Documentation/features: Explain kernel feature descriptions and add visualization script

2015-06-03T10:59:38Z

The previous patches added arch support matrices for more than 40 generic kernel features that need per architecture support. The structure of the feature descriptions is the following: Each feature has its own directory under Documentation/features/subsystem_name/feature_name/, and the arch-support.txt file shows its current arch porting status. For example, lockdep support is shown the following way: triton:~/tip> cat Documentation/features/locking/lockdep/arch-support.txt # # Feature name: lockdep # Kconfig: LOCKDEP_SUPPORT # description: arch supports the runtime locking correctness debug facility # ----------------------- | arch |status| ----------------------- | alpha: | TODO | | arc: | ok | | arm: | ok | | arm64: | ok | | avr32: | ok | | blackfin: | ok | | c6x: | TODO | | cris: | TODO | | frv: | TODO | | h8300: | TODO | | hexagon: | ok | | ia64: | TODO | | m32r: | TODO | | m68k: | TODO | | metag: | ok | | microblaze: | ok | | mips: | ok | | mn10300: | TODO | | nios2: | TODO | | openrisc: | TODO | | parisc: | TODO | | powerpc: | ok | | s390: | ok | | score: | ok | | sh: | ok | | sparc: | ok | | tile: | ok | | um: | ok | | unicore32: | ok | | x86: | ok | | xtensa: | ok | ----------------------- For generic kernel features that need architecture support, the arch-support.txt file in each feature directory shows the arch support matrix, for all upstream Linux architectures. The meaning of entries in the tables is: | ok | # feature supported by the architecture |TODO| # feature not yet supported by the architecture | .. | # feature cannot be supported by the hardware This directory structure can be used in the future to add other files - such as porting guides, testing description, etc. The Documentation/features/ hierarchy may also include generic kernel features that works on every architecture, in that case the arch-support.txt file will list every architecture as supported. To list an architecture's unsupported features, just do something like: triton:~/tip> git grep -lE 'x86.*TODO' Documentation/features/*/*/arch-support.txt Documentation/features/lib/strncasecmp/arch-support.txt Documentation/features/time/arch-tick-broadcast/arch-support.txt which will print the list of not yet supported features. The Documentation/features/list-arch.sh script will print the current support matrix of one architecture: triton:~/tip> Documentation/features/list-arch.sh # # Kernel feature support matrix of the 'x86' architecture: # core/ BPF-JIT : ok | HAVE_BPF_JIT # arch supports BPF JIT optimizations core/ generic-idle-thread : ok | GENERIC_SMP_IDLE_THREAD # arch makes use of the generic SMP idle thread facility core/ jump-labels : ok | HAVE_ARCH_JUMP_LABEL # arch supports live patched, high efficiency branches core/ tracehook : ok | HAVE_ARCH_TRACEHOOK # arch supports tracehook (ptrace) register handling APIs debug/ gcov-profile-all : ok | ARCH_HAS_GCOV_PROFILE_ALL # arch supports whole-kernel GCOV code coverage profiling debug/ KASAN : ok | HAVE_ARCH_KASAN # arch supports the KASAN runtime memory checker debug/ kgdb : ok | HAVE_ARCH_KGDB # arch supports the kGDB kernel debugger debug/ kprobes : ok | HAVE_KPROBES # arch supports live patched kernel probe debug/ kprobes-on-ftrace : ok | HAVE_KPROBES_ON_FTRACE # arch supports combined kprobes and ftrace live patching debug/ kretprobes : ok | HAVE_KRETPROBES # arch supports kernel function-return probes debug/ optprobes : ok | HAVE_OPTPROBES # arch supports live patched optprobes debug/ stackprotector : ok | HAVE_CC_STACKPROTECTOR # arch supports compiler driven stack overflow protection debug/ uprobes : ok | ARCH_SUPPORTS_UPROBES # arch supports live patched user probes debug/ user-ret-profiler : ok | HAVE_USER_RETURN_NOTIFIER # arch supports user-space return from system call profiler io/ dma-api-debug : ok | HAVE_DMA_API_DEBUG # arch supports DMA debug facilities io/ dma-contiguous : ok | HAVE_DMA_CONTIGUOUS # arch supports the DMA CMA (continuous memory allocator) io/ dma_map_attrs : ok | HAVE_DMA_ATTRS # arch provides dma_*map*_attrs() APIs io/ sg-chain : ok | ARCH_HAS_SG_CHAIN # arch supports chained scatter-gather lists lib/ strncasecmp : TODO | __HAVE_ARCH_STRNCASECMP # arch provides an optimized strncasecmp() function locking/ cmpxchg-local : ok | HAVE_CMPXCHG_LOCAL # arch supports the this_cpu_cmpxchg() API locking/ lockdep : ok | LOCKDEP_SUPPORT # arch supports the runtime locking correctness debug facility locking/ queued-rwlocks : ok | ARCH_USE_QUEUED_RWLOCKS # arch supports queued rwlocks locking/ queued-spinlocks : ok | ARCH_USE_QUEUED_SPINLOCKS # arch supports queued spinlocks locking/ rwsem-optimized : ok | Optimized asm/rwsem.h # arch provides optimized rwsem APIs perf/ kprobes-event : ok | HAVE_REGS_AND_STACK_ACCESS_API # arch supports kprobes with perf events perf/ perf-regs : ok | HAVE_PERF_REGS # arch supports perf events register access perf/ perf-stackdump : ok | HAVE_PERF_USER_STACK_DUMP # arch supports perf events stack dumps sched/ numa-balancing : ok | ARCH_SUPPORTS_NUMA_BALANCING # arch supports NUMA balancing seccomp/ seccomp-filter : ok | HAVE_ARCH_SECCOMP_FILTER # arch supports seccomp filters time/ arch-tick-broadcast : TODO | ARCH_HAS_TICK_BROADCAST # arch provides tick_broadcast() time/ clockevents : ok | GENERIC_CLOCKEVENTS # arch support generic clock events time/ context-tracking : ok | HAVE_CONTEXT_TRACKING # arch supports context tracking for NO_HZ_FULL time/ irq-time-acct : ok | HAVE_IRQ_TIME_ACCOUNTING # arch supports precise IRQ time accounting time/ modern-timekeeping : ok | !ARCH_USES_GETTIMEOFFSET # arch does not use arch_gettimeoffset() anymore time/ virt-cpuacct : ok | HAVE_VIRT_CPU_ACCOUNTING # arch supports precise virtual CPU time accounting vm/ ELF-ASLR : ok | ARCH_HAS_ELF_RANDOMIZE # arch randomizes the stack, heap and binary images of ELF binaries vm/ huge-vmap : ok | HAVE_ARCH_HUGE_VMAP # arch supports the ioremap_pud_enabled() and ioremap_pmd_enabled() VM APIs vm/ ioremap_prot : ok | HAVE_IOREMAP_PROT # arch has ioremap_prot() vm/ numa-memblock : ok | HAVE_MEMBLOCK_NODE_MAP # arch supports NUMA aware memblocks vm/ PG_uncached : ok | ARCH_USES_PG_UNCACHED # arch supports the PG_uncached page flag vm/ pmdp_splitting_flush : ok | __HAVE_ARCH_PMDP_SPLITTING_FLUSH # arch supports the pmdp_splitting_flush() VM API vm/ pte_special : ok | __HAVE_ARCH_PTE_SPECIAL # arch supports the pte_special()/pte_mkspecial() VM APIs vm/ THP : ok | HAVE_ARCH_TRANSPARENT_HUGEPAGE # arch supports transparent hugepages Cc: Cc: Cc: Cc: Andrew Morton Cc: H. Peter Anvin Cc: Jonathan Corbet Cc: Josh Triplett Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Ingo Molnar

Documentation/features/core: Add feature description and arch support status file for 'BPF-JIT'

2015-06-03T10:51:43Z