linux-stable.git/arch/x86/kernel/process_64.c, branch linux-4.7.y

x86/mm/pkeys: Do not skip PKRU register if debug registers are not used

2016-10-16T15:50:38+00:00

commit ba6d018e3d2f6a0fad58a668cadf66b2d1f80f59 upstream.

__show_regs() fails to dump the PKRU state when the debug registers are in
their default state because there is a return statement on the debug
register state.

Change the logic to report PKRU value even when debug registers are in
their default state.

Fixes:c0b17b5bd4b7 ("x86/mm/pkeys: Dump PKRU with other kernel registers")
Signed-off-by: Nicolas Iooss 
Acked-by: Dave Hansen 
Link: http://lkml.kernel.org/r/20160910183045.4618-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

x86/fsgsbase/64: Use TASK_SIZE_MAX for FSBASE/GSBASE upper limits

2016-05-20T07:10:03+00:00

The GSBASE upper limit exists to prevent user code from confusing
the paranoid idtentry path.  The FSBASE upper limit is just for
consistency.  There's no need to enforce a smaller limit for 32-bit
tasks.

Just use TASK_SIZE_MAX.  This simplifies the logic and will save a
few bytes of code.

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 
Link: http://lkml.kernel.org/r/5357f2fe0f103eabf005773b70722451eab09a89.1462897104.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/arch_prctl/64: Restore accidentally removed put_cpu() in ARCH_SET_GS

2016-05-13T11:50:15+00:00

This fixes an oversight in:

	731e33e39a5b95 ("Remove FSBASE/GSBASE < 4G optimization")

Signed-off-by: Mateusz Guzik 
Cc: Alexander Shishkin 
Cc: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Arnaldo Carvalho de Melo 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Jiri Olsa 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Stephane Eranian 
Cc: Thomas Gleixner 
Cc: Vince Weaver 
Link: http://lkml.kernel.org/r/1462913803-29634-1-git-send-email-mguzik@redhat.com
Signed-off-by: Ingo Molnar

x86/asm/64: Rename thread_struct's fs and gs to fsbase and gsbase

2016-04-29T09:56:42+00:00

Unlike ds and es, these are base addresses, not selectors.  Rename
them so their meaning is more obvious.

On x86_32, the field is still called fs.  Fixing that could make sense
as a future cleanup.

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 
Link: http://lkml.kernel.org/r/69a18a51c4cba0ce29a241e570fc618ad721d908.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/arch_prctl/64: Remove FSBASE/GSBASE < 4G optimization

2016-04-29T09:56:41+00:00

As far as I know, the optimization doesn't work on any modern distro
because modern distros use high addresses for ASLR.  Remove it.

The ptrace code was either wrong or very strange, but the behavior
with this patch should be essentially identical to the behavior
without this patch unless user code goes out of its way to mislead
ptrace.

On newer CPUs, once the FSGSBASE instructions are enabled, we won't
want to use the optimized variant anyway.

This isn't actually much of a performance regression, it has no effect
on normal dynamically linked programs, and it's a considerably
simplification. It also removes some nasty special cases from code
that is already way too full of special cases for comfort.

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 
Link: http://lkml.kernel.org/r/dd1599b08866961dba9d2458faa6bbd7fba471d7.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()

2016-04-19T08:44:52+00:00

The is_ia32_task()/is_x32_task() function names are a big misnomer: they
suggests that the compat-ness of a system call is a task property, which
is not true, the compatness of a system call purely depends on how it
was invoked through the system call layer.

A task may call 32-bit and 64-bit and x32 system calls without changing
any of its kernel visible state.

This specific minomer is also actively dangerous, as it might cause kernel
developers to use the wrong kind of security checks within system calls.

So rename it to in_{ia32,x32}_syscall().

Suggested-by: Andy Lutomirski 
Suggested-by: Ingo Molnar 
Signed-off-by: Dmitry Safonov 
[ Expanded the changelog. ]
Acked-by: Andy Lutomirski 
Cc: 0x7f454c46@gmail.com
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1460987025-30360-1-git-send-email-dsafonov@virtuozzo.com
Signed-off-by: Ingo Molnar

x86/asm, sched/x86: Rewrite the FS and GS context switch code

2016-04-13T08:20:42+00:00

The old code was incomprehensible and was buggy on AMD CPUs.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Rudolf Marek 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/5f6bde874c6fe6831c6711b5b1522a238ba035b4.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar

x86/arch_prctl: Fix ARCH_GET_FS and ARCH_GET_GS

2016-04-13T08:20:41+00:00

ARCH_GET_FS and ARCH_GET_GS attempted to figure out the fsbase and
gsbase respectively from saved thread state.  This was wrong: fsbase
and gsbase live in registers while a thread is running, not in
memory.

For reasons I can't fathom, the fsbase and gsbase code were
different.  Since neither was correct, I didn't try to figure out
what the point of the difference was.

Change it to simply read the MSRs.

The code for reading the base for a remote thread is also completely
wrong if the target thread uses its own descriptors (which is the case
for all 32-bit threaded programs), but fixing that is a different
story.

Signed-off-by: Andy Lutomirski 
Reviewed-by: Borislav Petkov 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Rudolf Marek 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/c6e7b507c72ca3bdbf6c7a8a3ceaa0334e873bd9.1460075211.git.luto@kernel.org
Signed-off-by: Ingo Molnar

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

2016-03-24T16:47:32+00:00

Pull x86 fixes from Ingo Molnar:
 "Misc fixes:

   - fix hotplug bugs
   - fix irq live lock
   - fix various topology handling bugs
   - fix APIC ACK ordering
   - fix PV iopl handling
   - fix speling
   - fix/tweak memcpy_mcsafe() return value
   - fix fbcon bug
   - remove stray prototypes"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/msr: Remove unused native_read_tscp()
  x86/apic: Remove declaration of unused hw_nmi_is_cpu_stuck
  x86/oprofile/nmi: Add missing hotplug FROZEN handling
  x86/hpet: Use proper mask to modify hotplug action
  x86/apic/uv: Fix the hotplug notifier
  x86/apb/timer: Use proper mask to modify hotplug action
  x86/topology: Use total_cpus not nr_cpu_ids for logical packages
  x86/topology: Fix Intel HT disable
  x86/topology: Fix logical package mapping
  x86/irq: Cure live lock in fixup_irqs()
  x86/tsc: Prevent NULL pointer deref in calibrate_delay_is_known()
  x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
  x86/iopl: Fix iopl capability check on Xen PV
  x86/iopl/64: Properly context-switch IOPL on Xen PV
  selftests/x86: Add an iopl test
  x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()
  x86/video: Don't assume all FB devices are PCI devices
  arch/x86/irq: Purge useless handler declarations from hw_irq.h
  x86: Fix misspellings in comments

x86/compat: remove is_compat_task()

2016-03-22T22:36:02+00:00

x86's is_compat_task always checked the current syscall type, not the
task type.  It has no non-arch users any more, so just remove it to
avoid confusion.

On x86, nothing should really be checking the task ABI.  There are
legitimate users for the syscall ABI and for the mm ABI.

Signed-off-by: Andy Lutomirski 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds