On Sun, Oct 17, 2021 at 02:38:17PM +0200, Christophe Leroy wrote:
> In preparation of making func_desc_t generic, change the ELFv2
> version to a struct containing 'addr' element.
>
> This allows using single helpers common to ELFv1 and ELFv2.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
> arch/powerpc/kernel/module_64.c | 32 ++++++++++++++------------------
> 1 file changed, 14 insertions(+), 18 deletions(-)
>
> diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
> index a89da0ee25e2..b687ef88c4c4 100644
> --- a/arch/powerpc/kernel/module_64.c
> +++ b/arch/powerpc/kernel/module_64.c
> @@ -33,19 +33,13 @@
> #ifdef PPC64_ELF_ABI_v2
>
> /* An address is simply the address of the function. */
> -typedef unsigned long func_desc_t;
> +typedef struct {
> + unsigned long addr;
> +} func_desc_t;
>
> static func_desc_t func_desc(unsigned long addr)
> {
> - return addr;
> -}
> -static unsigned long func_addr(unsigned long addr)
> -{
> - return addr;
> -}
> -static unsigned long stub_func_addr(func_desc_t func)
> -{
> - return func;
> + return (func_desc_t){addr};
There's only 1 element in the struct, so okay, but it hurt my eyes a
little. I would have been happier with:
return (func_desc_t){ .addr = addr; };
But of course that also looks bonkers because it starts with "return".
So no matter what I do my eyes bug out. ;)
So it's fine either way. :)
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> }
>
> /* PowerPC64 specific values for the Elf64_Sym st_other field. */
> @@ -70,14 +64,6 @@ static func_desc_t func_desc(unsigned long addr)
> {
> return *(struct func_desc *)addr;
> }
> -static unsigned long func_addr(unsigned long addr)
> -{
> - return func_desc(addr).addr;
> -}
> -static unsigned long stub_func_addr(func_desc_t func)
> -{
> - return func.addr;
> -}
> static unsigned int local_entry_offset(const Elf64_Sym *sym)
> {
> return 0;
> @@ -93,6 +79,16 @@ void *dereference_module_function_descriptor(struct module *mod, void *ptr)
> }
> #endif
>
> +static unsigned long func_addr(unsigned long addr)
> +{
> + return func_desc(addr).addr;
> +}
> +
> +static unsigned long stub_func_addr(func_desc_t func)
> +{
> + return func.addr;
> +}
> +
> #define STUB_MAGIC 0x73747562 /* stub */
>
> /* Like PPC32, we need little trampolines to do > 24-bit jumps (into
> --
> 2.31.1
>
--
Kees Cook
