Pull powerpc fixes from Michael Ellerman:

 - a revert of a recent change to the PTE bits for 32-bit BookS, which
   broke swap.

 - a "fix" to disable STRICT_KERNEL_RWX for 64-bit in Kconfig, as it's
   causing crashes for some people.

Thanks to Christophe Leroy and Rui Salvaterra.

* tag 'powerpc-5.7-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: Disable STRICT_KERNEL_RWX
  Revert "powerpc/32s: reorder Linux PTE bits to better match Hash PTE bits."

This reverts commit 697ece78f8f749aeea40f2711389901f0974017a.

The implementation of SWAP on powerpc requires page protection
bits to not be one of the least significant PTE bits.

Until the SWAP implementation is changed and this requirement voids,
we have to keep at least _PAGE_RW outside of the 3 last bits.

For now, revert to previous PTE bits order. A further rework
may come later.

Fixes: 697ece78f8f7 ("powerpc/32s: reorder Linux PTE bits to better match Hash PTE bits.")
Reported-by: Rui Salvaterra <rsalvaterra@gmail.com>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/b34706f8de87f84d135abb5f3ede6b6f16fb1f41.1589969799.git.christophe.leroy@csgroup.eu

Pull powerpc fixes from Michael Ellerman:

 - A fix for unrecoverable SLB faults in the interrupt exit path,
   introduced by the recent rewrite of interrupt exit in C.

 - Four fixes for our KUAP (Kernel Userspace Access Prevention) support
   on 64-bit. These are all fairly minor with the exception of the
   change to evaluate the get/put_user() arguments before we enable user
   access, which reduces the amount of code we run with user access
   enabled.

 - A fix for our secure boot IMA rules, if enforcement of module
   signatures is enabled at runtime rather than build time.

 - A fix to our 32-bit VDSO clock_getres() which wasn't falling back to
   the syscall for unknown clocks.

 - A build fix for CONFIG_PPC_KUAP_DEBUG on 32-bit BookS, and another
   for 40x.

Thanks to: Christophe Leroy, Hugh Dickins, Nicholas Piggin, Aurelien
Jarno, Mimi Zohar, Nayna Jain.

* tag 'powerpc-5.7-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/40x: Make more space for system call exception
  powerpc/vdso32: Fallback on getres syscall when clock is unknown
  powerpc/32s: Fix build failure with CONFIG_PPC_KUAP_DEBUG
  powerpc/ima: Fix secure boot rules in ima arch policy
  powerpc/64s/kuap: Restore AMR in fast_interrupt_return
  powerpc/64s/kuap: Restore AMR in system reset exception
  powerpc/64/kuap: Move kuap checks out of MSR[RI]=0 regions of exit code
  powerpc/64s: Fix unrecoverable SLB crashes due to preemption check
  powerpc/uaccess: Evaluate macro arguments once, before user access is allowed

gpr2 is not a parametre of kuap_check(), it doesn't exist.

Use gpr instead.

Fixes: a68c31fc01ef ("powerpc/32s: Implement Kernel Userspace Access Protection")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/ea599546f2a7771bde551393889e44e6b2632332.1587368807.git.christophe.leroy@c-s.fr

Hugh reported that his trusty G5 crashed after a few hours under load
with an "Unrecoverable exception 380".

The crash is in interrupt_return() where we check lazy_irq_pending(),
which calls get_paca() and with CONFIG_DEBUG_PREEMPT=y that goes to
check_preemption_disabled() via debug_smp_processor_id().

As Nick explained on the list:

  Problem is MSR[RI] is cleared here, ready to do the last few things
  for interrupt return where we're not allowed to take any other
  interrupts.

  SLB interrupts can happen just about anywhere aside from kernel
  text, global variables, and stack. When that hits, it appears to be
  unrecoverable due to RI=0.

The problematic access is in preempt_count() which is:

	return READ_ONCE(current_thread_info()->preempt_count);

Because of THREAD_INFO_IN_TASK, current_thread_info() just points to
current, so the access is to somewhere in kernel memory, but not on
the stack or in .data, which means it can cause an SLB miss. If we
take an SLB miss with RI=0 it is fatal.

The easiest solution is to add a version of lazy_irq_pending() that
doesn't do the preemption check and call it from the interrupt return
path.

Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C")
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200502143316.929341-1-mpe@ellerman.id.au

get/put_user() can be called with nontrivial arguments. fs/proc/page.c
has a good example:

    if (put_user(stable_page_flags(ppage), out)) {

stable_page_flags() is quite a lot of code, including spin locks in
the page allocator.

Ensure these arguments are evaluated before user access is allowed.

This improves security by reducing code with access to userspace, but
it also fixes a PREEMPT bug with KUAP on powerpc/64s:
stable_page_flags() is currently called with AMR set to allow writes,
it ends up calling spin_unlock(), which can call preempt_schedule. But
the task switch code can not be called with AMR set (it relies on
interrupts saving the register), so this blows up.

It's fine if the code inside allow_user_access() is preemptible,
because a timer or IPI will save the AMR, but it's not okay to
explicitly cause a reschedule.

Fixes: de78a9c42a79 ("powerpc: Add a framework for Kernel Userspace Access Protection")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200407041245.600651-1-npiggin@gmail.com

As the bug report [1] pointed out, <linux/vermagic.h> must be included
after <linux/module.h>.

I believe we should not impose any include order restriction. We often
sort include directives alphabetically, but it is just coding style
convention. Technically, we can include header files in any order by
making every header self-contained.

Currently, arch-specific MODULE_ARCH_VERMAGIC is defined in
<asm/module.h>, which is not included from <linux/vermagic.h>.

Hence, the straight-forward fix-up would be as follows:

|--- a/include/linux/vermagic.h
|+++ b/include/linux/vermagic.h
|@@ -1,5 +1,6 @@
| /* SPDX-License-Identifier: GPL-2.0 */
| #include <generated/utsrelease.h>
|+#include <linux/module.h>
|
| /* Simply sanity version stamp for modules. */
| #ifdef CONFIG_SMP

This works enough, but for further cleanups, I split MODULE_ARCH_VERMAGIC
definitions into <asm/vermagic.h>.

With this, <linux/module.h> and <linux/vermagic.h> will be orthogonal,
and the location of MODULE_ARCH_VERMAGIC definitions will be consistent.

For arc and ia64, MODULE_PROC_FAMILY is only used for defining
MODULE_ARCH_VERMAGIC. I squashed it.

For hexagon, nds32, and xtensa, I removed <asm/modules.h> entirely
because they contained nothing but MODULE_ARCH_VERMAGIC definition.
Kbuild will automatically generate <asm/modules.h> at build-time,
wrapping <asm-generic/module.h>.

[1] https://lore.kernel.org/lkml/20200411155623.GA22175@zn.tnic

Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Jessica Yu <jeyu@kernel.org>

In prepartion to support a pgprot_t argument for arch_add_memory().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Badger <ebadger@gigaio.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200306170846.9333-6-logang@deltatee.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There are many platforms with exact same value for VM_DATA_DEFAULT_FLAGS
This creates a default value for VM_DATA_DEFAULT_FLAGS in line with the
existing VM_STACK_DEFAULT_FLAGS.  While here, also define some more
macros with standard VMA access flag combinations that are used
frequently across many platforms.  Apart from simplification, this
reduces code duplication as well.

Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Rich Felker <dalias@libc.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Chris Zankel <chris@zankel.net>
Link: http://lkml.kernel.org/r/1583391014-8170-2-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull more powerpc updates from Michael Ellerman:
 "The bulk of this is the series to make CONFIG_COMPAT user-selectable,
  it's been around for a long time but was blocked behind the
  syscall-in-C series.

  Plus there's also a few fixes and other minor things.

  Summary:

   - A fix for a crash in machine check handling on pseries (ie. guests)

   - A small series to make it possible to disable CONFIG_COMPAT, and
     turn it off by default for ppc64le where it's not used.

   - A few other miscellaneous fixes and small improvements.

  Thanks to: Alexey Kardashevskiy, Anju T Sudhakar, Arnd Bergmann,
  Christophe Leroy, Dan Carpenter, Ganesh Goudar, Geert Uytterhoeven,
  Geoff Levand, Mahesh Salgaonkar, Markus Elfring, Michal Suchanek,
  Nicholas Piggin, Stephen Boyd, Wen Xiong"

* tag 'powerpc-5.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  selftests/powerpc: Always build the tm-poison test 64-bit
  powerpc: Improve ppc_save_regs()
  Revert "powerpc/64: irq_work avoid interrupt when called with hardware irqs enabled"
  powerpc/time: Replace <linux/clk-provider.h> by <linux/of_clk.h>
  powerpc/pseries/ddw: Extend upper limit for huge DMA window for persistent memory
  powerpc/perf: split callchain.c by bitness
  powerpc/64: Make COMPAT user-selectable disabled on littleendian by default.
  powerpc/64: make buildable without CONFIG_COMPAT
  powerpc/perf: consolidate valid_user_sp -> invalid_user_sp
  powerpc/perf: consolidate read_user_stack_32
  powerpc: move common register copy functions from signal_32.c to signal.c
  powerpc: Add back __ARCH_WANT_SYS_LLSEEK macro
  powerpc/ps3: Set CONFIG_UEVENT_HELPER=y in ps3_defconfig
  powerpc/ps3: Remove an unneeded NULL check
  powerpc/ps3: Remove duplicate error message
  powerpc/powernv: Re-enable imc trace-mode in kernel
  powerpc/perf: Implement a global lock to avoid races between trace, core and thread imc events.
  powerpc/pseries: Fix MCE handling on pseries
  selftests/eeh: Skip ahci adapters
  powerpc/64s: Fix doorbell wakeup msgclr optimisation