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 2BA201514CE for ; Wed, 27 Mar 2024 20:11:44 +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=1711570304; cv=none; b=GymEMNsMRAYYRtdW9NBhjBX/WZHbsgieBZlIAmxDliZG5WR0SeQFmkhsOX+OBcjgjO7BONZk7H/nSKVQzTVPk0PW5YPLtkxekuXgl2KbFDqvBFT9o8zdXOipzTTv5ZYwRaTy80EGTLw3wqNtp0Bv/5JBzqtIOptfzpggRdclyrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711570304; c=relaxed/simple; bh=9RqnoGIQw8HcQGs4/vUyTnbDTCMES9GHhJJHFJ6vc+w=; h=Date:To:From:Subject:Message-Id; b=fAXm6hDFktgo1rPx2OtQpWga04nb6KFiB2mMe4TDgvbvDfkxN6P7QmmR7vBkCzDt1AfCjphFIso64HbCoqPRlJH5jI8joJx2ZcuEt3fnHxccrlLr6iwvHQxlmpSiMNlt5MGX6ZXFlSvcmayIlk1jSQUZ1ZRfR5ykGNEY1pgQIvE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=po4bojNW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="po4bojNW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D16D0C433F1; Wed, 27 Mar 2024 20:11:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1711570303; bh=9RqnoGIQw8HcQGs4/vUyTnbDTCMES9GHhJJHFJ6vc+w=; h=Date:To:From:Subject:From; b=po4bojNWMUrM2Pt3OqPvWeL4Z+c8JvA7VsVUOlHIJvCPhuaCFbG3VI3fT+riJ0apK yfneSLEoRVyYM8Au2/AlzjENVXcL32Kz/QBdjBPXd7hDifSpd2yNXal9WQ2YroZQep jdKIN+p+zgDmJymCLAtmFSU/OpD8LRQksw/VrU5U= Date: Wed, 27 Mar 2024 13:11:43 -0700 To: mm-commits@vger.kernel.org,tglx@linutronix.de,peterz@infradead.org,npiggin@gmail.com,naveen.n.rao@linux.ibm.com,mpe@ellerman.id.au,mingo@redhat.com,luto@kernel.org,Liam.Howlett@oracle.com,kirill.shutemov@linux.intel.com,keescook@chromium.org,James.Bottomley@HansenPartnership.com,hpa@zytor.com,guoren@kernel.org,deller@gmx.de,debug@rivosinc.com,dave.hansen@linux.intel.com,dan.j.williams@intel.com,christophe.leroy@csgroup.eu,broonie@kernel.org,bp@alien8.de,ast@kernel.org,aneesh.kumar@kernel.org,rick.p.edgecombe@intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: + powerpc-use-initializer-for-struct-vm_unmapped_area_info.patch added to mm-unstable branch Message-Id: <20240327201143.D16D0C433F1@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: powerpc: use initializer for struct vm_unmapped_area_info has been added to the -mm mm-unstable branch. Its filename is powerpc-use-initializer-for-struct-vm_unmapped_area_info.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-use-initializer-for-struct-vm_unmapped_area_info.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Rick Edgecombe Subject: powerpc: use initializer for struct vm_unmapped_area_info Date: Mon, 25 Mar 2024 19:16:51 -0700 Future changes will need to add a new member to struct vm_unmapped_area_info. This would cause trouble for any call site that doesn't initialize the struct. Currently every caller sets each member manually, so if new members are added they will be uninitialized and the core code parsing the struct will see garbage in the new member. It could be possible to initialize the new member manually to 0 at each call site. This and a couple other options were discussed, and a working consensus (see links) was that in general the best way to accomplish this would be via static initialization with designated member initiators. Having some struct vm_unmapped_area_info instances not zero initialized will put those sites at risk of feeding garbage into vm_unmapped_area() if the convention is to zero initialize the struct and any new member addition misses a call site that initializes each member manually. It could be possible to leave the code mostly untouched, and just change the line: struct vm_unmapped_area_info info to: struct vm_unmapped_area_info info = {}; However, that would leave cleanup for the members that are manually set to zero, as it would no longer be required. So to be reduce the chance of bugs via uninitialized members, instead simply continue the process to initialize the struct this way tree wide. This will zero any unspecified members. Move the member initializers to the struct declaration when they are known at that time. Leave the members out that were manually initialized to zero, as this would be redundant for designated initializers. Link: https://lkml.kernel.org/r/20240326021656.202649-10-rick.p.edgecombe@intel.com Link: https://lore.kernel.org/lkml/202402280912.33AEE7A9CF@keescook/#t Link: https://lore.kernel.org/lkml/j7bfvig3gew3qruouxrh7z7ehjjafrgkbcmg6tcghhfh3rhmzi@wzlcoecgy5rs/ Signed-off-by: Rick Edgecombe Acked-by: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Aneesh Kumar K.V Cc: Naveen N. Rao Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Borislav Petkov (AMD) Cc: Dan Williams Cc: Dave Hansen Cc: Deepak Gupta Cc: Guo Ren Cc: Helge Deller Cc: H. Peter Anvin (Intel) Cc: Ingo Molnar Cc: "James E.J. Bottomley" Cc: Kees Cook Cc: Kirill A. Shutemov Cc: Liam R. Howlett Cc: Mark Brown Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andrew Morton --- arch/powerpc/mm/book3s64/slice.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) --- a/arch/powerpc/mm/book3s64/slice.c~powerpc-use-initializer-for-struct-vm_unmapped_area_info +++ a/arch/powerpc/mm/book3s64/slice.c @@ -282,12 +282,10 @@ static unsigned long slice_find_area_bot { int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT); unsigned long found, next_end; - struct vm_unmapped_area_info info; - - info.flags = 0; - info.length = len; - info.align_mask = PAGE_MASK & ((1ul << pshift) - 1); - info.align_offset = 0; + struct vm_unmapped_area_info info = { + .length = len, + .align_mask = PAGE_MASK & ((1ul << pshift) - 1), + }; /* * Check till the allow max value for this mmap request */ @@ -326,13 +324,13 @@ static unsigned long slice_find_area_top { int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT); unsigned long found, prev; - struct vm_unmapped_area_info info; + struct vm_unmapped_area_info info = { + .flags = VM_UNMAPPED_AREA_TOPDOWN, + .length = len, + .align_mask = PAGE_MASK & ((1ul << pshift) - 1), + }; unsigned long min_addr = max(PAGE_SIZE, mmap_min_addr); - info.flags = VM_UNMAPPED_AREA_TOPDOWN; - info.length = len; - info.align_mask = PAGE_MASK & ((1ul << pshift) - 1); - info.align_offset = 0; /* * If we are trying to allocate above DEFAULT_MAP_WINDOW * Add the different to the mmap_base. _ Patches currently in -mm which might be from rick.p.edgecombe@intel.com are proc-refactor-pde_get_unmapped_area-as-prep.patch mm-switch-mm-get_unmapped_area-to-a-flag.patch mm-introduce-arch_get_unmapped_area_vmflags.patch mm-remove-export-for-get_unmapped_area.patch mm-use-get_unmapped_area_vmflags.patch thp-add-thp_get_unmapped_area_vmflags.patch csky-use-initializer-for-struct-vm_unmapped_area_info.patch parisc-use-initializer-for-struct-vm_unmapped_area_info.patch powerpc-use-initializer-for-struct-vm_unmapped_area_info.patch treewide-use-initializer-for-struct-vm_unmapped_area_info.patch mm-take-placement-mappings-gap-into-account.patch x86-mm-implement-have_arch_unmapped_area_vmflags.patch x86-mm-care-about-shadow-stack-guard-gap-during-placement.patch selftests-x86-add-placement-guard-gap-test-for-shstk.patch