From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Tue, 2 Jun 2020 12:00:00 -0400 Subject: [PATCH] env: Add option to only ever append environment In-Reply-To: <098da29c-9457-9a8e-7ca2-67b71d3df8f9@denx.de> References: <20200529175404.627741-1-marex@denx.de> <7f9cd3ee-6661-4780-90cf-d2e81591a7ce@prevas.dk> <02e0326f-c93c-da9e-e0ec-dd3bc2dc9e4a@prevas.dk> <20200602124450.GA21630@bill-the-cat> <20200602143848.GH21630@bill-the-cat> <098da29c-9457-9a8e-7ca2-67b71d3df8f9@denx.de> Message-ID: <20200602160000.GM21630@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Tue, Jun 02, 2020 at 05:55:25PM +0200, Marek Vasut wrote: > On 6/2/20 4:38 PM, Tom Rini wrote: > > On Tue, Jun 02, 2020 at 02:47:12PM +0200, Marek Vasut wrote: > >> On 6/2/20 2:44 PM, Tom Rini wrote: > >>> On Tue, Jun 02, 2020 at 02:05:39PM +0200, Rasmus Villemoes wrote: > >>>> On 02/06/2020 13.04, Marek Vasut wrote: > >>>>> On 6/2/20 8:42 AM, Rasmus Villemoes wrote: > >>>>>> On 29/05/2020 19.54, Marek Vasut wrote: > >>>>>>> +config ENV_APPEND > >>>>>>> + bool "Always append the environment with new data" > >>>>>>> + default n > >>>>>>> + help > >>>>>>> + If defined, the environment hash table is only ever appended with new > >>>>>>> + data, but the existing hash table can never be dropped and reloaded > >>>>>>> + with newly imported data. This may be used in combination with static > >>>>>>> + flags to e.g. to protect variables which must not be modified. > >>>>>>> + > >>>>>>> config ENV_ACCESS_IGNORE_FORCE > >>>>>>> bool "Block forced environment operations" > >>>>>>> default n > >>>>>>> diff --git a/env/env.c b/env/env.c > >>>>>>> index 024d36fdbe..967a9d36d7 100644 > >>>>>>> --- a/env/env.c > >>>>>>> +++ b/env/env.c > >>>>>>> @@ -204,7 +204,9 @@ int env_load(void) > >>>>>>> ret = drv->load(); > >>>>>>> if (!ret) { > >>>>>>> printf("OK\n"); > >>>>>>> +#if !CONFIG_IS_ENABLED(ENV_APPEND) > >>>>>>> return 0; > >>>>>>> +#endif > >>>>>> > >>>>>> Don't use CONFIG_IS_ENABLED() unless you actually introduce both > >>>>>> CONFIG_FOO and CONFIG_SPL_FOO. Otherwise the above > >>>>>> CONFIG_IS_ENABLED(ENV_APPEND) is guaranteed to evaluate to false in SPL. > >>>>>> Of course that only matters if environment support is enabled in SPL, > >>>>>> but some actually use that. > >>>>> > >>>>> We actually want to use CONFIG_IS_ENABLED() as much as possible to make > >>>>> these options future-proof, so that others won't have to chase down all > >>>>> kinds of #ifdef CONFIG stuff and fix it later on for SPL/TPL/etc. > >>>>> > >>>> > >>>> That makes no sense. You're introducing something whose help text > >>>> doesn't spell out that the option only applies to U-Boot proper, and is > >>>> completely ignored in SPL (since CONFIG_SPL_ENV_APPEND never exists). > >>>> The reason it's ignored in SPL is that you use the SPL-or-not-SPL-aware > >>>> CONFIG_IS_ENABLED() helper, and you say that's so that somebody in the > >>>> future can implement CONFIG_SPL_ENV_APPEND? > >>>> > >>>> If you intend for ENV_APPEND to be something that's either set or not > >>>> set for a given board, then the code needs to use the SPL-agnostic > >>>> IS_ENABLED(CONFIG_ENV_APPEND). If you intend it to be something that can > >>>> be set independently for the env support in SPL vs U-Boot proper, you > >>>> need to add both config options and, as you do, use CONFIG_IS_ENABLED. > >>> > >>> How will this code behave if there is a mismatch between SPL and full > >>> U-Boot (disabled SPL, enabled full, as the patch stands today) ? > >> > >> One will append the environment, the other will override it (if you have > >> multiple envs enabled). > > > > So it sounds like it wouldn't be valid to have this option differ > > between SPL and main U-Boot? > > Consider the case where you have default env in SPL, and multiple envs > in U-Boot proper. Yes, today you can end up with cases where you build something that doesn't work as intended (likely something around falcon boot and/or boot count limit in env). Which is what I'm getting at here. Is there some cases where it would make any sense to enable this option in full U-Boot but disable it in SPL? -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 659 bytes Desc: not available URL: