On Mon, Dec 20, 2021 at 04:38:02PM +0000, Christophe Leroy wrote:
> 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: 7c8e2bdd5f0d ("livepatch: Apply vmlinux-specific KLP relocations early")
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> Acked-by: Petr Mladek <pmladek@xxxxxxxx>
> ---
> kernel/livepatch/core.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
> index 335d988bd811..c0789383807b 100644
> --- 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);
> --
> 2.33.1
>
Thanks for finding and fixing, lgtm.
Acked-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
-- Joe
