linux-kernel - [PATCH v3 15/16] modpost: Produce extended modversion information

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Message-ID: <20240806212106.617164-16-mmaurer@google.com>
Date: Tue,  6 Aug 2024 21:20:41 +0000
From: Matthew Maurer <mmaurer@...gle.com>
To: masahiroy@...nel.org, ndesaulniers@...gle.com, ojeda@...nel.org, 
	gary@...yguo.net, mcgrof@...nel.org, Alex Gaynor <alex.gaynor@...il.com>, 
	Wedson Almeida Filho <wedsonaf@...il.com>
Cc: Matthew Maurer <mmaurer@...gle.com>, rust-for-linux@...r.kernel.org, 
	linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org, neal@...pa.dev, 
	marcan@...can.st, j@...nau.net, asahi@...ts.linux.dev, 
	Nathan Chancellor <nathan@...nel.org>, Nicolas Schier <nicolas@...sle.eu>, Boqun Feng <boqun.feng@...il.com>, 
	"Björn Roy Baron" <bjorn3_gh@...tonmail.com>, Benno Lossin <benno.lossin@...ton.me>, 
	Andreas Hindborg <a.hindborg@...sung.com>, Alice Ryhl <aliceryhl@...gle.com>
Subject: [PATCH v3 15/16] modpost: Produce extended modversion information

Generate both the existing modversions format and the new extended one
when running modpost.

We no longer generate an error on long symbols in modpost, as they can
now be appropriately encoded in the extended section. These symbols will
be skipped in the previous encoding.

Signed-off-by: Matthew Maurer <mmaurer@...gle.com>
---
 scripts/mod/modpost.c | 39 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 3 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index d16d0ace2775..8f9a4f262567 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1856,15 +1856,48 @@ static void add_versions(struct buffer *b, struct module *mod)
 			continue;
 		}
 		if (strlen(s->name) >= MODULE_NAME_LEN) {
-			error("too long symbol \"%s\" [%s.ko]\n",
-			      s->name, mod->name);
-			break;
+			/* this symbol will only be in the extended info */
+			continue;
 		}
 		buf_printf(b, "\t{ %#8x, \"%s\" },\n",
 			   s->crc, s->name);
 	}
 
 	buf_printf(b, "};\n");
+
+	buf_printf(b, "static const s32 ____version_ext_crcs[]\n");
+	buf_printf(b, "__used __section(\"__version_ext_crcs\") = {\n");
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
+		if (!s->module)
+			continue;
+		if (!s->crc_valid) {
+			/*
+			 * We already warned on this when producing the legacy
+			 * modversions table.
+			 */
+			continue;
+		}
+		buf_printf(b, "\t%#8x,\n", s->crc);
+	}
+	buf_printf(b, "};\n");
+
+	buf_printf(b, "static const char ____version_ext_names[]\n");
+	buf_printf(b, "__used __section(\"__version_ext_names\") =\n");
+	list_for_each_entry(s, &mod->unresolved_symbols, list) {
+		if (!s->module)
+			continue;
+		if (!s->crc_valid) {
+			/*
+			 * We already warned on this when producing the legacy
+			 * modversions table.
+			 * We need to skip its name too, as the indexes in
+			 * both tables need to align.
+			 */
+			continue;
+		}
+		buf_printf(b, "\t\"%s\\0\"\n", s->name);
+	}
+	buf_printf(b, ";\n");
 }
 
 static void add_depends(struct buffer *b, struct module *mod)
-- 
2.46.0.rc2.264.g509ed76dc8-goog