From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 49389411A0E; Thu, 3 Sep 2026 09:29:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788427769; cv=none; b=NTMN+7SBMBlyB2GqjnzHZ/qwm4Ldrvgoo24s1F6ZecchMDNN+xhqXsTknoRV51/PzAeCLwjuOdu4YcuD5gIXe7gu0n7y4g1gx1wWaMApgA+ZRGz2BQ7LKb6QzP3diqlei65mabKah3Mt1IDpN3wIHEguFIBA/MUCjngzscCWxnM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788427769; c=relaxed/simple; bh=GANaTsmhBJhv32/yhc8gi7G+dYWfdszS5LlzA2ScMKE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=jBW3oH5olc7MjzWVXWUeZbCZhqdr5A9c0bqyIGj7xK12MLIX7GQZEERGoNDlAwx8h8u/IFpEcFv1pvkWMo+J7ieRc/RrwPKe/ziQ1sISf4Amx5E7xZ80zIYCqhUU694go7a/S0FnbVBJQUhaIvKbXDGDu/7o3UnB0lqblseDD2g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VrdwkTOy; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VrdwkTOy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD30A1F00A3D; Thu, 3 Sep 2026 09:29:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788427767; bh=9taLyiYqD93JJjaXvNS2H0Tq/XxgRc4w/Y2D/omzLAc=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=VrdwkTOyGAsb/ezHXc+RSd05q9lbZbkXr7tUSHsqn9+YHwi+EFYdLGxBjm5CEXVMa 5auPqef474FyEjKgj8ThRoUCvfHGgYnQrQthDskjPXuoECP/k/VPsudCaoY75xMYPe xtW1Ik2FAt0F+TbQfVXOeFkTvnDfu7oeMBf1BzIBXeP6yqK6YCQrNsfEBrCap0Tjnd AEHtUNOOUJvwzM8VRrjFghlSTKBiJJS98np8SWdOVL7n9OzZ0N5F+VXzsoYuEgNsT0 CrJbqG/BJ0ZyOoKN5/1tIx4deMMBTz6zHMCQzDcQyqbkmPUr9RlGTsoj/fbb33i1/Z M4WhiG9yMbmJw== From: "Mike Rapoport (Microsoft)" Date: Thu, 03 Sep 2026 12:28:31 +0300 Subject: [PATCH v3 5/6] mm/execmem: use VM_FLUSH_RESET_PERMS for ROX cache allocations Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260903-execmem-set-vm-perms-v0-2-v3-5-949b64a9f755@kernel.org> References: <20260903-execmem-set-vm-perms-v0-2-v3-0-949b64a9f755@kernel.org> In-Reply-To: <20260903-execmem-set-vm-perms-v0-2-v3-0-949b64a9f755@kernel.org> To: Andrew Morton Cc: =?utf-8?q?Adrian_Barna=C5=9B?= , Albert Ou , Alexander Gordeev , Alexandre Ghiti , Andy Lutomirski , Borislav Petkov , Brendan Jackman , Catalin Marinas , Christian Borntraeger , Dave Hansen , David Hildenbrand , Gerald Schaefer , Heiko Carstens , Huacai Chen , Ingo Molnar , Len Brown , Mike Rapoport , Palmer Dabbelt , Paul Walmsley , Pavel Machek , Peter Zijlstra , "H. Peter Anvin" , "Rafael J. Wysocki" , Ryan Roberts , Sven Schnelle , Thomas Gleixner , Uladzislau Rezki , Vasily Gorbik , WANG Xuerui , Will Deacon , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, loongarch@lists.linux.dev X-Mailer: b4 0.17-dev Initially execmem completely removed direct map alias for the memory allocated for the ROX cache in PMD_SIZE chunks. When that memory was freed, its direct map was restored also in PMD_SIZE chunks to avoid fragmentation of the direct map caused by vmalloc::vm_reset_perms(). This required execmem to implement the wrappers for set_direct_map APIs for proper sequencing of removal and restoration of the direct map aliases. Since then x86's CPA gained support for collapsing the direct map page tables for ROX pages and execmem switched from removing ROX caches from the direct map to making them ROX there, so execmem only needs to update direct map alias permissions when freeing the ROX cache memory. vmalloc already handles those updates for areas with VM_FLUSH_RESET_PERMS set and vmalloc::vm_reset_perms() does not force split of the direct map for PMD_SIZE chunks. Set the area permissions with set_vm_flush_reset_perms() when populating the execmem cache just before flipping the area to ROX. This way freeing an allocated area on an error path won't incur two updates of the direct map alias of that area and TLB flushing in vm_reset_perms(). Signed-off-by: Mike Rapoport (Microsoft) --- mm/execmem.c | 40 +++++++--------------------------------- 1 file changed, 7 insertions(+), 33 deletions(-) diff --git a/mm/execmem.c b/mm/execmem.c index 74a178a87e758..ad07cae9ed585 100644 --- a/mm/execmem.c +++ b/mm/execmem.c @@ -113,28 +113,6 @@ static inline unsigned long mas_range_len(struct ma_state *mas) return mas->last - mas->index + 1; } -static int execmem_set_direct_map_valid(struct vm_struct *vm, bool valid) -{ - unsigned int nr = (1 << get_vm_area_page_order(vm)); - unsigned int updated = 0; - int err = 0; - - for (int i = 0; i < vm->nr_pages; i += nr) { - err = set_direct_map_valid_noflush(vm->pages[i], nr, valid); - if (err) - goto err_restore; - updated += nr; - } - - return 0; - -err_restore: - for (int i = 0; i < updated; i += nr) - set_direct_map_valid_noflush(vm->pages[i], nr, !valid); - - return err; -} - static int execmem_force_rw(void *ptr, size_t size) { unsigned int nr = PAGE_ALIGN(size) >> PAGE_SHIFT; @@ -169,9 +147,6 @@ static void execmem_cache_clean(struct work_struct *work) if (IS_ALIGNED(size, PMD_SIZE) && IS_ALIGNED(mas.index, PMD_SIZE)) { - struct vm_struct *vm = find_vm_area(area); - - execmem_set_direct_map_valid(vm, true); mas_store_gfp(&mas, NULL, GFP_KERNEL); vfree(area); } @@ -301,6 +276,8 @@ static void *execmem_cache_populate_alloc(struct execmem_range *range, size_t si /* fill memory with instructions that will trap */ execmem_fill_trapping_insns(p, alloc_size); + set_vm_flush_reset_perms(p); + err = set_memory_rox((unsigned long)p, vm->nr_pages); if (err) goto err_free_mem; @@ -312,18 +289,15 @@ static void *execmem_cache_populate_alloc(struct execmem_range *range, size_t si */ mutex_lock(mutex); err = execmem_cache_add_locked(p, alloc_size, GFP_KERNEL); - if (err) - goto err_reset_direct_map; - - p = execmem_cache_alloc_locked(range, size); - + if (!err) + p = execmem_cache_alloc_locked(range, size); mutex_unlock(mutex); + if (err) + goto err_free_mem; + return p; -err_reset_direct_map: - mutex_unlock(mutex); - execmem_set_direct_map_valid(vm, true); err_free_mem: vfree(p); return NULL; -- 2.53.0