From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Tue, 2 Jun 2020 10:38:48 -0400 Subject: [PATCH] env: Add option to only ever append environment In-Reply-To: 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> Message-ID: <20200602143848.GH21630@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 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? -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 659 bytes Desc: not available URL: