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SubjectRE: [PATCH 2/7] tboot: Add return values for tboot_sleep
Date
> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@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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