From: Will Deacon <will.deacon@arm.com>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.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
Subject: Re: [PATCH] arm64: ftrace: Fix to enable syscall events on arm64
Date: Tue, 27 Nov 2018 16:58:49 +0000 [thread overview]
Message-ID: <20181127165848.GA19569@arm.com> (raw)
In-Reply-To: <154333618522.27355.8094935453351562295.stgit@devbox>
Hi Masami,
On Wed, Nov 28, 2018 at 01:29:45AM +0900, Masami Hiramatsu wrote:
> Since commit 4378a7d4be30 ("arm64: implement syscall wrappers")
> introduced "__arm64_" prefix to all syscall wrapper symbols in
> sys_call_table, syscall tracer can not find corresponding
> metadata from syscall name. In the result, we have no syscall
> ftrace events on arm64 kernel, and some bpf testcases are failed
> on arm64.
>
> To fix this issue, this introduces custom
> arch_syscall_match_sym_name() which skips first 8 bytes when
> comparing the syscall and symbol names.
>
> Fixes: 4378a7d4be30 ("arm64: implement syscall wrappers")
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: stable@vger.kernel.org
> ---
> arch/arm64/include/asm/ftrace.h | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
> index caa955f10e19..a710f79db442 100644
> --- a/arch/arm64/include/asm/ftrace.h
> +++ b/arch/arm64/include/asm/ftrace.h
> @@ -56,6 +56,15 @@ static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs)
> {
> return is_compat_task();
> }
> +
> +#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
> +
> +static inline bool arch_syscall_match_sym_name(const char *sym,
> + const char *name)
> +{
> + /* Since all syscall functions have __arm64_ prefix, we must skip it */
> + return !strcmp(sym + 8, name);
> +}
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?
Will
next prev parent reply other threads:[~2018-11-27 16:58 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 [this message]
2018-11-27 18:18 ` Steven Rostedt
2018-11-27 23:55 ` Masami Hiramatsu
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
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=20181127165848.GA19569@arm.com \
--to=will.deacon@arm.com \
--cc=catalin.marinas@arm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mark.rutland@arm.com \
--cc=masami.hiramatsu@linaro.org \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=naresh.kamboju@linaro.org \
--cc=rostedt@goodmis.org \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
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;
as well as URLs for NNTP newsgroup(s).