diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 54504013c74915c2ed923fb3afde024a69cdae6b..02a4adb4a99992cd4c47c66123df23847fb12bc9 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -1038,6 +1038,7 @@ defined(CONFIG_AUTOFDO_CLANG) || defined(CONFIG_PROPELLER_CLANG)
*(.discard) \
*(.discard.*) \
*(.export_symbol) \
+ *(.no_trim_symbol) \
*(.modinfo) \
/* ld.bfd warns about .gnu.version* even when not emitted */ \
*(.gnu.version*) \
diff --git a/include/linux/module.h b/include/linux/module.h
index 23792d5d7b74bdbf7efaecd627e138e7746e2cfe..30e5b19bafa983e70e2a0509e0ccc3d7f58a7d6f 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -306,7 +306,10 @@ extern int modules_disabled; /* for sysctl */
/* Get/put a kernel symbol (calls must be symmetric) */
void *__symbol_get(const char *symbol);
void *__symbol_get_gpl(const char *symbol);
-#define symbol_get(x) ((typeof(&x))(__symbol_get(__stringify(x))))
+#define symbol_get(x) ({ \
+ static const char __notrim[] \
+ __used __section(".no_trim_symbol") = __stringify(x); \
+ (typeof(&x))(__symbol_get(__stringify(x))); })
/* modules using other modules: kdb wants to see this. */
struct module_use {
diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn
index a7003c1e66c7dd4c516b0e3ae1acaf15e6d54036..dc081cf46d211c86c1eb725368e04129befd7a9c 100644
--- a/scripts/Makefile.extrawarn
+++ b/scripts/Makefile.extrawarn
@@ -31,6 +31,11 @@ KBUILD_CFLAGS-$(CONFIG_CC_NO_ARRAY_BOUNDS) += -Wno-array-bounds
ifdef CONFIG_CC_IS_CLANG
# The kernel builds with '-std=gnu11' so use of GNU extensions is acceptable.
KBUILD_CFLAGS += -Wno-gnu
+
+# Clang checks for overflow/truncation with '%p', while GCC does not:
+# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219
+KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow-non-kprintf)
+KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation-non-kprintf)
else
# gcc inanely warns about local variables called 'main'
@@ -105,11 +110,6 @@ KBUILD_CFLAGS += $(call cc-disable-warning, packed-not-aligned)
KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow)
ifdef CONFIG_CC_IS_GCC
KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation)
-else
-# Clang checks for overflow/truncation with '%p', while GCC does not:
-# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111219
-KBUILD_CFLAGS += $(call cc-disable-warning, format-overflow-non-kprintf)
-KBUILD_CFLAGS += $(call cc-disable-warning, format-truncation-non-kprintf)
endif
KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index ad55ef201aacbd85ac8c169da8b1b6478a758edf..cad20f0e66ee9cf5942b51f37cdd8e52802493e4 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -305,7 +305,7 @@ endef
# These are shared by some Makefile.* files.
ifdef CONFIG_LTO_CLANG
-# Run $(LD) here to covert LLVM IR to ELF in the following cases:
+# Run $(LD) here to convert LLVM IR to ELF in the following cases:
# - when this object needs objtool processing, as objtool cannot process LLVM IR
# - when this is a single-object module, as modpost cannot process LLVM IR
cmd_ld_single = $(if $(objtool-enabled)$(is-single-obj-m), ; $(LD) $(ld_flags) -r -o $(tmp-target) $@; mv $(tmp-target) $@)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index e18ae7dc8140a6d3d3bd26dd67cb1db5546b003d..36b28987a2f07584e1b2337d4e9ca3a1ae1ce635 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -507,6 +507,9 @@ static int parse_elf(struct elf_info *info, const char *filename)
info->modinfo_len = sechdrs[i].sh_size;
} else if (!strcmp(secname, ".export_symbol")) {
info->export_symbol_secndx = i;
+ } else if (!strcmp(secname, ".no_trim_symbol")) {
+ info->no_trim_symbol = (void *)hdr + sechdrs[i].sh_offset;
+ info->no_trim_symbol_len = sechdrs[i].sh_size;
}
if (sechdrs[i].sh_type == SHT_SYMTAB) {
@@ -1566,6 +1569,14 @@ static void read_symbols(const char *modname)
/* strip trailing .o */
mod = new_module(modname, strlen(modname) - strlen(".o"));
+ /* save .no_trim_symbol section for later use */
+ if (info.no_trim_symbol_len) {
+ mod->no_trim_symbol = xmalloc(info.no_trim_symbol_len);
+ memcpy(mod->no_trim_symbol, info.no_trim_symbol,
+ info.no_trim_symbol_len);
+ mod->no_trim_symbol_len = info.no_trim_symbol_len;
+ }
+
if (!mod->is_vmlinux) {
license = get_modinfo(&info, "license");
if (!license)
@@ -1728,6 +1739,28 @@ static void handle_white_list_exports(const char *white_list)
free(buf);
}
+/*
+ * Keep symbols recorded in the .no_trim_symbol section. This is necessary to
+ * prevent CONFIG_TRIM_UNUSED_KSYMS from dropping EXPORT_SYMBOL because
+ * symbol_get() relies on the symbol being present in the ksymtab for lookups.
+ */
+static void keep_no_trim_symbols(struct module *mod)
+{
+ unsigned long size = mod->no_trim_symbol_len;
+
+ for (char *s = mod->no_trim_symbol; s; s = next_string(s , &size)) {
+ struct symbol *sym;
+
+ /*
+ * If find_symbol() returns NULL, this symbol is not provided
+ * by any module, and symbol_get() will fail.
+ */
+ sym = find_symbol(s);
+ if (sym)
+ sym->used = true;
+ }
+}
+
static void check_modname_len(struct module *mod)
{
const char *mod_name;
@@ -2254,6 +2287,8 @@ int main(int argc, char **argv)
read_symbols_from_files(files_source);
list_for_each_entry(mod, &modules, list) {
+ keep_no_trim_symbols(mod);
+
if (mod->dump_file || mod->is_vmlinux)
continue;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index ffd0a52a606efab8297f9df88047e5d29eef61a3..59366f456b76590b44b62742a6052f1792293d6f 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -111,6 +111,8 @@ struct module_alias {
*
* @dump_file: path to the .symvers file if loaded from a file
* @aliases: list head for module_aliases
+ * @no_trim_symbol: .no_trim_symbol section data
+ * @no_trim_symbol_len: length of the .no_trim_symbol section
*/
struct module {
struct list_head list;
@@ -128,6 +130,8 @@ struct module {
// Actual imported namespaces
struct list_head imported_namespaces;
struct list_head aliases;
+ char *no_trim_symbol;
+ unsigned int no_trim_symbol_len;
char name[];
};
@@ -141,6 +145,8 @@ struct elf_info {
char *strtab;
char *modinfo;
unsigned int modinfo_len;
+ char *no_trim_symbol;
+ unsigned int no_trim_symbol_len;
/* support for 32bit section numbers */
diff --git a/scripts/module.lds.S b/scripts/module.lds.S
index c2f80f9141d407a94eac4aae1560c17c129a84ee..450f1088d5fd3643c9763abe4282bc62b45bd46b 100644
--- a/scripts/module.lds.S
+++ b/scripts/module.lds.S
@@ -16,6 +16,7 @@ SECTIONS {
*(.discard)
*(.discard.*)
*(.export_symbol)
+ *(.no_trim_symbol)
}
__ksymtab 0 : ALIGN(8) { *(SORT(___ksymtab+*)) }
diff --git a/scripts/package/install-extmod-build b/scripts/package/install-extmod-build
index bb6e23c1174ec049ff22451da88d4fe0a4e5d3bb..b724626ea0ca0d3e95526e05754a8a8207906c19 100755
--- a/scripts/package/install-extmod-build
+++ b/scripts/package/install-extmod-build
@@ -63,7 +63,7 @@ if [ "${CC}" != "${HOSTCC}" ]; then
# Clear VPATH and srcroot because the source files reside in the output
# directory.
# shellcheck disable=SC2016 # $(MAKE), $(CC), and $(build) will be expanded by Make
- "${MAKE}" run-command KBUILD_RUN_COMMAND='+$(MAKE) HOSTCC=$(CC) VPATH= srcroot=. $(build)='"${destdir}"/scripts
+ "${MAKE}" run-command KBUILD_RUN_COMMAND='+$(MAKE) HOSTCC="$(CC)" VPATH= srcroot=. $(build)='"${destdir}"/scripts
rm -f "${destdir}/scripts/Kbuild"
fi