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From: David Daney <ddaney.cavm@gmail.com>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: James Hogan <james.hogan@imgtec.com>,
	Matt Redfearn <matt.redfearn@imgtec.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	linux-mips@linux-mips.org
Subject: Re: [PATCH 1/9] MIPS: traps: 64bit kernels should read CP0_EBase 64bit
Date: Fri, 07 Oct 2016 08:41:29 -0700	[thread overview]
Message-ID: <57F7C229.9040608@gmail.com> (raw)
In-Reply-To: <57F7C0D5.6000007@gmail.com>

On 10/07/2016 08:35 AM, David Daney wrote:
> On 10/06/2016 09:18 AM, Maciej W. Rozycki wrote:
>> Hi James,
>>
>>>>   This does look wrong to me, as I noted above EBase is 64-bit with
>>>> MIPS64
>>>> processors as from architecture revision 3.50.  Also I don't think
>>>> we want
>>>
>>> MIPS64 PRA (I'm looking at r5 and r6) seems to allow for write-gate not
>>> to be implemented, in which case the register is only 32-bits.
>>
>>   Indeed, but we need to be prepared to handle the width of 64 bits and
>> `cpu_has_mips64r6' does not seem to me to be the right condition.
>
> It is not the proper condition.
>
> The presence of a 64-bit EBase should be probed for.
>
> The proper check is to test of the EBase[WG] (bit 11) can be set to 1.
> It it can, this indicates that EBase supports 64-bit accesses.
>

One more thing...

In r5 systems, the only time 64-bit Ebase is really interesting is for 
virtualization.

You could also gate probing WG on the presence of the VZ capability.



> David.
>
>
>

  reply	other threads:[~2016-10-07 15:41 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-01 16:30 [PATCH 0/9] MIPS: General EVA fixes & cleanups James Hogan
2016-09-01 16:30 ` [PATCH 1/9] MIPS: traps: 64bit kernels should read CP0_EBase 64bit James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-21 13:08   ` Ralf Baechle
2016-09-21 15:01     ` Matt Redfearn
2016-09-21 15:01       ` Matt Redfearn
2016-10-02 10:30       ` Maciej W. Rozycki
2016-10-05 15:56         ` James Hogan
2016-10-05 15:56           ` James Hogan
2016-10-06 16:18           ` Maciej W. Rozycki
2016-10-06 18:05             ` James Hogan
2016-10-06 18:05               ` James Hogan
2016-10-06 19:56               ` Maciej W. Rozycki
2016-10-06 20:19                 ` James Hogan
2016-10-06 20:19                   ` James Hogan
2016-10-06 22:41                   ` Maciej W. Rozycki
2016-10-06 22:50                     ` James Hogan
2016-10-06 22:50                       ` James Hogan
2016-10-06 23:07                       ` Maciej W. Rozycki
2016-10-07 15:35             ` David Daney
2016-10-07 15:41               ` David Daney [this message]
2016-10-07 17:39                 ` Maciej W. Rozycki
2016-09-01 16:30 ` [PATCH 2/9] MIPS: traps: Convert ebase to KSeg0 James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-01 16:30 ` [PATCH 3/9] MIPS: traps: Ensure full EBase is written James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-21 13:19   ` Ralf Baechle
2016-09-01 16:30 ` [PATCH 4/9] MIPS: c-r4k: Drop bc_wback_inv() from icache flush James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-01 16:30 ` [PATCH 5/9] MIPS: c-r4k: Split user/kernel flush_icache_range() James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-01 16:30 ` [PATCH 6/9] MIPS: cacheflush: Use __flush_icache_user_range() James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-01 16:30 ` [PATCH 7/9] MIPS: uprobes: Flush icache via kernel address James Hogan
2016-09-01 16:30   ` James Hogan
2016-09-21 13:26   ` Ralf Baechle
2016-09-21 18:15     ` Leonid Yegoshin
2016-09-21 18:15       ` Leonid Yegoshin
2016-09-22 21:15       ` James Hogan
2016-09-22 21:15         ` James Hogan
2016-09-22 21:38         ` Leonid Yegoshin
2016-09-22 21:38           ` Leonid Yegoshin
2016-09-22 21:42           ` Leonid Yegoshin
2016-09-22 21:42             ` Leonid Yegoshin
2016-09-22 22:13           ` James Hogan
2016-09-22 22:27             ` Leonid Yegoshin
2016-09-22 22:27               ` Leonid Yegoshin
2016-09-23  7:10               ` James Hogan
2016-09-01 16:30 ` [PATCH 8/9] MIPS: KVM: Use __local_flush_icache_user_range() James Hogan
2016-09-01 16:30 ` [PATCH 9/9] MIPS: c-r4k: Fix flush_icache_range() for EVA James Hogan
2016-09-01 16:30   ` James Hogan

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