Commit Graph

31 Commits

Author SHA1 Message Date
Guo Ren
3e7b669c6c
riscv: Cleanup unnecessary define in asm-offset.c
- 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 <guoren@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-07-30 11:37:44 -07:00
Greentime Hu
ed48b297fe
riscv: Enable context tracking
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
        | |       |   ||||       |         |
   <idle>-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
   <idle>-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 <greentime.hu@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-07-30 11:37:34 -07:00
Guo Ren
3c46979829
riscv: Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT
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 <guoren@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-07-30 11:37:32 -07:00
Anup Patel
24dc17005c
RISC-V: Remove do_IRQ() function
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 <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-06-09 19:11:24 -07:00
Linus Torvalds
eab4002660 RISC-V Patches for the 5.7 Merge Window, Part 1
This tag contains the patches I'd like to target for 5.7.  It has 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.
 
 This builds and boots for me.  There is one merge conflict, it's just a Kconfig
 merge issue.  I can publish a resolved branch if you'd like.
 
 I don't anticipate a part two, but I'll probably have something early in the
 RCs to finish up the K210 support.
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Merge tag 'riscv-for-linus-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

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
  ...
2020-04-09 10:51:30 -07:00
Tycho Andersen
af33d2433b
riscv: fix seccomp reject syscall code path
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 <david.abdurachmanov@gmail.com>
Signed-off-by: Tycho Andersen <tycho@tycho.ws>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-03-05 13:58:15 -08:00
Palmer Dabbelt
fdff9911f2
RISC-V: Inline the assembly register save/restore macros
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 <ndesaulniers@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2020-03-03 10:33:21 -08:00
Linus Torvalds
c677124e63 Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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
  ...
2020-01-28 10:07:09 -08:00
David Abdurachmanov
556f47ac60 riscv: reject invalid syscalls below -1
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 <david.abdurachmanov@sifive.com>
Fixes: 5340627e3f ("riscv: add support for SECCOMP and SECCOMP_FILTER")
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-12-27 21:50:57 -08:00
Thomas Gleixner
29ff64929e sched/rt, riscv: Use CONFIG_PREEMPTION
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 <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul Walmsley <paul.walmsley@sifive.com> # for arch/riscv
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-riscv@lists.infradead.org
Link: https://lore.kernel.org/r/20191015191821.11479-17-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-12-08 14:37:34 +01:00
Paul Walmsley
5ba9aa56e6 Merge branch 'next/nommu' into for-next
Conflicts:
	arch/riscv/boot/Makefile
	arch/riscv/include/asm/sbi.h
2019-11-22 18:59:09 -08:00
Christoph Hellwig
6bd33e1ece riscv: add nommu support
The kernel runs in M-mode without using page tables, and thus can't run
bare metal without help from additional firmware.

Most of the patch is just stubbing out code not needed without page
tables, but there is an interesting detail in the signals implementation:

 - The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO
   entry point, but the ELF VDSO is not supported for nommu Linux.
   We instead copy the code to call the syscall onto the stack.

In addition to enabling the nommu code a new defconfig for a small
kernel image that can run in nommu mode on qemu is also provided, to run
a kernel in qemu you can use the following command line:

qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \
	-kernel arch/riscv/boot/loader \
	-drive file=rootfs.ext2,format=raw,id=hd0 \
	-device virtio-blk-device,drive=hd0

Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards
 around PCI_IOBASE definition to fix build issues; fixed checkpatch
 issues; move the PCI_IO_* and VMEMMAP address space macros along
 with the others; resolve sparse warning]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-17 15:17:39 -08:00
Christoph Hellwig
a4c3733d32 riscv: abstract out CSR names for supervisor vs machine mode
Many of the privileged CSRs exist in a supervisor and machine version
that are used very similarly.  Provide versions of the CSR names and
fields that map to either the S-mode or M-mode variant depending on
a new CONFIG_RISCV_M_MODE kconfig symbol.

Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>
and Paul Walmsley <paul.walmsley@sifive.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de> # for drivers/clocksource, drivers/irqchip
[paul.walmsley@sifive.com: updated to apply]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-05 09:20:42 -08:00
David Abdurachmanov
5340627e3f riscv: add support for SECCOMP and SECCOMP_FILTER
This patch was extensively tested on Fedora/RISCV (applied by default on
top of 5.2-rc7 kernel for <2 months). The patch was also tested with 5.3-rc
on QEMU and SiFive Unleashed board.

libseccomp (userspace) was rebased:
https://github.com/seccomp/libseccomp/pull/134

Fully passes libseccomp regression testing (simulation and live).

There is one failing kernel selftest: global.user_notification_signal

v1 -> v2:
  - return immediately if secure_computing(NULL) returns -1
  - fixed whitespace issues
  - add missing seccomp.h
  - remove patch #2 (solved now)
  - add riscv to seccomp kernel selftest

Signed-off-by: David Abdurachmanov <david.abdurachmanov@sifive.com>
Cc: keescook@chromium.org
Cc: me@carlosedp.com
Tested-by: Carlos de Paula <me@carlosedp.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/linux-riscv/CAEn-LTp=ss0Dfv6J00=rCAy+N78U2AmhqJNjfqjr2FDpPYjxEQ@mail.gmail.com/
Link: https://lore.kernel.org/linux-riscv/CAJr-aD=UnCN9E_mdVJ2H5nt=6juRSWikZnA5HxDLQxXLbsRz-w@mail.gmail.com/
[paul.walmsley@sifive.com: cleaned up Cc: lines; fixed spelling and
 checkpatch issues; updated to apply]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-10-29 11:32:10 -07:00
Valentin Schneider
cd9e72b800 RISC-V: entry: Remove unneeded need_resched() loop
Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.

Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-10-09 16:48:27 -07:00
Palmer Dabbelt
18856604b3 RISC-V: Clear load reservations while restoring hart contexts
This is almost entirely a comment.  The bug is unlikely to manifest on
existing hardware because there is a timeout on load reservations, but
manifests on QEMU because there is no timeout.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-10-01 13:16:40 -07:00
Vincent Chen
c82dd6d078 riscv: Avoid interrupts being erroneously enabled in handle_exception()
When the handle_exception function addresses an exception, the interrupts
will be unconditionally enabled after finishing the context save. However,
It may erroneously enable the interrupts if the interrupts are disabled
before entering the handle_exception.

For example, one of the WARN_ON() condition is satisfied in the scheduling
where the interrupt is disabled and rq.lock is locked. The WARN_ON will
trigger a break exception and the handle_exception function will enable the
interrupts before entering do_trap_break function. During the procedure, if
a timer interrupt is pending, it will be taken when interrupts are enabled.
In this case, it may cause a deadlock problem if the rq.lock is locked
again in the timer ISR.

Hence, the handle_exception() can only enable interrupts when the state of
sstatus.SPIE is 1.

This patch is tested on HiFive Unleashed board.

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
[paul.walmsley@sifive.com: updated to apply]
Fixes: bcae803a21 ("RISC-V: Enable IRQ during exception handling")
Cc: David Abdurachmanov <david.abdurachmanov@sifive.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-09-20 08:42:34 -07:00
Bin Meng
4f3f900846 riscv: Using CSR numbers to access CSRs
Since commit a3182c91ef ("RISC-V: Access CSRs using CSR numbers"),
we should prefer accessing CSRs using their CSR numbers, but there
are several leftovers like sstatus / sptbr we missed.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-08-30 11:04:19 -07:00
Thomas Gleixner
50acfb2b76 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2 this program is distributed
  in the hope that it will be useful but without any warranty without
  even the implied warranty of merchantability or fitness for a
  particular purpose see the gnu general public license for more
  details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 97 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.025053186@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-05 17:36:37 +02:00
Anup Patel
a3182c91ef
RISC-V: Access CSRs using CSR numbers
We should prefer accessing CSRs using their CSR numbers because:
1. It compiles fine with older toolchains.
2. We can use latest CSR names in #define macro names of CSR numbers
   as-per RISC-V spec.
3. We can access newly added CSRs even if toolchain does not recognize
   newly addes CSRs by name.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-05-16 20:42:11 -07:00
Vincent Chen
99fd6e875d
RISC-V: Add _TIF_NEED_RESCHED check for kernel thread when CONFIG_PREEMPT=y
The cond_resched() can be used to yield the CPU resource if
CONFIG_PREEMPT is not defined. Otherwise, cond_resched() is a dummy
function. In order to avoid kernel thread occupying entire CPU,
when CONFIG_PREEMPT=y, the kernel thread needs to follow the
rescheduling mechanism like a user thread.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-01-23 12:56:19 -08:00
David Abdurachmanov
efe75c494f
riscv: add audit support
On RISC-V (riscv) audit is supported through generic lib/audit.c.
The patch adds required arch specific definitions.

Signed-off-by: David Abdurachmanov <david.abdurachmanov@gmail.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2019-01-07 08:22:39 -08:00
Palmer Dabbelt
d26c4bbf99
RISC-V: SMP cleanup and new features
This patch series now has evolved to contain several related changes.

1. Updated the assorted cleanup series by Palmer.
The original cleanup patch series can be found here.
http://lists.infradead.org/pipermail/linux-riscv/2018-August/001232.html

2. Implemented decoupling linux logical CPU ids from hart id.
Some of the work has been inspired from ARM64.
Tested on QEMU & HighFive Unleashed board with/without SMP enabled.

3. Included Anup's cleanup and IPI stat patch.

All the patch series have been combined to avoid conflicts as a lot of
common code is changed different patch sets. Atish has mostly addressed
review comments and fixed checkpatch errors from Palmer's and Anup's
series.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-22 17:41:43 -07:00
Anup Patel
1ed4237ab6
RISC-V: No need to pass scause as arg to do_IRQ()
The scause is already part of pt_regs so no need to pass
scause as separate arg to do_IRQ().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-22 17:03:35 -07:00
Alan Kao
e68ad867f7
Extract FPU context operations from entry.S
We move __fstate_save and __fstate_restore to a new source
file, fpu.S.

Signed-off-by: Alan Kao <alankao@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Cc: Vincent Chen <vincentc@andestech.com>
Cc: Zong Li <zong@andestech.com>
Cc: Nick Hu <nickhu@andestech.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-10-22 17:02:22 -07:00
Christoph Hellwig
6ea0f26a79
RISC-V: implement low-level interrupt handling
Add support for a routine that dispatches exceptions with the interrupt
flags set to either the IPI or irqdomain code (and the clock source in the
future).

Loosely based on the irq-riscv-int.c irqchip driver from the RISC-V tree.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-08-13 08:31:31 -07:00
Palmer Dabbelt
cc6c98485f RISC-V: Move to the new GENERIC_IRQ_MULTI_HANDLER handler
The existing mechanism for handling IRQs on RISC-V is pretty ugly: the irq
entry code selects the handler via Kconfig dependencies.

Use the new generic IRQ handling infastructure, which allows boot time
registration of the low level entry handler.

This does add an additional load to the interrupt latency, but there's a
lot of tuning left to be done there on RISC-V so it's OK for now.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Stafford Horne <shorne@gmail.com>
Cc: jonas@southpole.se
Cc: catalin.marinas@arm.com
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux@armlinux.org.uk
Cc: stefan.kristiansson@saunalahti.fi
Cc: openrisc@lists.librecores.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lkml.kernel.org/r/20180307235731.22627-3-palmer@sifive.com
2018-03-14 21:46:29 +01:00
zongbox@gmail.com
bcae803a21
RISC-V: Enable IRQ during exception handling
Interrupt is allowed during exception handling.
There are warning messages if the kernel enables the configuration
'CONFIG_DEBUG_ATOMIC_SLEEP=y'.

BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:23
in_atomic(): 0, irqs_disabled(): 1, pid: 43, name: ash
CPU: 0 PID: 43 Comm: ash Tainted:  G	 W	 4.15.0-rc8-00089-g89ffdae-dirty #17
Call Trace:
[<000000009abb1587>] walk_stackframe+0x0/0x7a
[<00000000d4f3d088>] ___might_sleep+0x102/0x11a
[<00000000b1fd792a>] down_read+0x18/0x28
[<000000000289ec01>] do_page_fault+0x86/0x2f6
[<00000000012441f6>] _do_fork+0x1b4/0x1e0
[<00000000f46c3e3b>] ret_from_syscall+0xa/0xe

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Zong Li <zong@andestech.com>
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-02-20 10:56:14 -08:00
Christoph Hellwig
fe9b842f72
riscv: disable SUM in the exception handler
The SUM bit is enabled at the beginning of the copy_{to,from}_user and
{get,put}_user routines, and cleared before they return.  But these user
copy helper can be interrupted by exceptions, in which case the SUM bit
will remain set, which leads to elevated privileges for the code running
in exception context, as that can now access userspace address space
unconditionally.  This frequently happens when the user copy routines
access freshly allocated user memory that hasn't been faulted in, and a
pagefault needs to be taken before the user copy routines can continue.

Fix this by unconditionally clearing SUM when the exception handler is
called - the restore code will automatically restore it based on the
saved value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-30 19:12:38 -08:00
Christoph Hellwig
1125203c13
riscv: rename SR_* constants to match the spec
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
2018-01-07 15:14:39 -08:00
Palmer Dabbelt
7db91e57a0 RISC-V: Task implementation
This patch contains the implementation of tasks on RISC-V, most of which
is involved in task switching.

Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>
2017-09-26 15:26:46 -07:00