kbuild: modpost warn if export version crc is missing

This catches the failing ceph CRC on with:

    LD      vmlinux.o
    MODPOST vmlinux.o
  WARNING: EXPORT symbol "ceph_monc_do_statfs" [vmlinux] version
  generation failed, symbol will not be versioned.

When the modules referring to exported symbols are built, there is an
existing warning for missing CRC, but it's not always the case such
any such module will be built, and in any case it is useful to get a
warning at the source.

This gets a little verbose with CONFIG_DEBUG_SECTION_MISMATCH,
producing a warning with each object linked, but I didn't think
that warranted extra complexity to avoid.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michal Marek <mmarek@suse.com>

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index bd834975909510335322ec8f34970573a8708dfc..08f62a1af67d5a9899cdbb62c23941de24c52e46 100644 (file)
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -609,6 +609,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
 {
        unsigned int crc;
        enum export export;
+       bool is_crc = false;
 
        if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
            strncmp(symname, "__ksymtab", 9) == 0)
@@ -618,6 +619,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
 
        /* CRC'd symbol */
        if (strncmp(symname, CRC_PFX, strlen(CRC_PFX)) == 0) {
+               is_crc = true;
                crc = (unsigned int) sym->st_value;
                sym_update_crc(symname + strlen(CRC_PFX), mod, crc,
                                export);
@@ -663,6 +665,10 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
                else
                        symname++;
 #endif
+               if (is_crc) {
+                       const char *e = is_vmlinux(mod->name) ?"":".ko";
+                       warn("EXPORT symbol \"%s\" [%s%s] version generation failed, symbol will not be versioned.\n", symname + strlen(CRC_PFX), mod->name, e);
+               }
                mod->unres = alloc_symbol(symname,
                                          ELF_ST_BIND(sym->st_info) == STB_WEAK,
                                          mod->unres);