The offset range data for builtin modules is generated using:
- modules.builtin.modinfo: associates object files with module names
- vmlinux.map: provides load order of sections and offset of first member
per section
- vmlinux.o.map: provides offset of object file content per section
- .*.cmd: build cmd file with KBUILD_MODFILE and KBUILD_MODNAME
The generated data will look like:
.text 00000000-00000000 = _text
.text 0000baf0-0000cb10 amd_uncore
.text 0009bd10-0009c8e0 iosf_mbi
...
.text 008e6660-008e9630 snd_soc_wcd_mbhc
.text 008e9630-008ea610 snd_soc_wcd9335 snd_soc_wcd934x snd_soc_wcd938x
.text 008ea610-008ea780 snd_soc_wcd9335
...
.data 00000000-00000000 = _sdata
.data 0000f020-0000f680 amd_uncore
For each ELF section, it lists the offset of the first symbol. This can
be used to determine the base address of the section at runtime.
Next, it lists (in strict ascending order) offset ranges in that section
that cover the symbols of one or more builtin modules. Multiple ranges
can apply to a single module, and ranges can be shared between modules.
Signed-off-by: Kris Van Hees <kris.van.hees@xxxxxxxxxx>
Reviewed-by: Nick Alcock <nick.alcock@xxxxxxxxxx>
---
Changes since v2:
- 1st arg to generate_builtin_ranges.awk is now modules.builtin.modinfo
- Switched from using modules.builtin.objs to parsing .*.cmd files
- Parse data from .*.cmd in generate_builtin_ranges.awk
---
scripts/generate_builtin_ranges.awk | 232 ++++++++++++++++++++++++++++
1 file changed, 232 insertions(+)
create mode 100755 scripts/generate_builtin_ranges.awk
diff --git a/scripts/generate_builtin_ranges.awk b/scripts/generate_builtin_ranges.awk
new file mode 100755
index 0000000000000..6975a9c7266d9
--- /dev/null
+++ b/scripts/generate_builtin_ranges.awk
@@ -0,0 +1,232 @@
+#!/usr/bin/gawk -f
+# SPDX-License-Identifier: GPL-2.0
+# generate_builtin_ranges.awk: Generate address range data for builtin modules
+# Written by Kris Van Hees <kris.van.hees@xxxxxxxxxx>
+#
+# Usage: generate_builtin_ranges.awk modules.builtin.modinfo vmlinux.map \
+# vmlinux.o.map > modules.builtin.ranges
+#
+
+BEGIN {
+ # modules.builtin.modinfo uses \0 as record separator
+ # All other files use \n.
+ RS = "[\n\0]";
+}
+
+# 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, mfn, s) {
+ if (fn in omod)
+ return omod[fn];
+
+ if (match(fn, /\/[^/]+$/) == 0)
+ return "";
+
+ obj = fn;
+ mod = "";
+ mfn = "";
+ fn = substr(fn, 1, RSTART) "." substr(fn, RSTART + 1) ".cmd";
+ if (getline s <fn == 1) {
+ if (match(s, /DKBUILD_MODNAME=[^ ]+/) > 0) {
+ mod = substr(s, RSTART + 17, RLENGTH - 17);
+ gsub(/['"]/, "", mod);
+ gsub(/:/, " ", mod);
+ }
+
+ if (match(s, /DKBUILD_MODFILE=[^ ]+/) > 0) {
+ mfn = substr(s, RSTART + 17, RLENGTH - 17);
+ gsub(/['"]/, "", mfn);
+ gsub(/:/, " ", mfn);
+ }
+ }
+ close(fn);
+
+# tmp = $0;
+# $0 = s;
+# print mod " " mfn " " obj " " $NF;
+# $0 = tmp;
+
+ # 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))
+ return "";
+ if (mods[mod] != mfn)
+ return "";
+ }
+
+ # 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;
+}
+
+FNR == 1 {
+ FC++;
+}
+
+# (1-old) Build a mapping to associate object files with built-in module names.
+#
+# The first file argument is used as input (modules.builtin.objs).
+#
+FC == 1 && old_behaviour {
+ sub(/:/, "");
+ mod = $1;
+ sub(/([^/]*\/)+/, "", mod);
+ sub(/\.o$/, "", mod);
+ gsub(/-/, "_", mod);
+
+ if (NF > 1) {
+ for (i = 2; i <= NF; i++) {
+ if ($i in mods)
+ mods[$i] = mods[$i] " " mod;
+ else
+ mods[$i] = mod;
+ }
+ } else
+ mods[$1] = mod;
+
+ next;
+}
+
+# (1) Build a lookup map of built-in module names.
+#
+# The first file argument is used as input (modules.builtin.modinfo).
+#
+# We are interested in lines that follow the format
+# <modname>.file=<path>
+# and use them to record <modname>
+#
+FC == 1 && /^[^\.]+.file=/ {
+ gsub(/[\.=]/, " ");
+# print $1 " -> " $3;
+ mods[$1] = $3;
+ next;
+}
+
+# (2) Determine the load address for each section.
+#
+# The second file argument is used as input (vmlinux.map).
+#
+# Since some AWK implementations cannot handle large integers, we strip of the
+# first 4 hex digits from the address. This is safe because the kernel space
+# is not large enough for addresses to extend into those digits.
+#
+FC == 2 && /^\./ && NF > 2 {
+ if (type)
+ delete sect_addend[type];
+
+ if ($1 ~ /percpu/)
+ next;
+
+ raw_addr = $2;
+ addr_prefix = "^" substr($2, 1, 6);
+ sub(addr_prefix, "0x", $2);
+ base = strtonum($2);
+ type = $1;
+ anchor = 0;
+ sect_base[type] = base;
+
+ next;
+}
+
+!type {
+ next;
+}
+
+# (3) We need to determine the base address of the section so that ranges can
+# be expressed based on offsets from the base address. This accommodates the
+# kernel sections getting loaded at different addresses than what is recorded
+# in vmlinux.map.
+#
+# At runtime, we will need to determine the base address of each section we are
+# interested in. We do that by recording the offset of the first symbol in the
+# section. Once we know the address of this symbol in the running kernel, we
+# can calculate the base address of the section.
+#
+# If possible, we use an explicit anchor symbol (sym = .) listed at the base
+# address (offset 0).
+#
+# If there is no such symbol, we record the first symbol in the section along
+# with its offset.
+#
+# We also determine the offset of the first member in the section in case the
+# final linking inserts some content between the start of the section and the
+# first member. I.e. in that case, vmlinux.map will list the first member at
+# a non-zero offset whereas vmlinux.o.map will list it at offset 0. We record
+# the addend so we can apply it when processing vmlinux.o.map (next).
+#
+FC == 2 && !anchor && raw_addr == $1 && $3 == "=" && $4 == "." {
+ anchor = sprintf("%s %08x-%08x = %s", type, 0, 0, $2);
+ sect_anchor[type] = anchor;
+
+ next;
+}
+
+FC == 2 && !anchor && $1 ~ /^0x/ && $2 !~ /^0x/ && NF <= 4 {
+ sub(addr_prefix, "0x", $1);
+ addr = strtonum($1) - base;
+ anchor = sprintf("%s %08x-%08x = %s", type, addr, addr, $2);
+ sect_anchor[type] = anchor;
+
+ next;
+}
+
+FC == 2 && base && /^ \./ && $1 == type && NF == 4 {
+ sub(addr_prefix, "0x", $2);
+ addr = strtonum($2);
+ sect_addend[type] = addr - base;
+
+ if (anchor) {
+ base = 0;
+ type = 0;
+ }
+
+ next;
+}
+
+# (4) Collect offset ranges (relative to the section base address) for built-in
+# modules.
+#
+FC == 3 && /^ \./ && NF == 4 && $3 != "0x0" {
+ type = $1;
+ if (!(type in sect_addend))
+ next;
+
+ sub(addr_prefix, "0x", $2);
+ addr = strtonum($2) + sect_addend[type];
+
+ mod = get_module_info($4);
+# printf "[%s, %08x] %s [%s] %08x\n", mod_name, mod_start, $4, mod, addr;
+ if (mod == mod_name)
+ next;
+
+ if (mod_name) {
+ idx = mod_start + sect_base[type] + sect_addend[type];
+ entries[idx] = sprintf("%s %08x-%08x %s", type, mod_start, addr, mod_name);
+ count[type]++;
+ }
+# if (mod == "")
+# printf "ENTRY WITHOUT MOD - MODULE MAY END AT %08x\n", addr
+
+ mod_name = mod;
+ mod_start = addr;
+}
+
+END {
+ for (type in count) {
+ if (type in sect_anchor)
+ entries[sect_base[type]] = sect_anchor[type];
+ }
+
+ n = asorti(entries, indices);
+ for (i = 1; i <= n; i++)
+ print entries[indices[i]];
+}
--
2.43.0
