From: Andy Lutomirski <luto@kernel.org>
To: Igor Stoppa <igor.stoppa@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
Igor Stoppa <igor.stoppa@huawei.com>,
Nadav Amit <nadav.amit@gmail.com>,
Kees Cook <keescook@chromium.org>,
linux-integrity <linux-integrity@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 04/12] __wr_after_init: x86_64: __wr_op
Date: Fri, 21 Dec 2018 09:23:03 -0800 [thread overview]
Message-ID: <CALCETrU8GZbF2oWYeKUVKBURuh1zeMqcHM5RMTchiDsdrSSVPA@mail.gmail.com> (raw)
In-Reply-To: <d5e8523a-3afd-d992-1af3-b329985c5ed5@gmail.com>
On Thu, Dec 20, 2018 at 11:19 AM Igor Stoppa <igor.stoppa@gmail.com> wrote:
>
>
>
> On 20/12/2018 20:49, Matthew Wilcox wrote:
>
> > I think you're causing yourself more headaches by implementing this "op"
> > function.
>
> I probably misinterpreted the initial criticism on my first patchset,
> about duplication. Somehow, I'm still thinking to the endgame of having
> higher-level functions, like list management.
>
> > Here's some generic code:
>
> thank you, I have one question, below
>
> > void *wr_memcpy(void *dst, void *src, unsigned int len)
> > {
> > wr_state_t wr_state;
> > void *wr_poking_addr = __wr_addr(dst);
> >
> > local_irq_disable();
> > wr_enable(&wr_state);
> > __wr_memcpy(wr_poking_addr, src, len);
>
> Is __wraddr() invoked inside wm_memcpy() instead of being invoked
> privately within __wr_memcpy() because the code is generic, or is there
> some other reason?
>
> > wr_disable(&wr_state);
> > local_irq_enable();
> >
> > return dst;
> > }
> >
> > Now, x86 can define appropriate macros and functions to use the temporary_mm
> > functionality, and other architectures can do what makes sense to them.
> >
I suspect that most architectures will want to do this exactly like
x86, though, but sure, it could be restructured like this.
On x86, I *think* that __wr_memcpy() will want to special-case len ==
1, 2, 4, and (on 64-bit) 8 byte writes to keep them atomic. i'm
guessing this is the same on most or all architectures.
>
> --
> igor
next prev parent reply other threads:[~2018-12-21 17:23 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-19 21:33 [RFC v2 PATCH 0/12] hardening: statically allocated protected memory Igor Stoppa
2018-12-19 21:33 ` [PATCH 01/12] x86_64: memset_user() Igor Stoppa
2018-12-19 21:33 ` [PATCH 02/12] __wr_after_init: linker section and label Igor Stoppa
2018-12-19 21:33 ` [PATCH 03/12] __wr_after_init: generic header Igor Stoppa
2018-12-21 19:38 ` Nadav Amit
2018-12-21 19:45 ` Matthew Wilcox
2018-12-23 2:28 ` Igor Stoppa
2018-12-19 21:33 ` [PATCH 04/12] __wr_after_init: x86_64: __wr_op Igor Stoppa
2018-12-20 16:53 ` Igor Stoppa
2018-12-20 17:20 ` Thiago Jung Bauermann
2018-12-20 17:46 ` Igor Stoppa
2018-12-20 18:49 ` Matthew Wilcox
2018-12-20 19:19 ` Igor Stoppa
2018-12-20 19:27 ` Matthew Wilcox
2018-12-21 17:23 ` Andy Lutomirski [this message]
2018-12-21 17:42 ` Igor Stoppa
2018-12-19 21:33 ` [PATCH 05/12] __wr_after_init: x86_64: debug writes Igor Stoppa
2018-12-19 21:33 ` [PATCH 06/12] __wr_after_init: Documentation: self-protection Igor Stoppa
2018-12-19 21:33 ` [PATCH 07/12] __wr_after_init: lkdtm test Igor Stoppa
2018-12-19 21:33 ` [PATCH 08/12] rodata_test: refactor tests Igor Stoppa
2018-12-19 21:33 ` [PATCH 09/12] rodata_test: add verification for __wr_after_init Igor Stoppa
2018-12-19 21:33 ` [PATCH 10/12] __wr_after_init: test write rare functionality Igor Stoppa
2018-12-19 21:33 ` [PATCH 11/12] IMA: turn ima_policy_flags into __wr_after_init Igor Stoppa
2018-12-20 17:30 ` Thiago Jung Bauermann
2018-12-20 17:49 ` Igor Stoppa
2018-12-19 21:33 ` [PATCH 12/12] x86_64: __clear_user as case of __memset_user Igor Stoppa
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