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From: Mike Rapoport <rppt@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Jürgen Groß" <jgross@suse.com>,
	linux-kernel@vger.kernel.org, x86@kernel.org, xin@zytor.com,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH 3/3] x86/alternative: make kernel ITS thunks read-only
Date: Wed, 28 May 2025 20:31:19 +0300	[thread overview]
Message-ID: <aDdIZ9vBQ3JQoIN5@kernel.org> (raw)
In-Reply-To: <20250528155821.GD39944@noisy.programming.kicks-ass.net>

On Wed, May 28, 2025 at 05:58:21PM +0200, Peter Zijlstra wrote:
> On Wed, May 28, 2025 at 03:30:33PM +0200, Jürgen Groß wrote:
> 
> > Have a look at its_fini_mod().
> 
> Oh, that's what you mean. But this still isn't very nice, you now have
> restore_rox() without make_temp_rw(), which was the intended usage
> pattern.
> 
> Bah, I hate how execmem works different for !PSE, Mike, you see a sane
> way to fix this?

The least ugly thing I could think of is to replace the current pattern of

	execmem_alloc()
	exemem_make_temp_rw()
	/* update */
	execmem_restore_rox()

with

	execmem_alloc_rw()
	/* update */
	execmem_protect()

but I still haven't got to try it.

-- 
Sincerely yours,
Mike.

  parent reply	other threads:[~2025-05-28 17:31 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-28 12:35 [PATCH 0/3] x86: Fix some bugs related to ITS mitigation Juergen Gross
2025-05-28 12:35 ` [PATCH 1/3] x86/execmem: don't use PAGE_KERNEL protection for code pages Juergen Gross
2025-05-28 17:27   ` Mike Rapoport
2025-05-28 18:22     ` Jürgen Groß
2025-05-30  7:44     ` Peter Zijlstra
2025-05-28 12:35 ` [PATCH 2/3] x86/mm/pat: don't collapse pages without PSE set Juergen Gross
2025-06-11  9:30   ` [tip: x86/urgent] " tip-bot2 for Juergen Gross
2025-05-28 12:35 ` [PATCH 3/3] x86/alternative: make kernel ITS thunks read-only Juergen Gross
2025-05-28 13:10   ` Peter Zijlstra
2025-05-28 13:19     ` Jürgen Groß
2025-05-28 13:22       ` Peter Zijlstra
2025-05-28 13:30         ` Jürgen Groß
2025-05-28 15:58           ` Peter Zijlstra
2025-05-28 16:17             ` Peter Zijlstra
2025-05-28 17:24             ` Mike Rapoport
2025-05-28 17:31             ` Mike Rapoport [this message]
2025-06-03 11:17             ` Mike Rapoport
2025-05-29  4:09   ` kernel test robot

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