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From: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
To: Matt Fleming <matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
Cc: Matt Fleming
	<matt.fleming-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org"
	<x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>,
	"linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org"
	<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
	"hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org"
	<hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	Leif Lindholm
	<leif.lindholm-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Roy Franz <roy.franz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Mark Salter <msalter-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH 2/2] efi: implement mandatory locking for UEFI Runtime Services
Date: Mon, 7 Jul 2014 22:43:31 +0200	[thread overview]
Message-ID: <CAKv+Gu91CQADTQ8KMjXQPwVDvW1XkUYO2E5=Mu=aAtrB8B3q_A@mail.gmail.com> (raw)
In-Reply-To: <20140707202954.GC27474-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>

On 7 July 2014 22:29, Matt Fleming <matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org> wrote:
> On Wed, 02 Jul, at 12:10:02PM, Ard Biesheuvel wrote:
>> According to section 7.1 of the UEFI spec, Runtime Services are not fully
>> reentrant, and there are particular combinations of calls that need to be
>> serialized.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
>> ---
>>  drivers/firmware/efi/runtime-wrappers.c | 109 +++++++++++++++++++++++++++++---
>>  1 file changed, 99 insertions(+), 10 deletions(-)
>
> Ard, what's going on with this one? I didn't see it resubmitted along
> with v3 of "efi/arm64: handle missing virtual mapping for UEFI System
> Table".
>
> Note that we already have a lock to serialize access to the UEFI
> variable services in the form of __efivars->lock, see
> drivers/firmware/efi/vars.c. It's a spinlock because of the context we
> may need to create variables in from efi_pstore_write().
>

As the patch says, the UEFI spec is very clear on which combinations
of calls are not reentrant.
I don't think the rtc_lock and the efivars->lock quite cover that completely ...

WARNING: multiple messages have this Message-ID (diff)
From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] efi: implement mandatory locking for UEFI Runtime Services
Date: Mon, 7 Jul 2014 22:43:31 +0200	[thread overview]
Message-ID: <CAKv+Gu91CQADTQ8KMjXQPwVDvW1XkUYO2E5=Mu=aAtrB8B3q_A@mail.gmail.com> (raw)
In-Reply-To: <20140707202954.GC27474@console-pimps.org>

On 7 July 2014 22:29, Matt Fleming <matt@console-pimps.org> wrote:
> On Wed, 02 Jul, at 12:10:02PM, Ard Biesheuvel wrote:
>> According to section 7.1 of the UEFI spec, Runtime Services are not fully
>> reentrant, and there are particular combinations of calls that need to be
>> serialized.
>>
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>>  drivers/firmware/efi/runtime-wrappers.c | 109 +++++++++++++++++++++++++++++---
>>  1 file changed, 99 insertions(+), 10 deletions(-)
>
> Ard, what's going on with this one? I didn't see it resubmitted along
> with v3 of "efi/arm64: handle missing virtual mapping for UEFI System
> Table".
>
> Note that we already have a lock to serialize access to the UEFI
> variable services in the form of __efivars->lock, see
> drivers/firmware/efi/vars.c. It's a spinlock because of the context we
> may need to create variables in from efi_pstore_write().
>

As the patch says, the UEFI spec is very clear on which combinations
of calls are not reentrant.
I don't think the rtc_lock and the efivars->lock quite cover that completely ...

  parent reply	other threads:[~2014-07-07 20:43 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-02 10:10 [PATCH 1/2] efi/arm64: fix potential NULL dereference of efi.systab Ard Biesheuvel
2014-07-02 10:10 ` Ard Biesheuvel
     [not found] ` <1404295802-28030-1-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2014-07-02 10:10   ` [PATCH 2/2] efi: implement mandatory locking for UEFI Runtime Services Ard Biesheuvel
2014-07-02 10:10     ` Ard Biesheuvel
     [not found]     ` <1404295802-28030-2-git-send-email-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2014-07-07 20:29       ` Matt Fleming
2014-07-07 20:29         ` Matt Fleming
     [not found]         ` <20140707202954.GC27474-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
2014-07-07 20:43           ` Ard Biesheuvel [this message]
2014-07-07 20:43             ` Ard Biesheuvel
     [not found]             ` <CAKv+Gu91CQADTQ8KMjXQPwVDvW1XkUYO2E5=Mu=aAtrB8B3q_A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-08  8:54               ` Ard Biesheuvel
2014-07-08  8:54                 ` Ard Biesheuvel
     [not found]                 ` <CAKv+Gu8LbfuuEYyhAeu3dUiKHqzN_UFMbOjY0agVihbmmVL9CA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-08  9:29                   ` Matt Fleming
2014-07-08  9:29                     ` Matt Fleming
     [not found]                     ` <20140708092958.GD27474-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org>
2014-07-08  9:45                       ` Ard Biesheuvel
2014-07-08  9:45                         ` Ard Biesheuvel
     [not found]                         ` <CAKv+Gu9HkJgsnzUAROVwPKaHGHRU9FwAp+eOT8N8kYDR3Dda+w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-08  9:52                           ` Matt Fleming
2014-07-08  9:52                             ` Matt Fleming
2014-07-02 10:13   ` [PATCH 1/2] efi/arm64: fix potential NULL dereference of efi.systab Ard Biesheuvel
2014-07-02 10:13     ` Ard Biesheuvel
     [not found]     ` <CAKv+Gu-SLQC82q7Rj5ZusbFxwysy7KpRhZ=vw1ipXu9kvq46aQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-02 14:29       ` Mark Salter
2014-07-02 14:29         ` Mark Salter
     [not found]         ` <1404311385.19665.15.camel-PDpCo7skNiwAicBL8TP8PQ@public.gmane.org>
2014-07-03 16:04           ` Ard Biesheuvel
2014-07-03 16:04             ` Ard Biesheuvel
2014-07-04 13:38   ` Catalin Marinas
2014-07-04 13:38     ` Catalin Marinas
     [not found]     ` <20140704133844.GG16404-5wv7dgnIgG8@public.gmane.org>
2014-07-04 13:54       ` Ard Biesheuvel
2014-07-04 13:54         ` Ard Biesheuvel
     [not found]         ` <CAKv+Gu_VJZuzio8oyDA4OKwaeZj3J4WY_kX4s-_zhs1rk35b7A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-07-04 15:32           ` Catalin Marinas
2014-07-04 15:32             ` Catalin Marinas

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