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From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "luto@kernel.org" <luto@kernel.org>, "bp@alien8.de" <bp@alien8.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
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Subject: Re: [PATCH v2 13/20] Add set_alias_ function and x86 implementation
Date: Tue, 12 Feb 2019 00:01:37 +0000
Message-ID: <3c34b566afb814ae40665916a0834cdd52d548a2.camel@intel.com> (raw)
In-Reply-To: <CALCETrX2AOTTZOQafZgOFxiQsFgdYHVaLonXTqTa3RUs5MPVUQ@mail.gmail.com>

On Mon, 2019-02-11 at 14:59 -0800, Andy Lutomirski wrote:
> On Mon, Feb 11, 2019 at 11:09 AM Borislav Petkov <bp@alien8.de> wrote:
> > 
> > On Mon, Jan 28, 2019 at 04:34:15PM -0800, Rick Edgecombe wrote:
> > > This adds two new functions set_alias_default_noflush and
> > 
> > s/This adds/Add/
> > 
> > > set_alias_nv_noflush for setting the alias mapping for the page to its
> > 
> > Please end function names with parentheses, below too.
> > 
> > > default valid permissions and to an invalid state that cannot be cached in
> > > a TLB, respectively. These functions to not flush the TLB.
> > 
> > s/to/do/
> > 
> > Also, pls put that description as comments over the functions in the
> > code. Otherwise that "nv" as part of the name doesn't really explain
> > what it does.
> > 
> > Actually, you could just as well call the function
> > 
> > set_alias_invalid_noflush()
> > 
> > All the other words are written in full, no need to have "nv" there.
> 
> Why are you calling this an "alias"?  You're modifying the direct map.
> Your patches are thinking of the direct map as an alias of the vmap
> mapping, but that does seem a bit backwards.  How about
> set_direct_map_invalid_noflush(), etc?
> 
I picked it up from some of the names in arch/x86/mm/pageattr.c:
CPA_NO_CHECK_ALIAS, set_memory_np_noalias(), etc. In that file the directmap
address seems to be the "alias". For 32 bit with highmem though, this would also
set permissions for a kmap mapping as well (if one existed), since that address
will be returned from page_address().

Yea, in vmalloc, vm_unmap_aliases talks about the vmap address "alias". So I
guess calling it "alias" is ambiguous. But does set_direct_map_invalid_noflush
make sense in the highmem case?

I couldn't think of any names that I loved, which is why I ran the
set_alias_*_noflush names by people in an earlier version, although looking back
only Ard chimed in on that. "set_direct_map_invalid_noflush" is fine with me if
nobody objects.

Thanks,

Rick

  reply index

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-29  0:34 [PATCH v2 00/20] Merge text_poke fixes and executable lockdowns Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 01/20] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 02/20] x86/jump_label: Use text_poke_early() during early init Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 03/20] x86/mm: temporary mm struct Rick Edgecombe
2019-01-31 11:29   ` Borislav Petkov
2019-01-31 22:19     ` Nadav Amit
2019-02-01  0:08       ` Borislav Petkov
2019-02-01  0:25         ` Nadav Amit
2019-02-04 14:28       ` Borislav Petkov
2019-01-29  0:34 ` [PATCH v2 04/20] fork: provide a function for copying init_mm Rick Edgecombe
2019-02-05  8:53   ` Borislav Petkov
2019-02-05  9:03     ` Nadav Amit
2019-01-29  0:34 ` [PATCH v2 05/20] x86/alternative: initializing temporary mm for patching Rick Edgecombe
2019-02-05  9:18   ` Borislav Petkov
2019-02-11  0:39   ` Nadav Amit
2019-02-11  5:18     ` Andy Lutomirski
2019-02-11 18:04       ` Nadav Amit
2019-02-11 19:07         ` Andy Lutomirski
2019-02-11 19:18           ` Nadav Amit
2019-02-11 22:47             ` Andy Lutomirski
2019-02-12 18:23               ` Nadav Amit
2019-01-29  0:34 ` [PATCH v2 06/20] x86/alternative: use temporary mm for text poking Rick Edgecombe
2019-02-05  9:58   ` Borislav Petkov
2019-02-05 11:31     ` Peter Zijlstra
2019-02-05 12:35       ` Borislav Petkov
2019-02-05 13:25         ` Peter Zijlstra
2019-02-05 17:54         ` Nadav Amit
2019-02-05 13:29       ` Peter Zijlstra
2019-01-29  0:34 ` [PATCH v2 07/20] x86/kgdb: avoid redundant comparison of patched code Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 08/20] x86/ftrace: set trampoline pages as executable Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 09/20] x86/kprobes: instruction pages initialization enhancements Rick Edgecombe
2019-02-11 18:22   ` Borislav Petkov
2019-02-11 19:36     ` Nadav Amit
2019-01-29  0:34 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Rick Edgecombe
2019-02-11 18:29   ` Borislav Petkov
2019-02-11 18:45     ` Nadav Amit
2019-02-11 19:01       ` Borislav Petkov
2019-02-11 19:09         ` Nadav Amit
2019-02-11 19:10           ` Borislav Petkov
2019-02-11 19:27             ` Nadav Amit
2019-02-11 19:42               ` Borislav Petkov
2019-02-11 20:32                 ` Nadav Amit
2019-03-07 15:10                   ` [PATCH] x86/cpufeature: Remove __pure attribute to _static_cpu_has() Borislav Petkov
2019-03-07 16:43                     ` hpa
2019-03-07 17:02                       ` Borislav Petkov
2019-03-07  7:29                 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Borislav Petkov
2019-03-07 16:53                   ` hpa
2019-03-07 17:06                     ` Borislav Petkov
2019-03-07 20:02                       ` Andy Lutomirski
2019-03-07 20:25                         ` Borislav Petkov
2019-01-29  0:34 ` [PATCH v2 11/20] x86/jump-label: remove support for custom poker Rick Edgecombe
2019-02-11 18:37   ` Borislav Petkov
2019-01-29  0:34 ` [PATCH v2 12/20] x86/alternative: Remove the return value of text_poke_*() Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 13/20] Add set_alias_ function and x86 implementation Rick Edgecombe
2019-02-11 19:09   ` Borislav Petkov
2019-02-11 19:27     ` Edgecombe, Rick P
2019-02-11 22:59     ` Andy Lutomirski
2019-02-12  0:01       ` Edgecombe, Rick P [this message]
2019-01-29  0:34 ` [PATCH v2 14/20] mm: Make hibernate handle unmapped pages Rick Edgecombe
2019-02-19 11:04   ` Borislav Petkov
2019-02-19 21:28     ` Edgecombe, Rick P
2019-02-20 16:07       ` Borislav Petkov
2019-01-29  0:34 ` [PATCH v2 15/20] vmalloc: New flags for safe vfree on special perms Rick Edgecombe
2019-02-19 12:48   ` Borislav Petkov
2019-02-19 19:42     ` Edgecombe, Rick P
2019-02-20 16:14       ` Borislav Petkov
2019-01-29  0:34 ` [PATCH v2 16/20] modules: Use vmalloc special flag Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 17/20] bpf: " Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 18/20] x86/ftrace: " Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 19/20] x86/kprobes: " Rick Edgecombe
2019-01-29  0:34 ` [PATCH v2 20/20] x86/alternative: comment about module removal races Rick Edgecombe

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