> From: Konrad Rzeszutek Wilk [mailto:konrad.w...@oracle.com]
> Sent: Thursday, January 12, 2012 12:23 PM
eturn values for tboot_sleep
> 
> On Thu, Jan 12, 2012 at 09:49:58AM -0800, Konrad Rzeszutek Wilk wrote:
> > On Tue, Jan 10, 2012 at 08:10:53PM +0000, Cihula, Joseph wrote:
> > > ACK, but tboot_sleep() calls tboot_shutdown() and there are error 
> > > conditions in that which you
> are not reflecting upward--i.e. you should make tboot_shutdown() return an 
> 'int' and propagate its
> errors through tboot_sleep().
> >
> > Hey Joe,
> >
> > Thanks for looking at the patches.
> >
> > Right now [with this patch applied] the code looks as so:
> >
> > 297
> > 298         tboot_shutdown(acpi_shutdown_map[sleep_state]);
> > 299         return 0;
> > 300 }
> >
> >
> > If we do make tboot_shutdown() return an int, there will be a need to
> > modify other callers: native_machine_emergency_restart,
> > native_machine_halt, native_machine_power_off, and native_play_dead as well.
> >
> > Perhaps that could be done in another patch and leave this one as is
> > where the 'tboot_sleep' would just return 0 instead of 'return
> > tboot_shutdown(...)' ?
> >
> > Perhaps another way to do this is to extract the common code of
> > tboot_sleep and tboot_shutdown?

I'd be happier to see the callers above changed to handle a tboot_shutdown() 
that returned an error than splitting this up and only checking the error in 
one path.

Joe

> 
> Like this (not yet tested):
> 
> diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c index 
> 6410744..2f93a50 100644
> --- a/arch/x86/kernel/tboot.c
> +++ b/arch/x86/kernel/tboot.c
> @@ -212,17 +212,16 @@ static int tboot_setup_sleep(void)  {
>       /* S3 shutdown requested, but S3 not supported by the kernel... */
>       BUG();
> -     return -1;
> +     return -ENOSYS;
>  }
> 
>  #endif
> 
> -void tboot_shutdown(u32 shutdown_type)
> -{
> -     void (*shutdown)(void);
> +static int tboot_check(u32 shutdown_type) {
> +
> 
>       if (!tboot_enabled())
> -             return;
> +             return -ENODEV;
> 
>       /*
>        * if we're being called before the 1:1 mapping is set up then just @@ 
> -230,12 +229,21 @@
> void tboot_shutdown(u32 shutdown_type)
>        * due to very early panic()
>        */
>       if (!tboot_pg_dir)
> -             return;
> +             return -EBUSY;
> 
>       /* if this is S3 then set regions to MAC */
> -     if (shutdown_type == TB_SHUTDOWN_S3)
> -             if (tboot_setup_sleep())
> -                     return;
> +     if (shutdown_type == TB_SHUTDOWN_S3) {
> +             int err = tboot_setup_sleep();
> +             if (err)
> +                     return err;
> +     }
> +
> +     return 0;
> +}
> +
> +static void __tboot_shutdown(u32 shutdown_type) {
> +     void (*shutdown)(void);
> 
>       tboot->shutdown_type = shutdown_type;
> 
> @@ -248,6 +256,13 @@ void tboot_shutdown(u32 shutdown_type)
>       while (1)
>               halt();
>  }
> +void tboot_shutdown(u32 shutdown_type)
> +{
> +     if (!tboot_check(shutdown_type))
> +             return;
> +
> +     __tboot_shutdown(shutdown_type);
> +}
> 
>  static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)  { @@ -279,9 
> +294,17 @@ static
> int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
>               /* S3: */ TB_SHUTDOWN_S3,
>               /* S4: */ TB_SHUTDOWN_S4,
>               /* S5: */ TB_SHUTDOWN_S5 };
> +     int err;
> 
> -     if (!tboot_enabled())
> -             return 0;
> +     if (sleep_state >= ACPI_S_STATE_COUNT ||
> +         acpi_shutdown_map[sleep_state] == -1) {
> +             pr_warning("unsupported sleep state 0x%x\n", sleep_state);
> +             return -ENOSYS;
> +     }
> +
> +     err = tboot_check(acpi_shutdown_map[sleep_state]);
> +     if (!err && err != EBUSY)
> +             return err;
> 
>       tboot_copy_fadt(&acpi_gbl_FADT);
>       tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control; @@ -289,13 +312,7 @@ 
> static int
> tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
>       /* we always use the 32b wakeup vector */
>       tboot->acpi_sinfo.vector_width = 32;
> 
> -     if (sleep_state >= ACPI_S_STATE_COUNT ||
> -         acpi_shutdown_map[sleep_state] == -1) {
> -             pr_warning("unsupported sleep state 0x%x\n", sleep_state);
> -             return -1;
> -     }
> -
> -     tboot_shutdown(acpi_shutdown_map[sleep_state]);
> +     __tboot_shutdown((acpi_shutdown_map[sleep_state]));
>       return 0;
>  }
> 

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