[Qemu-devel] [Bug 1679358] [NEW] ARM: SCTLR fields not being preserved

[Qemu-devel] [Bug 1679358] [NEW] ARM: SCTLR fields not being preserved

[Yifan]

Public bug reported:

There are fields in SCTLR that are RAO/SBOP or WI or in the case of the
RR field, accessible only in secure mode. Currently it seems that qemu
just propagates any write to SCTLR to the register and this screwed up
in a bootloader that I am debugging.

** Affects: qemu
     Importance: Undecided
         Status: New

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Title:
  ARM: SCTLR fields not being preserved

Status in QEMU:
  New

Bug description:
  There are fields in SCTLR that are RAO/SBOP or WI or in the case of
  the RR field, accessible only in secure mode. Currently it seems that
  qemu just propagates any write to SCTLR to the register and this
  screwed up in a bootloader that I am debugging.

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Re: [Qemu-devel] [Bug 1679358] [NEW] ARM: SCTLR fields not being preserved

[Peter Maydell]

On 3 April 2017 at 23:17, Yifan <yifanlu94@gmail.com> wrote:
> There are fields in SCTLR that are RAO/SBOP or WI or in the case of the
> RR field, accessible only in secure mode. Currently it seems that qemu
> just propagates any write to SCTLR to the register and this screwed up
> in a bootloader that I am debugging.

Yes, we're a bit loose in QEMU on the handling of reserved bits.

Note that most of the SCTLR bits like this are RAO/SBOP or RAZ/SBZP,
so the guest should not be writing wrong values to them.

thanks
-- PMM

[Qemu-devel] [Bug 1679358] Re: ARM: SCTLR fields not being preserved

[Yifan]

So there won't be a fix in the future? I'm working with debugging a
proprietary bootloader that I do not have the source code for. I wonder
if this becomes an issue for any other platform targets.

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Title:
  ARM: SCTLR fields not being preserved

Status in QEMU:
  New

Bug description:
  There are fields in SCTLR that are RAO/SBOP or WI or in the case of
  the RR field, accessible only in secure mode. Currently it seems that
  qemu just propagates any write to SCTLR to the register and this
  screwed up in a bootloader that I am debugging.

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[Qemu-devel] [Bug 1679358] Re: ARM: SCTLR fields not being preserved

[Peter Maydell]

Well, I wouldn't object to a patch to fix it (it would have to correctly
handle the various different versions of the CPU architecture we
implement, etc), but I'm not planning on writing one today myself.

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Title:
  ARM: SCTLR fields not being preserved

Status in QEMU:
  New

Bug description:
  There are fields in SCTLR that are RAO/SBOP or WI or in the case of
  the RR field, accessible only in secure mode. Currently it seems that
  qemu just propagates any write to SCTLR to the register and this
  screwed up in a bootloader that I am debugging.

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[Qemu-devel] [Bug 1679358] Re: ARM: SCTLR fields not being preserved

[Peter Maydell]

** Tags added: arm

** Summary changed:

- ARM: SCTLR fields not being preserved
+ ARM: RES0/RES1 SCTLR fields not read-only

** Changed in: qemu
       Status: New => Confirmed

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Title:
  ARM: RES0/RES1 SCTLR fields not read-only

Status in QEMU:
  Confirmed

Bug description:
  There are fields in SCTLR that are RAO/SBOP or WI or in the case of
  the RR field, accessible only in secure mode. Currently it seems that
  qemu just propagates any write to SCTLR to the register and this
  screwed up in a bootloader that I am debugging.

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[Bug 1679358] Re: ARM: RES0/RES1 SCTLR fields not read-only

[Thomas Huth]

The QEMU project is currently moving its bug tracking to another system.
For this we need to know which bugs are still valid and which could be
closed already. Thus we are setting the bug state to "Incomplete" now.

If the bug has already been fixed in the latest upstream version of QEMU,
then please close this ticket as "Fix released".

If it is not fixed yet and you think that this bug report here is still
valid, then you have two options:

1) If you already have an account on gitlab.com, please open a new ticket
for this problem in our new tracker here:

    https://gitlab.com/qemu-project/qemu/-/issues

and then close this ticket here on Launchpad (or let it expire auto-
matically after 60 days). Please mention the URL of this bug ticket on
Launchpad in the new ticket on GitLab.

2) If you don't have an account on gitlab.com and don't intend to get
one, but still would like to keep this ticket opened, then please switch
the state back to "New" within the next 60 days (otherwise it will get
closed as "Expired"). We will then eventually migrate the ticket auto-
matically to the new system (but you won't be the reporter of the bug
in the new system and thus won't get notified on changes anymore).

Thank you and sorry for the inconvenience.


** Changed in: qemu
       Status: Confirmed => Incomplete

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Title:
  ARM: RES0/RES1 SCTLR fields not read-only

Status in QEMU:
  Incomplete

Bug description:
  There are fields in SCTLR that are RAO/SBOP or WI or in the case of
  the RR field, accessible only in secure mode. Currently it seems that
  qemu just propagates any write to SCTLR to the register and this
  screwed up in a bootloader that I am debugging.

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[Bug 1679358] Re: ARM: RES0/RES1 SCTLR fields not read-only

[Launchpad Bug Tracker]

[Expired for QEMU because there has been no activity for 60 days.]

** Changed in: qemu
       Status: Incomplete => Expired

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Title:
  ARM: RES0/RES1 SCTLR fields not read-only

Status in QEMU:
  Expired

Bug description:
  There are fields in SCTLR that are RAO/SBOP or WI or in the case of
  the RR field, accessible only in secure mode. Currently it seems that
  qemu just propagates any write to SCTLR to the register and this
  screwed up in a bootloader that I am debugging.

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1679358/+subscriptions