From: "Nicholas Piggin" <npiggin@gmail•com>
To: "Nathan Lynch" <nathanl@linux•ibm.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 16:47:17 +1000 [thread overview]
Message-ID: <COOKTPAPKWXZ.2GIUNVQ3HOF6C@bobo> (raw)
In-Reply-To: <87tu2i8x0e.fsf@linux.ibm.com>
On Tue Nov 29, 2022 at 9:44 AM AEST, Nathan Lynch wrote:
> "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?
I have some machine check injection patches for qemu but they never got
merged... I can point you to them if you need.
Should try get those merged again.
Thanks,
Nick
next prev parent reply other threads:[~2022-11-29 6:48 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
2022-11-29 20:24 ` Nathan Lynch
2022-11-30 7:43 ` Michael Ellerman
2022-11-29 6:47 ` Nicholas Piggin [this message]
2022-12-08 12:40 ` [PATCH 00/13] RTAS maintenance Michael Ellerman
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=COOKTPAPKWXZ.2GIUNVQ3HOF6C@bobo \
--to=npiggin@gmail$(echo .)com \
--cc=ajd@linux$(echo .)ibm.com \
--cc=ldufour@linux$(echo .)ibm.com \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=nathanl@linux$(echo .)ibm.com \
--cc=nnac123@linux$(echo .)ibm.com \
--cc=tyreld@linux$(echo .)ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox