From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 425B220E30B; Sat, 19 Oct 2024 22:46:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729377973; cv=none; b=jloepPp1d7Nuc7e1LWc1XVExgGhBtXaPjj3Hz87qrqK7VdoWu0Nb18VPFvaHUVllZTjonCpieczR9ckRmAtTBNTNpMG6Xh5Zxd2Fka1wBsX/LVNx4N3CKy/aNHN1qFkjRyi4ZGCCXIGf2SClB+PVmf3On4fIvpMZBw2frLirVPM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729377973; c=relaxed/simple; bh=cD5eaMzUFo7t+XYDnFM25WIUwCFcdwXaz1SfpP4a6SE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VrVskNPF42l1W/1DXPdkGhvXLLLpAEFvCH6gwUi4qrlliavypVT7TFvQJy50uOIPeP/8NTdEHog/CP/CdprKwV2oxwc+0aUpE38KntgPgWUZkIpBoRPZ2jQifZN+VjOLdtCxPNS19rmsl9uQ9V35sxjb3z7M9JAHvf72DrtK0P4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=raBET/eq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="raBET/eq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A187C4CEC5; Sat, 19 Oct 2024 22:46:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729377972; bh=cD5eaMzUFo7t+XYDnFM25WIUwCFcdwXaz1SfpP4a6SE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=raBET/eqnMHymvQ7ghoiJNJzhJfHKuWETI4KcodqrLn6OQ/Y9CKtRyA2t4EAlqgdL hZ8GXfGOFi/KBP9oOEyOznfd0G9uHgQFOCCAyoXDyjtw5nXygFTG2CrK0T0RFUBMS3 dw6lBjU8rrQg3O+nhowKfheReV2QdNr7rWdr90u1jL/xItyfqX/Q3Me8KZXxc+SLgs Bgsl1ciX2BowyzgKq/taZpeBj4IacVWutv5wVHimbHiaNsgZE0UEMAbBKocO0BFYoV nD2awtEWshprtgJwrLo1F7dN4Asn2HkQ91l7gW0Dv7NafPgx9Qm2IawXuSLgLc1IAt hvIMZRfR3Mm9A== Date: Sat, 19 Oct 2024 15:46:09 -0700 From: Luis Chamberlain To: Mike Rapoport Cc: Andrew Morton , Andreas Larsson , Andy Lutomirski , Ard Biesheuvel , Arnd Bergmann , Borislav Petkov , Brian Cain , Catalin Marinas , Christoph Hellwig , Christophe Leroy , Dave Hansen , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , Kent Overstreet , "Liam R. Howlett" , Mark Rutland , Masami Hiramatsu , Matt Turner , Max Filippov , Michael Ellerman , Michal Simek , Oleg Nesterov , Palmer Dabbelt , Peter Zijlstra , Richard Weinberger , Russell King , Song Liu , Stafford Horne , Steven Rostedt , Suren Baghdasaryan , Thomas Bogendoerfer , Thomas Gleixner , Uladzislau Rezki , Vineet Gupta , Will Deacon , bpf@vger.kernel.org, linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-trace-kernel@vger.kernel.org, linux-um@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH v6 7/8] execmem: add support for cache of large ROX pages Message-ID: References: <20241016122424.1655560-1-rppt@kernel.org> <20241016122424.1655560-8-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-hexagon@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241016122424.1655560-8-rppt@kernel.org> On Wed, Oct 16, 2024 at 03:24:23PM +0300, Mike Rapoport wrote: > From: "Mike Rapoport (Microsoft)" > > Using large pages to map text areas reduces iTLB pressure and improves > performance. > > Extend execmem_alloc() with an ability to use huge pages with ROX > permissions as a cache for smaller allocations. > > To populate the cache, a writable large page is allocated from vmalloc with > VM_ALLOW_HUGE_VMAP, filled with invalid instructions and then remapped as > ROX. > > The direct map alias of that large page is exculded from the direct map. > > Portions of that large page are handed out to execmem_alloc() callers > without any changes to the permissions. > > When the memory is freed with execmem_free() it is invalidated again so > that it won't contain stale instructions. > > An architecture has to implement execmem_fill_trapping_insns() callback > and select ARCH_HAS_EXECMEM_ROX configuration option to be able to use > the ROX cache. > > The cache is enabled on per-range basis when an architecture sets > EXECMEM_ROX_CACHE flag in definition of an execmem_range. > > Signed-off-by: Mike Rapoport (Microsoft) Reviewed-by: Luis Chamberlain Luis