Re: [PATCH 11/13] powerpc/rtas: strengthen do_enter_rtas() type safety, drop inline

[Andrew Donnellan <ajd@linux.ibm.com>]

On Fri, 2022-11-18 at 09:07 -0600, Nathan Lynch wrote:
> Make do_enter_rtas() take a pointer to struct rtas_args and do the
> __pa() conversion in one place instead of leaving it to callers. This
> also makes it possible to introduce enter/exit tracepoints that
> access
> the rtas_args struct fields.
> 
> There's no apparent reason to force inlining of do_enter_rtas()
> either, and it seems to bloat the code a bit. Let the compiler
> decide.
> 
> Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>

Makes sense!

Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>

> ---
>  arch/powerpc/kernel/rtas.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> index a88db3b3486f..198366d641d0 100644
> --- a/arch/powerpc/kernel/rtas.c
> +++ b/arch/powerpc/kernel/rtas.c
> @@ -522,7 +522,7 @@ static const struct rtas_function
> *rtas_token_to_function(s32 token)
>  /* This is here deliberately so it's only used in this file */
>  void enter_rtas(unsigned long);
>  
> -static inline void do_enter_rtas(unsigned long args)
> +static void do_enter_rtas(struct rtas_args *args)
>  {
>         unsigned long msr;
>  
> @@ -537,7 +537,7 @@ static inline void do_enter_rtas(unsigned long
> args)
>  
>         hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
>  
> -       enter_rtas(args);
> +       enter_rtas(__pa(args));
>  
>         srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
>  }
> @@ -908,7 +908,7 @@ static char *__fetch_rtas_last_error(char
> *altbuf)
>         save_args = rtas.args;
>         rtas.args = err_args;
>  
> -       do_enter_rtas(__pa(&rtas.args));
> +       do_enter_rtas(&rtas.args);
>  
>         err_args = rtas.args;
>         rtas.args = save_args;
> @@ -955,7 +955,7 @@ va_rtas_call_unlocked(struct rtas_args *args, int
> token, int nargs, int nret,
>         for (i = 0; i < nret; ++i)
>                 args->rets[i] = 0;
>  
> -       do_enter_rtas(__pa(args));
> +       do_enter_rtas(args);
>  }
>  
>  void rtas_call_unlocked(struct rtas_args *args, int token, int
> nargs, int nret, ...)
> @@ -1731,7 +1731,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user
> *, uargs)
>         flags = lock_rtas();
>  
>         rtas.args = args;
> -       do_enter_rtas(__pa(&rtas.args));
> +       do_enter_rtas(&rtas.args);
>         args = rtas.args;
>  
>         /* A -1 return code indicates that the last command couldn't

-- 
Andrew Donnellan    OzLabs, ADL Canberra
ajd@linux.ibm.com   IBM Australia Limited