linux.git/arch/csky/kernel, branch v5.15

csky: Fixup regs.sr broken in ptrace

2021-10-15T23:20:12+00:00

gpr_get() return the entire pt_regs (include sr) to userspace, if we
don't restore the C bit in gpr_set, it may break the ALU result in
that context. So the C flag bit is part of gpr context, that's why
riscv totally remove the C bit in the ISA. That makes sr reg clear
from userspace to supervisor privilege.

Signed-off-by: Guo Ren 
Cc: Al Viro 
Cc: stable@vger.kernel.org

csky: don't let sigreturn play with priveleged bits of status register

2021-10-15T23:20:12+00:00

csky restore_sigcontext() blindly overwrites regs->sr with the value
it finds in sigcontext.  Attacker can store whatever they want in there,
which includes things like S-bit.  Userland shouldn't be able to set
that, or anything other than C flag (bit 0).

Do the same thing other architectures with protected bits in flags
register do - preserve everything that shouldn't be settable in
user mode, picking the rest from the value saved is sigcontext.

Signed-off-by: Al Viro 
Signed-off-by: Guo Ren 
Cc: stable@vger.kernel.org

entry: rseq: Call rseq_handle_notify_resume() in tracehook_notify_resume()

2021-09-22T14:24:01+00:00

Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now
that the two function are always called back-to-back by architectures
that have rseq.  The rseq helper is stubbed out for architectures that
don't support rseq, i.e. this is a nop across the board.

Note, tracehook_notify_resume() is horribly named and arguably does not
belong in tracehook.h as literally every line of code in it has nothing
to do with tracing.  But, that's been true since commit a42c6ded827d
("move key_repace_session_keyring() into tracehook_notify_resume()")
first usurped tracehook_notify_resume() back in 2012.  Punt cleaning that
mess up to future patches.

No functional change intended.

Acked-by: Mathieu Desnoyers 
Signed-off-by: Sean Christopherson 
Message-Id: <20210901203030.1292304-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini

arch/csky/kernel/probes/kprobes.c: fix bugon.cocci warnings

2021-09-03T16:58:09+00:00

Use BUG_ON instead of a if condition followed by BUG.

Generated by: scripts/coccinelle/misc/bugon.cocci

Link: https://lkml.kernel.org/r/alpine.DEB.2.22.394.2107061049150.7197@hadrien
Fixes: 7d37cb2c912d ("lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS")
Signed-off-by: kernel test robot 
Signed-off-by: Julia Lawall 
Reported-by: kernel test robot 
Cc: Julian Braha 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

csky: convert to setup_initial_init_mm()

2021-07-08T18:48:21+00:00

Use setup_initial_init_mm() helper to simplify code.

Link: https://lkml.kernel.org/r/20210608083418.137226-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang 
Acked-by: Guo Ren 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'sched-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2021-06-28T19:14:19+00:00

Pull scheduler udpates from Ingo Molnar:

- Changes to core scheduling facilities:

- Add "Core Scheduling" via CONFIG_SCHED_CORE=y, which enables
coordinated scheduling across SMT siblings. This is a much
requested feature for cloud computing platforms, to allow the
flexible utilization of SMT siblings, without exposing untrusted
domains to information leaks & side channels, plus to ensure more
deterministic computing performance on SMT systems used by
heterogenous workloads.

There are new prctls to set core scheduling groups, which allows
more flexible management of workloads that can share siblings.

- Fix task->state access anti-patterns that may result in missed
wakeups and rename it to ->__state in the process to catch new
abuses.

- Load-balancing changes:

- Tweak newidle_balance for fair-sched, to improve 'memcache'-like
workloads.

- "Age" (decay) average idle time, to better track & improve
workloads such as 'tbench'.

- Fix & improve energy-aware (EAS) balancing logic & metrics.

- Fix & improve the uclamp metrics.

- Fix task migration (taskset) corner case on !CONFIG_CPUSET.

- Fix RT and deadline utilization tracking across policy changes

- Introduce a "burstable" CFS controller via cgroups, which allows
bursty CPU-bound workloads to borrow a bit against their future
quota to improve overall latencies & batching. Can be tweaked via
/sys/fs/cgroup/cpu//cpu.cfs_burst_us.

- Rework assymetric topology/capacity detection & handling.

- Scheduler statistics & tooling:

- Disable delayacct by default, but add a sysctl to enable it at
runtime if tooling needs it. Use static keys and other
optimizations to make it more palatable.

- Use sched_clock() in delayacct, instead of ktime_get_ns().

- Misc cleanups and fixes.

* tag 'sched-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
sched/doc: Update the CPU capacity asymmetry bits
sched/topology: Rework CPU capacity asymmetry detection
sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag
psi: Fix race between psi_trigger_create/destroy
sched/fair: Introduce the burstable CFS controller
sched/uclamp: Fix uclamp_tg_restrict()
sched/rt: Fix Deadline utilization tracking during policy change
sched/rt: Fix RT utilization tracking during policy change
sched: Change task_struct::state
sched,arch: Remove unused TASK_STATE offsets
sched,timer: Use __set_current_state()
sched: Add get_current_state()
sched,perf,kvm: Fix preemption condition
sched: Introduce task_is_running()
sched: Unbreak wakeups
sched/fair: Age the average idle time
sched/cpufreq: Consider reduced CPU capacity in energy calculation
sched/fair: Take thermal pressure into account while estimating energy
thermal/cpufreq_cooling: Update offline CPUs per-cpu thermal_pressure
sched/fair: Return early from update_tg_cfs_load() if delta == 0
...

sched,arch: Remove unused TASK_STATE offsets

2021-06-18T09:43:09+00:00

All 6 architectures define TASK_STATE in asm-offsets, but then never
actually use it. Remove the definitions to make sure they never will.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20210611082838.472811363@infradead.org

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

kprobes: Do not increment probe miss count in the fault handler

2021-06-03T13:47:26+00:00

Kprobes has a counter 'nmissed', that is used to count the number of
times a probe handler was not called. This generally happens when we hit
a kprobe while handling another kprobe.

However, if one of the probe handlers causes a fault, we are currently
incrementing 'nmissed'. The comment in fault handler indicates that this
can be used to account faults taken by the probe handlers. But, this has
never been the intention as is evident from the comment above 'nmissed'
in 'struct kprobe':

	/*count the number of times this probe was temporarily disarmed */
	unsigned long nmissed;

Signed-off-by: Naveen N. Rao 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Masami Hiramatsu 
Link: https://lkml.kernel.org/r/20210601120150.672652-1-naveen.n.rao@linux.vnet.ibm.com

kprobes: Remove kprobe::fault_handler

2021-06-01T14:00:08+00:00

The reason for kprobe::fault_handler(), as given by their comment:

 * We come here because instructions in the pre/post
 * handler caused the page_fault, this could happen
 * if handler tries to access user space by
 * copy_from_user(), get_user() etc. Let the
 * user-specified handler try to fix it first.

Is just plain bad. Those other handlers are ran from non-preemptible
context and had better use _nofault() functions. Also, there is no
upstream usage of this.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Christoph Hellwig 
Acked-by: Masami Hiramatsu 
Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org