From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-x235.google.com (mail-it0-x235.google.com [IPv6:2607:f8b0:4001:c0b::235]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id F30481A1F48 for ; Thu, 22 Sep 2016 04:40:09 -0700 (PDT) Received: by mail-it0-x235.google.com with SMTP id 186so78669265itf.0 for ; Thu, 22 Sep 2016 04:40:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=XGOJEbgBPRNuGlh/dvQQzamGBb/GHOfouyPe975RRbA=; b=PQV1QrL7LszHXdtuxW0H5YgLFCv0/lpxD2EGQo9A+A4HqJdcuQLlU66cVguDLZNuoH SahSTBRrhJfkWVVLwECL6VQ5H8m75PAg51HA56MLjZiLpfY8dYbFbmM541vmATevsqM+ qE/iFI1ZJHxAzb7LCFyCJQ3wHXEVkoctD9DYM= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=XGOJEbgBPRNuGlh/dvQQzamGBb/GHOfouyPe975RRbA=; b=PJuOaz/FWyyKk48CbRSQLAz828M/fxqmwrQEuPddgZkqZUdpRJUzUzRVPRfM5HtxG7 pz8ShNBXQg0Nvz7TvQzG1ZwMRXs8LtXMMFo3gM1hWuC4iFE/ncFxFyFxaMxkp6RZzXF9 hngrHkdJPdsEHYnZw+3DGGUTzKlmB0bXogTIKyNQKFE/bU1QNCsrLSkHXCC7Bq4jBte7 M2PH7JH+HDNFy4NPXEyBdc+gNPz2GcQ/hzbUzBQg2X9FDf6cTMRIsISdnVBclS6xP20P 4s3WkDX1BA4TO9TS7nr5EWv+bquqLnf3giGGJhvZLj16J2MhYjU5TfEmPQms/npdc8x5 RHpQ== X-Gm-Message-State: AE9vXwOB8kMPj2xSMW69KlE8QefQv3U64hKnDL3VtXXhP2hajClHiqb0rq6ojcyHo8FhxQuPbbJBmA2s0w1pCD0K X-Received: by 10.36.20.204 with SMTP id 195mr10588797itg.83.1474544409252; Thu, 22 Sep 2016 04:40:09 -0700 (PDT) MIME-Version: 1.0 Received: by 10.36.204.195 with HTTP; Thu, 22 Sep 2016 04:40:08 -0700 (PDT) In-Reply-To: <620161a6-dab1-2e12-3a3e-39aab4d265b5@akeo.ie> References: <88690c52-2185-13cb-2f61-eabedeb59b03@akeo.ie> <620161a6-dab1-2e12-3a3e-39aab4d265b5@akeo.ie> From: Ard Biesheuvel Date: Thu, 22 Sep 2016 12:40:08 +0100 Message-ID: To: Pete Batard Cc: "edk2-devel@lists.01.org" Subject: Re: [PATCH 0/1] MdeModulePkg/EbcDxe: add ARM support X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Sep 2016 11:40:10 -0000 Content-Type: text/plain; charset=UTF-8 On 22 September 2016 at 12:26, Pete Batard wrote: > On 2016.09.22 12:14, Ard Biesheuvel wrote: >> >> For X64 and AARCH64, the issue does not exist because the EBC spec >> mandates that all function arguments are widened to the native word >> size. So when executing on a 64-bit architecture, the EBC stack looks >> differently from what you describe above, and maps seamlessly onto the >> register assignment mandated by the respective calling conventions. > > > Ah, I see that you're right, and that I was trying to solve an issue that > shouldn't exist: > > From UEFI 2.6, paragraph 21.9.3: > > "32-bit integers are pushed as natural size (since they > should be passed as 64-bit parameter values on 64-bit machines)." > > I must admit I was a bit curious as to why this problem wouldn't have been > picked before. > > > So that leaves only the issue you mentioned. But then I'm not too hopeful > with the timeframe for Arm/EBC integration when you say "we need language > spec and compiler updates before we can fully support this"... > > Do you know if work has been started on this? Or are we just going to > consider that this is too troublesome a problem to fix? > We are debating this internally. Even on AArch64, there are numerous issues with EBC drivers, even if the code itself executes fine (this is mainly related to PCI drivers that don't bother to enable support for 64-bit DMA since this is never needed on Intel platforms) So while EBC is of high importance to many Linaro members, I am not sure if that includes 32-bit ARM support. -- Ard.