linux.git/arch/riscv/kernel/entry.S, branch v5.12

riscv: keep interrupts disabled for BREAKPOINT exception

2021-04-16T04:32:40+00:00

Current riscv's kprobe handlers are run with both preemption and
interrupt enabled, this violates kprobe requirements. Fix this issue
by keeping interrupts disabled for BREAKPOINT exception.

Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
Cc: stable@vger.kernel.org
Signed-off-by: Jisheng Zhang 
Reviewed-by: Masami Hiramatsu 
[Palmer: add a comment]
Signed-off-by: Palmer Dabbelt

riscv,entry: fix misaligned base for excp_vect_table

2021-04-02T04:37:05+00:00

In RV64, the size of each entry in excp_vect_table is 8 bytes. If the
base of the table is not 8-byte aligned, loading an entry in the table
will raise a misaligned exception. Although such exception will be
handled by opensbi/bbl, this still causes performance degradation.

Signed-off-by: Zihao Yu 
Reviewed-by: Anup Patel 
Signed-off-by: Palmer Dabbelt

riscv: Trace irq on only interrupt is enabled

2021-01-13T04:16:35+00:00

We should call irq trace only if interrupt is going to be enabled during
excecption handling. Otherwise, it results in following warning during
boot with lock debugging enabled.

[    0.000000] ------------[ cut here ]------------
[    0.000000] DEBUG_LOCKS_WARN_ON(early_boot_irqs_disabled)
[    0.000000] WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:4085 lockdep_hardirqs_on_prepare+0x22a/0x22e
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.0-00022-ge20097fb37e2-dirty #548
[    0.000000] epc: c005d5d4 ra : c005d5d4 sp : c1c01e80
[    0.000000]  gp : c1d456e0 tp : c1c0a980 t0 : 00000000
[    0.000000]  t1 : ffffffff t2 : 00000000 s0 : c1c01ea0
[    0.000000]  s1 : c100f360 a0 : 0000002d a1 : c00666ee
[    0.000000]  a2 : 00000000 a3 : 00000000 a4 : 00000000
[    0.000000]  a5 : 00000000 a6 : c1c6b390 a7 : 3ffff00e
[    0.000000]  s2 : c2384fe8 s3 : 00000000 s4 : 00000001
[    0.000000]  s5 : c1c0a980 s6 : c1d48000 s7 : c1613b4c
[    0.000000]  s8 : 00000fff s9 : 80000200 s10: c1613b40
[    0.000000]  s11: 00000000 t3 : 00000000 t4 : 00000000
[    0.000000]  t5 : 00000001 t6 : 00000000

Fixes: 3c4697982982 ("riscv:Enable LOCKDEP_SUPPORT & fixup TRACE_IRQFLAGS_SUPPORT")

Signed-off-by: Atish Patra 
Signed-off-by: Palmer Dabbelt

riscv: Enable interrupts during syscalls with M-Mode

2021-01-08T02:04:25+00:00

When running is M-Mode (no MMU config), MPIE does not get set. This
results in all syscalls being executed with interrupts disabled as
handle_exception never sets SR_IE as it always sees SR_PIE being
cleared. Fix this by always force enabling interrupts in
handle_syscall when CONFIG_RISCV_M_MODE is enabled.

Signed-off-by: Damien Le Moal 
Reviewed-by: Palmer Dabbelt 
Signed-off-by: Palmer Dabbelt

riscv: return -ENOSYS for syscall -1

2021-01-08T02:01:34+00:00

Properly return -ENOSYS for syscall -1 instead of leaving the return value
uninitialized.  This fixes the strace teststuite.

Fixes: 5340627e3fe0 ("riscv: add support for SECCOMP and SECCOMP_FILTER")
Cc: stable@vger.kernel.org
Signed-off-by: Andreas Schwab 
Reviewed-by: Tycho Andersen 
Signed-off-by: Palmer Dabbelt

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
  ...