[ Upstream commit b9920fdd5a751df129808e7fa512e9928223ee05 ]

PJ4 is a v7 core that incorporates a iWMMXt coprocessor. However, GCC
does not support this combination (its iWMMXt configuration always
implies v5te), and so there is no v6/v7 user space that actually makes
use of this, beyond generic support for things like setjmp() that
preserve/restore the iWMMXt register file using generic LDC/STC
instructions emitted in assembler.  As [0] appears to imply, this logic
is triggered for the init process at boot, and so most user threads will
have a iWMMXt register context associated with it, even though it is
never used.

At this point, it is highly unlikely that such GCC support will ever
materialize (and Clang does not implement support for iWMMXt to begin
with).

This means that advertising iWMMXt support on these cores results in
context switch overhead without any associated benefit, and so it is
better to simply ignore the iWMMXt unit on these systems. So rip out the
support. Doing so also fixes the issue reported in [0] related to UNDEF
handling of co-processor #0/#1 instructions issued from user space
running in Thumb2 mode.

The PJ4 cores are used in four platforms: Armada 370/xp, Dove (Cubox,
d2plug), MMP2 (xo-1.75) and Berlin (Google TV). Out of these, only the
first is still widely used, but that one actually doesn't have iWMMXt
but instead has only VFPV3-D16, and so it is not impacted by this
change.

Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218427 [0]

Fixes: 8bcba70cb5c22 ("ARM: entry: Disregard Thumb undef exception ...")
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit dccf78d39f1069a5ddf4328bf0c97aa5f2f4296e ]

Ignat Korchagin complained that a potential config regression was
introduced by commit 89cde455915f ("kexec: consolidate kexec and crash
options into kernel/Kconfig.kexec").  Before the commit, CONFIG_CRASH_DUMP
has no dependency on CONFIG_KEXEC.  After the commit, CRASH_DUMP selects
KEXEC.  That enforces system to have CONFIG_KEXEC=y as long as
CONFIG_CRASH_DUMP=Y which people may not want.

In Ignat's case, he sets CONFIG_CRASH_DUMP=y, CONFIG_KEXEC_FILE=y and
CONFIG_KEXEC=n because kexec_load interface could have security issue if
kernel/initrd has no chance to be signed and verified.

CRASH_DUMP has select of KEXEC because Eric, author of above commit, met a
LKP report of build failure when posting patch of earlier version.  Please
see below link to get detail of the LKP report:

    https://lore.kernel.org/all/3e8eecd1-a277-2cfb-690e-5de2eb7b988e@oracle.com/T/#u

In fact, that LKP report is triggered because arm's <asm/kexec.h> is
wrapped in CONFIG_KEXEC ifdeffery scope.  That is wrong.  CONFIG_KEXEC
controls the enabling/disabling of kexec_load interface, but not kexec
feature.  Removing the wrongly added CONFIG_KEXEC ifdeffery scope in
<asm/kexec.h> of arm allows us to drop the select KEXEC for CRASH_DUMP.
Meanwhile, change arch/arm/kernel/Makefile to let machine_kexec.o
relocate_kernel.o depend on KEXEC_CORE.

Link: https://lkml.kernel.org/r/20231128054457.659452-1-bhe@redhat.com
Fixes: 89cde455915f ("kexec: consolidate kexec and crash options into kernel/Kconfig.kexec")
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Ignat Korchagin <ignat@cloudflare.com>
Tested-by: Ignat Korchagin <ignat@cloudflare.com>	[compile-time only]
Tested-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Tested-by: Eric DeVolder <eric_devolder@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Pull ARM updates from Russell King:

 - update unwinder to cope with module PLTs

 - enable UBSAN on ARM

 - improve kernel fault message

 - update UEFI runtime page tables dump

 - avoid clang's __aeabi_uldivmod generated in NWFPE code

 - disable FIQs on CPU shutdown paths

 - update XOR register usage

 - a number of build updates (using .arch, thread pointer, removal of
   lazy evaluation in Makefile)

 - conversion of stacktrace code to stackwalk

 - findbit assembly updates

 - hwcap feature updates for ARMv8 CPUs

 - instruction dump updates for big-endian platforms

 - support for function error injection

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (31 commits)
  ARM: 9279/1: support function error injection
  ARM: 9277/1: Make the dumped instructions are consistent with the disassembled ones
  ARM: 9276/1: Refactor dump_instr()
  ARM: 9275/1: Drop '-mthumb' from AFLAGS_ISA
  ARM: 9274/1: Add hwcap for Speculative Store Bypassing Safe
  ARM: 9273/1: Add hwcap for Speculation Barrier(SB)
  ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MM
  ARM: 9271/1: vfp: Add hwcap for FEAT_AA32BF16
  ARM: 9270/1: vfp: Add hwcap for FEAT_FHM
  ARM: 9269/1: vfp: Add hwcap for FEAT_DotProd
  ARM: 9268/1: vfp: Add hwcap FPHP and ASIMDHP for FEAT_FP16
  ARM: 9267/1: Define Armv8 registers in AArch32 state
  ARM: findbit: add unwinder information
  ARM: findbit: operate by words
  ARM: findbit: convert to macros
  ARM: findbit: provide more efficient ARMv7 implementation
  ARM: findbit: document ARMv5 bit offset calculation
  ARM: 9259/1: stacktrace: Convert stacktrace to generic ARCH_STACKWALK
  ARM: 9258/1: stacktrace: Make stack walk callback consistent with generic code
  ARM: 9265/1: pass -march= only to compiler
  ...

Similar to commit a6c30873ee4a ("ARM: 8989/1: use .fpu assembler
directives instead of assembler arguments").

GCC and GNU binutils support setting the "sub arch" via -march=,
-Wa,-march, target function attribute, and .arch assembler directive.

Clang was missing support for -Wa,-march=, but this was implemented in
clang-13.

The behavior of both GCC and Clang is to
prefer -Wa,-march= over -march= for assembler and assembler-with-cpp
sources, but Clang will warn about the -march= being unused.

clang: warning: argument unused during compilation: '-march=armv6k'
[-Wunused-command-line-argument]

Since most assembler is non-conditionally assembled with one sub arch
(modulo arch/arm/delay-loop.S which conditionally is assembled as armv4
based on CONFIG_ARCH_RPC, and arch/arm/mach-at91/pm-suspend.S which is
conditionally assembled as armv7-a based on CONFIG_CPU_V7), prefer the
.arch assembler directive.

Add a few more instances found in compile testing as found by Arnd and
Nathan.

Link: https://github.com/llvm/llvm-project/commit/1d51c699b9e2ebc5bcfdbe85c74cc871426333d4
Link: https://bugs.llvm.org/show_bug.cgi?id=48894
Link: https://github.com/ClangBuiltLinux/linux/issues/1195
Link: https://github.com/ClangBuiltLinux/linux/issues/1315

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Pull Kbuild updates from Masahiro Yamada:

 - Remove potentially incomplete targets when Kbuid is interrupted by
   SIGINT etc in case GNU Make may miss to do that when stderr is piped
   to another program.

 - Rewrite the single target build so it works more correctly.

 - Fix rpm-pkg builds with V=1.

 - List top-level subdirectories in ./Kbuild.

 - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in
   kallsyms.

 - Avoid two different modules in lib/zstd/ having shared code, which
   potentially causes building the common code as build-in and modular
   back-and-forth.

 - Unify two modpost invocations to optimize the build process.

 - Remove head-y syntax in favor of linker scripts for placing
   particular sections in the head of vmlinux.

 - Bump the minimal GNU Make version to 3.82.

 - Clean up misc Makefiles and scripts.

* tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits)
  docs: bump minimal GNU Make version to 3.82
  ia64: simplify esi object addition in Makefile
  Revert "kbuild: Check if linker supports the -X option"
  kbuild: rebuild .vmlinux.export.o when its prerequisite is updated
  kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o
  zstd: Fixing mixed module-builtin objects
  kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols
  kallsyms: take the input file instead of reading stdin
  kallsyms: drop duplicated ignore patterns from kallsyms.c
  kbuild: reuse mksysmap output for kallsyms
  mksysmap: update comment about __crc_*
  kbuild: remove head-y syntax
  kbuild: use obj-y instead extra-y for objects placed at the head
  kbuild: hide error checker logs for V=1 builds
  kbuild: re-run modpost when it is updated
  kbuild: unify two modpost invocations
  kbuild: move vmlinux.o rule to the top Makefile
  kbuild: move .vmlinux.objs rule to Makefile.modpost
  kbuild: list sub-directories in ./Kbuild
  Makefile.compiler: replace cc-ifversion with compiler-specific macros
  ...

The objects placed at the head of vmlinux need special treatments:

 - arch/$(SRCARCH)/Makefile adds them to head-y in order to place
   them before other archives in the linker command line.

 - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of
   obj-y to avoid them going into built-in.a.

This commit gets rid of the latter.

Create vmlinux.a to collect all the objects that are unconditionally
linked to vmlinux. The objects listed in head-y are moved to the head
of vmlinux.a by using 'ar m'.

With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y
for builtin objects.

There is no *.o that is directly linked to vmlinux. Drop unneeded code
in scripts/clang-tools/gen_compile_commands.py.

$(AR) mPi needs 'T' to workaround the llvm-ar bug. The fix was suggested
by Nathan Chancellor [1].

[1]: https://lore.kernel.org/llvm/YyjjT5gQ2hGMH0ni@dev-arch.thelio-3990X/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

The dma-isa.c was shared between footbridge and shark a long time ago,
but as shark was removed, it can be made footbridge specific again.

The fb_dma bits in turn are not used at all and can be removed.

All the ISA related files are now built into the platform regardless
of CONFIG_ISA, as they just refer to on-chip devices rather than actual
ISA cards.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Pull ARM updates from Russell King:
 "Updates for IRQ stacks and virtually mapped stack support, and ftrace:

   - Support for IRQ and vmap'ed stacks

     This covers all the work related to implementing IRQ stacks and
     vmap'ed stacks for all 32-bit ARM systems that are currently
     supported by the Linux kernel, including RiscPC and Footbridge. It
     has been submitted for review in four different waves:

      - IRQ stacks support for v7 SMP systems [0]

      - vmap'ed stacks support for v7 SMP systems[1]

      - extending support for both IRQ stacks and vmap'ed stacks for all
        remaining configurations, including v6/v7 SMP multiplatform
        kernels and uniprocessor configurations including v7-M [2]

      - fixes and updates in [3]

   - ftrace fixes and cleanups

     Make all flavors of ftrace available on all builds, regardless of
     ISA choice, unwinder choice or compiler [4]:

      - use ADD not POP where possible

      - fix a couple of Thumb2 related issues

      - enable HAVE_FUNCTION_GRAPH_FP_TEST for robustness

      - enable the graph tracer with the EABI unwinder

      - avoid clobbering frame pointer registers to make Clang happy

   - Fixes for the above"

[0] https://lore.kernel.org/linux-arm-kernel/20211115084732.3704393-1-ardb@kernel.org/
[1] https://lore.kernel.org/linux-arm-kernel/20211122092816.2865873-1-ardb@kernel.org/
[2] https://lore.kernel.org/linux-arm-kernel/20211206164659.1495084-1-ardb@kernel.org/
[3] https://lore.kernel.org/linux-arm-kernel/20220124174744.1054712-1-ardb@kernel.org/
[4] https://lore.kernel.org/linux-arm-kernel/20220203082204.1176734-1-ardb@kernel.org/

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: (62 commits)
  ARM: fix building NOMMU ARMv4/v5 kernels
  ARM: unwind: only permit stack switch when unwinding call_with_stack()
  ARM: Revert "unwind: dump exception stack from calling frame"
  ARM: entry: fix unwinder problems caused by IRQ stacks
  ARM: unwind: set frame.pc correctly for current-thread unwinding
  ARM: 9184/1: return_address: disable again for CONFIG_ARM_UNWIND=y
  ARM: 9183/1: unwind: avoid spurious warnings on bogus code addresses
  Revert "ARM: 9144/1: forbid ftrace with clang and thumb2_kernel"
  ARM: mach-bcm: disable ftrace in SMC invocation routines
  ARM: cacheflush: avoid clobbering the frame pointer
  ARM: kprobes: treat R7 as the frame pointer register in Thumb2 builds
  ARM: ftrace: enable the graph tracer with the EABI unwinder
  ARM: unwind: track location of LR value in stack frame
  ARM: ftrace: enable HAVE_FUNCTION_GRAPH_FP_TEST
  ARM: ftrace: avoid unnecessary literal loads
  ARM: ftrace: avoid redundant loads or clobbering IP
  ARM: ftrace: use trampolines to keep .init.text in branching range
  ARM: ftrace: use ADD not POP to counter PUSH at entry
  ARM: ftrace: ensure that ADR takes the Thumb bit into account
  ARM: make get_current() and __my_cpu_offset() __always_inline
  ...

Commit 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI
unwinder") removed the dummy version of return_address() that was
provided for the CONFIG_ARM_UNWIND=y case, on the assumption that the
removal of the kernel_text_address() call from unwind_frame() in the
preceding patch made it safe to do so.

However, this turns out not to be the case: Corentin reports warnings
about suspicious RCU usage and other strange behavior that seems to
originate in the stack unwinding that occurs in return_address().

Given that the function graph tracer (which is what these changes were
enabling for CONFIG_ARM_UNWIND=y builds) does not appear to care about
this distinction, let's revert return_address() to the old state.

Cc: Corentin Labbe <clabbe.montjoie@gmail.com>
Fixes: 41918ec82eb6 ("ARM: ftrace: enable the graph tracer with the EABI unwinder")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reported-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

As per other architectures, add support for reporting the Spectre
vulnerability status via sysfs CPU.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>