diff options
| author | Greentime Hu <greentime.hu@sifive.com> | 2020-06-24 17:03:16 +0800 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2020-07-30 11:37:34 -0700 |
| commit | ed48b297fe211400531a129c592165958d661def (patch) | |
| tree | 37e9216cecd39fe95439785bd936a7ee6b47a8fd /arch/riscv | |
| parent | 298447928bb1c6bda9ad6f2ce3958d15c329816b (diff) | |
| download | linux-ed48b297fe211400531a129c592165958d661def.tar.gz | |
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>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/Kconfig | 1 | ||||
| -rw-r--r-- | arch/riscv/kernel/entry.S | 16 |
2 files changed, 16 insertions, 1 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 543335df7376..b7efe87329dd 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -53,6 +53,7 @@ config RISCV select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_ASM_MODVERSIONS + select HAVE_CONTEXT_TRACKING select HAVE_COPY_THREAD_TLS select HAVE_DMA_CONTIGUOUS if MMU select HAVE_EBPF_JIT if MMU diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index 45c81e49462d..124506ef4c5d 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -100,6 +100,16 @@ _save_context: #ifdef CONFIG_TRACE_IRQFLAGS call trace_hardirqs_off #endif + +#ifdef CONFIG_CONTEXT_TRACKING + /* If previous state is in user mode, call context_tracking_user_exit. */ + li a0, SR_PP + and a0, s1, a0 + bnez a0, skip_context_tracking + call context_tracking_user_exit +skip_context_tracking: +#endif + /* * MSB of cause differentiates between * interrupts and exceptions @@ -145,7 +155,7 @@ _save_context: tail do_trap_unknown handle_syscall: -#ifdef CONFIG_TRACE_IRQFLAGS +#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING) /* Recover a0 - a7 for system calls */ REG_L a0, PT_A0(sp) REG_L a1, PT_A1(sp) @@ -227,6 +237,10 @@ resume_userspace: andi s1, s0, _TIF_WORK_MASK bnez s1, work_pending +#ifdef CONFIG_CONTEXT_TRACKING + call context_tracking_user_enter +#endif + /* Save unwound kernel stack pointer in thread_info */ addi s0, sp, PT_SIZE_ON_STACK REG_S s0, TASK_TI_KERNEL_SP(tp) |