm: Fix pud/pmd interfaces to handle large PAT bit
  x86/asm: Add pud/pmd mask interfaces to handle large PAT bit
  x86/asm: Move PUD_PAGE macros to page_types.h
  x86/vdso32: Define PGTABLE_LEVELS to 32bit VDSO

x86/entry/32: Fix FS and GS restore in opportunistic SYSEXIT

2015-10-18T10:11:16+00:00

We either need to restore them before popping and thus changing
ESP, or we need to adjust the offsets.  The former is simpler.

Reported-and-tested-by: Borislav Petkov 
Signed-off-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 5f310f739b4c x86/entry/32: ("Re-implement SYSENTER using the new C path")
Link: http://lkml.kernel.org/r/461e5c7d8fa3821529893a4893ac9c4bc37f9e17.1445035014.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/entry/32: Fix entry_INT80_32() to expect interrupts to be on

2015-10-18T10:11:16+00:00

When I rewrote entry_INT80_32, I thought that int80 was an
interrupt gate.  It's a trap gate.  *facepalm*

Thanks to Brian Gerst for pointing out that it's better to
change the entry code than to change the gate type.

Suggested-by: Brian Gerst 
Reported-and-tested-by: Borislav Petkov 
Signed-off-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Fixes: 150ac78d63af ("x86/entry/32: Switch INT80 to the new C syscall path")
Link: http://lkml.kernel.org/r/dc09d9b574a5c1dcca996847875c73f8341ce0ad.1445035014.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/entry/64/compat: Document sysenter_fix_flags's reason for existence

2015-10-11T09:06:40+00:00

The code under the label can normally be inline, without the
jumping back and forth but the latter is an optimization.

Document that.

Signed-off-by: Borislav Petkov 
Acked-by: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20151009170859.GA24266@pd.tnic
Signed-off-by: Ingo Molnar