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* treewide: replace '---help---' in Kconfig files with 'help'Masahiro Yamada2020-06-13427-2448/+2448
| | | | | | | | | | | | | | | | | | | | | | | | | | Since commit 84af7a6194e4 ("checkpatch: kconfig: prefer 'help' over '---help---'"), the number of '---help---' has been gradually decreasing, but there are still more than 2400 instances. This commit finishes the conversion. While I touched the lines, I also fixed the indentation. There are a variety of indentation styles found. a) 4 spaces + '---help---' b) 7 spaces + '---help---' c) 8 spaces + '---help---' d) 1 space + 1 tab + '---help---' e) 1 tab + '---help---' (correct indentation) f) 1 tab + 1 space + '---help---' g) 1 tab + 2 spaces + '---help---' In order to convert all of them to 1 tab + 'help', I ran the following commend: $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/' Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* kbuild: fix broken builds because of GZIP,BZIP2,LZOP variablesDenis Efremov2020-06-118-34/+20
| | | | | | | | | | | | | | | Redefine GZIP, BZIP2, LZOP variables as KGZIP, KBZIP2, KLZOP resp. GZIP, BZIP2, LZOP env variables are reserved by the tools. The original attempt to redefine them internally doesn't work in makefiles/scripts intercall scenarios, e.g., "make GZIP=gzip bindeb-pkg" and results in broken builds. There can be other broken build commands because of this, so the universal solution is to use non-reserved env variables for the compression tools. Fixes: 8dfb61dcbace ("kbuild: add variables for compression tools") Signed-off-by: Denis Efremov <efremov@linux.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
* samples: binderfs: really compile this sample and fix build issuesMasahiro Yamada2020-06-114-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Even after commit c624adc9cb6e ("samples: fix binderfs sample"), this sample is never compiled. 'hostprogs' teaches Kbuild that this is a host program, but not enough to order to compile it. You must add it to 'always-y' to really compile it. Since this sample has never been compiled in upstream, various issues are left unnoticed. [1] compilers without <linux/android/binderfs.h> are still widely used <linux/android/binderfs.h> is only available since commit c13295ad219d ("binderfs: rename header to binderfs.h"), i.e., Linux 5.0 If your compiler is based on UAPI headers older than Linux 5.0, you will see the following error: samples/binderfs/binderfs_example.c:16:10: fatal error: linux/android/binderfs.h: No such file or directory #include <linux/android/binderfs.h> ^~~~~~~~~~~~~~~~~~~~~~~~~~ compilation terminated. You cannot rely on compilers having such a new header. The common approach is to install UAPI headers of this kernel into usr/include, and then add it to the header search path. I added 'depends on HEADERS_INSTALL' in Kconfig, and '-I usr/include' compiler flag in Makefile. [2] compile the sample for target architecture Because headers_install works for the target architecture, only the native compiler was able to build sample code that requires '-I usr/include'. Commit 7f3a59db274c ("kbuild: add infrastructure to build userspace programs") added the new syntax 'userprogs' to compile user-space programs for the target architecture. Use it, and then 'ifndef CROSS_COMPILE' will go away. I added 'depends on CC_CAN_LINK' because $(CC) is not necessarily capable of linking user-space programs. [3] use subdir-y to descend into samples/binderfs Since this directory does not contain any kernel-space code, it has no point in generating built-in.a or modules.order. Replace obj-$(CONFIG_...) with subdir-$(CONFIG_...). [4] -Wunused-variable warning If I compile this, I see the following warning. samples/binderfs/binderfs_example.c: In function 'main': samples/binderfs/binderfs_example.c:21:9: warning: unused variable 'len' [-Wunused-variable] 21 | size_t len; | ^~~ I removed the unused 'len'. [5] CONFIG_ANDROID_BINDERFS is not required Since this is a user-space standalone program, it is independent of the kernel configuration. Remove 'depends on ANDROID_BINDERFS'. Fixes: 9762dc1432e1 ("samples: add binderfs sample program") Fixes: c624adc9cb6e ("samples: fix binderfs sample") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
* Merge branch 'work.epoll' of ↵Linus Torvalds2020-06-111-26/+38
|\ | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull epoll update from Al Viro: "epoll conversion to read_iter from Jens; I thought there might be more epoll stuff this cycle, but uaccess took too much time" * 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: eventfd: convert to f_op->read_iter()
| * eventfd: convert to f_op->read_iter()Jens Axboe2020-05-071-26/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | eventfd is using ->read() as it's file_operations read handler, but this prevents passing in information about whether a given IO operation is blocking or not. We can only use the file flags for that. To support async (-EAGAIN/poll based) retries for io_uring, we need ->read_iter() support. Convert eventfd to using ->read_iter(). With ->read_iter(), we can support IOCB_NOWAIT. Ensure the fd setup is done such that we set file->f_mode with FMODE_NOWAIT. [missing include added] Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'work.misc' of ↵Linus Torvalds2020-06-112-5/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs fixes from Al Viro: "A couple of trivial patches that fell through the cracks last cycle" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: fix indentation in deactivate_super() vfs: Remove duplicated d_mountpoint check in __is_local_mountpoint
| * | fs: fix indentation in deactivate_super()Yufen Yu2020-05-291-1/+1
| | | | | | | | | | | | | | | | | | | | | Fix the breaked indent in deactive_super(). Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | vfs: Remove duplicated d_mountpoint check in __is_local_mountpointNikolay Borisov2020-05-291-4/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | This function acts as an out-of-line helper for is_local_mountpoint is only called after the latter verifies the dentry is not a mountpoint. There's no semantic changes and the resulting object code is smaller: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-26 (-26) Function old new delta __is_local_mountpoint 147 121 -26 Total: Before=34161, After=34135, chg -0.08% Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'work.sysctl' of ↵Linus Torvalds2020-06-117-13/+14
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull sysctl fixes from Al Viro: "Fixups to regressions in sysctl series" * 'work.sysctl' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: sysctl: reject gigantic reads/write to sysctl files cdrom: fix an incorrect __user annotation on cdrom_sysctl_info trace: fix an incorrect __user annotation on stack_trace_sysctl random: fix an incorrect __user annotation on proc_do_entropy net/sysctl: remove leftover __user annotations on neigh_proc_dointvec* net/sysctl: use cpumask_parse in flow_limit_cpu_sysctl
| * | sysctl: reject gigantic reads/write to sysctl filesChristoph Hellwig2020-06-101-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of triggering a WARN_ON deep down in the page allocator just give up early on allocations that are way larger than the usual sysctl values. Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | cdrom: fix an incorrect __user annotation on cdrom_sysctl_infoChristoph Hellwig2020-06-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | No user pointers for sysctls anymore. Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Reported-by: build test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | trace: fix an incorrect __user annotation on stack_trace_sysctlChristoph Hellwig2020-06-082-6/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | No user pointers for sysctls anymore. Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Reported-by: build test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | random: fix an incorrect __user annotation on proc_do_entropyChristoph Hellwig2020-06-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | No user pointers for sysctls anymore. Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Reported-by: build test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | net/sysctl: remove leftover __user annotations on neigh_proc_dointvec*Christoph Hellwig2020-06-081-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the leftover __user annotation on the prototypes for neigh_proc_dointvec*. The implementations already got this right, but the headers kept the __user tags around. Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Reported-by: build test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | net/sysctl: use cpumask_parse in flow_limit_cpu_sysctlChristoph Hellwig2020-06-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | cpumask_parse_user works on __user pointers, so this is wrong now. Fixes: 32927393dc1c ("sysctl: pass kernel pointers to ->proc_handler") Reported-by: build test robot <lkp@intel.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | Merge branch 'uaccess.i915' of ↵Linus Torvalds2020-06-115-58/+28
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull i915 uaccess updates from Al Viro: "Low-hanging fruit in i915; there are several trickier followups, but that'll wait for the next cycle" * 'uaccess.i915' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: i915:get_engines(): get rid of pointless access_ok() i915: alloc_oa_regs(): get rid of pointless access_ok() i915 compat ioctl(): just use drm_ioctl_kernel() i915: switch copy_perf_config_registers_or_number() to unsafe_put_user() i915: switch query_{topology,engine}_info() to copy_to_user()
| * | | i915:get_engines(): get rid of pointless access_ok()Al Viro2020-05-021-5/+0
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | i915: alloc_oa_regs(): get rid of pointless access_ok()Al Viro2020-05-021-3/+0
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | i915 compat ioctl(): just use drm_ioctl_kernel()Al Viro2020-05-021-9/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | compat_alloc_user_space() is a bad kludge; the sooner it goes, the better... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | i915: switch copy_perf_config_registers_or_number() to unsafe_put_user()Al Viro2020-05-022-31/+17
| | | | | | | | | | | | | | | | | | | | | | | | ... and the rest of query_perf_config_data() to normal uaccess primitives Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | i915: switch query_{topology,engine}_info() to copy_to_user()Al Viro2020-05-021-10/+6
| | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | | Merge branch 'uaccess.misc' of ↵Linus Torvalds2020-06-119-122/+135
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc uaccess updates from Al Viro: "Assorted uaccess patches for this cycle - the stuff that didn't fit into thematic series" * 'uaccess.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() x86: kvm_hv_set_msr(): use __put_user() instead of 32bit __clear_user() user_regset_copyout_zero(): use clear_user() TEST_ACCESS_OK _never_ had been checked anywhere x86: switch cp_stat64() to unsafe_put_user() binfmt_flat: don't use __put_user() binfmt_elf_fdpic: don't use __... uaccess primitives binfmt_elf: don't bother with __{put,copy_to}_user() pselect6() and friends: take handling the combined 6th/7th args into helper
| * | | | bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user()Al Viro2020-06-031-19/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... rather than open-coding it, and badly, at that. Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | x86: kvm_hv_set_msr(): use __put_user() instead of 32bit __clear_user()Al Viro2020-06-031-1/+1
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | user_regset_copyout_zero(): use clear_user()Al Viro2020-06-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | that's the only caller of __clear_user() in generic code, and it's not hot enough to bother with skipping access_ok(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | TEST_ACCESS_OK _never_ had been checked anywhereAl Viro2020-06-031-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Once upon a time the predecessor of that thing (TEST_VERIFY_AREA) used to be. However, that had been gone for years now (and the patch that introduced TEST_ACCESS_OK has not touched any ifdefs - they got gradually removed later). Just bury it... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | x86: switch cp_stat64() to unsafe_put_user()Al Viro2020-06-031-18/+22
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | binfmt_flat: don't use __put_user()Al Viro2020-06-031-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ... and check the return value Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | binfmt_elf_fdpic: don't use __... uaccess primitivesAl Viro2020-06-031-12/+19
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | binfmt_elf: don't bother with __{put,copy_to}_user()Al Viro2020-06-031-8/+8
| | | | | | | | | | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | | | pselect6() and friends: take handling the combined 6th/7th args into helperAl Viro2020-05-301-48/+64
| |/ / / | | | | | | | | | | | | | | | | | | | | ... and use unsafe_get_user(), while we are at it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | | Merge branch 'proc-linus' of ↵Linus Torvalds2020-06-111-4/+6
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace Pull proc fix from Eric Biederman: "Syzbot found a NULL pointer dereference if kzalloc of s_fs_info fails" * 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: proc: s_fs_info may be NULL when proc_kill_sb is called
| * | | | proc: s_fs_info may be NULL when proc_kill_sb is calledAlexey Gladkov2020-06-101-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | syzbot found that proc_fill_super() fails before filling up sb->s_fs_info, deactivate_locked_super() will be called and sb->s_fs_info will be NULL. The proc_kill_sb() does not expect fs_info to be NULL which is wrong. Link: https://lore.kernel.org/lkml/0000000000002d7ca605a7b8b1c5@google.com Reported-by: syzbot+4abac52934a48af5ff19@syzkaller.appspotmail.com Fixes: fa10fed30f25 ("proc: allow to mount many instances of proc in one pid namespace") Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
* | | | | Merge branch 'rwonce/rework' of ↵Linus Torvalds2020-06-1018-719/+161
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/will/linux Pull READ/WRITE_ONCE rework from Will Deacon: "This the READ_ONCE rework I've been working on for a while, which bumps the minimum GCC version and improves code-gen on arm64 when stack protector is enabled" [ Side note: I'm _really_ tempted to raise the minimum gcc version to 4.9, so that we can just say that we require _Generic() support. That would allow us to more cleanly handle a lot of the cases where we depend on very complex macros with 'sizeof' or __builtin_choose_expr() with __builtin_types_compatible_p() etc. This branch has a workaround for sparse not handling _Generic(), either, but that was already fixed in the sparse development branch, so it's really just gcc-4.9 that we'd require. - Linus ] * 'rwonce/rework' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux: compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparse compiler_types.h: Optimize __unqual_scalar_typeof compilation time compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long) compiler-types.h: Include naked type in __pick_integer_type() match READ_ONCE: Fix comment describing 2x32-bit atomicity gcov: Remove old GCC 3.4 support arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros READ_ONCE: Drop pointer qualifiers when reading from scalar types READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() arm64: csum: Disable KASAN for do_csum() fault_inject: Don't rely on "return value" from WRITE_ONCE() net: tls: Avoid assigning 'const' pointer to non-const pointer netfilter: Avoid assigning 'const' pointer to non-const pointer compiler/gcc: Raise minimum GCC version for kernel builds to 4.8
| * | | | | compiler_types.h: Use unoptimized __unqual_scalar_typeof for sparseMarco Elver2020-06-051-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the file is being checked with sparse, use the unoptimized version of __unqual_scalar_typeof(), since sparse does not support _Generic. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/202005280727.lXn1VnTw%lkp@intel.com Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | compiler_types.h: Optimize __unqual_scalar_typeof compilation timeMarco Elver2020-06-051-1/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the compiler supports C11's _Generic, use it to speed up compilation times of __unqual_scalar_typeof(). GCC version 4.9 or later and all supported versions of Clang support the feature (the oldest supported compiler that doesn't support _Generic is GCC 4.8, for which we use the slower alternative). The non-_Generic variant relies on multiple expansions of __pick_integer_type -> __pick_scalar_type -> __builtin_choose_expr, which increases pre-processed code size, and can cause compile times to increase in files with numerous expansions of READ_ONCE(), or other users of __unqual_scalar_typeof(). Summary of compile-time benchmarking done by Arnd Bergmann: <baseline normalized time> clang-11 gcc-9 this patch 0.78 0.91 ideal 0.76 0.86 See https://lkml.kernel.org/r/CAK8P3a3UYQeXhiufUevz=rwe09WM_vSTCd9W+KvJHJcOeQyWVA@mail.gmail.com Further compile-testing done with: gcc 4.8, 4.9, 5.5, 6.4, 7.5, 8.4; clang 9, 10. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Arnd Bergmann <arnd@arndb.de> Link: https://lkml.kernel.org/r/20200527103236.148700-1-elver@google.com Link: https://lkml.kernel.org/r/CAK8P3a0RJtbVi1JMsfik=jkHCNFv+DJn_FeDg-YLW+ueQW3tNg@mail.gmail.com [will: tweak new macros to make them a bit more readable] Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | compiler.h: Enforce that READ_ONCE_NOCHECK() access size is sizeof(long)Will Deacon2020-06-051-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE_NOCHECK() unconditionally performs a sizeof(long)-sized access, so enforce that the size of the pointed-to object that we are loading from is the same size as 'long'. Reported-by: Marco Elver <elver@google.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | compiler-types.h: Include naked type in __pick_integer_type() matchWill Deacon2020-06-051-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __pick_integer_type() checks whether the type of its first argument is compatible with an explicitly signed or unsigned integer type, returning the compatible type if it exists. Unfortunately, 'char' is neither compatible with 'signed char' nor 'unsigned char', so add a check against the naked type to allow the __unqual_scalar_typeof() macro to strip qualifiers from char types without an explicit signedness. Reported-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | READ_ONCE: Fix comment describing 2x32-bit atomicityWill Deacon2020-06-051-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | READ_ONCE() permits 64-bit accesses on 32-bit architectures, since this crops up in a few places and is generally harmless because either the upper bits are always zero (e.g. for a virtual address or 32-bit time_t) or the architecture provides 64-bit atomicity anyway. Update the corresponding comment above compiletime_assert_rwonce_type(), which incorrectly states that 32-bit x86 provides 64-bit atomicity, and instead reference 32-bit Armv7 with LPAE. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | gcov: Remove old GCC 3.4 supportWill Deacon2020-04-163-599/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel requires at least GCC 4.8 in order to build, and so there is no need to cater for the pre-4.7 gcov format. Remove the obsolete code. Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macrosWill Deacon2020-04-161-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Passing volatile-qualified pointers to the arm64 implementations of the load-acquire/store-release macros results in a re-load from the stack and a bunch of associated stack-protector churn due to the temporary result variable inheriting the volatile semantics thanks to the use of 'typeof()'. Define these temporary variables using 'unqual_scalar_typeof' to drop the volatile qualifier in the case that they are scalar types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Acked-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macrosWill Deacon2020-04-161-8/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Passing volatile-qualified pointers to the asm-generic implementations of the load-acquire macros results in a re-load from the stack due to the temporary result variable inheriting the volatile semantics thanks to the use of 'typeof()'. Define these temporary variables using 'unqual_scalar_typeof' to drop the volatile qualifier in the case that they are scalar types. Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | READ_ONCE: Drop pointer qualifiers when reading from scalar typesWill Deacon2020-04-162-3/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Passing a volatile-qualified pointer to READ_ONCE() is an absolute trainwreck for code generation: the use of 'typeof()' to define a temporary variable inside the macro means that the final evaluation in macro scope ends up forcing a read back from the stack. When stack protector is enabled (the default for arm64, at least), this causes the compiler to vomit up all sorts of junk. Unfortunately, dropping pointer qualifiers inside the macro poses quite a challenge, especially since the pointed-to type is permitted to be an aggregate, and this is relied upon by mm/ code accessing things like 'pmd_t'. Based on numerous hacks and discussions on the mailing list, this is the best I've managed to come up with. Introduce '__unqual_scalar_typeof()' which takes an expression and, if the expression is an optionally qualified 8, 16, 32 or 64-bit scalar type, evaluates to the unqualified type. Other input types, including aggregates, remain unchanged. Hopefully READ_ONCE() on volatile aggregate pointers isn't something we do on a fast-path. Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accessesWill Deacon2020-04-162-4/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | {READ,WRITE}_ONCE() cannot guarantee atomicity for arbitrary data sizes. This can be surprising to callers that might incorrectly be expecting atomicity for accesses to aggregate structures, although there are other callers where tearing is actually permissable (e.g. if they are using something akin to sequence locking to protect the access). Linus sayeth: | We could also look at being stricter for the normal READ/WRITE_ONCE(), | and require that they are | | (a) regular integer types | | (b) fit in an atomic word | | We actually did (b) for a while, until we noticed that we do it on | loff_t's etc and relaxed the rules. But maybe we could have a | "non-atomic" version of READ/WRITE_ONCE() that is used for the | questionable cases? The slight snag is that we also have to support 64-bit accesses on 32-bit architectures, as these appear to be widespread and tend to work out ok if either the architecture supports atomic 64-bit accesses (x86, armv7) or if the variable being accesses represents a virtual address and therefore only requires 32-bit atomicity in practice. Take a step in that direction by introducing a variant of 'compiletime_assert_atomic_type()' and use it to check the pointer argument to {READ,WRITE}_ONCE(). Expose __{READ,WRITE}_ONCE() variants which are allowed to tear and convert the one broken caller over to the new macros. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE()Will Deacon2020-04-161-79/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The implementations of {READ,WRITE}_ONCE() suffer from a significant amount of indirection and complexity due to a historic GCC bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 which was originally worked around by 230fa253df63 ("kernel: Provide READ_ONCE and ASSIGN_ONCE"). Since GCC 4.8 is fairly vintage at this point and we emit a warning if we detect it during the build, return {READ,WRITE}_ONCE() to their former glory with an implementation that is easier to understand and, crucially, more amenable to optimisation. A side effect of this simplification is that WRITE_ONCE() no longer returns a value, but nobody seems to be relying on that and the new behaviour is aligned with smp_store_release(). Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | arm64: csum: Disable KASAN for do_csum()Will Deacon2020-04-151-8/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | do_csum() over-reads the source buffer and therefore abuses READ_ONCE_NOCHECK() to avoid tripping up KASAN. In preparation for READ_ONCE_NOCHECK() becoming a macro, and therefore losing its '__no_sanitize_address' annotation, just annotate do_csum() explicitly and fall back to normal loads. Cc: Mark Rutland <mark.rutland@arm.com> Cc: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | fault_inject: Don't rely on "return value" from WRITE_ONCE()Will Deacon2020-04-151-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's a bit weird that WRITE_ONCE() evaluates to the value it stores and it's different to smp_store_release(), which can't be used this way. In preparation for preventing this in WRITE_ONCE(), change the fault injection code to use a local variable instead. Cc: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | net: tls: Avoid assigning 'const' pointer to non-const pointerWill Deacon2020-04-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tls_build_proto() uses WRITE_ONCE() to assign a 'const' pointer to a 'non-const' pointer. Cleanups to the implementation of WRITE_ONCE() mean that this will give rise to a compiler warning, just like a plain old assignment would do: | net/tls/tls_main.c: In function ‘tls_build_proto’: | ./include/linux/compiler.h:229:30: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers] | net/tls/tls_main.c:640:4: note: in expansion of macro ‘smp_store_release’ | 640 | smp_store_release(&saved_tcpv6_prot, prot); | | ^~~~~~~~~~~~~~~~~ Drop the const qualifier from the local 'prot' variable, as it isn't needed. Cc: Boris Pismenny <borisp@mellanox.com> Cc: Aviad Yehezkel <aviadye@mellanox.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | netfilter: Avoid assigning 'const' pointer to non-const pointerWill Deacon2020-04-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nf_remove_net_hook() uses WRITE_ONCE() to assign a 'const' pointer to a 'non-const' pointer. Cleanups to the implementation of WRITE_ONCE() mean that this will give rise to a compiler warning, just like a plain old assignment would do: | In file included from ./include/linux/export.h:43, | from ./include/linux/linkage.h:7, | from ./include/linux/kernel.h:8, | from net/netfilter/core.c:9: | net/netfilter/core.c: In function ‘nf_remove_net_hook’: | ./include/linux/compiler.h:216:30: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers] | *(volatile typeof(x) *)&(x) = (val); \ | ^ | net/netfilter/core.c:379:3: note: in expansion of macro ‘WRITE_ONCE’ | WRITE_ONCE(orig_ops[i], &dummy_ops); | ^~~~~~~~~~ Follow the pattern used elsewhere in this file and add a cast to 'void *' to squash the warning. Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: Jozsef Kadlecsik <kadlec@netfilter.org> Cc: Florian Westphal <fw@strlen.de> Cc: "David S. Miller" <davem@davemloft.net> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
| * | | | | compiler/gcc: Raise minimum GCC version for kernel builds to 4.8Will Deacon2020-04-156-13/+10
| | |_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is very rare to see versions of GCC prior to 4.8 being used to build the mainline kernel. These old compilers are also know to have codegen issues which can lead to silent miscompilation: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145 Raise the minimum GCC version for kernel build to 4.8 and remove some tautological Kconfig dependencies as a consequence. Cc: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Will Deacon <will@kernel.org>
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