The CPACF code makes some assumptions about the availablity of hardware
support. E.g. if the machine supports KM(AES-256) without chaining it is
assumed that KMC(AES-256) with chaining is available as well. For the
existing CPUs this is true but the architecturally correct way is to
check each CPACF functions on its own. This is what the query function
of each instructions is all about.
Reviewed-by: NHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The aes and the des module register multiple crypto algorithms
dependent on the availability of specific CPACF instructions.
To simplify the deregistration with crypto_unregister_alg add
an array with pointers to the successfully registered algorithms
and use it for the error handling in the init function and in
the module exit function.
Reviewed-by: NHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The CPACF instructions can complete with three different condition codes:
CC=0 for successful completion, CC=1 if the protected key verification
failed, and CC=3 for partial completion.

The inline functions will restart the CPACF instruction for partial
completion, this removes the CC=3 case. The CC=1 case is only relevant
for the protected key functions of the KM, KMC, KMAC and KMCTR
instructions. As the protected key functions are not used by the
current code, there is no need for any kind of return code handling.
Reviewed-by: NHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Use a separate define for the decryption modifier bit instead of
duplicating the function codes for encryption / decrypton.
In addition use an unsigned type for the function code.
Reviewed-by: NHarald Freudenberger <freude@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Using vector registers is slightly faster:

raid6: vx128x8  gen() 19705 MB/s
raid6: vx128x8  xor() 11886 MB/s
raid6: using algorithm vx128x8 gen() 19705 MB/s
raid6: .... xor() 11886 MB/s, rmw enabled

vs the software algorithms:

raid6: int64x1  gen()  3018 MB/s
raid6: int64x1  xor()  1429 MB/s
raid6: int64x2  gen()  4661 MB/s
raid6: int64x2  xor()  3143 MB/s
raid6: int64x4  gen()  5392 MB/s
raid6: int64x4  xor()  3509 MB/s
raid6: int64x8  gen()  4441 MB/s
raid6: int64x8  xor()  3207 MB/s
raid6: using algorithm int64x4 gen() 5392 MB/s
raid6: .... xor() 3509 MB/s, rmw enabled
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The machine check handler will do one of two things if the floating-point
control, a floating point register or a vector register can not be
revalidated:
1) if the PSW indicates user mode the process is terminated
2) if the PSW indicates kernel mode the system is stopped

To unconditionally stop the system for 2) is incorrect.

There are three possible outcomes if the floating-point control, a
floating point register or a vector registers can not be revalidated:
1) The kernel is inside a kernel_fpu_begin/kernel_fpu_end block and
   needs the register. The system is stopped.
2) No active kernel_fpu_begin/kernel_fpu_end block and the CIF_CPU bit
   is not set. The user space process needs the register and is killed.
3) No active kernel_fpu_begin/kernel_fpu_end block and the CIF_FPU bit
   is set. Neither the kernel nor the user space process needs the
   lost register. Just revalidate it and continue.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

In case of nested user of the FPU or vector registers in the kernel
the current code uses the mask of the FPU/vector registers of the
previous contexts to decide which registers to save and restore.
E.g. if the previous context used KERNEL_VXR_V0V7 and the next
context wants to use KERNEL_VXR_V24V31 the first 8 vector registers
are stored to the FPU state structure. But this is not necessary
as the next context does not use these registers.

Rework the FPU/vector register save and restore code. The new code
does a few things differently:
1) A lowcore field is used instead of a per-cpu variable.
2) The kernel_fpu_end function now has two parameters just like
   kernel_fpu_begin. The register flags are required by both
   functions to save / restore the minimal register set.
3) The inline functions kernel_fpu_begin/kernel_fpu_end now do the
   update of the register masks. If the user space FPU registers
   have already been stored neither save_fpu_regs nor the
   __kernel_fpu_begin/__kernel_fpu_end functions have to be called
   for the first context. In this case kernel_fpu_begin adds 7
   instructions and kernel_fpu_end adds 4 instructions.
3) The inline assemblies in __kernel_fpu_begin / __kernel_fpu_end
   to save / restore the vector registers are simplified a bit.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

To make the vx-insn.h more versatile avoid cpp preprocessor macros
and allow to use plain numbers for vector and general purpose register
operands. With that you can emit an .include from a C file into the
assembler text and then use the vx-insn macros in inline assemblies.

For example:

asm (".include \"asm/vx-insn.h\"");

static inline void xor_vec(int x, int y, int z)
{
	asm volatile("VX %0,%1,%2"
		     : : "i" (x), "i" (y), "i" (z));
}
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The increment might not be atomic and we're not holding the
timekeeper_lock. Therefore we might lose an update to count, resulting in
VDSO being trapped in a loop. As other archs also simply update the
values and count doesn't seem to have an impact on reloading of these
values in VDSO code, let's just remove the update of tb_update_count.
Suggested-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

By leaving fixup_cc unset, only the clock comparator of the cpu actually
doing the sync is fixed up until now.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

There are still some etr leftovers and wrong comments, let's clean that up.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The way we call do_adjtimex() today is broken. It has 0 effect, as
ADJ_OFFSET_SINGLESHOT (0x0001) in the kernel maps to !ADJ_ADJTIME
(in contrast to user space where it maps to  ADJ_OFFSET_SINGLESHOT |
ADJ_ADJTIME - 0x8001). !ADJ_ADJTIME will silently ignore all adjustments
without STA_PLL being active. We could switch to ADJ_ADJTIME or turn
STA_PLL on, but still we would run into some problems:

- Even when switching to nanoseconds, we lose accuracy.
- Successive calls to do_adjtimex() will simply overwrite any leftovers
  from the previous call (if not fully handled)
- Anything that NTP does using the sysctl heavily interferes with our
  use.
- !ADJ_ADJTIME will silently round stuff > or < than 0.5 seconds

Reusing do_adjtimex() here just feels wrong. The whole STP synchronization
works right now *somehow* only, as do_adjtimex() does nothing and our
TOD clock jumps in time, although it shouldn't. This is especially bad
as the clock could jump backwards in time. We will have to find another
way to fix this up.

As leap seconds are also not properly handled yet, let's just get rid of
all this complex logic altogether and use the correct clock_delta for
fixing up the clock comparator and keeping the sched_clock monotonic.

This change should have 0 effect on the current STP mechanism. Once we
know how to best handle sync events and leap second updates, we'll start
with a fresh implementation.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Pull facility mask patch from the KVM tree.

* tag 's390forkvm' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux
  KVM: s390: generate facility mask from readable list

Automatically generate the KVM facility mask out of a readable list.
Manually changing the masks is very error prone, especially if the
special IBM bit numbering has to be considered.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The 'report_error' interface for PCI devices found on s390 can be
used by a user space program to inject an adapter error notification.
Add a new kernel interface zpci_report_error to allow a PCI device
driver to inject these error notifications without a detour over
user space.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

cio_cancel was declared twice. Remove one of them.
Signed-off-by: NDong Jia Shi <bjsdjshi@linux.vnet.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Merge the __p[m|u]xdp_idte and __p[m|u]dp_idte_local functions into a
single __p[m|u]dp_idte function with an additional parameter.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Merge the __ptep_ipte and __ptep_ipte_local functions into a single
__ptep_ipte function with an additional parameter. The __pte_ipte_range
function is still extra as the while loops makes it hard to merge.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The __tlb_flush_mm() helper uses a global flush if the mm struct
has a gmap structure attached to it. Replace the global flush with
two individual flushes by means of the IDTE instruction if only a
single gmap is attached the the mm.
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

The local-clearing control of the IDTE instruction does not have any effect
for the clearing-by-ASCE operation. Only the invalidation-and-clearing
operation respects the local-clearing bit.

Remove __tlb_flush_idte_local and simplify the batched TLB flushing code.
Reviewed-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Pull f2fs fixes from Jaegeuk Kim:
 - fsmark regression
 - i_size race condition
 - wrong conditions in f2fs_move_file_range

* tag 'for-f2fs-v4.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs:
  f2fs: avoid potential deadlock in f2fs_move_file_range
  f2fs: allow copying file range only in between regular files
  Revert "f2fs: move i_size_write in f2fs_write_end"
  Revert "f2fs: use percpu_rw_semaphore"

Pull hardened usercopy fixes from Kees Cook:
 - avoid signed math problems on unexpected compilers
 - avoid false positives at very end of kernel text range checks

* tag 'usercopy-v4.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  usercopy: fix overlap check for kernel text
  usercopy: avoid potentially undefined behavior in pointer math

Pull crypto fixes from Herbert Xu:
 "This fixes a number of memory corruption bugs in the newly added
  sha256-mb/sha256-mb code"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: sha512-mb - fix ctx pointer
  crypto: sha256-mb - fix ctx pointer and digest copy

When running with a local patch which moves the '_stext' symbol to the
very beginning of the kernel text area, I got the following panic with
CONFIG_HARDENED_USERCOPY:

  usercopy: kernel memory exposure attempt detected from ffff88103dfff000 (<linear kernel text>) (4096 bytes)
  ------------[ cut here ]------------
  kernel BUG at mm/usercopy.c:79!
  invalid opcode: 0000 [#1] SMP
  ...
  CPU: 0 PID: 4800 Comm: cp Not tainted 4.8.0-rc3.after+ #1
  Hardware name: Dell Inc. PowerEdge R720/0X3D66, BIOS 2.5.4 01/22/2016
  task: ffff880817444140 task.stack: ffff880816274000
  RIP: 0010:[<ffffffff8121c796>] __check_object_size+0x76/0x413
  RSP: 0018:ffff880816277c40 EFLAGS: 00010246
  RAX: 000000000000006b RBX: ffff88103dfff000 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffff88081f80dfa8 RDI: ffff88081f80dfa8
  RBP: ffff880816277c90 R08: 000000000000054c R09: 0000000000000000
  R10: 0000000000000005 R11: 0000000000000006 R12: 0000000000001000
  R13: ffff88103e000000 R14: ffff88103dffffff R15: 0000000000000001
  FS:  00007fb9d1750800(0000) GS:ffff88081f800000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000021d2000 CR3: 000000081a08f000 CR4: 00000000001406f0
  Stack:
   ffff880816277cc8 0000000000010000 000000043de07000 0000000000000000
   0000000000001000 ffff880816277e60 0000000000001000 ffff880816277e28
   000000000000c000 0000000000001000 ffff880816277ce8 ffffffff8136c3a6
  Call Trace:
   [<ffffffff8136c3a6>] copy_page_to_iter_iovec+0xa6/0x1c0
   [<ffffffff8136e766>] copy_page_to_iter+0x16/0x90
   [<ffffffff811970e3>] generic_file_read_iter+0x3e3/0x7c0
   [<ffffffffa06a738d>] ? xfs_file_buffered_aio_write+0xad/0x260 [xfs]
   [<ffffffff816e6262>] ? down_read+0x12/0x40
   [<ffffffffa06a61b1>] xfs_file_buffered_aio_read+0x51/0xc0 [xfs]
   [<ffffffffa06a6692>] xfs_file_read_iter+0x62/0xb0 [xfs]
   [<ffffffff812224cf>] __vfs_read+0xdf/0x130
   [<ffffffff81222c9e>] vfs_read+0x8e/0x140
   [<ffffffff81224195>] SyS_read+0x55/0xc0
   [<ffffffff81003a47>] do_syscall_64+0x67/0x160
   [<ffffffff816e8421>] entry_SYSCALL64_slow_path+0x25/0x25
  RIP: 0033:[<00007fb9d0c33c00>] 0x7fb9d0c33c00
  RSP: 002b:00007ffc9c262f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
  RAX: ffffffffffffffda RBX: fffffffffff8ffff RCX: 00007fb9d0c33c00
  RDX: 0000000000010000 RSI: 00000000021c3000 RDI: 0000000000000004
  RBP: 00000000021c3000 R08: 0000000000000000 R09: 00007ffc9c264d6c
  R10: 00007ffc9c262c50 R11: 0000000000000246 R12: 0000000000010000
  R13: 00007ffc9c2630b0 R14: 0000000000000004 R15: 0000000000010000
  Code: 81 48 0f 44 d0 48 c7 c6 90 4d a3 81 48 c7 c0 bb b3 a2 81 48 0f 44 f0 4d 89 e1 48 89 d9 48 c7 c7 68 16 a3 81 31 c0 e8 f4 57 f7 ff <0f> 0b 48 8d 90 00 40 00 00 48 39 d3 0f 83 22 01 00 00 48 39 c3
  RIP  [<ffffffff8121c796>] __check_object_size+0x76/0x413
   RSP <ffff880816277c40>

The checked object's range [ffff88103dfff000, ffff88103e000000) is
valid, so there shouldn't have been a BUG.  The hardened usercopy code
got confused because the range's ending address is the same as the
kernel's text starting address at 0xffff88103e000000.  The overlap check
is slightly off.

Fixes: f5509cc1 ("mm: Hardened usercopy")
Signed-off-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NKees Cook <keescook@chromium.org>

check_bogus_address() checked for pointer overflow using this expression,
where 'ptr' has type 'const void *':

	ptr + n < ptr

Since pointer wraparound is undefined behavior, gcc at -O2 by default
treats it like the following, which would not behave as intended:

	(long)n < 0

Fortunately, this doesn't currently happen for kernel code because kernel
code is compiled with -fno-strict-overflow.  But the expression should be
fixed anyway to use well-defined integer arithmetic, since it could be
treated differently by different compilers in the future or could be
reported by tools checking for undefined behavior.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NKees Cook <keescook@chromium.org>

Pull ARC fixes from Vineet Gupta:

 - support for Syscall ABI v4 with upstream gcc 6.x

 - lockdep fix (Daniel Mentz)

 - gdb register clobber (Liav Rehana)

 - couple of missing exports for modules

 - other fixes here and there

* tag 'arc-4.8-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: export __udivdi3 for modules
  ARC: mm: fix build breakage with STRICT_MM_TYPECHECKS
  ARC: export kmap
  ARC: Support syscall ABI v4
  ARC: use correct offset in pt_regs for saving/restoring user mode r25
  ARC: Elide redundant setup of DMA callbacks
  ARC: Call trace_hardirqs_on() before enabling irqs

Pull GPIO fixes from Linus Walleij:
 "Here are a few GPIO fixes for v4.8.

  I was expecting some fallout from the new chardev rework but nothing
  like that turned up att all.  Instead a Kconfig confusion that I think
  I have finally nailed, then some ordinary driver noise and trivia.

  This fixes a Kconfig issue with UM: when I made GPIOLIB available to
  all archs, that included UM, but the OF part of GPIOLIB requires
  HAS_IOMEM, so we add HAS_IOMEM as a dependency to OF_GPIO.

  This in turn exposed the fact that a few GPIO drivers were implicitly
  assuming OF_GPIO as their dependency but instead depended on OF alone
  (the typical problem being a pointer inside gpio_chip not existing
  unless OF_GPIO is selected) and then UM would fail to compile with
  these drivers instead.  Then I lost patience and made any GPIO driver
  depending on just OF depend on OF_GPIO instead, that is certainly what
  they meant and the only thing that makes sense anyway.  GPIO with just
  OF but !OF_GPIO does not make sense.

  Also a fix for the max730x driver data pointer, and a minor comment
  fix for the GPIO tools"

* tag 'gpio-v4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
  gpio: make any OF dependent driver depend on OF_GPIO
  gpio: Fix OF build problem on UM
  gpio: max730x: set gpiochip data pointer before using it
  tools/gpio: fix gpio-event-mon header comment

Pull two parisc fixes from Helge Deller:
 "The first patch ensures that the high-res cr16 clocksource (which was
  added in kernel 4.7) gets choosen as default clocksource for parisc.

  The second patch moves the #define of EREFUSED down inside errno.h and
  thus unbreaks building the gccgo compiler"

* 'parisc-4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix order of EREFUSED define in errno.h
  parisc: Fix automatic selection of cr16 clocksource

This is an entirely new driver instead of yet another set of patches
to sb_edac.c because:

1) Mapping from PCI devices to socket/memory controller is significantly
   different. Skylake scatters devices on a socket across a number of
   PCI buses.
2) There is an extra level of interleaving via the "mcroute" register
   that would be a little messy to squeeze into the old driver.
3) Validation is getting too expensive. Changes to sb_edac need to
   be checked against Sandy Bridge, Ivy Bridge, Haswell, Broadwell and
   Knights Landing.
Acked-by: NAristeu Rozanski <aris@redhat.com>
Acked-by: NBorislav Petkov <bp@suse.de>
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When building gccgo in userspace, errno.h gets parsed and the go include file
sysinfo.go is generated.

Since EREFUSED is defined to the same value as ECONNREFUSED, and ECONNREFUSED
is defined later on in errno.h, this leads to go complaining that EREFUSED
isn't defined yet.

Fix this trivial problem by moving the define of EREFUSED down after
ECONNREFUSED in errno.h (and clean up the indenting while touching this line).
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org

Commit 54b66800 (parisc: Add native high-resolution sched_clock()
implementation) added support to use the CPU-internal cr16 counters as reliable
clocksource with the help of HAVE_UNSTABLE_SCHED_CLOCK.

Sadly the commit missed to remove the hack which prevented cr16 to become the
default clocksource even on SMP systems.
Signed-off-by: NHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.7+

Some module using div_u64() was failing to link because the libgcc 64-bit
divide assist routine was not being exported for modules

Reported-by: avinashp@quantenna.com
Cc: stable@vger.kernel.org
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

The kernel test robot reported a usercopy failure in the new hardened
sanity checks, due to a page-crossing copy of the FPU state into the
task structure.

This happened because the kernel test robot was testing with SLOB, which
doesn't actually do the required book-keeping for slab allocations, and
as a result the hardening code didn't realize that the task struct
allocation was one single allocation - and the sanity checks fail.

Since SLOB doesn't even claim to support hardening (and you really
shouldn't use it), the straightforward solution is to just make the
usercopy hardening code depend on the allocator supporting it.
Reported-by: Nkernel test robot <xiaolong.ye@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull i2c fixes from Wolfram Sang:
 "I2C has some pretty standard driver bugfixes and one minor cleanup"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: meson: Use complete() instead of complete_all()
  i2c: brcmstb: Use complete() instead of complete_all()
  i2c: bcm-kona: Use complete() instead of complete_all()
  i2c: bcm-iproc: Use complete() instead of complete_all()
  i2c: at91: fix support of the "alternative command" feature
  i2c: ocores: add missed clk_disable_unprepare() on failure paths
  i2c: cros-ec-tunnel: Fix usage of cros_ec_cmd_xfer()
  i2c: mux: demux-pinctrl: properly roll back when adding adapter fails

|  CC      mm/memory.o
| In file included from ../mm/memory.c:53:0:
| ../include/linux/pfn_t.h: In function ‘pfn_t_pte’:
| ../include/linux/pfn_t.h:78:2: error: conversion to non-scalar type requested
|  return pfn_pte(pfn_t_to_pfn(pfn), pgprot);

With STRICT_MM_TYPECHECKS pte_t is a struct and the offending code
forces a cast which ends up shifting a struct and hence the gcc warning.

Note that in recent past some of the arches (aarch64, s390) made
STRICT_MM_TYPECHECKS default, but we don't for ARC as this leads to slightly
worse generated code, given ARC ABI definition of returning structs
(which pte_t would become)

Quoting from ARC ABI...

  "Results of type struct are returned in a caller-supplied temporary
  variable whose address is passed in r0.
  For such functions, the arguments are shifted so that they are
  passed in r1 and up."

So
 - struct to be returned would be allocated on stack requiring extra
   code at call sites
 - callee updates stack memory to facilitate the return (vs. simple
   MOV into return reg r0)

Hence STRICT_MM_TYPECHECKS is not enabled by default for ARC

Cc: <stable@vger.kernel.org>   #4.4+
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

|  MODPOST 7 modules
| ERROR: "kmap" [fs/ext2/ext2.ko] undefined!
| ../scripts/Makefile.modpost:91: recipe for target '__modpost' failed

Cc: <stable@vger.kernel.org>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

The syscall ABI includes the gcc functional calling ABI since a syscall
implies userland caller and kernel callee.

The current gcc ABI (v3) for ARCv2 ISA required 64-bit data be passed in
even-odd register pairs, (potentially punching reg holes when passing such
values as args). This was partly driven by the fact that the double-word
LDD/STD instructions in ARCv2 expect the register alignment and thus gcc
forcing this avoids extra MOV at the cost of a few unused register (which we
have plenty anyways).

This however was rejected as part of upstreaming gcc port to HS. So the new
ABI v4 doesn't enforce the even-odd reg restriction.

Do note that for ARCompact ISA builds v3 and v4 are practically the same in
terms of gcc code generation.

In terms of change management, we infer the new ABI if gcc 6.x onwards
is used for building the kernel.

This also needs a stable backport to enable older kernels to work with
new tools/user-space

Cc: <stable@vger.kernel.org>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>

User mode callee regs are explicitly collected before signal delivery or
breakpoint trap. r25 is special for kernel as it serves as task pointer,
so user mode value is clobbered very early. It is saved in pt_regs where
generally only scratch (aka caller saved) regs are saved.

The code to access the corresponding pt_regs location had a subtle bug as
it was using load/store with scaling of offset, whereas the offset was already
byte wise correct. So fix this by replacing LD.AS with a standard LD

Cc: <stable@vger.kernel.org>
Signed-off-by: NLiav Rehana <liavr@mellanox.com>
Reviewed-by: NAlexey Brodkin <abrodkin@synopsys.com>
[vgupta: rewrote title and commit log]
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>