linux.git/arch/riscv/kernel/entry.S, branch v5.9

riscv: Cleanup unnecessary define in asm-offset.c

2020-07-30T18:37:44+00:00

 - TASK_THREAD_SP is duplicated define
 - TASK_STACK is no use at all
 - Don't worry about thread_info's offset in task_struct, have
   a look on comment in include/linux/sched.h:

struct task_struct {
	/*
	 * For reasons of header soup (see current_thread_info()), this
	 * must be the first element of task_struct.
	 */
	struct thread_info		thread_info;

Signed-off-by: Guo Ren 
Signed-off-by: Palmer Dabbelt

riscv: Enable context tracking

2020-07-30T18:37:34+00:00

This patch implements and enables context tracking for riscv (which is a
prerequisite for CONFIG_NO_HZ_FULL support)

It adds checking for previous state in the entry that all excepttions and
interrupts goes to and calls context_tracking_user_exit() if it comes from
user space. It also calls context_tracking_user_enter() if it will return
to user space before restore_all.

This patch is tested with the dynticks-testing testcase in
qemu-system-riscv64 virt machine and Unleashed board.
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/dynticks-testing.git

We can see the log here. The tick got mostly stopped during the execution
of the user loop.

                        _-----=> irqs-off
                       / _----=> need-resched
                      | / _---=> hardirq/softirq
                      || / _--=> preempt-depth
                      ||| /     delay
     TASK-PID   CPU#  ||||    TIMESTAMP  FUNCTION
        | |       |   ||||       |         |
   -0     [001] d..2   604.183512: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=taskset next_pid=273 next_prio=120
user_loop-273   [001] d.h1   604.184788: hrtimer_expire_entry: hrtimer=000000002eda5fab function=tick_sched_timer now=604176096300
user_loop-273   [001] d.s2   604.184897: workqueue_queue_work: work struct=00000000383402c2 function=vmstat_update workqueue=00000000f36d35d4 req_cpu=1 cpu=1
user_loop-273   [001] dns2   604.185039: tick_stop: success=0 dependency=SCHED
user_loop-273   [001] dn.1   604.185103: tick_stop: success=0 dependency=SCHED
user_loop-273   [001] d..2   604.185154: sched_switch: prev_comm=taskset prev_pid=273 prev_prio=120 prev_state=R+ ==> next_comm=kworker/1:1 next_pid=46 next_prio=120
    <...>-46    [001] ....   604.185194: workqueue_execute_start: work struct 00000000383402c2: function vmstat_update
    <...>-46    [001] d..2   604.185266: sched_switch: prev_comm=kworker/1:1 prev_pid=46 prev_prio=120 prev_state=I ==> next_comm=taskset next_pid=273 next_prio=120
user_loop-273   [001] d.h1   604.188812: hrtimer_expire_entry: hrtimer=000000002eda5fab function=tick_sched_timer now=604180133400
user_loop-273   [001] d..1   604.189050: tick_stop: success=1 dependency=NONE
user_loop-273   [001] d..2   614.251386: sched_switch: prev_comm=user_loop prev_pid=273 prev_prio=120 prev_state=X ==> next_comm=swapper/1 next_pid=0 next_prio=120
   -0     [001] d..2   614.315391: sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=taskset next_pid=276 next_prio=120

Signed-off-by: Greentime Hu 
Signed-off-by: Palmer Dabbelt

riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT

2020-07-30T18:37:32+00:00

Lockdep is needed by proving the spinlocks and rwlocks. To suupport
it, we need fixup TRACE_IRQFLAGS_SUPPORT in kernel/entry.S. This
patch follow Documentation/irqflags-tracing.txt.

Signed-off-by: Guo Ren 
Signed-off-by: Palmer Dabbelt

RISC-V: Remove do_IRQ() function

2020-06-10T02:11:24+00:00

The only thing do_IRQ() does is call handle_arch_irq function
pointer. We can very well call handle_arch_irq function pointer
directly from assembly and remove do_IRQ() function hence this
patch.

Signed-off-by: Anup Patel 
Reviewed-by: Atish Patra 
Signed-off-by: Palmer Dabbelt

Merge tag 'riscv-for-linus-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2020-04-09T17:51:30+00:00

Pull RISC-V updates from Palmer Dabbelt:
 "This contains a handful of new features:

   - Partial support for the Kendryte K210.

     There are still a few outstanding issues that I have patches for,
     but I don't actually have a board to test them so they're not
     included yet.

   - SBI v0.2 support.

   - Fixes to support for building with LLVM-based toolchains. The
     resulting images are known not to boot yet.

  I don't anticipate a part two, but I'll probably have something early
  in the RCs to finish up the K210 support"

* tag 'riscv-for-linus-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (38 commits)
  riscv: create a loader.bin boot image for Kendryte SoC
  riscv: Kendryte K210 default config
  riscv: Add Kendryte K210 device tree
  riscv: Select required drivers for Kendryte SOC
  riscv: Add Kendryte K210 SoC support
  riscv: Add SOC early init support
  riscv: Unaligned load/store handling for M_MODE
  RISC-V: Support cpu hotplug
  RISC-V: Add supported for ordered booting method using HSM
  RISC-V: Add SBI HSM extension definitions
  RISC-V: Export SBI error to linux error mapping function
  RISC-V: Add cpu_ops and modify default booting method
  RISC-V: Move relocate and few other functions out of __init
  RISC-V: Implement new SBI v0.2 extensions
  RISC-V: Introduce a new config for SBI v0.1
  RISC-V: Add SBI v0.2 extension definitions
  RISC-V: Add basic support for SBI v0.2
  RISC-V: Mark existing SBI as 0.1 SBI.
  riscv: Use macro definition instead of magic number
  riscv: Add support to dump the kernel page tables
  ...

riscv: fix seccomp reject syscall code path

2020-03-05T21:58:15+00:00

If secure_computing() rejected a system call, we were previously setting
the system call number to -1, to indicate to later code that the syscall
failed. However, if something (e.g. a user notification) was sleeping, and
received a signal, we may set a0 to -ERESTARTSYS and re-try the system call
again.

In this case, seccomp "denies" the syscall (because of the signal), and we
would set a7 to -1, thus losing the value of the system call we want to
restart.

Instead, let's return -1 from do_syscall_trace_enter() to indicate that the
syscall was rejected, so we don't clobber the value in case of -ERESTARTSYS
or whatever.

This commit fixes the user_notification_signal seccomp selftest on riscv to
no longer hang. That test expects the system call to be re-issued after the
signal, and it wasn't due to the above bug. Now that it is, everything
works normally.

Note that in the ptrace (tracer) case, the tracer can set the register
values to whatever they want, so we still need to keep the code that
handles out-of-bounds syscalls. However, we can drop the comment.

We can also drop syscall_set_nr(), since it is no longer used anywhere, and
the code that re-loads the value in a7 because of it.

Reported in: https://lore.kernel.org/bpf/CAEn-LTp=ss0Dfv6J00=rCAy+N78U2AmhqJNjfqjr2FDpPYjxEQ@mail.gmail.com/

Reported-by: David Abdurachmanov 
Signed-off-by: Tycho Andersen 
Reviewed-by: Kees Cook 
Signed-off-by: Palmer Dabbelt

RISC-V: Inline the assembly register save/restore macros

2020-03-03T18:33:21+00:00

These are only used once, and when reading the code I've always found them to
be more of a headache than a benefit.  While they were never worth removing
before, LLVM's integrated assembler doesn't support LOCAL so rather that trying
to figure out how to refactor the macros it seems saner to just inline them.

Reviewed-by: Nick Desaulniers 
Signed-off-by: Palmer Dabbelt

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2020-01-28T18:07:09+00:00

Pull scheduler updates from Ingo Molnar:
 "These were the main changes in this cycle:

   - More -rt motivated separation of CONFIG_PREEMPT and
     CONFIG_PREEMPTION.

   - Add more low level scheduling topology sanity checks and warnings
     to filter out nonsensical topologies that break scheduling.

   - Extend uclamp constraints to influence wakeup CPU placement

   - Make the RT scheduler more aware of asymmetric topologies and CPU
     capacities, via uclamp metrics, if CONFIG_UCLAMP_TASK=y

   - Make idle CPU selection more consistent

   - Various fixes, smaller cleanups, updates and enhancements - please
     see the git log for details"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
  sched/fair: Define sched_idle_cpu() only for SMP configurations
  sched/topology: Assert non-NUMA topology masks don't (partially) overlap
  idle: fix spelling mistake "iterrupts" -> "interrupts"
  sched/fair: Remove redundant call to cpufreq_update_util()
  sched/psi: create /proc/pressure and /proc/pressure/{io|memory|cpu} only when psi enabled
  sched/fair: Fix sgc->{min,max}_capacity calculation for SD_OVERLAP
  sched/fair: calculate delta runnable load only when it's needed
  sched/cputime: move rq parameter in irqtime_account_process_tick
  stop_machine: Make stop_cpus() static
  sched/debug: Reset watchdog on all CPUs while processing sysrq-t
  sched/core: Fix size of rq::uclamp initialization
  sched/uclamp: Fix a bug in propagating uclamp value in new cgroups
  sched/fair: Load balance aggressively for SCHED_IDLE CPUs
  sched/fair : Improve update_sd_pick_busiest for spare capacity case
  watchdog: Remove soft_lockup_hrtimer_cnt and related code
  sched/rt: Make RT capacity-aware
  sched/fair: Make EAS wakeup placement consider uclamp restrictions
  sched/fair: Make task_fits_capacity() consider uclamp restrictions
  sched/uclamp: Rename uclamp_util_with() into uclamp_rq_util_with()
  sched/uclamp: Make uclamp util helpers use and return UL values
  ...

riscv: reject invalid syscalls below -1

2019-12-28T05:50:57+00:00

Running "stress-ng --enosys 4 -t 20 -v" showed a large number of kernel oops
with "Unable to handle kernel paging request at virtual address" message. This
happens when enosys stressor starts testing random non-valid syscalls.

I forgot to redirect any syscall below -1 to sys_ni_syscall.

With the patch kernel oops messages are gone while running stress-ng enosys
stressor.

Signed-off-by: David Abdurachmanov 
Fixes: 5340627e3fe0 ("riscv: add support for SECCOMP and SECCOMP_FILTER")
Signed-off-by: Paul Walmsley

sched/rt, riscv: Use CONFIG_PREEMPTION

2019-12-08T13:37:34+00:00

CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT.
Both PREEMPT and PREEMPT_RT require the same functionality which today
depends on CONFIG_PREEMPT.

Switch the entry code over to use CONFIG_PREEMPTION.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Acked-by: Paul Walmsley  # for arch/riscv
Cc: Albert Ou 
Cc: Linus Torvalds 
Cc: Palmer Dabbelt 
Cc: Peter Zijlstra 
Cc: linux-riscv@lists.infradead.org
Link: https://lore.kernel.org/r/20191015191821.11479-17-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar