Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon,  1 May 2023 09:54:12 -0700
In-Reply-To: <20230501165450.15352-1-surenb@google.com>
Mime-Version: 1.0
References: <20230501165450.15352-1-surenb@google.com>
Message-ID: <20230501165450.15352-3-surenb@google.com>
Subject: [PATCH 02/40] scripts/kallysms: Always include __start and __stop symbols
From:   Suren Baghdasaryan <surenb@google.com>
To:     akpm@linux-foundation.org
Cc:     kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz,
        hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de,
        dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com,
        corbet@lwn.net, void@manifault.com, peterz@infradead.org,
        juri.lelli@redhat.com, ldufour@linux.ibm.com,
        catalin.marinas@arm.com, will@kernel.org, arnd@arndb.de,
        tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com,
        x86@kernel.org, peterx@redhat.com, david@redhat.com,
        axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org,
        nathan@kernel.org, dennis@kernel.org, tj@kernel.org,
        muchun.song@linux.dev, rppt@kernel.org, paulmck@kernel.org,
        pasha.tatashin@soleen.com, yosryahmed@google.com,
        yuzhao@google.com, dhowells@redhat.com, hughd@google.com,
        andreyknvl@gmail.com, keescook@chromium.org,
        ndesaulniers@google.com, gregkh@linuxfoundation.org,
        ebiggers@google.com, ytcoode@gmail.com, vincent.guittot@linaro.org,
        dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
        bristot@redhat.com, vschneid@redhat.com, cl@linux.com,
        penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com,
        glider@google.com, elver@google.com, dvyukov@google.com,
        shakeelb@google.com, songmuchun@bytedance.com, jbaron@akamai.com,
        rientjes@google.com, minchan@google.com, kaleshsingh@google.com,
        surenb@google.com, kernel-team@android.com,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        iommu@lists.linux.dev, linux-arch@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-modules@vger.kernel.org, kasan-dev@googlegroups.com,
        cgroups@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

From: Kent Overstreet <kent.overstreet@linux.dev>

These symbols are used to denote section boundaries: by always including
them we can unify loading sections from modules with loading built-in
sections, which leads to some significant cleanup.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
---
 scripts/kallsyms.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c
index 0d2db41177b2..7b7dbeb5bd6e 100644
--- a/scripts/kallsyms.c
+++ b/scripts/kallsyms.c
@@ -203,6 +203,11 @@ static int symbol_in_range(const struct sym_entry *s,
 	return 0;
 }
 
+static bool string_starts_with(const char *s, const char *prefix)
+{
+	return strncmp(s, prefix, strlen(prefix)) == 0;
+}
+
 static int symbol_valid(const struct sym_entry *s)
 {
 	const char *name = sym_name(s);
@@ -210,6 +215,14 @@ static int symbol_valid(const struct sym_entry *s)
 	/* if --all-symbols is not specified, then symbols outside the text
 	 * and inittext sections are discarded */
 	if (!all_symbols) {
+		/*
+		 * Symbols starting with __start and __stop are used to denote
+		 * section boundaries, and should always be included:
+		 */
+		if (string_starts_with(name, "__start_") ||
+		    string_starts_with(name, "__stop_"))
+			return 1;
+
 		if (symbol_in_range(s, text_ranges,
 				    ARRAY_SIZE(text_ranges)) == 0)
 			return 0;
-- 
2.40.1.495.gc816e09b53d-goog