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From: Marvin H?user <Marvin.Haeuser@outlook.com>
To: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>
Subject: [MdeModulePkg/PeiCore] How is Data being NULL on entry ensured?
Date: Sat, 13 Aug 2016 02:01:19 +0000	[thread overview]
Message-ID: <VI1PR06MB1792C370D7C5725632BCE87580100@VI1PR06MB1792.eurprd06.prod.outlook.com> (raw)

Dear list subscribers,

I have just been looking around the PeiCore code and wondered, how it is ensured, that the third ("Data") argument of the entry point is NULL on the first run.
EFI_PEI_CORE_ENTRY_POINT only has two arguments and hence most SEC implementations, including MdeModulePkg/SecCore, are going to pass only the first two arguments to the entry point.
I'm aware that the code works and I have never seen an occasion of it failing or seeming to fail because of this design, though I wondered, how is it assured, that the third argument, which is not part of the first call, is being NULL on entry and not some leftover on the temporary stack/in the argument 3 register?

Thank you for your time!

Regards,
Marvin.


             reply	other threads:[~2016-08-13  2:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-13  2:01 Marvin H?user [this message]
2016-08-13  2:47 ` [MdeModulePkg/PeiCore] How is Data being NULL on entry ensured? Andrew Fish
2016-08-13  2:53   ` Marvin H?user

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