From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36CF3EB64DB for ; Mon, 19 Jun 2023 09:19:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230047AbjFSJTJ (ORCPT ); Mon, 19 Jun 2023 05:19:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229618AbjFSJTH (ORCPT ); Mon, 19 Jun 2023 05:19:07 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 92DBA83; Mon, 19 Jun 2023 02:19:05 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 279F612FC; Mon, 19 Jun 2023 02:19:49 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.28.22]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8B0053F64C; Mon, 19 Jun 2023 02:19:03 -0700 (PDT) Date: Mon, 19 Jun 2023 10:19:00 +0100 From: Mark Rutland To: Kent Overstreet Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-bcachefs@vger.kernel.org, Kent Overstreet , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , linux-mm@kvack.org, Kees Cook , Andy Lutomirski Subject: Re: [PATCH 07/32] mm: Bring back vmalloc_exec Message-ID: References: <20230509165657.1735798-1-kent.overstreet@linux.dev> <20230509165657.1735798-8-kent.overstreet@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230509165657.1735798-8-kent.overstreet@linux.dev> Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, May 09, 2023 at 12:56:32PM -0400, Kent Overstreet wrote: > From: Kent Overstreet > > This is needed for bcachefs, which dynamically generates per-btree node > unpack functions. Much like Kees and Andy, I have concerns with adding new code generators to the kernel. Even ignoring the actual code generation, there are a bunch of subtle ordering/maintenance/synchronization concerns across architectures, and we already have a fair amount of pain with the existing cases. Can you share more detail on how you want to use this? >From a quick scan of your gitweb for the bcachefs-for-upstream branch I couldn't spot the relevant patches. Thanks, Mark. > > Signed-off-by: Kent Overstreet > Cc: Andrew Morton > Cc: Uladzislau Rezki > Cc: Christoph Hellwig > Cc: linux-mm@kvack.org > --- > include/linux/vmalloc.h | 1 + > kernel/module/main.c | 4 +--- > mm/nommu.c | 18 ++++++++++++++++++ > mm/vmalloc.c | 21 +++++++++++++++++++++ > 4 files changed, 41 insertions(+), 3 deletions(-) > > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > index 69250efa03..ff147fe115 100644 > --- a/include/linux/vmalloc.h > +++ b/include/linux/vmalloc.h > @@ -145,6 +145,7 @@ extern void *vzalloc(unsigned long size) __alloc_size(1); > extern void *vmalloc_user(unsigned long size) __alloc_size(1); > extern void *vmalloc_node(unsigned long size, int node) __alloc_size(1); > extern void *vzalloc_node(unsigned long size, int node) __alloc_size(1); > +extern void *vmalloc_exec(unsigned long size, gfp_t gfp_mask) __alloc_size(1); > extern void *vmalloc_32(unsigned long size) __alloc_size(1); > extern void *vmalloc_32_user(unsigned long size) __alloc_size(1); > extern void *__vmalloc(unsigned long size, gfp_t gfp_mask) __alloc_size(1); > diff --git a/kernel/module/main.c b/kernel/module/main.c > index d3be89de70..9eaa89e84c 100644 > --- a/kernel/module/main.c > +++ b/kernel/module/main.c > @@ -1607,9 +1607,7 @@ static void dynamic_debug_remove(struct module *mod, struct _ddebug_info *dyndbg > > void * __weak module_alloc(unsigned long size) > { > - return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, > - GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, > - NUMA_NO_NODE, __builtin_return_address(0)); > + return vmalloc_exec(size, GFP_KERNEL); > } > > bool __weak module_init_section(const char *name) > diff --git a/mm/nommu.c b/mm/nommu.c > index 57ba243c6a..8d9ab19e39 100644 > --- a/mm/nommu.c > +++ b/mm/nommu.c > @@ -280,6 +280,24 @@ void *vzalloc_node(unsigned long size, int node) > } > EXPORT_SYMBOL(vzalloc_node); > > +/** > + * vmalloc_exec - allocate virtually contiguous, executable memory > + * @size: allocation size > + * > + * Kernel-internal function to allocate enough pages to cover @size > + * the page level allocator and map them into contiguous and > + * executable kernel virtual space. > + * > + * For tight control over page level allocator and protection flags > + * use __vmalloc() instead. > + */ > + > +void *vmalloc_exec(unsigned long size, gfp_t gfp_mask) > +{ > + return __vmalloc(size, gfp_mask); > +} > +EXPORT_SYMBOL_GPL(vmalloc_exec); > + > /** > * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) > * @size: allocation size > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 31ff782d36..2ebb9ea7f0 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3401,6 +3401,27 @@ void *vzalloc_node(unsigned long size, int node) > } > EXPORT_SYMBOL(vzalloc_node); > > +/** > + * vmalloc_exec - allocate virtually contiguous, executable memory > + * @size: allocation size > + * > + * Kernel-internal function to allocate enough pages to cover @size > + * the page level allocator and map them into contiguous and > + * executable kernel virtual space. > + * > + * For tight control over page level allocator and protection flags > + * use __vmalloc() instead. > + * > + * Return: pointer to the allocated memory or %NULL on error > + */ > +void *vmalloc_exec(unsigned long size, gfp_t gfp_mask) > +{ > + return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, > + gfp_mask, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, > + NUMA_NO_NODE, __builtin_return_address(0)); > +} > +EXPORT_SYMBOL_GPL(vmalloc_exec); > + > #if defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA32) > #define GFP_VMALLOC32 (GFP_DMA32 | GFP_KERNEL) > #elif defined(CONFIG_64BIT) && defined(CONFIG_ZONE_DMA) > -- > 2.40.1 > >