find_bit API and bitmap API are closely related, but inclusion paths
are different - include/asm-generic and include/linux, correspondingly.
In the past it made a lot of troubles due to circular dependencies
and/or undefined symbols. Fix this by moving find.h under include/linux.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Pull tty/serial driver updates from Greg KH:
"Here is the big set of tty/serial driver updates for 5.17-rc1.
Nothing major in here, just lots of good updates and fixes, including:
- more tty core cleanups from Jiri as well as mxser driver cleanups.
This is the majority of the core diffstat
- tty documentation updates from Jiri
- platform_get_irq() updates
- various serial driver updates for new features and hardware
- fifo usage for 8250 console, reducing cpu load a lot
- LED fix for keyboards, long-time bugfix that went through many
revisions
- minor cleanups
All have been in linux-next for a while with no reported problems"
* tag 'tty-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (119 commits)
serial: core: Keep mctrl register state and cached copy in sync
serial: stm32: correct loop for dma error handling
serial: stm32: fix flow control transfer in DMA mode
serial: stm32: rework TX DMA state condition
serial: stm32: move tx dma terminate DMA to shutdown
serial: pl011: Drop redundant DTR/RTS preservation on close/open
serial: pl011: Drop CR register reset on set_termios
serial: pl010: Drop CR register reset on set_termios
serial: liteuart: fix MODULE_ALIAS
serial: 8250_bcm7271: Fix return error code in case of dma_alloc_coherent() failure
Revert "serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2"
tty: goldfish: Use platform_get_irq() to get the interrupt
serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2
tty: serial: meson: Drop the legacy compatible strings and clock code
serial: pmac_zilog: Use platform_get_irq() to get the interrupt
serial: bcm63xx: Use platform_get_irq() to get the interrupt
serial: ar933x: Use platform_get_irq() to get the interrupt
serial: vt8500: Use platform_get_irq() to get the interrupt
serial: altera_jtaguart: Use platform_get_irq_optional() to get the interrupt
serial: pxa: Use platform_get_irq() to get the interrupt
...
Pull locking updates from Borislav Petkov:
"Lots of cleanups and preparation. Highlights:
- futex: Cleanup and remove runtime futex_cmpxchg detection
- rtmutex: Some fixes for the PREEMPT_RT locking infrastructure
- kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and
annotate the racy owner->on_cpu access *once*.
- atomic64: Dead-Code-Elemination"
[ Description above by Peter Zijlstra ]
* tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/atomic: atomic64: Remove unusable atomic ops
futex: Fix additional regressions
locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.h
x86/mm: Include spinlock_t definition in pgtable.
locking: Mark racy reads of owner->on_cpu
locking: Make owner_on_cpu() into <linux/sched.h>
lockdep/selftests: Adapt ww-tests for PREEMPT_RT
lockdep/selftests: Skip the softirq related tests on PREEMPT_RT
lockdep/selftests: Unbalanced migrate_disable() & rcu_read_lock().
lockdep/selftests: Avoid using local_lock_{acquire|release}().
lockdep: Remove softirq accounting on PREEMPT_RT.
locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().
locking/rtmutex: Squash self-deadlock check for ww_rt_mutex.
locking: Remove rt_rwlock_is_contended().
sched: Trigger warning if ->migration_disabled counter underflows.
futex: Fix sparc32/m68k/nds32 build regression
futex: Remove futex_cmpxchg detection
futex: Ensure futex_atomic_cmpxchg_inatomic() is present
kernel/locking: Use a pointer in ww_mutex_trylock().
Pull ARM updates from Russell King:
- amba bus irq rework
- add kfence support
- support for Cortex M33 and M55 CPUs
- kbuild updates for decompressor
- let core code manage thread_info::cpu
- avoid unpredictable NOP encoding in decompressor
- reduce information printed in calltraces
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: reduce the information printed in call traces
ARM: 9168/1: Add support for Cortex-M55 processor
ARM: 9167/1: Add support for Cortex-M33 processor
ARM: 9166/1: Support KFENCE for ARM
ARM: 9165/1: mm: Provide is_write_fault()
ARM: 9164/1: mm: Provide set_memory_valid()
ARM: 9163/1: amba: Move of_amba_device_decode_irq() into amba_probe()
ARM: 9162/1: amba: Kill sysfs attribute file of irq
ARM: 9161/1: mm: mark private VM_FAULT_X defines as vm_fault_t
ARM: 9159/1: decompressor: Avoid UNPREDICTABLE NOP encoding
ARM: 9158/1: leave it to core code to manage thread_info::cpu
ARM: 9154/1: decompressor: do not copy source files while building
Pull power management updates from Rafael Wysocki:
"The most signigicant change here is the addition of a new cpufreq
'P-state' driver for AMD processors as a better replacement for the
venerable acpi-cpufreq driver.
There are also other cpufreq updates (in the core, intel_pstate, ARM
drivers), PM core updates (mostly related to adding new macros for
declaring PM operations which should make the lives of driver
developers somewhat easier), and a bunch of assorted fixes and
cleanups.
Summary:
- Add new P-state driver for AMD processors (Huang Rui).
- Fix initialization of min and max frequency QoS requests in the
cpufreq core (Rafael Wysocki).
- Fix EPP handling on Alder Lake in intel_pstate (Srinivas
Pandruvada).
- Make intel_pstate update cpuinfo.max_freq when notified of HWP
capabilities changes and drop a redundant function call from that
driver (Rafael Wysocki).
- Improve IRQ support in the Qcom cpufreq driver (Ard Biesheuvel,
Stephen Boyd, Vladimir Zapolskiy).
- Fix double devm_remap() in the Mediatek cpufreq driver (Hector
Yuan).
- Introduce thermal pressure helpers for cpufreq CPU cooling (Lukasz
Luba).
- Make cpufreq use default_groups in kobj_type (Greg Kroah-Hartman).
- Make cpuidle use default_groups in kobj_type (Greg Kroah-Hartman).
- Fix two comments in cpuidle code (Jason Wang, Yang Li).
- Allow model-specific normal EPB value to be used in the intel_epb
sysfs attribute handling code (Srinivas Pandruvada).
- Simplify locking in pm_runtime_put_suppliers() (Rafael Wysocki).
- Add safety net to supplier device release in the runtime PM core
code (Rafael Wysocki).
- Capture device status before disabling runtime PM for it (Rafael
Wysocki).
- Add new macros for declaring PM operations to allow drivers to
avoid guarding them with CONFIG_PM #ifdefs or __maybe_unused and
update some drivers to use these macros (Paul Cercueil).
- Allow ACPI hardware signature to be honoured during restore from
hibernation (David Woodhouse).
- Update outdated operating performance points (OPP) documentation
(Tang Yizhou).
- Reduce log severity for informative message regarding frequency
transition failures in devfreq (Tzung-Bi Shih).
- Add DRAM frequency controller devfreq driver for Allwinner sunXi
SoCs (Samuel Holland).
- Add missing COMMON_CLK dependency to sun8i devfreq driver (Arnd
Bergmann).
- Add support for new layout of Psys PowerLimit Register on SPR to
the Intel RAPL power capping driver (Zhang Rui).
- Fix typo in a comment in idle_inject.c (Jason Wang).
- Remove unused function definition from the DTPM (Dynamit Thermal
Power Management) power capping framework (Daniel Lezcano).
- Reduce DTPM trace verbosity (Daniel Lezcano)"
* tag 'pm-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (53 commits)
x86, sched: Fix undefined reference to init_freq_invariance_cppc() build error
cpufreq: amd-pstate: Fix Kconfig dependencies for AMD P-State
cpufreq: amd-pstate: Fix struct amd_cpudata kernel-doc comment
cpuidle: use default_groups in kobj_type
x86: intel_epb: Allow model specific normal EPB value
MAINTAINERS: Add AMD P-State driver maintainer entry
Documentation: amd-pstate: Add AMD P-State driver introduction
cpufreq: amd-pstate: Add AMD P-State performance attributes
cpufreq: amd-pstate: Add AMD P-State frequencies attributes
cpufreq: amd-pstate: Add boost mode support for AMD P-State
cpufreq: amd-pstate: Add trace for AMD P-State module
cpufreq: amd-pstate: Introduce the support for the processors with shared memory solution
cpufreq: amd-pstate: Add fast switch function for AMD P-State
cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors
ACPI: CPPC: Add CPPC enable register function
ACPI: CPPC: Check present CPUs for determining _CPC is valid
ACPI: CPPC: Implement support for SystemIO registers
x86/msr: Add AMD CPPC MSR definitions
x86/cpufeatures: Add AMD Collaborative Processor Performance Control feature flag
cpufreq: use default_groups in kobj_type
...
Merge cpufreq updates for 5.17-rc1:
- Add new P-state driver for AMD processors (Huang Rui).
- Fix initialization of min and max frequency QoS requests in the
cpufreq core (Rafael Wysocki).
- Fix EPP handling on Alder Lake in intel_pstate (Srinivas Pandruvada).
- Make intel_pstate update cpuinfo.max_freq when notified of HWP
capabilities changes and drop a redundant function call from that
driver (Rafael Wysocki).
- Improve IRQ support in the Qcom cpufreq driver (Ard Biesheuvel,
Stephen Boyd, Vladimir Zapolskiy).
- Fix double devm_remap() in the Mediatek cpufreq driver (Hector Yuan).
- Introduce thermal pressure helpers for cpufreq CPU cooling (Lukasz
Luba).
- Make cpufreq use default_groups in kobj_type (Greg Kroah-Hartman).
* pm-cpufreq: (32 commits)
x86, sched: Fix undefined reference to init_freq_invariance_cppc() build error
cpufreq: amd-pstate: Fix Kconfig dependencies for AMD P-State
cpufreq: amd-pstate: Fix struct amd_cpudata kernel-doc comment
MAINTAINERS: Add AMD P-State driver maintainer entry
Documentation: amd-pstate: Add AMD P-State driver introduction
cpufreq: amd-pstate: Add AMD P-State performance attributes
cpufreq: amd-pstate: Add AMD P-State frequencies attributes
cpufreq: amd-pstate: Add boost mode support for AMD P-State
cpufreq: amd-pstate: Add trace for AMD P-State module
cpufreq: amd-pstate: Introduce the support for the processors with shared memory solution
cpufreq: amd-pstate: Add fast switch function for AMD P-State
cpufreq: amd-pstate: Introduce a new AMD P-State driver to support future processors
ACPI: CPPC: Add CPPC enable register function
ACPI: CPPC: Check present CPUs for determining _CPC is valid
ACPI: CPPC: Implement support for SystemIO registers
x86/msr: Add AMD CPPC MSR definitions
x86/cpufeatures: Add AMD Collaborative Processor Performance Control feature flag
cpufreq: use default_groups in kobj_type
cpufreq: mediatek-hw: Fix double devm_remap in hotplug case
cpufreq: intel_pstate: Update cpuinfo.max_freq on HWP_CAP changes
...
Pull ARM SoC updates from Arnd Bergmann:
"These are all minor bug fixes and cleanups to code in arch/arm and
arch/arm64 that is specific to one SoC, updating Kconfig symbols, the
MAINTAINERS file, and removing some dead code"
* tag 'soc-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
arm64: exynos: Enable Exynos Multi-Core Timer driver
ARM: ixp4xx: remove unused header file pata_ixp4xx_cf.h
ARM: ixp4xx: remove dead configs CPU_IXP43X and CPU_IXP46X
MAINTAINERS: Add Florian as BCM5301X and BCM53573 maintainer
ARM: samsung: Remove HAVE_S3C2410_I2C and use direct dependencies
ARM: imx: rename DEBUG_IMX21_IMX27_UART to DEBUG_IMX27_UART
ARM: imx: remove dead left-over from i.MX{27,31,35} removal
ARM: s3c: add one more "fallthrough" statement in Jive
ARM: s3c: include header for prototype of s3c2410_modify_misccr
ARM: shmobile: rcar-gen2: Add missing of_node_put()
Nathan reports that the new get_current() and per-CPU offset accessors
may cause problems at build time due to the use of a literal to hold the
address of the respective variables. This is due to the fact that LLD
before v14 does not support the PC-relative group relocations that are
normally used for this, and the fallback relies on literals but does not
emit the literal pools explictly using the .ltorg directive.
./arch/arm/include/asm/current.h:53:6: error: out of range pc-relative fixup value
asm(LOAD_SYM_ARMV6(%0, __current) : "=r"(cur));
^
./arch/arm/include/asm/insn.h:25:2: note: expanded from macro 'LOAD_SYM_ARMV6'
" ldr " #reg ", =" #sym " nt"
^
<inline asm>:1:3: note: instantiated into assembly here
ldr r0, =__current
^
Since emitting a literal pool in this particular case is not possible,
let's avoid the LOAD_SYM_ARMV6() entirely, and use the ordinary C
assigment instead.
As it turns out, there are other such cases, and here, using .ltorg to
emit the literal pool within range of the LDR instruction would be
possible due to the presence of an unconditional branch right after it.
Unfortunately, putting .ltorg directives in subsections appears to
confuse the Clang inline assembler, resulting in similar errors even
though the .ltorg is most definitely within range.
So let's fix this by emitting the literal explicitly, and not rely on
the assembler to figure this out. This means we have move the fallback
out of the LOAD_SYM_ARMV6() macro and into the callers.
Link: https://github.com/ClangBuiltLinux/linux/issues/1551
Fixes: 9c46929e79 ("ARM: implement THREAD_INFO_IN_TASK for uniprocessor systems")
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Pull ARM cpufreq updates for 5.17-rc1 from Viresh Kumar:
"- Qcom cpufreq driver updates improve irq support (Ard Biesheuvel, Stephen Boyd,
and Vladimir Zapolskiy).
- Fixes double devm_remap for mediatek driver (Hector Yuan).
- Introduces thermal pressure helpers (Lukasz Luba)."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: mediatek-hw: Fix double devm_remap in hotplug case
cpufreq: qcom-hw: Use optional irq API
cpufreq: qcom-hw: Set CPU affinity of dcvsh interrupts
cpufreq: qcom-hw: Fix probable nested interrupt handling
cpufreq: qcom-cpufreq-hw: Avoid stack buffer for IRQ name
arch_topology: Remove unused topology_set_thermal_pressure() and related
cpufreq: qcom-cpufreq-hw: Use new thermal pressure update function
cpufreq: qcom-cpufreq-hw: Update offline CPUs per-cpu thermal pressure
thermal: cpufreq_cooling: Use new thermal pressure update function
arch_topology: Introduce thermal pressure update function
Pull EFI fix from Ard Biesheuvel:
"Another EFI fix for v5.16:
- Prevent missing prototype warning from breaking the build under
CONFIG_WERROR=y"
* tag 'efi-urgent-for-v5.16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
efi: Move efifb_setup_from_dmi() prototype from arch headers
Add architecture specific implementation details for KFENCE and enable
KFENCE on ARM. In particular, this implements the required interface in
<asm/kfence.h>.
KFENCE requires that attributes for pages from its memory pool can
individually be set. Therefore, force the kfence pool to be mapped
at page granularity.
Testing this patch using the testcases in kfence_test.c and all passed
with or without ARM_LPAE.
Acked-by: Marco Elver <elver@google.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Since commit bcf9033e54 ("sched: move CPU field back into thread_info
if THREAD_INFO_IN_TASK=y"), the CPU field in thread_info went back to
being managed by the core code, so we no longer have to keep it in sync
in arch code.
While at it, mark THREAD_INFO_IN_TASK as done for ARM in the
documentation.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Commit 8633ef82f1 ("drivers/firmware: consolidate EFI framebuffer setup
for all arches") made the Generic System Framebuffers (sysfb) driver able
to be built on non-x86 architectures.
But it left the efifb_setup_from_dmi() function prototype declaration in
the architecture specific headers. This could lead to the following
compiler warning as reported by the kernel test robot:
drivers/firmware/efi/sysfb_efi.c:70:6: warning: no previous prototype for function 'efifb_setup_from_dmi' [-Wmissing-prototypes]
void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
^
drivers/firmware/efi/sysfb_efi.c:70:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
Fixes: 8633ef82f1 ("drivers/firmware: consolidate EFI framebuffer setup for all arches")
Reported-by: kernel test robot <lkp@intel.com>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://lore.kernel.org/r/20211126001333.555514-1-javierm@redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
The printk header file includes ratelimit_types.h for its __ratelimit()
based usage. It is required for the static initializer used in
printk_ratelimited(). It uses a raw_spinlock_t and includes the
spinlock_types.h.
PREEMPT_RT substitutes spinlock_t with a rtmutex based implementation and so
its spinlock_t implmentation (provided by spinlock_rt.h) includes rtmutex.h and
atomic.h which leads to recursive includes where defines are missing.
By including only the raw_spinlock_t defines it avoids the atomic.h
related includes at this stage.
An example on powerpc:
| CALL scripts/atomic/check-atomics.sh
|In file included from include/linux/bug.h:5,
| from include/linux/page-flags.h:10,
| from kernel/bounds.c:10:
|arch/powerpc/include/asm/page_32.h: In function âclear_pageâ:
|arch/powerpc/include/asm/bug.h:87:4: error: implicit declaration of function â=80=98__WARNâ=80=99 [-Werror=3Dimplicit-function-declaration]
| 87 | __WARN(); \
| | ^~~~~~
|arch/powerpc/include/asm/page_32.h:48:2: note: in expansion of macro âWARN_ONâ=99
| 48 | WARN_ON((unsigned long)addr & (L1_CACHE_BYTES - 1));
| | ^~~~~~~
|arch/powerpc/include/asm/bug.h:58:17: error: invalid application of âsizeofâ=99 to incomplete type âstruct bug_entryâ=99
| 58 | "i" (sizeof(struct bug_entry)), \
| | ^~~~~~
|arch/powerpc/include/asm/bug.h:89:3: note: in expansion of macro âBUG_ENTRYâ=99
| 89 | BUG_ENTRY(PPC_TLNEI " %4, 0", \
| | ^~~~~~~~~
|arch/powerpc/include/asm/page_32.h:48:2: note: in expansion of macro âWARN_ONâ=99
| 48 | WARN_ON((unsigned long)addr & (L1_CACHE_BYTES - 1));
| | ^~~~~~~
|In file included from arch/powerpc/include/asm/ptrace.h:298,
| from arch/powerpc/include/asm/hw_irq.h:12,
| from arch/powerpc/include/asm/irqflags.h:12,
| from include/linux/irqflags.h:16,
| from include/asm-generic/cmpxchg-local.h:6,
| from arch/powerpc/include/asm/cmpxchg.h:526,
| from arch/powerpc/include/asm/atomic.h:11,
| from include/linux/atomic.h:7,
| from include/linux/rwbase_rt.h:6,
| from include/linux/rwlock_types.h:55,
| from include/linux/spinlock_types.h:74,
| from include/linux/ratelimit_types.h:7,
| from include/linux/printk.h:10,
| from include/asm-generic/bug.h:22,
| from arch/powerpc/include/asm/bug.h:109,
| from include/linux/bug.h:5,
| from include/linux/page-flags.h:10,
| from kernel/bounds.c:10:
|include/linux/thread_info.h: In function â=80=98copy_overflowâ=80=99:
|include/linux/thread_info.h:210:2: error: implicit declaration of function â=80=98WARNâ=80=99 [-Werror=3Dimplicit-function-declaration]
| 210 | WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
| | ^~~~
The WARN / BUG include pulls in printk.h and then ptrace.h expects WARN
(from bug.h) which is not yet complete. Even hw_irq.h has WARN_ON()
statements.
On POWERPC64 there are missing atomic64 defines while building 32bit
VDSO:
| VDSO32C arch/powerpc/kernel/vdso32/vgettimeofday.o
|In file included from include/linux/atomic.h:80,
| from include/linux/rwbase_rt.h:6,
| from include/linux/rwlock_types.h:55,
| from include/linux/spinlock_types.h:74,
| from include/linux/ratelimit_types.h:7,
| from include/linux/printk.h:10,
| from include/linux/kernel.h:19,
| from arch/powerpc/include/asm/page.h:11,
| from arch/powerpc/include/asm/vdso/gettimeofday.h:5,
| from include/vdso/datapage.h:137,
| from lib/vdso/gettimeofday.c:5,
| from <command-line>:
|include/linux/atomic-arch-fallback.h: In function âarch_atomic64_incâ=99:
|include/linux/atomic-arch-fallback.h:1447:2: error: implicit declaration of function âarch_atomic64_addâ; did you mean âarch_atomic_addâ? [-Werror=3Dimpl
|icit-function-declaration]
| 1447 | arch_atomic64_add(1, v);
| | ^~~~~~~~~~~~~~~~~
| | arch_atomic_add
The generic fallback is not included, atomics itself are not used. If
kernel.h does not include printk.h then it comes later from the bug.h
include.
Allow asm/spinlock_types.h to be included from
linux/spinlock_types_raw.h.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211129174654.668506-12-bigeasy@linutronix.de
On UP systems, only a single task can be 'current' at the same time,
which means we can use a global variable to track it. This means we can
also enable THREAD_INFO_IN_TASK for those systems, as in that case,
thread_info is accessed via current rather than the other way around,
removing the need to store thread_info at the base of the task stack.
This, in turn, permits us to enable IRQ stacks and vmap'ed stacks on UP
systems as well.
To partially mitigate the performance overhead of this arrangement, use
a ADD/ADD/LDR sequence with the appropriate PC-relative group
relocations to load the value of current when needed. This means that
accessing current will still only require a single load as before,
avoiding the need for a literal to carry the address of the global
variable in each function. However, accessing thread_info will now
require this load as well.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Defer TPIDURO updates for user space until exit also for CPU_V6+SMP
configurations so that we can decide at runtime whether to use it to
carry the current pointer, provided that we are running on a CPU that
actually implements this register. This is needed for
THREAD_INFO_IN_TASK support for UP systems, which requires that all SMP
capable systems use the TPIDRURO based access to 'current' as the only
remaining alternative will be a global variable which only works on UP.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Permit the use of the TPIDRPRW system register for carrying the per-CPU
offset in generic SMP configurations that also target non-SMP capable
ARMv6 cores. This uses the SMP_ON_UP code patching framework to turn all
TPIDRPRW accesses into reads/writes of entry #0 in the __per_cpu_offset
array.
While at it, switch over some existing direct TPIDRPRW accesses in asm
code to invocations of a new helper that is patched in the same way when
necessary.
Note that CPU_V6+SMP without SMP_ON_UP results in a kernel that does not
boot on v6 CPUs without SMP extensions, so add this dependency to
Kconfig as well.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
We will be adding variable loads to various hot paths, so it makes sense
to add a helper macro that can load variables from asm code without the
use of literal pool entries. On v7 or later, we can simply use MOVW/MOVT
pairs, but on earlier cores, this requires a bit of hackery to emit a
instruction sequence that implements this using a sequence of ADD/LDR
instructions.
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Add support for the R_ARM_ALU_PC_Gn_NC and R_ARM_LDR_PC_G2 group
relocations [0] so we can use them in modules. These will be used to
load the current task pointer from a global variable without having to
rely on a literal pool entry to carry the address of this variable,
which may have a significant negative impact on cache utilization for
variables that are used often and in many different places, as each
occurrence will result in a literal pool entry and therefore a line in
the D-cache.
[0] 'ELF for the ARM architecture'
https://github.com/ARM-software/abi-aa/releases
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
The last user of arch_irq_handler_default is gone now, so the
entry-macro-multi.S file and all references to mach/entry-macro.S can
be removed, as well as the asm_do_IRQ() entrypoint into the interrupt
handling routines implemented in C.
Note: The ARMv7-M entry still uses its own top-level IRQ entry, calling
nvic_handle_irq() from assembly. This could be changed to go through
generic_handle_arch_irq() as well, but it's unclear to me if there are
any benefits.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[ardb: keep irq_handler macro as it carries all the IRQ stack handling]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
This is one of the last platforms using the old entry path.
While this code path is spread over a few files, it is fairly
straightforward to convert it into an equivalent C version,
leaving the existing algorithm and all the priority handling
the same.
Unlike most irqchip drivers, this means reading the status
register(s) in a loop and always handling the highest-priority
irq first.
The IOMD_IRQREQC and IOMD_IRQREQD registers are not actaully
used here, but I left the code in place for the time being,
to keep the conversion as direct as possible. It could be
removed in a cleanup on top.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
[ardb: drop obsolete IOMD_IRQREQC/IOMD_IRQREQD handling]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
IOMD_IRQREQC nor IOMD_IRQREQD are ever defined, so any conditionally
compiled code that depends on them is dead code, and can be removed.
Suggested-by: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Wire up the generic support for managing task stack allocations via vmalloc,
and implement the entry code that detects whether we faulted because of a
stack overrun (or future stack overrun caused by pushing the pt_regs array)
While this adds a fair amount of tricky entry asm code, it should be
noted that it only adds a TST + branch to the svc_entry path. The code
implementing the non-trivial handling of the overflow stack is emitted
out-of-line into the .text section.
Since on ARM, we rely on do_translation_fault() to keep PMD level page
table entries that cover the vmalloc region up to date, we need to
ensure that we don't hit such a stale PMD entry when accessing the
stack. So we do a dummy read from the new stack while still running from
the old one on the context switch path, and bump the vmalloc_seq counter
when PMD level entries in the vmalloc range are modified, so that the MM
switch fetches the latest version of the entries.
Note that we need to increase the per-mode stack by 1 word, to gain some
space to stash a GPR until we know it is safe to touch the stack.
However, due to the cacheline alignment of the struct, this does not
actually increase the memory footprint of the struct stack array at all.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Now that we no longer rely on the stack pointer to access the current
task struct or thread info, we can implement support for IRQ stacks
cleanly as well.
Define a per-CPU IRQ stack and switch to this stack when taking an IRQ,
provided that we were not already using that stack in the interrupted
context. This is never the case for IRQs taken from user space, but ones
taken while running in the kernel could fire while one taken from user
space has not completed yet.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
The existing code that dumps the contents of the pt_regs structure
passed to __entry routines does so while unwinding the callee frame, and
dereferences the stack pointer as a struct pt_regs*. This will no longer
work when we enable support for IRQ or overflow stacks, because the
struct pt_regs may live on the task stack, while we are executing from
another stack.
The unwinder has access to this information, but only while unwinding
the calling frame. So let's combine the exception stack dumping code
with the handling of the calling frame as well. By printing it before
dumping the caller/callee addresses, the output order is preserved.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
Add a bl_r macro that abstract the difference between the ways indirect
calls are performed on older and newer ARM architecture revisions.
The main difference is to prefer blx instructions over explicit LR
assignments when possible, as these tend to confuse the prediction logic
in out-of-order cores when speculating across a function return.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Keith Packard <keithpac@amazon.com>
Tested-by: Marc Zyngier <maz@kernel.org>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com> # ARMv7M
pci_remap_iospace() is standard PCI core function. Architecture code can
reimplement default core implementation if needs custom arch specific
functionality.
ARM needs custom implementation due to pci_ioremap_set_mem_type() hook
which allows ARM platforms to change mem type for iospace.
Implement this pci_remap_iospace() function for ARM architecture to
correctly handle pci_ioremap_set_mem_type() hook, which allows usage of
this standard PCI core function also for platforms which needs different
mem type (e.g. Marvell Armada 375, 38x and 39x).
Link: https://lore.kernel.org/r/20211124154116.916-2-pali@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Commit 89d4f98ae9 ("ARM: remove zte zx platform") missed to remove some
definitions for this platform's debug and serial, e.g., code dependent on
the config DEBUG_ZTE_ZX.
Fortunately, ./scripts/checkkconfigsymbols.py detects this and warns:
DEBUG_ZTE_ZX
Referencing files: arch/arm/include/debug/pl01x.S
Further review by Arnd Bergmann identified even more dead code in the
amba serial driver.
Remove all this left-over from the zte zx platform.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20211102063810.932-1-lukas.bulwahn@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is no need of this function (and related) since code has been
converted to use the new arch_update_thermal_pressure() API. The old
code can be removed.
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The thermal pressure is a mechanism which is used for providing
information about reduced CPU performance to the scheduler. Usually code
has to convert the value from frequency units into capacity units,
which are understandable by the scheduler. Create a common conversion code
which can be just used via a handy API.
Internally, the topology_update_thermal_pressure() operates on frequency
in MHz and max CPU frequency is taken from 'freq_factor' (per-cpu).
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Reviewed-by: Thara Gopinath <thara.gopinath@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Since commit 4b563a0666 ("ARM: imx: Remove imx21 support"), the config
DEBUG_IMX21_IMX27_UART is really only debug support for IMX27.
So, rename this option to DEBUG_IMX27_UART and adjust dependencies in
Kconfig and rename the definitions to IMX27 as further clean-up.
This issue was discovered with ./scripts/checkkconfigsymbols.py, which
reported that DEBUG_IMX21_IMX27_UART depends on the non-existing config
SOC_IMX21.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Many architectures do not include asm-generic/cacheflush.h, so turn
the includes on their head and add linux/cacheflush.h which includes
asm/cacheflush.h.
Move the flush_dcache_folio() declaration from asm-generic/cacheflush.h
to linux/cacheflush.h and change linux/highmem.h to include
linux/cacheflush.h instead of asm/cacheflush.h so that all necessary
places will see flush_dcache_folio().
More functions should have their default implementations moved in the
future, but those are for follow-on patches. This fixes csky, sparc and
sparc64 which were missed in the commit which added flush_dcache_folio().
Fixes: 08b0b0059b ("mm: Add flush_dcache_folio()")
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Pull asm-generic cleanup from Arnd Bergmann:
"This is a single cleanup from Peter Collingbourne, removing some dead
code"
* tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
arch: remove unused function syscall_set_arguments()
Pull tracing updates from Steven Rostedt:
- kprobes: Restructured stack unwinder to show properly on x86 when a
stack dump happens from a kretprobe callback.
- Fix to bootconfig parsing
- Have tracefs allow owner and group permissions by default (only
denying others). There's been pressure to allow non root to tracefs
in a controlled fashion, and using groups is probably the safest.
- Bootconfig memory managament updates.
- Bootconfig clean up to have the tools directory be less dependent on
changes in the kernel tree.
- Allow perf to be traced by function tracer.
- Rewrite of function graph tracer to be a callback from the function
tracer instead of having its own trampoline (this change will happen
on an arch by arch basis, and currently only x86_64 implements it).
- Allow multiple direct trampolines (bpf hooks to functions) be batched
together in one synchronization.
- Allow histogram triggers to add variables that can perform
calculations against the event's fields.
- Use the linker to determine architecture callbacks from the ftrace
trampoline to allow for proper parameter prototypes and prevent
warnings from the compiler.
- Extend histogram triggers to key off of variables.
- Have trace recursion use bit magic to determine preempt context over
if branches.
- Have trace recursion disable preemption as all use cases do anyway.
- Added testing for verification of tracing utilities.
- Various small clean ups and fixes.
* tag 'trace-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (101 commits)
tracing/histogram: Fix semicolon.cocci warnings
tracing/histogram: Fix documentation inline emphasis warning
tracing: Increase PERF_MAX_TRACE_SIZE to handle Sentinel1 and docker together
tracing: Show size of requested perf buffer
bootconfig: Initialize ret in xbc_parse_tree()
ftrace: do CPU checking after preemption disabled
ftrace: disable preemption when recursion locked
tracing/histogram: Document expression arithmetic and constants
tracing/histogram: Optimize division by a power of 2
tracing/histogram: Covert expr to const if both operands are constants
tracing/histogram: Simplify handling of .sym-offset in expressions
tracing: Fix operator precedence for hist triggers expression
tracing: Add division and multiplication support for hist triggers
tracing: Add support for creating hist trigger variables from literal
selftests/ftrace: Stop tracing while reading the trace file by default
MAINTAINERS: Update KPROBES and TRACING entries
test_kprobes: Move it from kernel/ to lib/
docs, kprobes: Remove invalid URL and add new reference
samples/kretprobes: Fix return value if register_kretprobe() failed
lib/bootconfig: Fix the xbc_get_info kerneldoc
...
Pull scheduler updates from Thomas Gleixner:
- Revert the printk format based wchan() symbol resolution as it can
leak the raw value in case that the symbol is not resolvable.
- Make wchan() more robust and work with all kind of unwinders by
enforcing that the task stays blocked while unwinding is in progress.
- Prevent sched_fork() from accessing an invalid sched_task_group
- Improve asymmetric packing logic
- Extend scheduler statistics to RT and DL scheduling classes and add
statistics for bandwith burst to the SCHED_FAIR class.
- Properly account SCHED_IDLE entities
- Prevent a potential deadlock when initial priority is assigned to a
newly created kthread. A recent change to plug a race between cpuset
and __sched_setscheduler() introduced a new lock dependency which is
now triggered. Break the lock dependency chain by moving the priority
assignment to the thread function.
- Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
- Improve idle balancing in general and especially for NOHZ enabled
systems.
- Provide proper interfaces for live patching so it does not have to
fiddle with scheduler internals.
- Add cluster aware scheduling support.
- A small set of tweaks for RT (irqwork, wait_task_inactive(), various
scheduler options and delaying mmdrop)
- The usual small tweaks and improvements all over the place
* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
sched/fair: Cleanup newidle_balance
sched/fair: Remove sysctl_sched_migration_cost condition
sched/fair: Wait before decaying max_newidle_lb_cost
sched/fair: Skip update_blocked_averages if we are defering load balance
sched/fair: Account update_blocked_averages in newidle_balance cost
x86: Fix __get_wchan() for !STACKTRACE
sched,x86: Fix L2 cache mask
sched/core: Remove rq_relock()
sched: Improve wake_up_all_idle_cpus() take #2
irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
sched: Add cluster scheduler level for x86
sched: Add cluster scheduler level in core and related Kconfig for ARM64
topology: Represent clusters of CPUs within a die
sched: Disable -Wunused-but-set-variable
sched: Add wrapper for get_wchan() to keep task blocked
x86: Fix get_wchan() to support the ORC unwinder
proc: Use task_is_running() for wchan in /proc/$pid/stat
...
Pull timer updates from Thomas Gleixner:
"Time, timers and timekeeping updates:
- No core updates
- No new clocksource/event driver
- A large rework of the ARM architected timer driver to prepare for
the support of the upcoming ARMv8.6 support
- Fix Kconfig options for Exynos MCT, Samsung PWM and TI DM timers
- Address a namespace collison in the ARC sp804 timer driver"
* tag 'timers-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource/drivers/timer-ti-dm: Select TIMER_OF
clocksource/drivers/exynosy: Depend on sub-architecture for Exynos MCT and Samsung PWM
clocksource/drivers/arch_arm_timer: Move workaround synchronisation around
clocksource/drivers/arm_arch_timer: Fix masking for high freq counters
clocksource/drivers/arm_arch_timer: Drop unnecessary ISB on CVAL programming
clocksource/drivers/arm_arch_timer: Remove any trace of the TVAL programming interface
clocksource/drivers/arm_arch_timer: Work around broken CVAL implementations
clocksource/drivers/arm_arch_timer: Advertise 56bit timer to the core code
clocksource/drivers/arm_arch_timer: Move MMIO timer programming over to CVAL
clocksource/drivers/arm_arch_timer: Fix MMIO base address vs callback ordering issue
clocksource/drivers/arm_arch_timer: Move drop _tval from erratum function names
clocksource/drivers/arm_arch_timer: Move system register timer programming over to CVAL
clocksource/drivers/arm_arch_timer: Extend write side of timer register accessors to u64
clocksource/drivers/arm_arch_timer: Drop CNT*_TVAL read accessors
clocksource/arm_arch_timer: Add build-time guards for unhandled register accesses
clocksource/drivers/arc_timer: Eliminate redefined macro error
Pull memory folios from Matthew Wilcox:
"Add memory folios, a new type to represent either order-0 pages or the
head page of a compound page. This should be enough infrastructure to
support filesystems converting from pages to folios.
The point of all this churn is to allow filesystems and the page cache
to manage memory in larger chunks than PAGE_SIZE. The original plan
was to use compound pages like THP does, but I ran into problems with
some functions expecting only a head page while others expect the
precise page containing a particular byte.
The folio type allows a function to declare that it's expecting only a
head page. Almost incidentally, this allows us to remove various calls
to VM_BUG_ON(PageTail(page)) and compound_head().
This converts just parts of the core MM and the page cache. For 5.17,
we intend to convert various filesystems (XFS and AFS are ready; other
filesystems may make it) and also convert more of the MM and page
cache to folios. For 5.18, multi-page folios should be ready.
The multi-page folios offer some improvement to some workloads. The
80% win is real, but appears to be an artificial benchmark (postgres
startup, which isn't a serious workload). Real workloads (eg building
the kernel, running postgres in a steady state, etc) seem to benefit
between 0-10%. I haven't heard of any performance losses as a result
of this series. Nobody has done any serious performance tuning; I
imagine that tweaking the readahead algorithm could provide some more
interesting wins. There are also other places where we could choose to
create large folios and currently do not, such as writes that are
larger than PAGE_SIZE.
I'd like to thank all my reviewers who've offered review/ack tags:
Christoph Hellwig, David Howells, Jan Kara, Jeff Layton, Johannes
Weiner, Kirill A. Shutemov, Michal Hocko, Mike Rapoport, Vlastimil
Babka, William Kucharski, Yu Zhao and Zi Yan.
I'd also like to thank those who gave feedback I incorporated but
haven't offered up review tags for this part of the series: Nick
Piggin, Mel Gorman, Ming Lei, Darrick Wong, Ted Ts'o, John Hubbard,
Hugh Dickins, and probably a few others who I forget"
* tag 'folio-5.16' of git://git.infradead.org/users/willy/pagecache: (90 commits)
mm/writeback: Add folio_write_one
mm/filemap: Add FGP_STABLE
mm/filemap: Add filemap_get_folio
mm/filemap: Convert mapping_get_entry to return a folio
mm/filemap: Add filemap_add_folio()
mm/filemap: Add filemap_alloc_folio
mm/page_alloc: Add folio allocation functions
mm/lru: Add folio_add_lru()
mm/lru: Convert __pagevec_lru_add_fn to take a folio
mm: Add folio_evictable()
mm/workingset: Convert workingset_refault() to take a folio
mm/filemap: Add readahead_folio()
mm/filemap: Add folio_mkwrite_check_truncate()
mm/filemap: Add i_blocks_per_folio()
mm/writeback: Add folio_redirty_for_writepage()
mm/writeback: Add folio_account_redirty()
mm/writeback: Add folio_clear_dirty_for_io()
mm/writeback: Add folio_cancel_dirty()
mm/writeback: Add folio_account_cleaned()
mm/writeback: Add filemap_dirty_folio()
...
If available, we use the __builtin_thread_pointer() helper to get the
value of the TLS register, to help the compiler understand that it
doesn't need to reload it every time we access 'current'.
Unfortunately, Clang fails to emit the MRC system register read
directly when building for Thumb2, and instead, it issues a call to the
__aeabi_read_tp helper, which the kernel does not provide, and so this
result in link failures at build time.
So create a special case for this, and emit the MRC directly using an
asm() block, just like we do when the helper is not available to begin
with.
Link: https://github.com/ClangBuiltLinux/linux/issues/1485
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
The code that implements the rarely used PID_IN_CONTEXTIDR feature
dereferences the 'task' field of struct thread_info directly, and this
is no longer possible when THREAD_INFO_IN_TASK=y, as the 'task' field is
omitted from the struct definition in that case. Instead, we should just
cast the thread_info pointer to a task_struct pointer, given that the
former is now the first member of the latter.
So use a helper that abstracts this, and provide implementations for
both cases.
Reported by: Arnd Bergmann <arnd@arndb.de>
Fixes: 18ed1c01a7 ("ARM: smp: Enable THREAD_INFO_IN_TASK")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
On BE32 kernels, the __opcode_to_mem_thumb32() interface is intentionally
not defined, but it is referenced whenever runtime patching is enabled
for the kernel, which may be for ftrace, jump label, kprobes or kgdb:
arch/arm/kernel/patch.c: In function '__patch_text_real':
arch/arm/kernel/patch.c:94:32: error: implicit declaration of function '__opcode_to_mem_thumb32' [-Werror=implicit-function-declaration]
94 | insn = __opcode_to_mem_thumb32(insn);
| ^~~~~~~~~~~~~~~~~~~~~~~
Since BE32 kernels never run Thumb2 code, we never end up using the
result of this call, so providing an extern declaration without
a definition makes it build correctly.
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
