We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c3238a ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f53 ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").

Then, much later, we ended up removing the workaround in commit
43c249ea0b1e ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.

Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround.  But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.

It looks like there are at least two separate issues that all hit in
this area:

 (a) some versions of gcc don't mark the asm goto as 'volatile' when it
     has outputs:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619
        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420

     which is easy to work around by just adding the 'volatile' by hand.

 (b) Internal compiler errors:

        https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422

     which are worked around by adding the extra empty 'asm' as a
     barrier, as in the original workaround.

but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.

but the same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.

Reported-and-tested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull percpu updates from Dennis Zhou:
 "Enable percpu page allocator for RISC-V.

  There are RISC-V configurations with sparse NUMA configurations and
  small vmalloc space causing dynamic percpu allocations to fail as the
  backing chunk stride is too far apart"

* tag 'percpu-for-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
  riscv: Enable pcpu page first chunk allocator
  mm: Introduce flush_cache_vmap_early()

Pull char/misc and other driver updates from Greg KH:
 "Here is the big set of char/misc and other driver subsystem changes
  for 6.8-rc1.

  Other than lots of binder driver changes (as you can see by the merge
  conflicts) included in here are:

   - lots of iio driver updates and additions

   - spmi driver updates

   - eeprom driver updates

   - firmware driver updates

   - ocxl driver updates

   - mhi driver updates

   - w1 driver updates

   - nvmem driver updates

   - coresight driver updates

   - platform driver remove callback api changes

   - tags.sh script updates

   - bus_type constant marking cleanups

   - lots of other small driver updates

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

* tag 'char-misc-6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (341 commits)
  android: removed duplicate linux/errno
  uio: Fix use-after-free in uio_open
  drivers: soc: xilinx: add check for platform
  firmware: xilinx: Export function to use in other module
  scripts/tags.sh: remove find_sources
  scripts/tags.sh: use -n to test archinclude
  scripts/tags.sh: add local annotation
  scripts/tags.sh: use more portable -path instead of -wholename
  scripts/tags.sh: Update comment (addition of gtags)
  firmware: zynqmp: Convert to platform remove callback returning void
  firmware: turris-mox-rwtm: Convert to platform remove callback returning void
  firmware: stratix10-svc: Convert to platform remove callback returning void
  firmware: stratix10-rsu: Convert to platform remove callback returning void
  firmware: raspberrypi: Convert to platform remove callback returning void
  firmware: qemu_fw_cfg: Convert to platform remove callback returning void
  firmware: mtk-adsp-ipc: Convert to platform remove callback returning void
  firmware: imx-dsp: Convert to platform remove callback returning void
  firmware: coreboot_table: Convert to platform remove callback returning void
  firmware: arm_scpi: Convert to platform remove callback returning void
  firmware: arm_scmi: Convert to platform remove callback returning void
  ...

Pull RISC-V updates from Palmer Dabbelt:

 - Support for many new extensions in hwprobe, along with a handful of
   cleanups

 - Various cleanups to our page table handling code, so we alwayse use
   {READ,WRITE}_ONCE

 - Support for the which-cpus flavor of hwprobe

 - Support for XIP kernels has been resurrected

* tag 'riscv-for-linus-6.8-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (52 commits)
  riscv: hwprobe: export Zicond extension
  riscv: hwprobe: export Zacas ISA extension
  riscv: add ISA extension parsing for Zacas
  dt-bindings: riscv: add Zacas ISA extension description
  riscv: hwprobe: export Ztso ISA extension
  riscv: add ISA extension parsing for Ztso
  use linux/export.h rather than asm-generic/export.h
  riscv: Remove SHADOW_OVERFLOW_STACK_SIZE macro
  riscv; fix __user annotation in save_v_state()
  riscv: fix __user annotation in traps_misaligned.c
  riscv: Select ARCH_WANTS_NO_INSTR
  riscv: Remove obsolete rv32_defconfig file
  riscv: Allow disabling of BUILTIN_DTB for XIP
  riscv: Fixed wrong register in XIP_FIXUP_FLASH_OFFSET macro
  riscv: Make XIP bootable again
  riscv: Fix set_direct_map_default_noflush() to reset _PAGE_EXEC
  riscv: Fix module_alloc() that did not reset the linear mapping permissions
  riscv: Fix wrong usage of lm_alias() when splitting a huge linear mapping
  riscv: Check if the code to patch lies in the exit section
  riscv: Use the same CPU operations for all CPUs
  ...

Pull asm-generic cleanups from Arnd Bergmann:
 "A series from Baoquan He cleans up the asm-generic/io.h to remove the
  ioremap_uc() definition from everything except x86, which still needs
  it for pre-PAT systems. This series notably contains a patch from
  Jiaxun Yang that converts MIPS to use asm-generic/io.h like every
  other architecture does, enabling future cleanups.

  Some of my own patches fix -Wmissing-prototype warnings in
  architecture specific code across several architectures. This is now
  needed as the warning is enabled by default. There are still some
  remaining warnings in minor platforms, but the series should catch
  most of the widely used ones make them more consistent with one
  another.

  David McKay fixes a bug in __generic_cmpxchg_local() when this is used
  on 64-bit architectures. This could currently only affect parisc64 and
  sparc64.

  Additional cleanups address from Linus Walleij, Uwe Kleine-König,
  Thomas Huth, and Kefeng Wang help reduce unnecessary inconsistencies
  between architectures"

* tag 'asm-generic-6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  asm-generic: Fix 32 bit __generic_cmpxchg_local
  Hexagon: Make pfn accessors statics inlines
  ARC: mm: Make virt_to_pfn() a static inline
  mips: remove extraneous asm-generic/iomap.h include
  sparc: Use $(kecho) to announce kernel images being ready
  arm64: vdso32: Define BUILD_VDSO32_64 to correct prototypes
  csky: fix arch_jump_label_transform_static override
  arch: add do_page_fault prototypes
  arch: add missing prepare_ftrace_return() prototypes
  arch: vdso: consolidate gettime prototypes
  arch: include linux/cpu.h for trap_init() prototype
  arch: fix asm-offsets.c building with -Wmissing-prototypes
  arch: consolidate arch_irq_work_raise prototypes
  hexagon: Remove CONFIG_HEXAGON_ARCH_VERSION from uapi header
  asm/io: remove unnecessary xlate_dev_mem_ptr() and unxlate_dev_mem_ptr()
  mips: io: remove duplicated codes
  arch/*/io.h: remove ioremap_uc in some architectures
  mips: add <asm-generic/io.h> including

Now that the driver core can properly handle constant struct bus_type,
move the locomo_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

It's also never used outside of arch/arm/common/locomo.c so make it
static and don't export it as no one is using it.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc:  <linux-arm-kernel@lists.infradead.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/2023121905-idiom-opossum-1ba3@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Create a new method to get a unique and fixed max frequency. Currently
cpuinfo.max_freq or the highest (or last) state of performance domain are
used as the max frequency when computing the frequency for a level of
utilization, but:

  - cpuinfo_max_freq can change at runtime. boost is one example of
    such change.

  - cpuinfo.max_freq and last item of the PD can be different leading to
    different results between cpufreq and energy model.

We need to save the reference frequency that has been used when computing
the CPUs capacity and use this fixed and coherent value to convert between
frequency and CPU's capacity.

In fact, we already save the frequency that has been used when computing
the capacity of each CPU. We extend the precision to save kHz instead of
MHz currently and we modify the type to be aligned with other variables
used when converting frequency to capacity and the other way.

[ mingo: Minor edits. ]

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20231211104855.558096-2-vincent.guittot@linaro.org

Instead of directly dereferencing page tables entries, which can cause
issues (see commit 20a004e7b017 ("arm64: mm: Use READ_ONCE/WRITE_ONCE when
accessing page tables"), let's introduce new functions to get the
pud/p4d/pgd entries (the pte and pmd versions already exist).

Note that arm pgd_t is actually an array so pgdp_get() is defined as a
macro to avoid a build error.

Those new functions will be used in subsequent commits by the riscv
architecture.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20231213203001.179237-3-alexghiti@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

The pcpu setup when using the page allocator sets up a new vmalloc
mapping very early in the boot process, so early that it cannot use the
flush_cache_vmap() function which may depend on structures not yet
initialized (for example in riscv, we currently send an IPI to flush
other cpus TLB).

But on some architectures, we must call flush_cache_vmap(): for example,
in riscv, some uarchs can cache invalid TLB entries so we need to flush
the new established mapping to avoid taking an exception.

So fix this by introducing a new function flush_cache_vmap_early() which
is called right after setting the new page table entry and before
accessing this new mapping. This new function implements a local flush
tlb on riscv and is no-op for other architectures (same as today).

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dennis Zhou <dennis@kernel.org>

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>