| From 45136479432b7068672efa460505e758e54bf571 Mon Sep 17 00:00:00 2001 |
| From: Zong Li <zong.li@sifive.com> |
| Date: Mon, 23 Dec 2019 16:46:14 +0800 |
| Subject: [PATCH] clocksource: riscv: add notrace to riscv_sched_clock |
| |
| commit 9d05c18e8d7de566ff68f221fcae65e78708dd1d upstream. |
| |
| When enabling ftrace graph tracer, it gets the tracing clock in |
| ftrace_push_return_trace(). Eventually, it invokes riscv_sched_clock() |
| to get the clock value. If riscv_sched_clock() isn't marked with |
| 'notrace', it will call ftrace_push_return_trace() and cause infinite |
| loop. |
| |
| The result of failure as follow: |
| |
| command: echo function_graph >current_tracer |
| [ 46.176787] Unable to handle kernel paging request at virtual address ffffffe04fb38c48 |
| [ 46.177309] Oops [#1] |
| [ 46.177478] Modules linked in: |
| [ 46.177770] CPU: 0 PID: 256 Comm: $d Not tainted 5.5.0-rc1 #47 |
| [ 46.177981] epc: ffffffe00035e59a ra : ffffffe00035e57e sp : ffffffe03a7569b0 |
| [ 46.178216] gp : ffffffe000d29b90 tp : ffffffe03a756180 t0 : ffffffe03a756968 |
| [ 46.178430] t1 : ffffffe00087f408 t2 : ffffffe03a7569a0 s0 : ffffffe03a7569f0 |
| [ 46.178643] s1 : ffffffe00087f408 a0 : 0000000ac054cda4 a1 : 000000000087f411 |
| [ 46.178856] a2 : 0000000ac054cda4 a3 : 0000000000373ca0 a4 : ffffffe04fb38c48 |
| [ 46.179099] a5 : 00000000153e22a8 a6 : 00000000005522ff a7 : 0000000000000005 |
| [ 46.179338] s2 : ffffffe03a756a90 s3 : ffffffe00032811c s4 : ffffffe03a756a58 |
| [ 46.179570] s5 : ffffffe000d29fe0 s6 : 0000000000000001 s7 : 0000000000000003 |
| [ 46.179809] s8 : 0000000000000003 s9 : 0000000000000002 s10: 0000000000000004 |
| [ 46.180053] s11: 0000000000000000 t3 : 0000003fc815749c t4 : 00000000000efc90 |
| [ 46.180293] t5 : ffffffe000d29658 t6 : 0000000000040000 |
| [ 46.180482] status: 0000000000000100 badaddr: ffffffe04fb38c48 cause: 000000000000000f |
| |
| Signed-off-by: Zong Li <zong.li@sifive.com> |
| Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
| [paul.walmsley@sifive.com: cleaned up patch description] |
| Fixes: 92e0d143fdef ("clocksource/drivers/riscv_timer: Provide the sched_clock") |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/clocksource/timer-riscv.c b/drivers/clocksource/timer-riscv.c |
| index 5e6038fbf115..47de8ed5beff 100644 |
| --- a/drivers/clocksource/timer-riscv.c |
| +++ b/drivers/clocksource/timer-riscv.c |
| @@ -50,7 +50,7 @@ static unsigned long long riscv_clocksource_rdtime(struct clocksource *cs) |
| return get_cycles64(); |
| } |
| |
| -static u64 riscv_sched_clock(void) |
| +static u64 notrace riscv_sched_clock(void) |
| { |
| return get_cycles64(); |
| } |
| -- |
| 2.7.4 |
| |