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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Clark Williams <williams@redhat.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Benjamin Peterson <benjamin@python.org>,
	David Ahern <dsahern@gmail.com>, Jiri Olsa <jolsa@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Wang Nan <wangnan0@huawei.com>
Subject: [PATCH 05/28] perf trace beauty: Allow syscalls to mask an argument before considering it
Date: Wed, 31 Oct 2018 13:44:45 -0300	[thread overview]
Message-ID: <20181031164508.4784-6-acme@kernel.org> (raw)
In-Reply-To: <20181031164508.4784-1-acme@kernel.org>

From: Arnaldo Carvalho de Melo <acme@redhat.com>

Take mount's 'flags' arg, to cope with this semantic, as defined in do_mount in fs/namespace.c:

  /*
   * Pre-0.97 versions of mount() didn't have a flags word.  When the
   * flags word was introduced its top half was required to have the
   * magic value 0xC0ED, and this remained so until 2.4.0-test9.
   * Therefore, if this magic number is present, it carries no
   * information and must be discarded.
   */

We need to mask this arg, and then see if it is zero, when we simply
don't print the arg name and value.

The next patch will use this for mount's 'flag' arg.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Benjamin Peterson <benjamin@python.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-btue14k5jemayuykfrwsnh85@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/builtin-trace.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 7081d7ea12e5..14fb63e17de5 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -614,6 +614,7 @@ static size_t syscall_arg__scnprintf_getrandom_flags(char *bf, size_t size,
 
 struct syscall_arg_fmt {
 	size_t	   (*scnprintf)(char *bf, size_t size, struct syscall_arg *arg);
+	unsigned long (*mask_val)(struct syscall_arg *arg, unsigned long val);
 	void	   *parm;
 	const char *name;
 	bool	   show_zero;
@@ -1487,6 +1488,19 @@ static size_t syscall__scnprintf_name(struct syscall *sc, char *bf, size_t size,
 	return scnprintf(bf, size, "arg%d: ", arg->idx);
 }
 
+/*
+ * Check if the value is in fact zero, i.e. mask whatever needs masking, such
+ * as mount 'flags' argument that needs ignoring some magic flag, see comment
+ * in tools/perf/trace/beauty/mount_flags.c
+ */
+static unsigned long syscall__mask_val(struct syscall *sc, struct syscall_arg *arg, unsigned long val)
+{
+	if (sc->arg_fmt && sc->arg_fmt[arg->idx].mask_val)
+		return sc->arg_fmt[arg->idx].mask_val(arg, val);
+
+	return val;
+}
+
 static size_t syscall__scnprintf_val(struct syscall *sc, char *bf, size_t size,
 				     struct syscall_arg *arg, unsigned long val)
 {
@@ -1535,6 +1549,11 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 				continue;
 
 			val = syscall_arg__val(&arg, arg.idx);
+			/*
+			 * Some syscall args need some mask, most don't and
+			 * return val untouched.
+			 */
+			val = syscall__mask_val(sc, &arg, val);
 
 			/*
  			 * Suppress this argument if its value is zero and
-- 
2.14.4


  parent reply	other threads:[~2018-10-31 16:45 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-31 16:44 [GIT PULL 00/24] perf/urgent improvements and fixes Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 01/28] tools include uapi: Grab a copy of linux/fs.h Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 02/28] perf beauty: Add a generator for MS_ mount/umount's flag constants Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 03/28] perf beauty: Switch from GPL v2.0 to LGPL v2.1 Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 04/28] perf beauty: Introduce strarray__scnprintf_flags() Arnaldo Carvalho de Melo
2018-10-31 16:44 ` Arnaldo Carvalho de Melo [this message]
2018-10-31 16:44 ` [PATCH 06/28] perf trace beauty: Beautify mount/umount's 'flags' argument Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 07/28] perf trace: Consider syscall aliases too Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 08/28] perf trace: Beautify the umount's 'name' argument Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 09/28] perf trace: Beautify mount's first pathname arg Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 10/28] perf top: Allow disabling the overwrite mode Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 11/28] perf top: Do not use overwrite mode by default Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 12/28] perf unwind: Take pgoff into account when reporting elf to libdwfl Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 13/28] perf cs-etm: Correct CPU mode for samples Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 14/28] perf callchain: Honour the ordering of PERF_CONTEXT_{USER,KERNEL,etc} Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 15/28] tools include uapi: Update linux/fs.h copy Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 16/28] tools arch uapi: Update asm-generic/unistd.h and arm64 unistd.h copies Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 17/28] tools include uapi: Update asound.h copy Arnaldo Carvalho de Melo
2018-10-31 17:00   ` Takashi Iwai
2018-10-31 17:27     ` Joe Perches
2018-10-31 18:32       ` Takashi Iwai
2018-10-31 19:29       ` Arnaldo Carvalho de Melo
2018-11-01 11:54         ` Takashi Sakamoto
2018-11-01 13:04           ` Arnaldo Carvalho de Melo
2018-11-01 13:57             ` Takashi Sakamoto
2018-10-31 19:28     ` Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 18/28] perf beauty: Add a generator for MAP_ mmap's flag constants Arnaldo Carvalho de Melo
2018-10-31 16:44 ` [PATCH 19/28] perf beauty: Wire up the mmap flags table generator to the Makefile Arnaldo Carvalho de Melo
2018-11-05 15:44   ` Guenter Roeck
2018-11-05 17:11     ` Arnaldo Carvalho de Melo
2018-11-05 18:46       ` Arnaldo Carvalho de Melo
2018-11-05 19:13         ` Arnaldo Carvalho de Melo
2018-11-05 21:18           ` Guenter Roeck
2018-11-06 19:18         ` [tip:perf/urgent] perf beauty: Use SRCARCH, ARCH=x86_64 must map to "x86" to find the headers tip-bot for Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 20/28] perf trace beauty: Use the mmap flags table generated from headers Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 21/28] tools include uapi: Update linux/mmap.h copy Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 22/28] tools headers: Sync the various kvm.h header copies Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 23/28] tools headers uapi: Update linux/netlink.h header copy Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 24/28] tools headers uapi: Update linux/if_link.h " Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 25/28] perf top: Start display thread earlier Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 26/28] perf tools: Don't clone maps from parent when synthesizing forks Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 27/28] perf intel-pt: Insert callchain context into synthesized callchains Arnaldo Carvalho de Melo
2018-10-31 16:45 ` [PATCH 28/28] perf intel-pt/bts: Calculate cpumode for synthesized samples Arnaldo Carvalho de Melo
2018-10-31 21:56 ` [GIT PULL 00/24] perf/urgent improvements and fixes Ingo Molnar

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