[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: [PATCH v6 1/8] xen: reuse x86 EFI stub functions for Arm
- To: Jan Beulich <jbeulich@xxxxxxxx>
- From: Wei Chen <Wei.Chen@xxxxxxx>
- Date: Fri, 1 Jul 2022 06:10:14 +0000
- Accept-language: en-US
- Arc-authentication-results: i=2; mx.microsoft.com 1; spf=pass (sender ip is 63.35.35.123) smtp.rcpttodomain=lists.xenproject.org smtp.mailfrom=arm.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=arm.com; dkim=pass (signature was verified) header.d=armh.onmicrosoft.com; arc=pass (0 oda=1 ltdi=1 spf=[1,1,smtp.mailfrom=arm.com] dkim=[1,1,header.d=arm.com] dmarc=[1,1,header.from=arm.com])
- Arc-authentication-results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=arm.com; dmarc=pass action=none header.from=arm.com; dkim=pass header.d=arm.com; arc=none
- Arc-message-signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=e5nRAd7+++XQ0MMPf4+/0cM+3o9eeyLo7pDIFjAhY6A=; b=HRmFOi3cCMMBYZltu2D3NsRUSFgKlTSLoLbYwHyF6X56GQ1VXMHd0zyBuJYYztkw7wCi+XIwI5yUEc4T5x39zKhSPijjFwvfdJVwiajrhXmjl4rhEE9jC/zVUliVXJQPltPlUl4jg6JiHM8V8CAB3LpgydnGJfE7EP3q/lanGsuzg50AFF0EVdYuUnMmWZRr5E/uFi5kTAv0Wi4gYroE7ANXLVj1e/O3glD4mtgoqJA/lPfIONv5cDM9Y+flVDITcBEvP/HWSBHkvgi61mqyQGgAaGxvly5+LUCBs4N1NPE7Wvrt/ctH/Orwa7QqbEIqWDAQKSmukbTQjzNBvWH0CA==
- Arc-message-signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=e5nRAd7+++XQ0MMPf4+/0cM+3o9eeyLo7pDIFjAhY6A=; b=j4BKZ/vMQ55dlgx6/wa9dkhdx7g/Cv/jGyhumfuTfzyrHb0minwb8hX2Tvh64Ug7qGCJQ7l4swNgJSpAY8j8Gg02bo38eENMxew+Uq7nMqQ7rHTZPl9ujieV32Ekuj+Maq6hg/GfNTaiIOWkVmXevoF5vRcL3W2bNxf8xipwX1g/clL7udY9cd4PSRckSffOqD+UJ5SV3parCXUOBkZTlwY6EIadHez8Us3VVVG0HL//NjoZKCGfvAvl0/DzJ07+BBXVNMVZO97qj7gk+xIMPMdQoY9jFuTIOZ9Omh3+mcc86xwYG/1ARh1PBLM661DOGd/gmPs6iUdY5sIDWH9x5Q==
- Arc-seal: i=2; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=pass; b=TK7O2mobrj+ieHVxT/M7fb3k+6uAFzqqPDdK6sfsdmH4RClpZWC8qBRxt3ZDr14iGV5x1WVWU3JhMcHQf0QTqIz824hmzRAoCn+wWjvfswHtoy2RUvbH+dBKb/kmbU7Fl7lUjRpWq+oeOWsaJLqsov1civ0URJfXb72Z0Juz/MjkNbfET8N2uLfM7gIs5JH+Kqdv+VgQNqA0azCTeRVMl5F934hodIgqqvWNuiUyITBuahfptQjN84msip6LdhSCnx6wZ8Q2SjjgR4i76VbxvofXuKU4ZgDMX5zJz+c7Uh9eaY0iAj271rq5J16p1Roxr5fRxrbEUm7Shl4d+FvoLQ==
- Arc-seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Bwfj4c6s8VtM6FE4pHb70lLsSQhMcLz/olgbW+utqtMFbyZ1qLHXlwEZU2YIcEkbqbcPEuffdYqiRtluKmGqdExqW4WlKZhg+irb7XJBJOUp3wP3ok4nd7dzXgJb1lZexhC2kjH7QrFbBekz/C2bqeM9ZBR6Jw5OM0oqsIO0Pre/kqnFUTqYtQvfIm0YllTmVORoNiKHUIsKRpqLMbqRkmEnb60vRXEN6KmPKJsi1hS8URSI9biazgEc4xubWRxCrYzT8w74pGUYX7egrOaOJdnulWaKeKr7xt4r27eIGzjhy9ZE7Rq3uqkjoz0LIcWpWvAfvL1D0LNhV8bg0o5+4Q==
- Authentication-results-original: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com;
- Cc: nd <nd@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Bertrand Marquis <Bertrand.Marquis@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>, Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Wei Liu <wl@xxxxxxx>, Jiamei Xie <Jiamei.Xie@xxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Julien Grall <julien@xxxxxxx>
- Delivery-date: Fri, 01 Jul 2022 06:10:53 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Nodisclaimer: true
- Original-authentication-results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=arm.com;
- Thread-index: AQHYfI531SRNO5A+8Ei3iOFoJrK02K1dB3iAgAE0OjCAABXrgIAAECwAgAAEoICAAARlgIAAAO0AgAmAA0CAABcRAIAA6+aAgAA2KgCAAALn8A==
- Thread-topic: [PATCH v6 1/8] xen: reuse x86 EFI stub functions for Arm
Hi Jan,
> -----Original Message-----
> From: Jan Beulich <jbeulich@xxxxxxxx>
> Sent: 2022年7月1日 13:54
> To: Wei Chen <Wei.Chen@xxxxxxx>
> Cc: nd <nd@xxxxxxx>; Stefano Stabellini <sstabellini@xxxxxxxxxx>; Bertrand
> Marquis <Bertrand.Marquis@xxxxxxx>; Volodymyr Babchuk
> <Volodymyr_Babchuk@xxxxxxxx>; Andrew Cooper <andrew.cooper3@xxxxxxxxxx>;
> Roger Pau Monné <roger.pau@xxxxxxxxxx>; Wei Liu <wl@xxxxxxx>; Jiamei Xie
> <Jiamei.Xie@xxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx; Julien Grall
> <julien@xxxxxxx>
> Subject: Re: [PATCH v6 1/8] xen: reuse x86 EFI stub functions for Arm
>
> >>>>> this way.
> >>>
> >>> I have taken a look into this warning:
> >>> This is because the "-fshort-wchar" flag causes GCC to generate
> >>> code that is not binary compatible with code generated without
> >>> that flag. Why this warning hasn't been triggered in Arm64 is
> >>> because we don't use any wchar in Arm64 codes.
> >>
> >> I don't think that's quite right - you actually say below that we
> >> do use it there when interacting with UEFI. There's no warning
> >> there solely because the information isn't embedded in the object
> >> files there, from all I can tell.
> >>
> >
> > Maybe I should describe it this way: Arm64 does not use wchar type
> > directly in any code for parameters, variables and return values.
> > So Arm64 object files are exactly the same with "-fshort-wchar" and
> > without "-fshort-wchar".
> >
> > Although Xen's EFI code interacts with UEFI firmware, similar to RPC
> > function calls, these code also do not explicitly use wchar.
>
> How does it not? There are ample string literals as well as enough
> uses of CHAR16 (the UEFI "abstraction" of wchar_t).
>
But I don't think CHAR16 will be affected by -fshort-wchar, because we
have specified CHAR16 as unsigned short type in typedef.
I'll try the -fno-short-wchar method from your subsequent mail, if it
works, that would be the least impactful way.
Cheers,
Wei Chen
> Jan
|
