ARM64 has asm implementation of memchr(), memcmp(), str[r]chr(),
str[n]cmp(), str[n]len().  KASAN don't see memory accesses in asm code,
thus it can potentially miss many bugs.

Ifdef out __HAVE_ARCH_* defines of these functions when KASAN is enabled,
so the generic implementations from lib/string.c will be used.

We can't just remove the asm functions because efistub uses them.  And we
can't have two non-weak functions either, so declare the asm functions as
weak.

Link: http://lkml.kernel.org/r/20180920135631.23833-2-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Kyeongdon Kim <kyeongdon.kim@lge.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

x0 is not callee-saved in the PCS. So there is no need to specify
-fcall-used-x0.

Clang doesn't currently support -fcall-used flags. This patch will help
building the kernel with clang.

Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Tri Vo <trong@android.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Unlike crc32c(), which is wired up to the crypto API internally so the
optimal driver is selected based on the platform's capabilities,
crc32_le() is implemented as a library function using a slice-by-8 table
based C implementation. Even though few of the call sites may be
bottlenecks, calling a time variant implementation with a non-negligible
D-cache footprint is a bit of a waste, given that ARMv8.1 and up mandates
support for the CRC32 instructions that were optional in ARMv8.0, but are
already widely available, even on the Cortex-A53 based Raspberry Pi.

So implement routines that use these instructions if available, and fall
back to the existing generic routines otherwise. The selection is based
on alternatives patching.

Note that this unconditionally selects CONFIG_CRC32 as a builtin. Since
CRC32 is relied upon by core functionality such as CONFIG_OF_FLATTREE,
this just codifies the status quo.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

The <asm-generic/bitops/{atomic,lock}.h> implementations are built around
the atomic-fetch ops, which we implement efficiently for both LSE and
LL/SC systems. Use that instead of our hand-rolled, out-of-line bitops.S.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: yamada.masahiro@socionext.com
Link: https://lore.kernel.org/lkml/1529412794-17720-9-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Otherwise modules that use these arithmetic operations will fail to
link. We accomplish this with the usual EXPORT_SYMBOL, which on most
architectures goes in the .S file but the ARM64 maintainers prefer that
insead it goes into arm64ksyms.

While we're at it, we also fix this up to use SPDX, and I personally
choose to relicense this as GPL2||BSD so that these symbols don't need
to be export_symbol_gpl, so all modules can use the routines, since
these are important general purpose compiler-generated function calls.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reported-by: PaX Team <pageexec@freemail.hu>
Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will.deacon@arm.com>

Our out-of-line atomics are built with a special calling convention,
preventing pointless stack spilling, and allowing us to patch call sites
with ARMv8.1 atomic instructions.

Instrumentation inserted by the compiler may result in calls to
functions not following this special calling convention, resulting in
registers being unexpectedly clobbered, and various problems resulting
from this.

For example, if a kernel is built with KCOV and ARM64_LSE_ATOMICS, the
compiler inserts calls to __sanitizer_cov_trace_pc in the prologues of
the atomic functions. This has been observed to result in spurious
cmpxchg failures, leading to a hang early on in the boot process.

This patch avoids such issues by preventing instrumentation of our
out-of-line atomics.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

Pull DeviceTree updates from Rob Herring:

 - Sync dtc to upstream version v1.4.6-9-gaadd0b65c987. This adds a
   bunch more warnings (hidden behind W=1).

 - Build dtc lexer and parser files instead of using shipped versions.

 - Rework overlay apply API to take an FDT as input and apply overlays
   in a single step.

 - Add a phandle lookup cache. This improves boot time by hundreds of
   msec on systems with large DT.

 - Add trivial mcp4017/18/19 potentiometers bindings.

 - Remove VLA stack usage in DT code.

* tag 'devicetree-for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (26 commits)
  of: unittest: fix an error code in of_unittest_apply_overlay()
  of: unittest: move misplaced function declaration
  of: unittest: Remove VLA stack usage
  of: overlay: Fix forgotten reference to of_overlay_apply()
  of: Documentation: Fix forgotten reference to of_overlay_apply()
  of: unittest: local return value variable related cleanups
  of: unittest: remove unneeded local return value variables
  dt-bindings: trivial: add various mcp4017/18/19 potentiometers
  of: unittest: fix an error test in of_unittest_overlay_8()
  of: cache phandle nodes to reduce cost of of_find_node_by_phandle()
  dt-bindings: rockchip-dw-mshc: use consistent clock names
  MAINTAINERS: Add linux/of_*.h headers to appropriate subsystems
  scripts: turn off some new dtc warnings by default
  scripts/dtc: Update to upstream version v1.4.6-9-gaadd0b65c987
  scripts/dtc: generate lexer and parser during build instead of shipping
  powerpc: boot: add strrchr function
  of: overlay: do not include path in full_name of added nodes
  of: unittest: clean up changeset test
  arm64/efi: Make strrchr() available to the EFI namespace
  ARM: boot: add strrchr function
  ...

In cases where x30 is used as a temporary in the out-of-line ll/sc atomics
(e.g. atomic_fetch_add), the compiler tends to put out a full stackframe,
which included pointing the x29 at the new frame.

Since these things aren't traceable anyway, we can pass -fomit-frame-pointer
to reduce the work when spilling. Since this is incompatible with -pg, we
also remove that from the CFLAGS for this file.

Signed-off-by: Will Deacon <will.deacon@arm.com>

libfdt gained a new dependency on strrchr, so make it available to the
EFI namespace before we update libfdt.

Thanks to Ard for providing this fix.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Rob Herring <robh@kernel.org>

Like we've done for get_user and put_user, ensure that user pointers
are masked before invoking the underlying __arch_{clear,copy_*}_user
operations.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>