From: David Laight <David.Laight@ACULAB.COM>
To: 'Joerg Roedel' <joro@8bytes.org>
Cc: "x86@kernel.org" <x86@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"hpa@zytor.com" <hpa@zytor.com>, Joerg Roedel <jroedel@suse.de>,
Kees Cook <keescook@chromium.org>,
Andy Lutomirski <luto@kernel.org>,
Uros Bizjak <ubizjak@gmail.com>,
Arvind Sankar <nivedita@alum.mit.edu>,
Ard Biesheuvel <ardb@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Fabio Aiuto <fabioaiuto83@gmail.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: RE: [PATCH] x86/efi: Restore Firmware IDT in before ExitBootServices()
Date: Fri, 20 Aug 2021 09:02:46 +0000 [thread overview]
Message-ID: <f68a175362984e4abbb0a1da2004c936@AcuMS.aculab.com> (raw)
In-Reply-To: <YR9tSuLyX8QHV5Pv@8bytes.org>
From: 'Joerg Roedel'
> Sent: 20 August 2021 09:52
>
> On Fri, Aug 20, 2021 at 08:43:47AM +0000, David Laight wrote:
> > Hmmm...
> > If Linux needs its own IDT then temporarily substituting the old IDT
> > prior to a UEFI call will cause 'grief' if a 'Linux' interrupt
> > happens during the UEFI call.
>
> This is neede only during very early boot before Linux called
> ExitBootServices(). Nothing that causes IRQs is set up by Linux yet. Of
> course the Firmware could have set something up, but Linux runs with
> IRQs disabled when on its own IDT at that stage.
So allocate and initialise the Linux IDT - so entries can be added.
But don't execute 'lidt' until later on.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2021-08-20 9:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-20 7:34 [PATCH] x86/efi: Restore Firmware IDT in before ExitBootServices() Joerg Roedel
2021-08-20 7:41 ` Ard Biesheuvel
2021-08-20 8:01 ` Joerg Roedel
2021-08-20 8:43 ` David Laight
2021-08-20 8:52 ` 'Joerg Roedel'
2021-08-20 9:02 ` David Laight [this message]
2021-08-20 10:19 ` 'Joerg Roedel'
2021-08-20 11:31 ` Ard Biesheuvel
2021-08-20 11:51 ` Joerg Roedel
2021-08-20 15:46 ` David Laight
2021-08-20 16:04 ` Joerg Roedel
2021-08-20 9:26 ` Borislav Petkov
2021-08-20 11:24 ` Borislav Petkov
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