gcov and kasan rely on compiler generated constructor code.
For modules, gcc-8 with gcov enabled generates .init_array section,
but on ppc64le it doesn't get executed. find_module_sections() never
finds .init_array section, because module_frob_arch_sections() renames
it to _init_array.

Avoid renaming .init_array section, so do_mod_ctors() can use it.

Cc: Michael Ellerman <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Christophe Leroy <[email protected]>
Signed-off-by: Jan Stancek <[email protected]>
---
I wasn't able to trace the comment:
  "We don't handle .init for the moment: rename to _init"
to original patch (it pre-dates .git). I'm not sure if it
still applies today, so I limited patch to .init_array. This
fixes gcov for modules for me on ppc64le 5.14.0-rc6.

Renaming issue is also mentioned in kasan patches here:
  
https://patchwork.ozlabs.org/project/linuxppc-dev/cover/20210319144058.772525-1-dja@axtens

 arch/powerpc/kernel/module_64.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 6baa676e7cb6..c604b13ea6bf 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -299,8 +299,16 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
                                          sechdrs[i].sh_size);
 
                /* We don't handle .init for the moment: rename to _init */
-               while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init")))
+               while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) {
+#ifdef CONFIG_CONSTRUCTORS
+                       /* find_module_sections() needs .init_array intact */
+                       if (strstr(secstrings + sechdrs[i].sh_name,
+                               ".init_array")) {
+                               break;
+                       }
+#endif
                        p[0] = '_';
+               }
 
                if (sechdrs[i].sh_type == SHT_SYMTAB)
                        dedotify((void *)hdr + sechdrs[i].sh_offset,
-- 
2.27.0

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