linux.git/arch/hexagon/kernel, branch v5.14

hexagon: use common DISCARDS macro

2021-07-08T18:48:20+00:00

ld.lld warns that the '.modinfo' section is not currently handled:

ld.lld: warning: kernel/built-in.a(workqueue.o):(.modinfo) is being placed in '.modinfo'
ld.lld: warning: kernel/built-in.a(printk/printk.o):(.modinfo) is being placed in '.modinfo'
ld.lld: warning: kernel/built-in.a(irq/spurious.o):(.modinfo) is being placed in '.modinfo'
ld.lld: warning: kernel/built-in.a(rcu/update.o):(.modinfo) is being placed in '.modinfo'

The '.modinfo' section was added in commit 898490c010b5 ("moduleparam:
Save information about built-in modules in separate file") to the DISCARDS
macro but Hexagon has never used that macro.  The unification of DISCARDS
happened in commit 023bf6f1b8bf ("linker script: unify usage of discard
definition") in 2009, prior to Hexagon being added in 2011.

Switch Hexagon over to the DISCARDS macro so that anything that is
expected to be discarded gets discarded.

Link: https://lkml.kernel.org/r/20210521011239.1332345-3-nathan@kernel.org
Fixes: e95bf452a9e2 ("Hexagon: Add configuration and makefiles for the Hexagon architecture.")
Signed-off-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Acked-by: Brian Cain 
Cc: David Rientjes 
Cc: Oliver Glitta 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hexagon: handle {,SOFT}IRQENTRY_TEXT in linker script

2021-07-08T18:48:20+00:00

Patch series "hexagon: Fix build error with CONFIG_STACKDEPOT and select CONFIG_ARCH_WANT_LD_ORPHAN_WARN".

This series fixes an error with ARCH=hexagon that was pointed out by the
patch "mm/slub: use stackdepot to save stack trace in objects".

The first patch fixes that error by handling the '.irqentry.text' and
'.softirqentry.text' sections.

The second patch switches Hexagon over to the common DISCARDS macro, which
should have been done when Hexagon was merged into the tree to match
commit 023bf6f1b8bf ("linker script: unify usage of discard definition").

The third patch selects CONFIG_ARCH_WANT_LD_ORPHAN_WARN so that something
like this does not happen again.

This patch (of 3):

Patch "mm/slub: use stackdepot to save stack trace in objects" in -mm
selects CONFIG_STACKDEPOT when CONFIG_STACKTRACE_SUPPORT is selected and
CONFIG_STACKDEPOT requires IRQENTRY_TEXT and SOFTIRQENTRY_TEXT to be
handled after commit 505a0ef15f96 ("kasan: stackdepot: move
filter_irq_stacks() to stackdepot.c") due to the use of the
__{,soft}irqentry_text_{start,end} section symbols.  If those sections are
not handled, the build is broken.

$ make ARCH=hexagon CROSS_COMPILE=hexagon-linux- LLVM=1 LLVM_IAS=1 defconfig all
...
ld.lld: error: undefined symbol: __irqentry_text_start
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a

ld.lld: error: undefined symbol: __irqentry_text_end
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a

ld.lld: error: undefined symbol: __softirqentry_text_start
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a

ld.lld: error: undefined symbol: __softirqentry_text_end
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a
>>> referenced by stackdepot.c
>>>               stackdepot.o:(filter_irq_stacks) in archive lib/built-in.a
...

Add these sections to the Hexagon linker script so the build continues to
work.  ld.lld's orphan section warning would have caught this prior to the
-mm commit mentioned above:

ld.lld: warning: kernel/built-in.a(softirq.o):(.softirqentry.text) is being placed in '.softirqentry.text'
ld.lld: warning: kernel/built-in.a(softirq.o):(.softirqentry.text) is being placed in '.softirqentry.text'
ld.lld: warning: kernel/built-in.a(softirq.o):(.softirqentry.text) is being placed in '.softirqentry.text'

Link: https://lkml.kernel.org/r/20210521011239.1332345-1-nathan@kernel.org
Link: https://lkml.kernel.org/r/20210521011239.1332345-2-nathan@kernel.org
Link: https://github.com/ClangBuiltLinux/linux/issues/1381
Fixes: 505a0ef15f96 ("kasan: stackdepot: move filter_irq_stacks() to stackdepot.c")
Signed-off-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Acked-by: Brian Cain 
Cc: Oliver Glitta 
Cc: Vlastimil Babka 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Introduce task_is_running()

2021-06-18T09:43:07+00:00

Replace a bunch of 'p->state == TASK_RUNNING' with a new helper:
task_is_running(p).

Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Davidlohr Bueso 
Acked-by: Geert Uytterhoeven 
Acked-by: Will Deacon 
Link: https://lore.kernel.org/r/20210611082838.222401495@infradead.org

Hexagon: add target builtins to kernel

2021-05-03T16:04:22+00:00

Add the compiler-rt builtins like memcpy to the hexagon kernel.

Signed-off-by: Sid Manning 
Add SYM_FUNC_START/END, ksyms exports
Signed-off-by: Brian Cain 

Tested-by: Nick Desaulniers

Hexagon: fix build errors

2021-05-03T16:04:18+00:00

Fix type-o in ptrace.c.
Add missing include: asm/hexagon_vm.h
Remove superfluous cast.
Replace 'p3_0' with 'preds'.

Signed-off-by: Sid Manning 
Add -mlong-calls to build flags.
Signed-off-by: Brian Cain 

Tested-by: Nick Desaulniers 
Reviewed-by: Nick Desaulniers

arch: setup PF_IO_WORKER threads like PF_KTHREAD

2021-02-22T00:25:22+00:00

PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign ->set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().

Signed-off-by: Jens Axboe

Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block

2020-12-16T20:33:35+00:00

Pull TIF_NOTIFY_SIGNAL updates from Jens Axboe:
 "This sits on top of of the core entry/exit and x86 entry branch from
  the tip tree, which contains the generic and x86 parts of this work.

  Here we convert the rest of the archs to support TIF_NOTIFY_SIGNAL.

  With that done, we can get rid of JOBCTL_TASK_WORK from task_work and
  signal.c, and also remove a deadlock work-around in io_uring around
  knowing that signal based task_work waking is invoked with the sighand
  wait queue head lock.

  The motivation for this work is to decouple signal notify based
  task_work, of which io_uring is a heavy user of, from sighand. The
  sighand lock becomes a huge contention point, particularly for
  threaded workloads where it's shared between threads. Even outside of
  threaded applications it's slower than it needs to be.

  Roman Gershman  reported that his networked
  workload dropped from 1.6M QPS at 80% CPU to 1.0M QPS at 100% CPU
  after io_uring was changed to use TIF_NOTIFY_SIGNAL. The time was all
  spent hammering on the sighand lock, showing 57% of the CPU time there
  [1].

  There are further cleanups possible on top of this. One example is
  TIF_PATCH_PENDING, where a patch already exists to use
  TIF_NOTIFY_SIGNAL instead. Hopefully this will also lead to more
  consolidation, but the work stands on its own as well"

[1] https://github.com/axboe/liburing/issues/215

* tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block: (28 commits)
  io_uring: remove 'twa_signal_ok' deadlock work-around
  kernel: remove checking for TIF_NOTIFY_SIGNAL
  signal: kill JOBCTL_TASK_WORK
  io_uring: JOBCTL_TASK_WORK is no longer used by task_work
  task_work: remove legacy TWA_SIGNAL path
  sparc: add support for TIF_NOTIFY_SIGNAL
  riscv: add support for TIF_NOTIFY_SIGNAL
  nds32: add support for TIF_NOTIFY_SIGNAL
  ia64: add support for TIF_NOTIFY_SIGNAL
  h8300: add support for TIF_NOTIFY_SIGNAL
  c6x: add support for TIF_NOTIFY_SIGNAL
  alpha: add support for TIF_NOTIFY_SIGNAL
  xtensa: add support for TIF_NOTIFY_SIGNAL
  arm: add support for TIF_NOTIFY_SIGNAL
  microblaze: add support for TIF_NOTIFY_SIGNAL
  hexagon: add support for TIF_NOTIFY_SIGNAL
  csky: add support for TIF_NOTIFY_SIGNAL
  openrisc: add support for TIF_NOTIFY_SIGNAL
  sh: add support for TIF_NOTIFY_SIGNAL
  um: add support for TIF_NOTIFY_SIGNAL
  ...

sched/idle: Fix arch_cpu_idle() vs tracing

2020-11-24T15:47:35+00:00

We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.

Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.

(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)

Reported-by: Sven Schnelle 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Mark Rutland 
Tested-by: Mark Rutland 
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org

hexagon: add support for TIF_NOTIFY_SIGNAL

2020-11-09T15:16:55+00:00

Wire up TIF_NOTIFY_SIGNAL handling for hexagon.

Cc: linux-hexagon@vger.kernel.org
Acked-by: Brian Cain 
Signed-off-by: Jens Axboe

tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume()

2020-10-17T21:04:36+00:00

All the callers currently do this, clean it up and move the clearing
into tracehook_notify_resume() instead.

Reviewed-by: Oleg Nesterov 
Reviewed-by: Thomas Gleixner 
Signed-off-by: Jens Axboe