When CONFIG_TRIM_UNUSED_KSYMS is enabled, I see some warnings like this:

  nm: arch/x86/entry/vdso/vdso32/note.o: no symbols

$NM (both GNU nm and llvm-nm) warns when no symbol is found in the
object. Suppress the stderr.

Fangrui Song mentioned binutils>=2.37 `nm -q` can be used to suppress
"no symbols" [1], and llvm-nm>=13.0.0 supports -q as well.

We cannot use it for now, but note it as a TODO.

[1]: https://sourceware.org/bugzilla/show_bug.cgi?id=27408

Fixes: bbda5ec6

 ("kbuild: simplify dependency generation for CONFIG_TRIM_UNUSED_KSYMS")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

It has been brought up a few times in various code reviews that clang
3.5 introduced -f{,no-}integrated-as as the preferred way to enable and
disable the integrated assembler, mentioning that -{no-,}integrated-as
are now considered legacy flags.

Switch the kernel over to using those variants in case there is ever a
time where clang decides to remove the non-'f' variants of the flag.

Also, fix a typo in a comment ("intergrated" -> "integrated").

Link: https://releases.llvm.org/3.5.0/tools/clang/docs/ReleaseNotes.html#new-compiler-flags


Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

-Wunused-but-set-variable and -Wunused-const-variable are both disabled
for the same reason but there is a blank line between them and no blank
line between -Wno-unused-const-variable and the block.

Shuffle the new line so that it is clear that the comment applied to
both flags and the next block is separate from them.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Whenever a warning is disabled, it is helpful for future travelers to
understand why the warning is disabled and why it is acceptable to do
so. Add a comment for -Wno-gnu so that people understand why it is
disabled.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Turning on -Wformat does not reveal any instances of this warning across
several different builds so remove this line to keep the number of
disabled warnings as slim as possible.

This has been disabled since commit 61163efa

 ("kbuild: LLVMLinux:
Add Kbuild support for building kernel with Clang"), which does not
explain exactly why it was turned off but since it was so long ago in
terms of both the kernel and LLVM so it is possible that some bug got
fixed along the way.

Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

if_changed, if_changed_dep, and if_changed_rule must have FORCE as a
prerequisite so the command line change is detected.

Documentation/kbuild/makefiles.rst clearly explains it:

  Note: It is a typical mistake to forget the FORCE prerequisite.

However, not all people follow the document.

This mistake occurred again and again, so a compelling force is needed.

Show a warning if FORCE is missing in the prerequisite of if_changed
and friends. Same for filechk.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nicolas Schier <n.schier@avm.de>

Add a new macro that expands into $(newer-prereqs)$(cmd-check).

It makes it easier to add common code for if_changed, if_changed_dep,
and if_changed_rule.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Add FORCE so that if_changed can detect the command line change.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

With CONFIG_LTO_CLANG, we currently link modules into native
code just before modpost, which means with TRIM_UNUSED_KSYMS
enabled, we still look at the LLVM bitcode in the .o files when
generating the list of used symbols. As the bitcode doesn't
yet have calls to compiler intrinsics and llvm-nm doesn't see
function references that only exist in function-level inline
assembly, we currently need a whitelist for TRIM_UNUSED_KSYMS to
work with LTO.

This change moves module LTO linking to happen earlier, and
thus avoids the issue with LLVM bitcode and TRIM_UNUSED_KSYMS
entirely, allowing us to also drop the whitelist from
gen_autoksyms.sh.

Link: https://github.com/ClangBuiltLinux/linux/issues/1369


Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Alexander Lobakin <alobakin@pm.me>
Tested-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler
during build time, and can slow down the build when these checks become
stale for our supported compilers, whose minimally supported versions
increases over time. See Documentation/process/changes.rst for the
current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler
version support for these flags may be verified on godbolt.org.

The following flags are GCC only and supported since at least GCC 4.9.
Remove cc-option and cc-disable-warning tests.
* -fno-tree-loop-im
* -Wno-maybe-uninitialized
* -fno-reorder-blocks
* -fno-ipa-cp-clone
* -fno-partial-inlining
* -femit-struct-debug-baseonly
* -fno-inline-functions-called-once
* -fconserve-stack

The following flags are supported by all supported versions of GCC and
Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests.
* -fno-delete-null-pointer-checks
* -fno-var-tracking
* -Wno-array-bounds

The following configs are made dependent on GCC, since they use GCC
specific flags.
* READABLE_ASM
* DEBUG_SECTION_MISMATCH

-mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a
comment.

--param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races
in the GCC 10 release; add a comment.

-Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV,
then again unconditionally; add it only once.

Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_*
then remove cc-option tests for Clang.

Link: https://github.com/ClangBuiltLinux/linux/issues/1436


Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Kees' post inspired me to get more involved. I still have a long way to
go in terms of mastery of GNU make, but at the least I can help with
more code review. It's also helpful for me to pick up on what's missing
from the LLVM ecosystem.

Link: https://security.googleblog.com/2021/08/linux-kernel-security-done-right.html


Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Ship minimal stdarg.h (1 type, 4 macros) as <linux/stdarg.h>.
stdarg.h is the only userspace header commonly used in the kernel.

GPL 2 version of <stdarg.h> can be extracted from
http://archive.debian.org/debian/pool/main/g/gcc-4.2/gcc-4.2_4.2.4.orig.tar.gz



Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Delete/fixup few includes in anticipation of global -isystem compile
option removal.

Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition
of uintptr_t error (one definition comes from <stddef.h>, another from
<linux/types.h>).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

LLVM_IAS=1 controls enabling clang's integrated assembler via
-integrated-as. This was an explicit opt in until we could enable
assembler support in Clang for more architecures. Now we have support
and CI coverage of LLVM_IAS=1 for all architecures except a few more
bugs affecting s390 and powerpc.

This commit flips the default from opt in via LLVM_IAS=1 to opt out via
LLVM_IAS=0.  CI systems or developers that were previously doing builds
with CC=clang or LLVM=1 without explicitly setting LLVM_IAS must now
explicitly opt out via LLVM_IAS=0, otherwise they will be implicitly
opted-in.

This finally shortens the command line invocation when cross compiling
with LLVM to simply:

$ make ARCH=arm64 LLVM=1

Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

LLVM_IAS is the user interface to set the -(no-)integrated-as flag,
and it should be used only for that purpose.

LLVM_IAS is checked in some places to determine the assembler type,
but it is not precise.

For example,

 $ make CC=gcc LLVM_IAS=1

... will use the GNU assembler (i.e. binutils) since LLVM_IAS=1 is
effective only when $(CC) is clang.

Of course, 'CC=gcc LLVM_IAS=1' is an odd combination, but the build
system can be more robust against such insane input.

Commit ba64beb1

 ("kbuild: check the minimum assembler version in
Kconfig") introduced CONFIG_AS_IS_GNU/LLVM, which is more precise
because Kconfig checks the version string from the assembler in use.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

As noted by Masahiro, document how we can generally infer CROSS_COMPILE
(and the more specific details about --target and --prefix) based on
ARCH.

Change use of env vars to command line parameters.

Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

We get constant feedback that the command line invocation of make is too
long when compiling with LLVM. CROSS_COMPILE is helpful when a toolchain
has a prefix of the target triple, or is an absolute path outside of
$PATH.

Since a Clang binary is generally multi-targeted, we can infer a given
target from SRCARCH/ARCH.  If CROSS_COMPILE is not set, simply set
--target= for CLANG_FLAGS, KBUILD_CFLAGS, and KBUILD_AFLAGS based on
$SRCARCH.

Previously, we'd cross compile via:
$ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make LLVM=1 LLVM_IAS=1
Now:
$ ARCH=arm64 make LLVM=1 LLVM_IAS=1

For native builds (not involving cross compilation) we now explicitly
specify a target triple rather than rely on the implicit host triple.

Link: https://github.com/ClangBuiltLinux/linux/issues/1399


Suggested-by: Arnd Bergmann <arnd@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Arnd Bergmann <arnd@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

With some of the changes we'd like to make to CROSS_COMPILE, the initial
block of clang flag handling which controls things like the target triple,
whether or not to use the integrated assembler and how to find GAS,
and erroring on unknown warnings is becoming unwieldy. Move it into its
own file under scripts/.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

It is always safe to use the same compiler for the kernel and external
modules, but in reality, some distributions such as Fedora release a
different version of GCC from the one used for building the kernel.

There was a long discussion about mixing different compilers [1].

I do not repeat it here, but at least, showing a heads up in that
case is better than nothing.

Linus suggested [2]:
  And a warning might be more palatable even if different compiler
  version work fine together. Just a heads up on "it looks like you
  might be mixing compiler versions" is a valid note, and isn't
  necessarily wrong. Even when they work well together, maybe you want
  to have people at least _aware_ of it.

This commit shows a warning unless the compiler is exactly the same.

  warning: the compiler differs from the one used to build the kernel
    The kernel was built by: gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3)
    You are using:           gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1)

Check the difference, and if it is OK with you, please proceed at your
risk.

To avoid the locale issue as in commit bcbcf50f ("kbuild: fix
ld-version.sh to not be affected by locale"), pass LC_ALL=C to
"$(CC) --version".

[1] https://lore.kernel.org/linux-hardening/efe6b039a544da8215d5e54aa7c4b6d1986fc2b0.1611607264.git.jpoimboe@redhat.com/
[2] https://lore.kernel.org/lkml/CAHk-=wgjwhDy-y4mQh34L+2aF=n6BjzHdqAW2=8wri5x7O04pA@mail.gmail.com/



Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Set the x bit to some scripts to make them directly executable.

Especially, scripts/checkdeclares.pl is not hooked by anyone.
It should be executable since it is tedious to type
'perl scripts/checkdeclares.pl'.

The original patch [1] set the x bit properly, but it was lost when
it was merged as commit 21917bde ("scripts: a new script for
checking duplicate struct declaration").

[1] https://lore.kernel.org/lkml/20210401110943.1010796-1-wanjiabing@vivo.com/



Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

As explained in commit 3204a7fb

 ("kbuild: prefix $(srctree)/ to some
included Makefiles"), I want to stop using --include-dir some day.

I already fixed up the top Makefile, but some arch Makefiles (mips, um,
x86) still include check-in Makefiles without $(srctree)/.

Fix them up so 'need-sub-make := 1' can go away for this case.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

When merging configuration fragments, it might be of interest to
identify mismatches (redefinitions) programmatically. Hence add the
option -s (strict mode) to instruct merge_config.sh to bail out in
case any redefinition has been detected.

With strict mode, warnings are emitted as before, but the script
terminates with rc=1. If -y is set to define "builtin having
precedence over modules", fragments are still allowed to set =m (while
the base config has =y). Strict mode will tolerate that as demotions
from =y to =m are ignored when setting -y.

Signed-off-by: Matthias Maennich <maennich@google.com>
Reviewed-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Pull timer fix from Thomas Gleixner:
 "A single timer fix:

   - Prevent a memory ordering issue in the timer expiry code which
     makes it possible to observe falsely that the callback has been
     executed already while that's not the case, which violates the
     guarantee of del_timer_sync()"

* tag 'timers-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Move clearing of base::timer_running under base:: Lock

Pull scheduler fix from Thomas Gleixner:
 "A single scheduler fix:

   - Prevent a double enqueue caused by rt_effective_prio() being
     invoked twice in __sched_setscheduler()"

* tag 'sched-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt: Fix double enqueue caused by rt_effective_prio

Pull perf fixes from Thomas Gleixner:
 "A set of perf fixes:

   - Correct the permission checks for perf event which send SIGTRAP to
     a different process and clean up that code to be more readable.

   - Prevent an out of bound MSR access in the x86 perf code which
     happened due to an incomplete limiting to the actually available
     hardware counters.

   - Prevent access to the AMD64_EVENTSEL_HOSTONLY bit when running
     inside a guest.

   - Handle small core counter re-enabling correctly by issuing an ACK
     right before reenabling it to prevent a stale PEBS record being
     kept around"

* tag 'perf-urgent-2021-08-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Apply mid ACK for small core
  perf/x86/amd: Don't touch the AMD64_EVENTSEL_HOSTONLY bit inside the guest
  perf/x86: Fix out of bound MSR access
  perf: Refactor permissions check into perf_check_permission()
  perf: Fix required permissions if sigtrap is requested

Pull char/misc driver fixes from Greg KH:
 "Here are some small char/misc driver fixes for 5.14-rc5.

  They resolve a few regressions that people reported:

   - acrn driver fix

   - fpga driver fix

   - interconnect tiny driver fixes

  All have been in linux-next for a while with no reported issues"

* tag 'char-misc-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  interconnect: Fix undersized devress_alloc allocation
  interconnect: qcom: icc-rpmh: Add BCMs to commit list in pre_aggregate
  interconnect: qcom: icc-rpmh: Ensure floor BW is enforced for all nodes
  fpga: dfl: fme: Fix cpu hotplug issue in performance reporting
  virt: acrn: Do hcall_destroy_vm() before resource release
  interconnect: Always call pre_aggregate before aggregate
  interconnect: Zero initial BW after sync-state

Merge tag 'driver-core-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are three tiny driver core and firmware loader fixes for
  5.14-rc5. They are:

   - driver core fix for when probing fails

   - firmware loader fixes for reported problems.

  All have been in linux-next for a while with no reported issues"

* tag 'driver-core-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  firmware_loader: fix use-after-free in firmware_fallback_sysfs
  firmware_loader: use -ETIMEDOUT instead of -EAGAIN in fw_load_sysfs_fallback
  drivers core: Fix oops when driver probe fails

Pull staging driver fixes from Greg KH:
 "Here are a few small staging driver fixes for 5.14-rc5 to resolve some
  reported problems. They include:

   - mt7621 driver fix

   - rtl8723bs driver fixes

   - rtl8712 driver fixes.

  Nothing major, just small problems resolved.

  All have been in linux-next for a while with no reported issues"

* tag 'staging-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: mt7621-pci: avoid to re-disable clock for those pcies not in use
  staging: rtl8712: error handling refactoring
  staging: rtl8712: get rid of flush_scheduled_work
  staging: rtl8723bs: select CONFIG_CRYPTO_LIB_ARC4
  staging: rtl8723bs: Fix a resource leak in sd_int_dpc

Pull tty/serial fixes from Greg KH:
 "Here are some small tty/serial driver fixes for 5.14-rc5 to resolve a
  number of reported problems.

  They include:

   - mips serial driver fixes

   - 8250 driver fixes for reported problems

   - fsl_lpuart driver fixes

   - other tiny driver fixes

  All have been in linux-next for a while with no reported problems"

* tag 'tty-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: 8250_pci: Avoid irq sharing for MSI(-X) interrupts.
  serial: 8250_mtk: fix uart corruption issue when rx power off
  tty: serial: fsl_lpuart: fix the wrong return value in lpuart32_get_mctrl
  serial: 8250_pci: Enumerate Elkhart Lake UARTs via dedicated driver
  serial: 8250: fix handle_irq locking
  serial: tegra: Only print FIFO error message when an error occurs
  MIPS: Malta: Do not byte-swap accesses to the CBUS UART
  serial: 8250: Mask out floating 16/32-bit bus bits
  serial: max310x: Unprepare and disable clock in error path

Pull USB driver fixes from Greg KH:
 "Here are some small USB driver fixes for 5.14-rc5. They resolve a
  number of small reported issues, including:

   - cdnsp driver fixes

   - usb serial driver fixes and device id updates

   - usb gadget hid fixes

   - usb host driver fixes

   - usb dwc3 driver fixes

   - other usb gadget driver fixes

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (21 commits)
  usb: typec: tcpm: Keep other events when receiving FRS and Sourcing_vbus events
  usb: dwc3: gadget: Avoid runtime resume if disabling pullup
  usb: dwc3: gadget: Use list_replace_init() before traversing lists
  USB: serial: ftdi_sio: add device ID for Auto-M3 OP-COM v2
  USB: serial: pl2303: fix GT type detection
  USB: serial: option: add Telit FD980 composition 0x1056
  USB: serial: pl2303: fix HX type detection
  USB: serial: ch341: fix character loss at high transfer rates
  usb: cdnsp: Fix the IMAN_IE_SET and IMAN_IE_CLEAR macro
  usb: cdnsp: Fixed issue with ZLP
  usb: cdnsp: Fix incorrect supported maximum speed
  usb: cdns3: Fixed incorrect gadget state
  usb: gadget: f_hid: idle uses the highest byte for duration
  Revert "thunderbolt: Hide authorized attribute if router does not support PCIe tunnels"
  usb: otg-fsm: Fix hrtimer list corruption
  usb: host: ohci-at91: suspend/resume ports after/before OHCI accesses
  usb: musb: Fix suspend and resume issues for PHYs on I2C and SPI
  usb: gadget: f_hid: added GET_IDLE and SET_IDLE handlers
  usb: gadget: f_hid: fixed NULL pointer dereference
  usb: gadget: remove leaked entry from udc driver list
  ...

Pull io_uring from Jens Axboe:
 "A few io-wq related fixes:

   - Fix potential nr_worker race and missing max_workers check from one
     path (Hao)

   - Fix race between worker exiting and new work queue (me)"

* tag 'io_uring-5.14-2021-08-07' of git://git.kernel.dk/linux-block:
  io-wq: fix lack of acct->nr_workers < acct->max_workers judgement
  io-wq: fix no lock protection of acct->nr_worker
  io-wq: fix race between worker exiting and activating free worker

Pull block fixes from Jens Axboe:
 "A few minor fixes:

   - Fix ldm kernel-doc warning (Bart)

   - Fix adding offset twice for DMA address in n64cart (Christoph)

   - Fix use-after-free in dasd path handling (Stefan)

   - Order kyber insert trace correctly (Vincent)

   - raid1 errored write handling fix (Wei)

   - Fix blk-iolatency queue get failure handling (Yu)"

* tag 'block-5.14-2021-08-07' of git://git.kernel.dk/linux-block:
  kyber: make trace_block_rq call consistent with documentation
  block/partitions/ldm.c: Fix a kernel-doc warning
  blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()
  n64cart: fix the dma address in n64cart_do_bvec
  s390/dasd: fix use after free in dasd path handling
  md/raid10: properly indicate failure when ending a failed write request

Pull RISC-V fixes from Palmer Dabbelt:

 - avoid dereferencing a null task pointer while walking the stack

 - fix the memory size in the HiFive Unleashed device tree

 - disable stack protectors when randstruct is enabled, which results in
   non-deterministic offsets during module builds

 - a pair of fixes to avoid relying on a constant physical memory base
   for the non-XIP builds

* tag 'riscv-for-linus-5.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  Revert "riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED"
  riscv: Get rid of CONFIG_PHYS_RAM_BASE in kernel physical address conversion
  riscv: Disable STACKPROTECTOR_PER_TASK if GCC_PLUGIN_RANDSTRUCT is enabled
  riscv: dts: fix memory size for the SiFive HiFive Unmatched
  riscv: stacktrace: Fix NULL pointer dereference

Merge tag 'kbuild-fixes-v5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - Correct the Extended Regular Expressions in tools

 - Adjust scripts/checkversion.pl for the current Kbuild

 - Unset sub_make_done for 'make install' to make DKMS work again

* tag 'kbuild-fixes-v5.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: cancel sub_make_done for the install target to fix DKMS
  scripts: checkversion: modernize linux/version.h search strings
  mips: Fix non-POSIX regexp
  x86/tools/relocs: Fix non-POSIX regexp

This reverts commit 9b79878c

.

The removal of this config exposes CONFIG_PHYS_RAM_BASE for all kernel
types: this value being implementation-specific, this breaks the
genericity of the RISC-V kernel so revert it.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Tested-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

The usage of CONFIG_PHYS_RAM_BASE for all kernel types was a mistake:
this value is implementation-specific and this breaks the genericity of
the RISC-V kernel.

Fix this by introducing a new variable phys_ram_base that holds this
value at runtime and use it in the kernel physical address conversion
macro. Since this value is used only for XIP kernels, evaluate it only if
CONFIG_XIP_KERNEL is set which in addition optimizes this macro for
standard kernels at compile-time.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Tested-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
Fixes: 44c92257

 ("RISC-V: enable XIP")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

The kyber ioscheduler calls trace_block_rq_insert() *after* the request
is added to the queue but the documentation for trace_block_rq_insert()
says that the call should be made *before* the request is added to the
queue.  Move the tracepoint for the kyber ioscheduler so that it is
consistent with the documentation.

Signed-off-by: Vincent Fu <vincent.fu@samsung.com>
Link: https://lore.kernel.org/r/20210804194913.10497-1-vincent.fu@samsung.com


Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull ext4 fixes from Ted Ts'o:
 "A regression fix, bug fix, and a comment cleanup for ext4"

* tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
  ext4: fix potential htree corruption when growing large_dir directories
  ext4: remove conflicting comment from __ext4_forget
  ext4: fix potential uninitialized access to retval in kmmpd

Pull tracing fixes from Steven Rostedt:
 "Fix tracepoint race between static_call and callback data

  As callbacks to a tracepoint are paired with the data that is passed
  in when the callback is registered to the tracepoint, it must have
  that data passed to the callback when the tracepoint is triggered,
  else bad things will happen. To keep the two together, they are both
  assigned to a tracepoint structure and added to an array. The
  tracepoint call site will dereference the structure (via RCU) and call
  the callback in that structure along with the data in that structure.
  This keeps the callback and data tightly coupled.

  Because of the overhead that retpolines have on tracepoint callbacks,
  if there's only one callback attached to a tracepoint (a common case),
  then it is called via a static call (code modified to do a direct call
  instead of an indirect call). But to implement this, the data had to
  be decoupled from the callback, as now the callback is implemented via
  a direct call from the static call and not an indirect call from the
  dereferenced structure.

  Note, the static call only calls a callback used when there's a single
  callback attached to the tracepoint. If more than one callback is
  attached to the same tracepoint, then the static call will call an
  iterator function that goes back to dereferencing the structure
  keeping the callback and its data tightly coupled again.

  Issues can arise when going from 0 callbacks to one, as the static
  call is assigned to the callback, and it must take care that the data
  passed to it is loaded before the static call calls the callback.
  Going from 1 to 2 callbacks is not an issue, as long as the static
  call is updated to the iterator before the tracepoint structure array
  is updated via RCU. Going from 2 to more or back down to 2 is not an
  issue as the iterator can handle all theses cases. But going from 2 to
  1, care must be taken as the static call is now calling a callback and
  the data that is loaded must be the data for that callback.

  Care was taken to ensure the callback and data would be in-sync, but
  after a bug was reported, it became clear that not enough was done to
  make sure that was the case. These changes address this.

  The first change is to compare the old and new data instead of the old
  and new callback, as it's the data that can corrupt the callback, even
  if the callback is the same (something getting freed).

  The next change is to convert these transitions into states, to make
  it easier to know when a synchronization is needed, and to perform
  those synchronizations. The problem with this patch is that it slows
  down disabling all events from under a second, to making it take over
  10 seconds to do the same work. But that is addressed in the final
  patch.

  The final patch uses the RCU state functions to keep track of the RCU
  state between the transitions, and only needs to perform the
  synchronization if an RCU synchronization hasn't been done already.
  This brings the performance of disabling all events back to its
  original value. That's because no synchronization is required between
  disabling tracepoints but is required when enabling a tracepoint after
  its been disabled. If an RCU synchronization happens after the
  tracepoint is disabled, and before it is re-enabled, there's no need
  to do the synchronization again.

  Both the second and third patch have subtle complexities that they are
  separated into two patches. But because the second patch causes such a
  regression in performance, the third patch adds a "Fixes" tag to the
  second patch, such that the two must be backported together and not
  just the second patch"

* tag 'trace-v5.14-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracepoint: Use rcu get state and cond sync for static call updates
  tracepoint: Fix static call function vs data state mismatch
  tracepoint: static call: Compare data on transition from 2->1 callees