From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will.deacon@arm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Naresh Kamboju <naresh.kamboju@linaro.org>,
Mark Rutland <mark.rutland@arm.com>,
Ingo Molnar <mingo@redhat.com>,
Masami Hiramatsu <masami.hiramatsu@linaro.org>,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
AKASHI Takahiro <takahiro.akashi@linaro.org>
Subject: Re: [PATCH] arm64: ftrace: Fix to enable syscall events on arm64
Date: Wed, 28 Nov 2018 08:55:55 +0900 [thread overview]
Message-ID: <20181128085555.a8987cbe18aa6d1d1f0a827e@kernel.org> (raw)
In-Reply-To: <20181127131859.79ce7da9@gandalf.local.home>
Hi Will,
On Tue, 27 Nov 2018 13:18:59 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Tue, 27 Nov 2018 16:58:49 +0000
> Will Deacon <will.deacon@arm.com> wrote:
>
> > This looks fine to me, but I'm curious about whether this is supposed to
> > work with compat syscalls as well, where the prefix is "__arm64_compat_".
> >
> > If we broadly follow the x86 lead, we'd have:
> >
> > return (!strncmp(sym, "__arm64_", 8) && !strcmp(sym + 8, name)) ||
> > (!strncmp(sym, "__arm64_compat_", 15) && !strcmp(sym + 15, name));
> >
> > Do we need to handle compat (i.e. 32-bit) tasks here?
>
> Only if you want to trace compat syscalls as well ;-)
Actually I thought about that, but I found below comment in
arch/arm64/include/asm/ftrace.h
* Because AArch32 mode does not share the same syscall table with AArch64,
* tracing compat syscalls may result in reporting bogus syscalls or even
* hang-up, so just do not trace them.
That's why I dropped compat syscall support.
Thank you,
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2018-11-27 23:56 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-27 15:22 File not found: /sys/kernel/debug/tracing/events/syscalls Naresh Kamboju
2018-11-27 16:11 ` Masami Hiramatsu
2018-11-27 16:29 ` [PATCH] arm64: ftrace: Fix to enable syscall events on arm64 Masami Hiramatsu
2018-11-27 16:32 ` Steven Rostedt
2018-11-27 16:58 ` Will Deacon
2018-11-27 18:18 ` Steven Rostedt
2018-11-27 23:55 ` Masami Hiramatsu [this message]
2018-11-28 12:05 ` Will Deacon
2018-11-28 14:22 ` Steven Rostedt
2018-11-28 19:59 ` Will Deacon
2018-11-29 5:38 ` Masami Hiramatsu
2018-11-29 5:39 ` [PATCH v2] " Masami Hiramatsu
2018-11-29 16:53 ` Catalin Marinas
2018-11-29 22:13 ` Masami Hiramatsu
2018-11-28 2:19 ` File not found: /sys/kernel/debug/tracing/events/syscalls Naresh Kamboju
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