[Next][PATCH v2] utils: add kernel config check utility

* [Next][PATCH v2] utils: add kernel config check utility
@ 2021-10-18  1:36 Hongzhan Chen
  2021-10-19 15:49 ` Jan Kiszka
  0 siblings, 1 reply; 4+ messages in thread
From: Hongzhan Chen @ 2021-10-18  1:36 UTC (permalink / raw)
  To: xenomai, jan.kiszka, hongzhan.chen

To check a kernel configuration for common issues which may increase
latency.

Signed-off-by: Hongzhan Chen <hongzhan.chen@intel.com>

diff --git a/configure.ac b/configure.ac
index 480a94768..2bf8eece3 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1017,6 +1017,7 @@ AC_CONFIG_FILES([ \
 	utils/net/rtnet \
 	utils/net/rtnet.conf \
 	utils/net/Makefile \
+	utils/chkkconf/Makefile \
 	demo/Makefile \
 	demo/posix/Makefile \
 	demo/posix/cyclictest/Makefile \
diff --git a/doc/asciidoc/Makefile.am b/doc/asciidoc/Makefile.am
index 8e33c7281..2bacb7c10 100644
--- a/doc/asciidoc/Makefile.am
+++ b/doc/asciidoc/Makefile.am
@@ -7,6 +7,7 @@ HTML_DOCS = 					\
 	html/asciidoc-icons			\
 	html/asciidoc-icons/callouts		\
 	html/man1/autotune			\
+	html/man1/chkkconf			\
 	html/man1/clocktest			\
 	html/man1/corectl			\
 	html/man1/dohell			\
@@ -36,6 +37,7 @@ TXT_DOCS =				\
 
 MAN1_DOCS = 			\
 	man1/autotune.1		\
+	man1/chkkconf.1 	\
 	man1/clocktest.1 	\
 	man1/corectl.1	 	\
 	man1/cyclictest.1 	\
diff --git a/doc/asciidoc/man1/chkkconf.adoc b/doc/asciidoc/man1/chkkconf.adoc
new file mode 100644
index 000000000..2e31d1a90
--- /dev/null
+++ b/doc/asciidoc/man1/chkkconf.adoc
@@ -0,0 +1,114 @@
+// ** The above line should force tbl to be a preprocessor **
+// Man page for chkkconf
+//
+// Copyright (C) 2015 Philippe Gerum <rpm@xenomai.org>
+//
+// You may distribute under the terms of the GNU General Public
+// License as specified in the file COPYING that comes with the
+// Xenomai distribution.
+//
+//
+CHKKCONF(1)
+==========
+:doctype: manpage
+:revdate: 2021/09/23
+:man source: Xenomai
+:man version: {xenover}
+:man manual: Xenomai Manual
+
+NAME
+----
+chkkconf - Check kernel .config
+
+SYNOPSIS
+---------
+*chkkconf* [ options ]
+
+DESCRIPTION
+------------
+*chkkconf* is a common utility to check kernel configuration based
+on specified checklist. The kernel configuration to verify is
+a regular .config file which contains all the settings for
+building a kernel image. The check list contains a series
+of single-line assertions which are tested against the
+contents of the kernel configuration. The default checklist
+file kconf-checklist contains assertions that may influence latency
+for xenomai. When we use the default checklist, the utility checks
+a kernel configuration for common issues which may increase latency.
+
+
+OPTIONS
+--------
+*chkkconf* accepts the following options:
+
+*--file*:: Specify a regular .config file. If none is specified,
+the command defaults to reading /proc/config.gz on the current
+machine. If this fails because any of CONFIG_IKCONFIG or
+CONFIG_IKCONFIG_PROC was disabled in the running kernel, the
+command fails.
+
+*--check-list*:: Specify a file that contains a series of single-line
+assertions which are tested against the contents of the kernel
+configuration. Each assertion follows the BNF-like syntax below:
+
+- assertion   : expr conditions
+            | "!" expr conditions
+
+- expr        : symbol /* matches =y and =m */
+            | symbol "=" tristate
+
+- tristate  : "y"
+          | "m"
+          | "n"
+
+- conditions  : dependency
+            | dependency arch
+
+- dependency  : "if" symbol       /* true if set as y/m */
+
+- arch        : "on" cputype
+
+- cputype     : $(uname -m)
+
+For instance:
+
+- CONFIG_FOO must be set whenever CONFIG_BAR is unset can be written as
+CONFIG_FOO if !CONFIG_BAR.
+
+- CONFIG_FOO must not be set can be written as !CONFIG_FOO, or
+conversely CONFIG_FOO=n.
+
+- CONFIG_FOO must be built as module on aarch32 or aarch64 can be
+written as CONFIG_FOO=m on aarch.
+
+- CONFIG_FOO must not be built-in on aarch64 if CONFIG_BAR is set can be
+written as !CONFIG_FOO=y if CONFIG_BAR on aarch.
+
+Assertions in the check list may apply to a particular CPU architecture.
+Normally, the command should be able to figure out which architecture
+the kernel configuration file applies to by inspecting the first lines,
+looking for the “Linux/” pattern. However, you might have to specify
+this information manually to the command using the -a option if the file
+referred to by the -f option does not contain such information.
+The architecture name (cputype) should match the output of $(uname -m)
+or some abbreviated portion of it. However, arm64 and arm are automatically
+translated to aarch64 and aarch32 when found in an assertion or passed to
+the -a option.
+
+*--arch*:: Specify CPU architecture that you want to check for.
+
+*--hash-size*:: Set the hash table size.
+
+*--quiet*:: Suppress output.
+
+*--help*::
+Display a short help.
+
+VERSIONS
+--------
+*chkkconf* appeared in Xenomai 3.2 for checking kernel .config.
+
+AUTHOR
+-------
+*chkkconf* was written by Philippe Gerum <rpm@xenomai.org> and ported
+by Hongzhan Chen <hongzhan.chen@intel.com> from xenomai4.
diff --git a/utils/Makefile.am b/utils/Makefile.am
index 81dbfda7c..4de6434a9 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -2,3 +2,4 @@ SUBDIRS = hdb
 if XENO_COBALT
 SUBDIRS += analogy autotune can net ps slackspot corectl
 endif
+SUBDIRS += chkkconf
diff --git a/utils/chkkconf/Makefile.am b/utils/chkkconf/Makefile.am
new file mode 100644
index 000000000..9a375ff0b
--- /dev/null
+++ b/utils/chkkconf/Makefile.am
@@ -0,0 +1,19 @@
+
+data_DATA = kconf-checklist
+
+CCLD = $(top_srcdir)/scripts/wrap-link.sh $(CC)
+
+sbin_PROGRAMS = chkkconf
+
+chkkconf_SOURCES = checkconfig.c
+
+chkkconf_CPPFLAGS = 		\
+	$(XENO_USER_CFLAGS)	\
+	-I$(top_srcdir)/include
+
+chkkconf_LDFLAGS = @XENO_AUTOINIT_LDFLAGS@ $(XENO_POSIX_WRAPPERS)
+
+chkkconf_LDADD =					\
+	 @XENO_CORE_LDADD@			\
+	 @XENO_USER_LDADD@			\
+	-lpthread -lrt
diff --git a/utils/chkkconf/checkconfig.c b/utils/chkkconf/checkconfig.c
new file mode 100644
index 000000000..b28180c3c
--- /dev/null
+++ b/utils/chkkconf/checkconfig.c
@@ -0,0 +1,356 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2020 Philippe Gerum  <rpm@xenomai.org>
+ */
+
+#include <unistd.h>
+#include <getopt.h>
+#include <stdbool.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <search.h>
+#include <error.h>
+#include <errno.h>
+#include <sys/utsname.h>
+
+#define DEFAULT_KCONFIG    "/proc/config.gz"
+#define DEFAULT_CHECKLIST  "/usr/xenomai/share/kconf-checklist"
+
+#define short_optlist "@hqf:L:a:H:"
+
+static int hash_size = 16384;
+
+static bool quiet;
+
+static const struct option options[] = {
+	{
+		.name = "file",
+		.has_arg = required_argument,
+		.val = 'f',
+	},
+	{
+		.name = "check-list",
+		.has_arg = required_argument,
+		.val = 'L',
+	},
+	{
+		.name = "arch",
+		.has_arg = required_argument,
+		.val = 'a',
+	},
+	{
+		.name = "hash-size",
+		.has_arg = required_argument,
+		.val = 'H',
+	},
+	{
+		.name = "quiet",
+		.has_arg = no_argument,
+		.val = 'q',
+	},
+	{
+		.name = "help",
+		.has_arg = no_argument,
+		.val = 'h',
+	},
+	{ /* Sentinel */ }
+};
+
+static char *hash_config(FILE *kconfp)
+{
+	char buf[BUFSIZ], *sym, *val, *arch = NULL;
+	ENTRY entry, *e;
+	int ret;
+
+	ret = hcreate(hash_size);
+	if (!ret)
+		error(1, errno, "hcreate(%d)", hash_size);
+
+	while (fgets(buf, sizeof(buf), kconfp)) {
+		if (*buf == '#') {
+			sscanf(buf, "# Linux/%m[^ ]", &arch);
+			continue;
+		}
+		ret = sscanf(buf, "%m[^=]=%ms\n", &sym, &val);
+		if (ret != 2)
+			continue;
+		if (strncmp(sym, "CONFIG_", 7))
+			continue;
+		if (strcmp(val, "y") && strcmp(val, "m"))
+			continue;
+		entry.key = sym;
+		entry.data = NULL;
+		e = hsearch(entry, FIND);
+		if (e)
+			continue; /* uhh? */
+		entry.data = val;
+		if (!hsearch(entry, ENTER))
+			error(1, ENOMEM, "h-table full -- try -H");
+	}
+
+	return arch;
+}
+
+static char *next_token(char **next)
+{
+	char *p = *next, *s;
+
+	for (;;) {
+		if (!*p) {
+			*next = p;
+			return strdup("");
+		}
+		if (!isspace(*p))
+			break;
+		p++;
+	}
+
+	s = p;
+
+	if (!isalnum(*p) && *p != '_') {
+		*next = p + 1;
+		return strndup(s, 1);
+	}
+
+	do {
+		if (!isalnum(*p) && *p != '_') {
+			*next = p;
+			return strndup(s, p - s);
+		}
+	} while (*++p);
+
+	*next = p;
+
+	return strdup(s);
+}
+
+static const char *get_arch_alias(const char *arch)
+{
+	if (!strcmp(arch, "arm64"))
+		return "aarch64";
+
+	if (!strcmp(arch, "arm"))
+		return "aarch32";
+
+	return arch;
+}
+
+static int apply_checklist(FILE *checkfp, const char *cpuarch)
+{
+	char buf[BUFSIZ], *token, *next, *sym, *val;
+	int lineno = 0, failed = 0;
+	bool not, notcond;
+	const char *arch;
+	ENTRY entry, *e;
+
+	while (fgets(buf, sizeof(buf), checkfp)) {
+		lineno++;
+		next = buf;
+
+		token = next_token(&next);
+		if (!*token || !strcmp(token, "#")) {
+			free(token);
+			continue;
+		}
+
+		not = *token == '!';
+		if (not) {
+			free(token);
+			token = next_token(&next);
+		}
+
+		sym = token;
+		if (strncmp(sym, "CONFIG_", 7))
+			error(1, EINVAL,
+				"invalid check list symbol '%s' at line %d",
+				sym, lineno);
+
+		token = next_token(&next);
+		val = NULL;
+		if (*token == '=') {
+			free(token);
+			val = next_token(&next);
+			token = next_token(&next);
+		}
+
+		if (!strcmp(token, "if")) {
+			free(token);
+			token = next_token(&next);
+			notcond = *token == '!';
+			if (notcond) {
+				free(token);
+				token = next_token(&next);
+			}
+			if (strncmp(token, "CONFIG_", 7))
+				error(1, EINVAL,
+					"invalid condition symbol '%s' at line %d",
+					token, lineno);
+			entry.key = token;
+			entry.data = NULL;
+			e = hsearch(entry, FIND);
+			free(token);
+			if (!((e && !notcond) || (!e && notcond)))
+				continue;
+			token = next_token(&next);
+		}
+
+		if (!strcmp(token, "on")) {
+			free(token);
+			token = next_token(&next);
+			arch = get_arch_alias(token);
+			if (strncmp(cpuarch, arch, strlen(arch))) {
+				free(token);
+				continue;
+			}
+		}
+
+		free(token);
+
+		entry.key = sym;
+		entry.data = NULL;
+		e = hsearch(entry, FIND);
+
+		if (val && !strcmp(val, "n"))
+			not = !not;
+
+		if (e && (not || (val && strcmp(val, e->data)))) {
+			if (!quiet)
+				printf("%s=%s\n", sym, (const char *)e->data);
+			failed++;
+		} else if (!e && !not) {
+			if (!quiet)
+				printf("%s=n\n", sym);
+			failed++;
+		}
+
+		free(sym);
+		if (val)
+			free(val);
+	}
+
+	return failed;
+}
+
+static void usage(char *arg0)
+{
+	fprintf(stderr, "usage: %s [options]:\n", basename(arg0));
+	fprintf(stderr, "-f --file=<.config>     Kconfig file to check [=/proc/config.gz]\n");
+	fprintf(stderr, "-L --check-list=<file>  configuration check list [=$datarootdir/kconf-checklist]\n");
+	fprintf(stderr, "-a --arch=<cpuarch>     CPU architecture assumed\n");
+	fprintf(stderr, "-H --hash-size=<N>      set the hash table size [=16384]\n");
+	fprintf(stderr, "-q --quiet              suppress output\n");
+	fprintf(stderr, "-h --help               this help\n");
+}
+
+int main(int argc, char *const argv[])
+{
+	const char *kconfig = DEFAULT_KCONFIG, *check_list = NULL,
+		*defarch, *arch = NULL, *p;
+	FILE *kconfp, *checkfp;
+	struct utsname ubuf;
+	int c, ret;
+	char *cmd;
+
+	opterr = 0;
+
+	for (;;) {
+		c = getopt_long(argc, argv, short_optlist, options, NULL);
+		if (c == EOF)
+			break;
+
+		switch (c) {
+		case 0:
+			break;
+		case 'f':
+			kconfig = optarg;
+			break;
+		case 'L':
+			check_list = optarg;
+			break;
+		case 'a':
+			arch = optarg;
+			break;
+		case 'H':
+			hash_size = atoi(optarg);
+			if (hash_size < 16384)
+				hash_size = 16384;
+			break;
+		case 'q':
+			quiet = true;
+			break;
+		case 'h':
+			usage(argv[0]);
+			return 0;
+		case '@':
+			printf("check kernel configuration\n");
+			return 0;
+		default:
+			usage(argv[0]);
+			return 1;
+		}
+	}
+
+	if (optind < argc) {
+		usage(argv[0]);
+		return 1;
+	}
+
+	/*
+	 * We may be given a gzipped input file. Finding gunzip on a
+	 * minimalist rootfs (e.g. busybox) may be more likely than
+	 * having the zlib development files available from a common
+	 * cross-toolchain. So go for popen-ing gunzip on the target
+	 * instead of depending on libz on the development host.
+	 */
+	if (!strcmp(kconfig, "-")) {
+		kconfp = stdin;
+	} else {
+		p = strstr(kconfig, ".gz");
+		if (!p || strcmp(p, ".gz")) {
+			kconfp = fopen(kconfig, "r");
+		} else {
+			if (access(kconfig, R_OK))
+				error(1, errno, "cannot access %s%s",
+					kconfig,
+					strcmp(kconfig, DEFAULT_KCONFIG) ? "" :
+					"\n(you need CONFIG_IKCONFIG_PROC enabled)");
+			ret = asprintf(&cmd, "gunzip -c %s", kconfig);
+			if (ret < 0)
+				error(1, ENOMEM, "asprintf()");
+			kconfp = popen(cmd, "r");
+			free(cmd);
+		}
+		if (kconfp == NULL)
+			error(1, errno, "cannot open %s for reading", kconfig);
+	}
+
+	defarch = hash_config(kconfp);
+
+	if (check_list == NULL)
+		check_list = DEFAULT_CHECKLIST;
+
+	if (access(check_list, R_OK))
+		error(1, errno, "cannot access %s", check_list);
+
+	checkfp = fopen(check_list, "r");
+	if (checkfp == NULL)
+		error(1, errno, "cannot open %s for reading", check_list);
+
+	if (arch == NULL) {
+		if (defarch) {
+			arch = get_arch_alias(defarch);
+		} else {
+			ret = uname(&ubuf);
+			if (ret)
+				error(1, errno, "utsname()");
+			arch = ubuf.machine;
+		}
+	} else {
+		arch = get_arch_alias(arch);
+	}
+
+	return apply_checklist(checkfp, arch);
+}
diff --git a/utils/chkkconf/kconf-checklist b/utils/chkkconf/kconf-checklist
new file mode 100644
index 000000000..ca7c0395d
--- /dev/null
+++ b/utils/chkkconf/kconf-checklist
@@ -0,0 +1,51 @@
+# Kconfig check list for dovetail-based xenomai
+#
+# This file contains assertions testing a set of configuration
+# settings from a kernel .config file, which are fed to evl-check.
+# Any failed assertion is reported.
+#
+#
+# check_list  : assertion
+# 	      | check_list assertion
+#
+# assertion   : expr conditions
+# 	      | "!" expr conditions
+#
+# expr	    : symbol /* matches =y and =m */
+# 	    | symbol "=" tristate
+#
+# tristate  : "y"
+# 	    | "m"
+# 	    | "n"
+#
+# conditions  : dependency
+# 	      | dependency arch
+#
+# dependency  : "if" symbol	/* true if set as y/m */
+#
+# arch	    : "on" cputype
+#
+# cputype   : $(uname -m)
+#
+# <arch> should match $(uname -m) or some abbreviated portion
+# of it.
+#
+# e.g.
+# "CONFIG_FOO must be set whenever CONFIG_BAR is UNset"
+# translates to: CONFIG_FOO if !CONFIG_BAR
+# "CONFIG_FOO must not be set"
+# translates to: !CONFIG_FOO, or conversely CONFIG_FOO=n
+# "CONFIG_FOO must be built as module on aarch32 or aarch64"
+# translates to: CONFIG_FOO=m on aarch
+
+CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y if CONFIG_CPU_FREQ
+CONFIG_DEBUG_HARD_LOCKS=n
+CONFIG_ACPI_PROCESSOR_IDLE=n
+CONFIG_LOCKDEP=n
+CONFIG_DEBUG_LIST=n
+CONFIG_DEBUG_VM=n
+CONFIG_DEBUG_PER_CPU_MAPS=n
+CONFIG_KASAN=n
+CONFIG_DEBUG_ENTRY=n
+CONFIG_FTRACE=n
+CONFIG_MIGRATION=n
-- 
2.17.1



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