livepatch: Fix build failure on 32 bits processors

Trying to build livepatch on powerpc/32 results in:

	kernel/livepatch/core.c: In function 'klp_resolve_symbols':
	kernel/livepatch/core.c:221:23: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
	  221 |                 sym = (Elf64_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
	      |                       ^
	kernel/livepatch/core.c:221:21: error: assignment to 'Elf32_Sym *' {aka 'struct elf32_sym *'} from incompatible pointer type 'Elf64_Sym *' {aka 'struct elf64_sym *'} [-Werror=incompatible-pointer-types]
	  221 |                 sym = (Elf64_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
	      |                     ^
	kernel/livepatch/core.c: In function 'klp_apply_section_relocs':
	kernel/livepatch/core.c:312:35: error: passing argument 1 of 'klp_resolve_symbols' from incompatible pointer type [-Werror=incompatible-pointer-types]
	  312 |         ret = klp_resolve_symbols(sechdrs, strtab, symndx, sec, sec_objname);
	      |                                   ^~~~~~~
	      |                                   |
	      |                                   Elf32_Shdr * {aka struct elf32_shdr *}
	kernel/livepatch/core.c:193:44: note: expected 'Elf64_Shdr *' {aka 'struct elf64_shdr *'} but argument is of type 'Elf32_Shdr *' {aka 'struct elf32_shdr *'}
	  193 | static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,
	      |                                ~~~~~~~~~~~~^~~~~~~

Fix it by using the right types instead of forcing 64 bits types.

Fixes: c52743b488bd ("livepatch: Apply vmlinux-specific KLP relocations early")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Petr Mladek <pmladek@suse.com>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5288e11b018a762ea3351cc8fb2d4f15093a4457.1640017960.git.christophe.leroy@csgroup.eu

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 585494ec464f98b623e88dae954f2eeabd19254e..bc475e62279d2a39687e5209d6eced904a6c4691 100644 (file)
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -190,7 +190,7 @@ static int klp_find_object_symbol(const char *objname, const char *name,
        return -EINVAL;
 }
 
-static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,
+static int klp_resolve_symbols(Elf_Shdr *sechdrs, const char *strtab,
                               unsigned int symndx, Elf_Shdr *relasec,
                               const char *sec_objname)
 {
@@ -218,7 +218,7 @@ static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,
        relas = (Elf_Rela *) relasec->sh_addr;
        /* For each rela in this klp relocation section */
        for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) {
-               sym = (Elf64_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
+               sym = (Elf_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info);
                if (sym->st_shndx != SHN_LIVEPATCH) {
                        pr_err("symbol %s is not marked as a livepatch symbol\n",
                               strtab + sym->st_name);