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From: Dave Hansen <dave.hansen@intel.com>
To: Ram Pai <linuxram@us.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	shakeelb@google.com, stable@kernel.org, tglx@linutronix.de,
	mpe@ellerman.id.au, mingo@kernel.org, akpm@linux-foundation.org,
	shuah@kernel.org
Subject: Re: [PATCH 4/9] x86, pkeys: override pkey when moving away from PROT_EXEC
Date: Thu, 26 Apr 2018 10:57:31 -0700	[thread overview]
Message-ID: <aedcb0b6-73f5-f72f-742e-b417131895d3@intel.com> (raw)
In-Reply-To: <20180407010919.GB15890@ram.oc3035372033.ibm.com>

On 04/06/2018 06:09 PM, Ram Pai wrote:
> Well :). my point is add this code and delete the other
> code that you add later in that function.

I don't think I'm understanding what your suggestion was.  I looked at
the code and I honestly do not think I can remove any of it.

For the plain (non-explicit pkey_mprotect()) case, there are exactly
four paths through __arch_override_mprotect_pkey(), resulting in three
different results.

1. New prot==PROT_EXEC, no pkey-exec support -> do not override
2. New prot!=PROT_EXEC, old VMA not PROT_EXEC-> do not override
3. New prot==PROT_EXEC, w/ pkey-exec support -> override to exec pkey
4. New prot!=PROT_EXEC, old VMA is PROT_EXEC -> override to default

I don't see any redundancy there, or any code that we can eliminate or
simplify.  It was simpler before, but that's what where bug was.

  reply	other threads:[~2018-04-26 17:57 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-26 17:27 [PATCH 0/9] [v2] x86, pkeys: two protection keys bug fixes Dave Hansen
2018-03-26 17:27 ` [PATCH 1/9] x86, pkeys: do not special case protection key 0 Dave Hansen
2018-03-26 17:47   ` Shuah Khan
2018-03-26 17:53     ` Dave Hansen
2018-03-26 17:58       ` Shuah Khan
2018-03-26 17:58         ` Shuah Khan
2018-03-26 17:27 ` [PATCH 2/9] x86, pkeys, selftests: save off 'prot' for allocations Dave Hansen
2018-03-26 17:27 ` [PATCH 3/9] x86, pkeys, selftests: add a test for pkey 0 Dave Hansen
2018-03-26 17:27 ` [PATCH 4/9] x86, pkeys: override pkey when moving away from PROT_EXEC Dave Hansen
2018-04-07  0:09   ` Ram Pai
2018-04-07  0:47     ` Dave Hansen
2018-04-07  1:09       ` Ram Pai
2018-04-26 17:57         ` Dave Hansen [this message]
2018-04-30  7:51           ` Ram Pai
2018-04-30 16:36             ` Dave Hansen
2018-04-25 22:10   ` Shakeel Butt
2018-04-26  8:55     ` Thomas Gleixner
2018-04-26 18:17       ` Dave Hansen
2018-03-26 17:27 ` [PATCH 5/9] x86, pkeys, selftests: fix pointer math Dave Hansen
2018-03-26 17:27 ` [PATCH 6/9] x86, pkeys, selftests: fix pkey exhaustion test off-by-one Dave Hansen
2018-03-26 17:27 ` [PATCH 7/9] x86, pkeys, selftests: factor out "instruction page" Dave Hansen
2018-03-26 17:27 ` [PATCH 8/9] x86, pkeys, selftests: add allow faults on unknown keys Dave Hansen
2018-03-26 17:27 ` [PATCH 9/9] x86, pkeys, selftests: add PROT_EXEC test Dave Hansen
  -- strict thread matches above, loose matches on Subject: below --
2018-04-27 17:45 [PATCH 0/9] [v3] x86, pkeys: two protection keys bug fixes Dave Hansen
2018-04-27 17:45 ` [PATCH 4/9] x86, pkeys: override pkey when moving away from PROT_EXEC Dave Hansen
2018-04-27 17:45   ` Dave Hansen
2018-03-23 18:09 [PATCH 0/9] x86, pkeys: two protection keys bug fixes Dave Hansen
2018-03-23 18:09 ` [PATCH 4/9] x86, pkeys: override pkey when moving away from PROT_EXEC Dave Hansen
2018-03-23 19:15   ` Shakeel Butt
2018-03-23 19:23     ` Dave Hansen
2018-03-23 19:27       ` Shakeel Butt
2018-03-23 19:29         ` Dave Hansen
2018-03-23 19:38       ` Thomas Gleixner
2018-03-23 19:45         ` Thomas Gleixner
2018-03-23 19:48           ` Dave Hansen

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