powerpc: Fix up TOC. for modules.

The kernel resolved the '.TOC.' to a fake symbol, so we need to fix it up
to point to our .toc section plus 0x8000.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 29 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index a8694d462079..f6544d7071d6 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -196,6 +196,24 @@ static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab)
         }
 }
 
+static Elf64_Sym *find_dot_toc(Elf64_Shdr *sechdrs,
+                               const char *strtab,
+                               unsigned int symindex)
+{
+        unsigned int i, numsyms;
+        Elf64_Sym *syms;
+
+        syms = (Elf64_Sym *)sechdrs[symindex].sh_addr;
+        numsyms = sechdrs[symindex].sh_size / sizeof(Elf64_Sym);
+
+        for (i = 1; i < numsyms; i++) {
+                if (syms[i].st_shndx == SHN_UNDEF
+                    && strcmp(strtab + syms[i].st_name, ".TOC.") == 0)
+                        return &syms[i];
+        }
+        return NULL;
+}
+
 int module_frob_arch_sections(Elf64_Ehdr *hdr,
                               Elf64_Shdr *sechdrs,
                               char *secstrings,
@@ -337,6 +355,17 @@ int apply_relocate_add(Elf64_Shdr *sechdrs,
 
         DEBUGP("Applying ADD relocate section %u to %u\n", relsec,
                sechdrs[relsec].sh_info);
+
+        /* First time we're called, we can fix up .TOC. */
+        if (!me->arch.toc_fixed) {
+                sym = find_dot_toc(sechdrs, strtab, symindex);
+                /* It's theoretically possible that a module doesn't want a
+                 * .TOC. so don't fail it just for that. */
+                if (sym)
+                        sym->st_value = my_r2(sechdrs, me);
+                me->arch.toc_fixed = true;
+        }
+
         for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
                 /* This is where to make the change */
                 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr