From: Kent Overstreet <kent.overstreet@linux.dev>
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
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Subject: Re: [PATCH 12/13] x86/jitalloc: prepare to allocate exectuatble memory as ROX
Date: Thu, 1 Jun 2023 14:38:04 -0400 [thread overview]
Message-ID: <ZHjljJfQjhVV/jNS@moria.home.lan> (raw)
In-Reply-To: <a51c041b61e2916d2b91c990349aabc6cb9836aa.camel@intel.com>
On Thu, Jun 01, 2023 at 06:13:44PM +0000, Edgecombe, Rick P wrote:
> > text_poke() _does_ create a separate RW mapping.
>
> Sorry, I meant a separate RW allocation.
Ah yes, that makes sense
>
> >
> > The thing that sucks about text_poke() is that it always does a full
> > TLB
> > flush, and AFAICT that's not remotely needed. What it really wants to
> > be
> > doing is conceptually just
> >
> > kmap_local()
> > mempcy()
> > kunmap_loca()
> > flush_icache();
> >
> > ...except that kmap_local() won't actually create a new mapping on
> > non-highmem architectures, so text_poke() open codes it.
>
> Text poke creates only a local CPU RW mapping. It's more secure because
> other threads can't write to it.
*nod*, same as kmap_local
> It also only needs to flush the local core when it's done since it's
> not using a shared MM.
Ahh! Thanks for that; perhaps the comment in text_poke() about IPIs
could be a bit clearer.
What is it (if anything) you don't like about text_poke() then? It looks
like it's doing broadly similar things to kmap_local(), so should be
in the same ballpark from a performance POV?
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next prev parent reply other threads:[~2023-06-01 18:38 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-01 10:12 [PATCH 00/13] mm: jit/text allocator Mike Rapoport
2023-06-01 10:12 ` [PATCH 01/13] nios2: define virtual address space for modules Mike Rapoport
2023-06-13 22:16 ` Dinh Nguyen
2023-06-01 10:12 ` [PATCH 02/13] mm: introduce jit_text_alloc() and use it instead of module_alloc() Mike Rapoport
2023-06-01 10:12 ` [PATCH 03/13] mm/jitalloc, arch: convert simple overrides of module_alloc to jitalloc Mike Rapoport
2023-06-01 10:12 ` [PATCH 04/13] mm/jitalloc, arch: convert remaining " Mike Rapoport
2023-06-01 22:35 ` Song Liu
2023-06-01 10:12 ` [PATCH 05/13] module, jitalloc: drop module_alloc Mike Rapoport
2023-06-01 10:12 ` [PATCH 06/13] mm/jitalloc: introduce jit_data_alloc() Mike Rapoport
2023-06-01 10:12 ` [PATCH 07/13] x86/ftrace: enable dynamic ftrace without CONFIG_MODULES Mike Rapoport
2023-06-01 10:12 ` [PATCH 08/13] arch: make jitalloc setup available regardless of CONFIG_MODULES Mike Rapoport
2023-06-01 10:12 ` [PATCH 09/13] kprobes: remove dependcy on CONFIG_MODULES Mike Rapoport
2023-06-01 10:12 ` [PATCH 10/13] modules, jitalloc: prepare to allocate executable memory as ROX Mike Rapoport
2023-06-01 10:12 ` [PATCH 11/13] ftrace: Add swap_func to ftrace_process_locs() Mike Rapoport
2023-06-01 10:12 ` [PATCH 12/13] x86/jitalloc: prepare to allocate exectuatble memory as ROX Mike Rapoport
2023-06-01 10:30 ` Peter Zijlstra
2023-06-01 11:07 ` Mike Rapoport
2023-06-02 0:02 ` Song Liu
2023-06-01 17:52 ` Kent Overstreet
2023-06-01 16:54 ` Edgecombe, Rick P
2023-06-01 18:00 ` Kent Overstreet
2023-06-01 18:13 ` Edgecombe, Rick P
2023-06-01 18:38 ` Kent Overstreet [this message]
2023-06-01 20:50 ` Edgecombe, Rick P
2023-06-01 23:54 ` Nadav Amit
2023-06-05 2:52 ` Steven Rostedt
2023-06-05 8:11 ` Mike Rapoport
2023-06-05 16:10 ` Edgecombe, Rick P
2023-06-05 20:42 ` Mike Rapoport
2023-06-05 21:01 ` Edgecombe, Rick P
2023-06-05 21:11 ` Nadav Amit
2023-06-04 21:47 ` Kent Overstreet
2023-06-01 22:49 ` Song Liu
2023-06-01 10:12 ` [PATCH 13/13] x86/jitalloc: make memory allocated for code ROX Mike Rapoport
2023-06-01 16:12 ` [PATCH 00/13] mm: jit/text allocator Mark Rutland
2023-06-01 18:14 ` Kent Overstreet
2023-06-02 9:35 ` Mark Rutland
2023-06-02 18:20 ` Song Liu
2023-06-03 21:11 ` Puranjay Mohan
2023-06-04 18:02 ` Kent Overstreet
2023-06-04 21:22 ` Song Liu
2023-06-04 21:40 ` Kent Overstreet
2023-06-05 4:05 ` Song Liu
2023-06-05 9:20 ` Mike Rapoport
2023-06-05 10:09 ` Mark Rutland
2023-06-06 10:16 ` Mike Rapoport
2023-06-06 18:21 ` Song Liu
2023-06-08 18:41 ` Mike Rapoport
2023-06-09 17:02 ` Song Liu
2023-06-12 21:34 ` Mike Rapoport
2023-06-13 18:56 ` Kent Overstreet
2023-06-13 21:09 ` Mike Rapoport
2023-07-20 8:53 ` Mike Rapoport
2023-06-05 21:13 ` Kent Overstreet
2023-06-02 0:36 ` Song Liu
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