The modules.builtin.ranges offset range data for builtin modules is
generated at compile time based on the list of built-in modules and
the vmlinux.map and vmlinux.o.map linker maps. This data can be used
to determine whether a symbol at a particular address belongs to
module code that was configured to be compiled into the kernel proper
as a built-in module (rather than as a standalone module).
This patch adds a script that uses the generated modules.builtin.ranges
data to annotate the symbols in the System.map with module names if
their address falls within a range that belongs to one or more built-in
modules.
It then processes the vmlinux.map (and if needed, vmlinux.o.map) to
verify the annotation:
- For each top-level section:
- For each object in the section:
- Determine whether the object is part of a built-in module
(using modules.builtin and the .*.cmd file used to compile
the object as suggested in [0])
- For each symbol in that object, verify that the built-in
module association (or lack thereof) matches the annotation
given to the symbol.
Signed-off-by: Kris Van Hees <kris.van.hees@xxxxxxxxxx>
Reviewed-by: Nick Alcock <nick.alcock@xxxxxxxxxx>
Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
Changes since v6:
- Applied Masahiro Yamada's suggestions to the AWK script.
Changes since v5:
- Added optional 6th argument to specify kernel build directory.
- Report error and exit if .*.o.cmd files cannot be read.
Changes since v4:
- New patch in the series
---
scripts/verify_builtin_ranges.awk | 356 ++++++++++++++++++++++++++++++
1 file changed, 356 insertions(+)
create mode 100755 scripts/verify_builtin_ranges.awk
diff --git a/scripts/verify_builtin_ranges.awk b/scripts/verify_builtin_ranges.awk
new file mode 100755
index 000000000000..93f66e9a8802
--- /dev/null
+++ b/scripts/verify_builtin_ranges.awk
@@ -0,0 +1,356 @@
+#!/usr/bin/gawk -f
+# SPDX-License-Identifier: GPL-2.0
+# verify_builtin_ranges.awk: Verify address range data for builtin modules
+# Written by Kris Van Hees <kris.van.hees@xxxxxxxxxx>
+#
+# Usage: verify_builtin_ranges.awk modules.builtin.ranges System.map \
+# modules.builtin vmlinux.map vmlinux.o.map \
+# [ <build-dir> ]
+#
+
+# Return the module name(s) (if any) associated with the given object.
+#
+# If we have seen this object before, return information from the cache.
+# Otherwise, retrieve it from the corresponding .cmd file.
+#
+function get_module_info(fn, mod, obj, s) {
+ if (fn in omod)
+ return omod[fn];
+
+ if (match(fn, /\/[^/]+$/) == 0)
+ return "";
+
+ obj = fn;
+ mod = "";
+ fn = kdir "/" substr(fn, 1, RSTART) "." substr(fn, RSTART + 1) ".cmd";
+ if (getline s <fn == 1) {
+ if (match(s, /DKBUILD_MODFILE=['"]+[^'"]+/) > 0) {
+ mod = substr(s, RSTART + 16, RLENGTH - 16);
+ gsub(/['"]/, "", mod);
+ }
+ } else {
+ print "ERROR: Failed to read: " fn "\n\n" \
+ " Invalid kernel build directory (" kdir ")\n" \
+ " or its content does not match " ARGV[1] >"/dev/stderr";
+ close(fn);
+ total = 0;
+ exit(1);
+ }
+ close(fn);
+
+ # A single module (common case) also reflects objects that are not part
+ # of a module. Some of those objects have names that are also a module
+ # name (e.g. core). We check the associated module file name, and if
+ # they do not match, the object is not part of a module.
+ if (mod !~ / /) {
+ if (!(mod in mods))
+ mod = "";
+ }
+
+ gsub(/([^/ ]*\/)+/, "", mod);
+ gsub(/-/, "_", mod);
+
+ # At this point, mod is a single (valid) module name, or a list of
+ # module names (that do not need validation).
+ omod[obj] = mod;
+ close(fn);
+
+ return mod;
+}
+
+# Return a representative integer value for a given hexadecimal address.
+#
+# Since all kernel addresses fall within the same memory region, we can safely
+# strip off the first 6 hex digits before performing the hex-to-dec conversion,
+# thereby avoiding integer overflows.
+#
+function addr2val(val) {
+ sub(/^0x/, "", val);
+ if (length(val) == 16)
+ val = substr(val, 5);
+ return strtonum("0x" val);
+}
+
+# Determine the kernel build directory to use (default is .).
+#
+BEGIN {
+ if (ARGC > 6) {
+ kdir = ARGV[ARGC - 1];
+ ARGV[ARGC - 1] = "";
+ } else
+ kdir = ".";
+}
+
+# (1) Load the built-in module address range data.
+#
+ARGIND == 1 {
+ ranges[FNR] = $0;
+ rcnt++;
+ next;
+}
+
+# (2) Annotate System.map symbols with module names.
+#
+ARGIND == 2 {
+ addr = addr2val($1);
+ name = $3;
+
+ while (addr >= mod_eaddr) {
+ if (sect_symb) {
+ if (sect_symb != name)
+ next;
+
+ sect_base = addr - sect_off;
+ if (dbg)
+ printf "[%s] BASE (%s) %016x - %016x = %016x\n", sect_name, sect_symb, addr, sect_off, sect_base >"/dev/stderr";
+ sect_symb = 0;
+ }
+
+ if (++ridx > rcnt)
+ break;
+
+ $0 = ranges[ridx];
+ sub(/-/, " ");
+ if ($4 != "=") {
+ sub(/-/, " ");
+ mod_saddr = strtonum("0x" $2) + sect_base;
+ mod_eaddr = strtonum("0x" $3) + sect_base;
+ $1 = $2 = $3 = "";
+ sub(/^ +/, "");
+ mod_name = $0;
+
+ if (dbg)
+ printf "[%s] %s from %016x to %016x\n", sect_name, mod_name, mod_saddr, mod_eaddr >"/dev/stderr";
+ } else {
+ sect_name = $1;
+ sect_off = strtonum("0x" $2);
+ sect_symb = $5;
+ }
+ }
+
+ idx = addr"-"name;
+ if (addr >= mod_saddr && addr < mod_eaddr)
+ sym2mod[idx] = mod_name;
+
+ next;
+}
+
+# Once we are done annotating the System.map, we no longer need the ranges data.
+#
+FNR == 1 && ARGIND == 3 {
+ delete ranges;
+}
+
+# (3) Build a lookup map of built-in module names.
+#
+# Lines from modules.builtin will be like:
+# kernel/crypto/lzo-rle.ko
+# and we record the object name "crypto/lzo-rle".
+#
+ARGIND == 3 {
+ sub(/kernel\//, ""); # strip off "kernel/" prefix
+ sub(/\.ko$/, ""); # strip off .ko suffix
+
+ mods[$1] = 1;
+ next;
+}
+
+# (4) Get a list of symbols (per object).
+#
+# Symbols by object are read from vmlinux.map, with fallback to vmlinux.o.map
+# if vmlinux is found to have inked in vmlinux.o.
+#
+
+# If we were able to get the data we need from vmlinux.map, there is no need to
+# process vmlinux.o.map.
+#
+FNR == 1 && ARGIND == 5 && total > 0 {
+ if (dbg)
+ printf "Note: %s is not needed.\n", FILENAME >"/dev/stderr";
+ exit;
+}
+
+# First determine whether we are dealing with a GNU ld or LLVM lld linker map.
+#
+ARGIND >= 4 && FNR == 1 && NF == 7 && $1 == "VMA" && $7 == "Symbol" {
+ map_is_lld = 1;
+ next;
+}
+
+# (LLD) Convert a section record fronm lld format to ld format.
+#
+ARGIND >= 4 && map_is_lld && NF == 5 && /[0-9] [^ ]/ {
+ $0 = $5 " 0x"$1 " 0x"$3 " load address 0x"$2;
+}
+
+# (LLD) Convert an object record from lld format to ld format.
+#
+ARGIND >= 4 && map_is_lld && NF == 5 && $5 ~ /:\(\./ {
+ gsub(/\)/, "");
+ sub(/:\(/, " ");
+ sub(/ vmlinux\.a\(/, " ");
+ $0 = " "$6 " 0x"$1 " 0x"$3 " " $5;
+}
+
+# (LLD) Convert a symbol record from lld format to ld format.
+#
+ARGIND >= 4 && map_is_lld && NF == 5 && $5 ~ /^[A-Za-z_][A-Za-z0-9_]*$/ {
+ $0 = " 0x" $1 " " $5;
+}
+
+# (LLD) We do not need any other ldd linker map records.
+#
+ARGIND >= 4 && map_is_lld && /^[0-9a-f]{16} / {
+ next;
+}
+
+# Handle section records with long section names (spilling onto a 2nd line).
+#
+ARGIND >= 4 && !map_is_lld && NF == 1 && /^[^ ]/ {
+ s = $0;
+ getline;
+ $0 = s " " $0;
+}
+
+# Next section - previous one is done.
+#
+ARGIND >= 4 && /^[^ ]/ {
+ sect = 0;
+}
+
+# Get the (top level) section name.
+#
+ARGIND >= 4 && /^[^ ]/ && $2 ~ /^0x/ && $3 ~ /^0x/ {
+ # Empty section or per-CPU section - ignore.
+ if (NF < 3 || $1 ~ /\.percpu/) {
+ sect = 0;
+ next;
+ }
+
+ sect = $1;
+
+ next;
+}
+
+# If we are not currently in a section we care about, ignore records.
+#
+!sect {
+ next;
+}
+
+# Handle object records with long section names (spilling onto a 2nd line).
+#
+ARGIND >= 4 && /^ [^ \*]/ && NF == 1 {
+ # If the section name is long, the remainder of the entry is found on
+ # the next line.
+ s = $0;
+ getline;
+ $0 = s " " $0;
+}
+
+# If the object is vmlinux.o, we need to consult vmlinux.o.map for per-object
+# symbol information
+#
+ARGIND == 4 && /^ [^ ]/ && NF == 4 {
+ idx = sect":"$1;
+ if (!(idx in sect_addend)) {
+ sect_addend[idx] = addr2val($2);
+ if (dbg)
+ printf "ADDEND %s = %016x\n", idx, sect_addend[idx] >"/dev/stderr";
+ }
+ if ($4 == "vmlinux.o") {
+ need_o_map = 1;
+ next;
+ }
+}
+
+# If data from vmlinux.o.map is needed, we only process section and object
+# records from vmlinux.map to determine which section we need to pay attention
+# to in vmlinux.o.map. So skip everything else from vmlinux.map.
+#
+ARGIND == 4 && need_o_map {
+ next;
+}
+
+# Get module information for the current object.
+#
+ARGIND >= 4 && /^ [^ ]/ && NF == 4 {
+ msect = $1;
+ mod_name = get_module_info($4);
+ mod_eaddr = addr2val($2) + addr2val($3);
+
+ next;
+}
+
+# Process a symbol record.
+#
+# Evaluate the module information obtained from vmlinux.map (or vmlinux.o.map)
+# as follows:
+# - For all symbols in a given object:
+# - If the symbol is annotated with the same module name(s) that the object
+# belongs to, count it as a match.
+# - Otherwise:
+# - If the symbol is known to have duplicates of which at least one is
+# in a built-in module, disregard it.
+# - If the symbol us not annotated with any module name(s) AND the
+# object belongs to built-in modules, count it as missing.
+# - Otherwise, count it as a mismatch.
+#
+ARGIND >= 4 && /^ / && NF == 2 && $1 ~ /^0x/ {
+ idx = sect":"msect;
+ if (!(idx in sect_addend))
+ next;
+
+ addr = addr2val($1);
+
+ # Handle the rare but annoying case where a 0-size symbol is placed at
+ # the byte *after* the module range. Based on vmlinux.map it will be
+ # considered part of the current object, but it falls just beyond the
+ # module address range. Unfortunately, its address could be at the
+ # start of another built-in module, so the only safe thing to do is to
+ # ignore it.
+ if (mod_name && addr == mod_eaddr)
+ next;
+
+ # If we are processing vmlinux.o.map, we need to apply the base address
+ # of the section to the relative address on the record.
+ #
+ if (ARGIND == 5)
+ addr += sect_addend[idx];
+
+ idx = addr"-"$2;
+ mod = "";
+ if (idx in sym2mod) {
+ mod = sym2mod[idx];
+ if (sym2mod[idx] == mod_name) {
+ mod_matches++;
+ matches++;
+ } else if (mod_name == "") {
+ print $2 " in " sym2mod[idx] " (should NOT be)";
+ mismatches++;
+ } else {
+ print $2 " in " sym2mod[idx] " (should be " mod_name ")";
+ mismatches++;
+ }
+ } else if (mod_name != "") {
+ print $2 " should be in " mod_name;
+ missing++;
+ } else
+ matches++;
+
+ total++;
+
+ next;
+}
+
+# Issue the comparison report.
+#
+END {
+ if (total) {
+ printf "Verification of %s:\n", ARGV[1];
+ printf " Correct matches: %6d (%d%% of total)\n", matches, 100 * matches / total;
+ printf " Module matches: %6d (%d%% of matches)\n", mod_matches, 100 * mod_matches / matches;
+ printf " Mismatches: %6d (%d%% of total)\n", mismatches, 100 * mismatches / total;
+ printf " Missing: %6d (%d%% of total)\n", missing, 100 * missing / total;
+ }
+}
--
2.45.2
