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From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/3] arm64: merge __enable_mmu and __turn_mmu_on
Date: Wed, 18 Mar 2015 12:09:24 +0000	[thread overview]
Message-ID: <20150318120924.GB19624@leverpostej> (raw)
In-Reply-To: <CAKv+Gu8vCjLnyBAcEfucFAj7KqB3qmfKvjowNRoG1dWXoFjYsQ@mail.gmail.com>

> >> - * Setup common bits before finally enabling the MMU. Essentially this is just
> >> - * loading the page table pointer and vector base registers.
> >> + * Enable the MMU. This completely changes the structure of the visible memory
> >> + * space. You will not be able to trace execution through this.
> >
> > I don't understand the last sentence. I recall being able to read and
> > eventually understand simulator instruction traces of this code. Is the
> > sentence referring to the Embedded Trace Macrocell or something?
> >
> 
> I guess the comment is a bit stale: it was inherited from the ARM
> version, where older platforms only have a single TTBR register, and
> switching address spaces is a bit more involved. On arm64, however,
> there are always two TTBR registers at EL1, and the address spaced
> they represent can never overlap, so there it isn't such a big deal.

Indeed. Feel free to drop it if you want.

Mark.

  reply	other threads:[~2015-03-18 12:09 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-17 10:11 [PATCH 0/3] more arm64 early boot stuff Ard Biesheuvel
2015-03-17 10:11 ` [PATCH 1/3] arm64: merge __enable_mmu and __turn_mmu_on Ard Biesheuvel
2015-03-17 13:51   ` Mark Rutland
2015-03-17 17:39   ` Christopher Covington
2015-03-18  7:47     ` Ard Biesheuvel
2015-03-18 12:09       ` Mark Rutland [this message]
2015-03-17 10:11 ` [PATCH 2/3] arm64: remove __calc_phys_offset Ard Biesheuvel
2015-03-17 14:46   ` Mark Rutland
2015-03-18  7:49     ` Ard Biesheuvel
2015-03-18 12:08       ` Mark Rutland
2015-03-17 10:11 ` [PATCH 3/3] arm64: enforce x1|x2|x3 == 0 upon kernel entry as per boot protocol Ard Biesheuvel
2015-03-17 13:25   ` Mark Rutland
2015-03-17 17:47   ` Christopher Covington
2015-03-18  7:49     ` Ard Biesheuvel

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