From: Michael Ellerman <mpe@ellerman.id.au>
To: Nathan Lynch <nathanl@linux.ibm.com>,
Nicholas Piggin <npiggin@gmail.com>,
linuxppc-dev@lists.ozlabs.org
Cc: tyreld@linux.ibm.com, nnac123@linux.ibm.com,
ldufour@linux.ibm.com, ajd@linux.ibm.com
Subject: Re: [PATCH 13/13] powerpc/rtas: place tracepoints in do_enter_rtas()
Date: Tue, 29 Nov 2022 11:49:52 +1100 [thread overview]
Message-ID: <87mt8abn4f.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <87tu2i8x0e.fsf@linux.ibm.com>
Nathan Lynch <nathanl@linux.ibm.com> writes:
> "Nicholas Piggin" <npiggin@gmail.com> writes:
>> On Sat Nov 19, 2022 at 1:07 AM AEST, Nathan Lynch wrote:
>>> Call the just-added rtas tracepoints in do_enter_rtas(), taking care
>>> to avoid function name lookups in the CPU offline path.
>>>
>>> Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
>>> ---
>>> arch/powerpc/kernel/rtas.c | 23 +++++++++++++++++++++++
>>> 1 file changed, 23 insertions(+)
>>>
>>> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
>>> index 198366d641d0..3487b42cfbf7 100644
>>> --- a/arch/powerpc/kernel/rtas.c
>>> +++ b/arch/powerpc/kernel/rtas.c
>>> @@ -38,6 +38,7 @@
>>> #include <asm/page.h>
>>> #include <asm/rtas.h>
>>> #include <asm/time.h>
>>> +#include <asm/trace.h>
>>> #include <asm/udbg.h>
>>>
>>> enum rtas_function_flags {
>>> @@ -525,6 +526,7 @@ void enter_rtas(unsigned long);
>>> static void do_enter_rtas(struct rtas_args *args)
>>> {
>>> unsigned long msr;
>>> + const char *name = NULL;
>>>
>>> /*
>>> * Make sure MSR[RI] is currently enabled as it will be forced later
>>> @@ -537,9 +539,30 @@ static void do_enter_rtas(struct rtas_args *args)
>>>
>>> hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
>>>
>>> + if ((trace_rtas_input_enabled() || trace_rtas_output_enabled())) {
>>> + /*
>>> + * rtas_token_to_function() uses xarray which uses RCU,
>>> + * but this code can run in the CPU offline path
>>> + * (e.g. stop-self), after it's become invalid to call
>>> + * RCU APIs.
>>> + */
>>
>> We can call this in real-mode via pseries_machine_check_realmode
>> -> fwnmi_release_errinfo, so tracing should be disabled for that
>> case too... Does this_cpu_set_ftrace_enabled(0) in the early
>> machine check handler cover that sufficiently?
>
> I suspect so, but I'd like to verify. Do you know how I could exercise
> this path in qemu or LPAR?
On a P9 or P10 LPAR you should be able to use tools/testing/selftests/powerpc/mce/inject-ra-err
cheers
next prev parent reply other threads:[~2022-11-29 0:50 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-18 15:07 [PATCH 00/13] RTAS maintenance Nathan Lynch
2022-11-18 15:07 ` [PATCH 01/13] powerpc/rtas: document rtas_call() Nathan Lynch
2022-11-22 2:46 ` Andrew Donnellan
2022-11-18 15:07 ` [PATCH 02/13] powerpc/rtasd: use correct OF API for event scan rate Nathan Lynch
2022-11-22 2:39 ` Andrew Donnellan
2022-11-18 15:07 ` [PATCH 03/13] powerpc/rtas: avoid device tree lookups in rtas_os_term() Nathan Lynch
2022-11-22 3:03 ` Andrew Donnellan
2022-11-28 18:08 ` Nathan Lynch
2022-11-28 2:29 ` Nicholas Piggin
2022-11-28 18:26 ` Nathan Lynch
2022-11-29 6:45 ` Nicholas Piggin
2022-11-29 15:37 ` Nathan Lynch
2022-11-18 15:07 ` [PATCH 04/13] powerpc/rtas: avoid scheduling " Nathan Lynch
2022-11-22 3:17 ` Andrew Donnellan
2022-11-28 2:34 ` Nicholas Piggin
2022-11-18 15:07 ` [PATCH 05/13] powerpc/pseries/eeh: use correct API for error log size Nathan Lynch
2022-11-22 3:21 ` Andrew Donnellan
2022-11-28 20:22 ` Nathan Lynch
2022-11-18 15:07 ` [PATCH 06/13] powerpc/rtas: clean up rtas_error_log_max initialization Nathan Lynch
2022-11-22 3:40 ` Andrew Donnellan
2022-11-18 15:07 ` [PATCH 07/13] powerpc/rtas: clean up includes Nathan Lynch
2022-11-22 4:45 ` Andrew Donnellan
2022-11-18 15:07 ` [PATCH 08/13] powerpc/rtas: define pr_fmt and convert printk call sites Nathan Lynch
2022-11-22 4:07 ` Andrew Donnellan
2022-11-18 15:07 ` [PATCH 09/13] powerpc/rtas: mandate RTAS syscall filtering Nathan Lynch
2022-11-22 4:20 ` Andrew Donnellan
2022-11-18 15:07 ` [PATCH 10/13] powerpc/rtas: improve function information lookups Nathan Lynch
2022-11-23 2:51 ` Andrew Donnellan
2022-11-23 19:32 ` Nick Child
2022-11-24 3:28 ` Andrew Donnellan
2022-11-28 21:19 ` Nathan Lynch
2022-11-29 0:08 ` Nathan Lynch
2022-11-29 7:23 ` Andrew Donnellan
2022-11-29 15:33 ` Nathan Lynch
2022-11-23 20:06 ` Nick Child
2022-11-28 21:57 ` Nathan Lynch
2022-11-18 15:07 ` [PATCH 11/13] powerpc/rtas: strengthen do_enter_rtas() type safety, drop inline Nathan Lynch
2022-11-23 3:23 ` Andrew Donnellan
2022-11-28 2:37 ` Nicholas Piggin
2022-11-18 15:07 ` [PATCH 12/13] powerpc/tracing: tracepoints for RTAS entry and exit Nathan Lynch
2022-11-28 2:54 ` Nicholas Piggin
2022-11-18 15:07 ` [PATCH 13/13] powerpc/rtas: place tracepoints in do_enter_rtas() Nathan Lynch
2022-11-28 3:07 ` Nicholas Piggin
2022-11-28 23:44 ` Nathan Lynch
2022-11-29 0:49 ` Michael Ellerman [this message]
2022-11-29 20:24 ` Nathan Lynch
2022-11-30 7:43 ` Michael Ellerman
2022-11-29 6:47 ` Nicholas Piggin
2022-12-08 12:40 ` [PATCH 00/13] RTAS maintenance Michael Ellerman
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