Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933597AbbEOHt7 (ORCPT ); Fri, 15 May 2015 03:49:59 -0400 Received: from mail-wi0-f176.google.com ([209.85.212.176]:38344 "EHLO mail-wi0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751932AbbEOHty (ORCPT ); Fri, 15 May 2015 03:49:54 -0400 Date: Fri, 15 May 2015 09:49:49 +0200 From: Ingo Molnar To: Michael Ellerman Cc: Andrew Morton , Josh Triplett , Borislav Petkov , Jonathan Corbet , Peter Zijlstra , Andy Lutomirski , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , Linus Torvalds , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH v2] Documentation/arch: Add kernel feature descriptions and arch support status under Documentation/features/ Message-ID: <20150515074949.GB14993@gmail.com> References: <20150513094622.GC11030@gmail.com> <20150513094756.GD11030@gmail.com> <20150513131835.GJ1517@pd.tnic> <20150513134842.GA1657@gmail.com> <20150513162757.GA21894@x> <20150513150523.ddd65d7cd51f820b78f0c8e3@linux-foundation.org> <20150514101518.GA27550@gmail.com> <20150514103544.GA7027@gmail.com> <20150514123835.1bf436bc35d711f8dbf9bc0f@linux-foundation.org> <1431644248.2981.1.camel@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1431644248.2981.1.camel@ellerman.id.au> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7869 Lines: 109 * Michael Ellerman wrote: > On Thu, 2015-05-14 at 12:38 -0700, Andrew Morton wrote: > > > Add arch support matrices for more than 40 generic kernel features > > > that need per architecture support. > > > > > > Each feature has its own directory under Documentation/features/feature_name/, > > > and the arch-support.txt file shows its current arch porting status. > > > > It would be nice to provide people with commit IDs to look at, but the > > IDs won't be known at the time the documentation file is created. We > > could provide patch titles. > > +1 on patch titles. Ok, I'll solve this. > > But still, let's not overdo it - get something in there, see how > > well it works, evolve it over time. > > > > I don't think we've heard from any (non-x86) arch maintainers? Do > > they consider this useful at all? Poke. > > Yes it is. I have my own version I've cobbled together for powerpc, > but this is much better. Please double check the PowerPC support matrix for correctness (if you haven't yet): # # Kernel feature support matrix of architecture 'powerpc': # arch-tick-broadcast: | ok | ARCH_HAS_TICK_BROADCAST # arch provides tick_broadcast() BPF-JIT: | ok | HAVE_BPF_JIT # arch supports BPF JIT optimizations clockevents: | ok | GENERIC_CLOCKEVENTS # arch support generic clock events cmpxchg-local: | TODO | HAVE_CMPXCHG_LOCAL # arch supports the this_cpu_cmpxchg() API context-tracking: | ok | HAVE_CONTEXT_TRACKING # arch supports context tracking for NO_HZ_FULL dma-api-debug: | ok | HAVE_DMA_API_DEBUG # arch supports DMA debug facilities dma-contiguous: | TODO | HAVE_DMA_CONTIGUOUS # arch supports the DMA CMA (continuous memory allocator) dma_map_attrs: | ok | HAVE_DMA_ATTRS # arch provides dma_*map*_attrs() APIs ELF-ASLR: | ok | ARCH_HAS_ELF_RANDOMIZE # arch randomizes the stack, heap and binary images of ELF binaries gcov-profile-all: | ok | ARCH_HAS_GCOV_PROFILE_ALL # arch supports whole-kernel GCOV code coverage profiling generic-idle-thread: | ok | GENERIC_SMP_IDLE_THREAD # arch makes use of the generic SMP idle thread facility huge-vmap: | TODO | HAVE_ARCH_HUGE_VMAP # arch supports the ioremap_pud_enabled() and ioremap_pmd_enabled() VM APIs ioremap_prot: | ok | HAVE_IOREMAP_PROT # arch has ioremap_prot() irq-time-acct: | ok | HAVE_IRQ_TIME_ACCOUNTING # arch supports precise IRQ time accounting jump-labels: | ok | HAVE_ARCH_JUMP_LABEL # arch supports live patched high efficiency branches KASAN: | TODO | HAVE_ARCH_KASAN # arch supports the KASAN runtime memory checker kgdb: | ok | HAVE_ARCH_KGDB # arch supports the kGDB kernel debugger kprobes: | ok | HAVE_KPROBES # arch supports live patched kernel probe kprobes-event: | ok | HAVE_REGS_AND_STACK_ACCESS_API # arch supports kprobes with perf events kprobes-on-ftrace: | TODO | HAVE_KPROBES_ON_FTRACE # arch supports combined kprobes and ftrace live patching kretprobes: | ok | HAVE_KRETPROBES # arch supports kernel function-return probes lockdep: | ok | LOCKDEP_SUPPORT # arch supports the runtime locking correctness debug facility modern-timekeeping: | ok | !ARCH_USES_GETTIMEOFFSET # arch does not use arch_gettimeoffset() anymore numa-balancing: | ok | ARCH_SUPPORTS_NUMA_BALANCING && 64BIT && NUMA # arch supports NUMA balancing numa-memblock: | ok | HAVE_MEMBLOCK_NODE_MAP # arch supports NUMA aware memblocks optprobes: | TODO | HAVE_OPTPROBES # arch supports live patched optprobes perf-regs: | TODO | HAVE_PERF_REGS # arch supports perf events register access perf-stackdump: | TODO | HAVE_PERF_USER_STACK_DUMP # arch supports perf events stack dumps PG_uncached: | TODO | ARCH_USES_PG_UNCACHED # arch supports the PG_uncached page flag pmdp_splitting_flush: | ok | #define __HAVE_ARCH_PMDP_SPLITTING_FLUSH # arch supports the pmdp_splitting_flush() VM API pte_special: | ok | #define __HAVE_ARCH_PTE_SPECIAL # arch supports the pte_special()/pte_mkspecial() VM APIs queued-rwlocks: | TODO | ARCH_USE_QUEUED_RWLOCKS # arch supports queued rwlocks queued-spinlocks: | TODO | ARCH_USE_QUEUED_SPINLOCKS # arch supports queued spinlocks rwsem-optimized: | ok | Optimized asm/rwsem.h # arch provides optimized rwsem APIs seccomp-filter: | TODO | HAVE_ARCH_SECCOMP_FILTER # arch supports seccomp filters sg-chain: | ok | ARCH_HAS_SG_CHAIN # arch supports chained scatter-gather lists stackprotector: | TODO | HAVE_CC_STACKPROTECTOR # arch supports compiler driven stack overflow protection strncasecmp: | TODO | __HAVE_ARCH_STRNCASECMP # arch provides an optimized strncasecmp() function THP: | ok | HAVE_ARCH_TRANSPARENT_HUGEPAGE && 64BIT # arch supports transparent hugepages tracehook: | ok | HAVE_ARCH_TRACEHOOK # arch supports tracehook (ptrace) register handling APIs uprobes: | ok | ARCH_SUPPORTS_UPROBES # arch supports live patched user probes user-ret-profiler: | TODO | HAVE_USER_RETURN_NOTIFIER # arch supports user-space return from system call profiler virt-cpuacct: | ok | HAVE_VIRT_CPU_ACCOUNTING || 64BIT # arch supports precise virtual CPU time accounting > I'd like to see more description in the individual files of what the > feature is, and preferably some pointers to what's needed to > implement it. Yeah, so I tried to add a short description to the feature file itself, and for many of these features that single sentence is the only documentation we have in the kernel source ... More comprehensive description can be added both to the Kconfig and to the feature description as well, by the maintainers of the individual features. > The kconfig for HAVE_ARCH_SECCOMP_FILTER is a good example of what I > mean. Yes, that's a positive example. It's the exception. > I realise retrofitting that for all these existing features is quite > time consuming, but for new features hopefully the bar can be raised > a little in terms of that description. Yeah. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/