[PATCH AUTOSEL 6.2 41/53] s390/idle: mark arch_cpu_idle() noinstr

Sasha Levin
2023-02-26T15:09:31Z

From: Heiko Carstens <hca@linux.ibm.com>

[ Upstream commit a9cbc1b471d291c865907542394f1c483b93a811 ]

linux-next commit ("cpuidle: tracing: Warn about !rcu_is_watching()")
adds a new warning which hits on s390's arch_cpu_idle() function:

RCU not on for: arch_cpu_idle+0x0/0x28
WARNING: CPU: 2 PID: 0 at include/linux/trace_recursion.h:162 arch_ftrace_ops_list_func+0x24c/0x258
Modules linked in:
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 6.2.0-rc6-next-20230202 #4
Hardware name: IBM 8561 T01 703 (z/VM 7.3.0)
Krnl PSW : 0404d00180000000 00000000002b55c0 (arch_ftrace_ops_list_func+0x250/0x258)
R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:1 PM:0 RI:0 EA:3
Krnl GPRS: c0000000ffffbfff 0000000080000002 0000000000000026 0000000000000000
0000037ffffe3a28 0000037ffffe3a20 0000000000000000 0000000000000000
0000000000000000 0000000000f4acf6 00000000001044f0 0000037ffffe3cb0
0000000000000000 0000000000000000 00000000002b55bc 0000037ffffe3bb8
Krnl Code: 00000000002b55b0: c02000840051 larl %r2,0000000001335652
00000000002b55b6: c0e5fff512d1 brasl %r14,0000000000157b58
#00000000002b55bc: af000000 mc 0,0
>00000000002b55c0: a7f4ffe7 brc 15,00000000002b558e
00000000002b55c4: 0707 bcr 0,%r7
00000000002b55c6: 0707 bcr 0,%r7
00000000002b55c8: eb6ff0480024 stmg %r6,%r15,72(%r15)
00000000002b55ce: b90400ef lgr %r14,%r15
Call Trace:
[<00000000002b55c0>] arch_ftrace_ops_list_func+0x250/0x258
([<00000000002b55bc>] arch_ftrace_ops_list_func+0x24c/0x258)
[<0000000000f5f0fc>] ftrace_common+0x1c/0x20
[<00000000001044f6>] arch_cpu_idle+0x6/0x28
[<0000000000f4acf6>] default_idle_call+0x76/0x128
[<00000000001cc374>] do_idle+0xf4/0x1b0
[<00000000001cc6ce>] cpu_startup_entry+0x36/0x40
[<0000000000119d00>] smp_start_secondary+0x140/0x150
[<0000000000f5d2ae>] restart_int_handler+0x6e/0x90

Mark arch_cpu_idle() noinstr like all other architectures with
CONFIG_ARCH_WANTS_NO_INSTR (should) have it to fix this.

Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kernel/idle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c
index 4bf1ee293f2b3..a0da049e73609 100644
--- a/arch/s390/kernel/idle.c
+++ b/arch/s390/kernel/idle.c
@@ -44,7 +44,7 @@ void account_idle_time_irq(void)
S390_lowcore.last_update_timer = idle->timer_idle_exit;
}

-void arch_cpu_idle(void)
+void noinstr arch_cpu_idle(void)
{
struct s390_idle_data *idle = this_cpu_ptr(&s390_idle);
unsigned long idle_time;
--
2.39.0