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2020-12-22Merge tag 'kbuild-v5.11' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Use /usr/bin/env for shebang lines in scripts - Remove useless -Wnested-externs warning flag - Update documents - Refactor log handling in modpost - Stop building modules without MODULE_LICENSE() tag - Make the insane combination of 'static' and EXPORT_SYMBOL an error - Improve genksyms to handle _Static_assert() * tag 'kbuild-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: Documentation/kbuild: Document platform dependency practises Documentation/kbuild: Document COMPILE_TEST dependencies genksyms: Ignore module scoped _Static_assert() modpost: turn static exports into error modpost: turn section mismatches to error from fatal() modpost: change license incompatibility to error() from fatal() modpost: turn missing MODULE_LICENSE() into error modpost: refactor error handling and clarify error/fatal difference modpost: rename merror() to error() kbuild: don't hardcode depmod path kbuild: doc: document subdir-y syntax kbuild: doc: clarify the difference between extra-y and always-y kbuild: doc: split if_changed explanation to a separate section kbuild: doc: merge 'Special Rules' and 'Custom kbuild commands' sections kbuild: doc: fix 'List directories to visit when descending' section kbuild: doc: replace arch/$(ARCH)/ with arch/$(SRCARCH)/ kbuild: doc: update the description about kbuild Makefiles Makefile.extrawarn: remove -Wnested-externs warning tweewide: Fix most Shebang lines
2020-12-21kbuild: don't hardcode depmod pathDominique Martinet1-1/+1
depmod is not guaranteed to be in /sbin, just let make look for it in the path like all the other invoked programs Signed-off-by: Dominique Martinet <asmadeus@codewreck.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-13Linux 5.10Linus Torvalds1-1/+1
2020-12-06Linux 5.10-rc7Linus Torvalds1-1/+1
2020-12-06Merge tag 'kbuild-fixes-v5.10-2' of ↵Linus Torvalds1-1/+9
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Move -Wcast-align to W=3, which tends to be false-positive and there is no tree-wide solution. - Pass -fmacro-prefix-map to KBUILD_CPPFLAGS because it is a preprocessor option and makes sense for .S files as well. - Disable -gdwarf-2 for Clang's integrated assembler to avoid warnings. - Disable --orphan-handling=warn for LLD 10.0.1 to avoid warnings. - Fix undesirable line breaks in *.mod files. * tag 'kbuild-fixes-v5.10-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: avoid split lines in .mod files kbuild: Disable CONFIG_LD_ORPHAN_WARN for ld.lld 10.0.1 kbuild: Hoist '--orphan-handling' into Kconfig Kbuild: do not emit debug info for assembly with LLVM_IAS=1 kbuild: use -fmacro-prefix-map for .S sources Makefile.extrawarn: move -Wcast-align to W=3
2020-12-01kbuild: Hoist '--orphan-handling' into KconfigNathan Chancellor1-0/+6
Currently, '--orphan-handling=warn' is spread out across four different architectures in their respective Makefiles, which makes it a little unruly to deal with in case it needs to be disabled for a specific linker version (in this case, ld.lld 10.0.1). To make it easier to control this, hoist this warning into Kconfig and the main Makefile so that disabling it is simpler, as the warning will only be enabled in a couple places (main Makefile and a couple of compressed boot folders that blow away LDFLAGS_vmlinx) and making it conditional is easier due to Kconfig syntax. One small additional benefit of this is saving a call to ld-option on incremental builds because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN. To keep the list of supported architectures the same, introduce CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to gain this automatically after all of the sections are specified and size asserted. A special thanks to Kees Cook for the help text on this config. Link: https://github.com/ClangBuiltLinux/linux/issues/1187 Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-29Linux 5.10-rc6Linus Torvalds1-1/+1
2020-11-28Merge tag 'kbuild-fixes-v5.10' of ↵Linus Torvalds1-3/+1
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild fixes from Masahiro Yamada: - Remove unused OBJSIZE variable. - Fix rootless deb-pkg build in a setgid directory. * tag 'kbuild-fixes-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: builddeb: Fix rootless build in setuid/setgid directory kbuild: remove unused OBJSIZE
2020-11-25Kbuild: do not emit debug info for assembly with LLVM_IAS=1Nick Desaulniers1-0/+2
Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: https://github.com/ClangBuiltLinux/linux/issues/716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-25kbuild: use -fmacro-prefix-map for .S sourcesDenys Zagorui1-1/+1
Follow-up to commit a73619a845d5 ("kbuild: use -fmacro-prefix-map to make __FILE__ a relative path"). Assembler sources also use __FILE__ macro so this flag should be also applied to those sources. Signed-off-by: Denys Zagorui <dzagorui@cisco.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-22Linux 5.10-rc5Linus Torvalds1-1/+1
2020-11-15Linux 5.10-rc4Linus Torvalds1-1/+1
2020-11-08Linux 5.10-rc3Linus Torvalds1-1/+1
2020-11-02kbuild: remove unused OBJSIZEVasily Gorbik1-3/+1
The "size" tool has been solely used by s390 to enforce .bss section usage restrictions in early startup code. Since commit 980d5f9ab36b ("s390/boot: enable .bss section for compressed kernel") and commit 2e83e0eb85ca ("s390: clean .bss before running uncompressed kernel") these restrictions have been lifted for the decompressor and uncompressed kernel and the size tool is now unused. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-11-01Linux 5.10-rc2Linus Torvalds1-1/+1
2020-10-25Linux 5.10-rc1Linus Torvalds1-2/+2
2020-10-22Merge tag 'kbuild-v5.10' of ↵Linus Torvalds1-24/+70
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Support 'make compile_commands.json' to generate the compilation database more easily, avoiding stale entries - Support 'make clang-analyzer' and 'make clang-tidy' for static checks using clang-tidy - Preprocess scripts/modules.lds.S to allow CONFIG options in the module linker script - Drop cc-option tests from compiler flags supported by our minimal GCC/Clang versions - Use always 12-digits commit hash for CONFIG_LOCALVERSION_AUTO=y - Use sha1 build id for both BFD linker and LLD - Improve deb-pkg for reproducible builds and rootless builds - Remove stale, useless scripts/namespace.pl - Turn -Wreturn-type warning into error - Fix build error of deb-pkg when CONFIG_MODULES=n - Replace 'hostname' command with more portable 'uname -n' - Various Makefile cleanups * tag 'kbuild-v5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (34 commits) kbuild: Use uname for LINUX_COMPILE_HOST detection kbuild: Only add -fno-var-tracking-assignments for old GCC versions kbuild: remove leftover comment for filechk utility treewide: remove DISABLE_LTO kbuild: deb-pkg: clean up package name variables kbuild: deb-pkg: do not build linux-headers package if CONFIG_MODULES=n kbuild: enforce -Werror=return-type scripts: remove namespace.pl builddeb: Add support for all required debian/rules targets builddeb: Enable rootless builds builddeb: Pass -n to gzip for reproducible packages kbuild: split the build log of kallsyms kbuild: explicitly specify the build id style scripts/setlocalversion: make git describe output more reliable kbuild: remove cc-option test of -Werror=date-time kbuild: remove cc-option test of -fno-stack-check kbuild: remove cc-option test of -fno-strict-overflow kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant Makefiles kbuild: remove redundant CONFIG_KASAN check from scripts/Makefile.kasan kbuild: do not create built-in objects for external module builds ...
2020-10-21kbuild: Only add -fno-var-tracking-assignments for old GCC versionsMark Wielaard1-1/+5
Some old GCC versions between 4.5.0 and 4.9.1 might miscompile code with -fvar-tracking-assingments (which is enabled by default with -g -O2). Commit 2062afb4f804 ("Fix gcc-4.9.0 miscompilation of load_balance() in scheduler") added -fno-var-tracking-assignments unconditionally to work around this. But newer versions of GCC no longer have this bug, so only add it for versions of GCC before 5.0. This allows various tools such as a perf probe or gdb debuggers or systemtap to resolve variable locations using dwarf locations in more code. Signed-off-by: Mark Wielaard <mark@klomp.org> Acked-by: Ian Rogers <irogers@google.com> Reviewed-by: Andi Kleen <andi@firstfloor.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-15Merge tag 'net-next-5.10' of ↵Linus Torvalds1-1/+3
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: - Add redirect_neigh() BPF packet redirect helper, allowing to limit stack traversal in common container configs and improving TCP back-pressure. Daniel reports ~10Gbps => ~15Gbps single stream TCP performance gain. - Expand netlink policy support and improve policy export to user space. (Ge)netlink core performs request validation according to declared policies. Expand the expressiveness of those policies (min/max length and bitmasks). Allow dumping policies for particular commands. This is used for feature discovery by user space (instead of kernel version parsing or trial and error). - Support IGMPv3/MLDv2 multicast listener discovery protocols in bridge. - Allow more than 255 IPv4 multicast interfaces. - Add support for Type of Service (ToS) reflection in SYN/SYN-ACK packets of TCPv6. - In Multi-patch TCP (MPTCP) support concurrent transmission of data on multiple subflows in a load balancing scenario. Enhance advertising addresses via the RM_ADDR/ADD_ADDR options. - Support SMC-Dv2 version of SMC, which enables multi-subnet deployments. - Allow more calls to same peer in RxRPC. - Support two new Controller Area Network (CAN) protocols - CAN-FD and ISO 15765-2:2016. - Add xfrm/IPsec compat layer, solving the 32bit user space on 64bit kernel problem. - Add TC actions for implementing MPLS L2 VPNs. - Improve nexthop code - e.g. handle various corner cases when nexthop objects are removed from groups better, skip unnecessary notifications and make it easier to offload nexthops into HW by converting to a blocking notifier. - Support adding and consuming TCP header options by BPF programs, opening the doors for easy experimental and deployment-specific TCP option use. - Reorganize TCP congestion control (CC) initialization to simplify life of TCP CC implemented in BPF. - Add support for shipping BPF programs with the kernel and loading them early on boot via the User Mode Driver mechanism, hence reusing all the user space infra we have. - Support sleepable BPF programs, initially targeting LSM and tracing. - Add bpf_d_path() helper for returning full path for given 'struct path'. - Make bpf_tail_call compatible with bpf-to-bpf calls. - Allow BPF programs to call map_update_elem on sockmaps. - Add BPF Type Format (BTF) support for type and enum discovery, as well as support for using BTF within the kernel itself (current use is for pretty printing structures). - Support listing and getting information about bpf_links via the bpf syscall. - Enhance kernel interfaces around NIC firmware update. Allow specifying overwrite mask to control if settings etc. are reset during update; report expected max time operation may take to users; support firmware activation without machine reboot incl. limits of how much impact reset may have (e.g. dropping link or not). - Extend ethtool configuration interface to report IEEE-standard counters, to limit the need for per-vendor logic in user space. - Adopt or extend devlink use for debug, monitoring, fw update in many drivers (dsa loop, ice, ionic, sja1105, qed, mlxsw, mv88e6xxx, dpaa2-eth). - In mlxsw expose critical and emergency SFP module temperature alarms. Refactor port buffer handling to make the defaults more suitable and support setting these values explicitly via the DCBNL interface. - Add XDP support for Intel's igb driver. - Support offloading TC flower classification and filtering rules to mscc_ocelot switches. - Add PTP support for Marvell Octeontx2 and PP2.2 hardware, as well as fixed interval period pulse generator and one-step timestamping in dpaa-eth. - Add support for various auth offloads in WiFi APs, e.g. SAE (WPA3) offload. - Add Lynx PHY/PCS MDIO module, and convert various drivers which have this HW to use it. Convert mvpp2 to split PCS. - Support Marvell Prestera 98DX3255 24-port switch ASICs, as well as 7-port Mediatek MT7531 IP. - Add initial support for QCA6390 and IPQ6018 in ath11k WiFi driver, and wcn3680 support in wcn36xx. - Improve performance for packets which don't require much offloads on recent Mellanox NICs by 20% by making multiple packets share a descriptor entry. - Move chelsio inline crypto drivers (for TLS and IPsec) from the crypto subtree to drivers/net. Move MDIO drivers out of the phy directory. - Clean up a lot of W=1 warnings, reportedly the actively developed subsections of networking drivers should now build W=1 warning free. - Make sure drivers don't use in_interrupt() to dynamically adapt their code. Convert tasklets to use new tasklet_setup API (sadly this conversion is not yet complete). * tag 'net-next-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2583 commits) Revert "bpfilter: Fix build error with CONFIG_BPFILTER_UMH" net, sockmap: Don't call bpf_prog_put() on NULL pointer bpf, selftest: Fix flaky tcp_hdr_options test when adding addr to lo bpf, sockmap: Add locking annotations to iterator netfilter: nftables: allow re-computing sctp CRC-32C in 'payload' statements net: fix pos incrementment in ipv6_route_seq_next net/smc: fix invalid return code in smcd_new_buf_create() net/smc: fix valid DMBE buffer sizes net/smc: fix use-after-free of delayed events bpfilter: Fix build error with CONFIG_BPFILTER_UMH cxgb4/ch_ipsec: Replace the module name to ch_ipsec from chcr net: sched: Fix suspicious RCU usage while accessing tcf_tunnel_info bpf: Fix register equivalence tracking. rxrpc: Fix loss of final ack on shutdown rxrpc: Fix bundle counting for exclusive connections netfilter: restore NF_INET_NUMHOOKS ibmveth: Identify ingress large send packets. ibmveth: Switch order of ibmveth_helper calls. cxgb4: handle 4-tuple PEDIT to NAT mode translation selftests: Add VRF route leaking tests ...
2020-10-13Revert "kbuild: disable clang's default use of -fmerge-all-constants"Nick Desaulniers1-9/+0
This reverts commit 87e0d4f0f37fb0c8c4aeeac46fff5e957738df79. -fno-merge-all-constants has been the default since clang-6; the minimum supported version of clang in the kernel is clang-10 (10.0.1). Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Marco Elver <elver@google.com> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200902225911.209899-3-ndesaulniers@google.com Link: https://reviews.llvm.org/rL329300. Link: https://github.com/ClangBuiltLinux/linux/issues/9 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-10-12kbuild: enforce -Werror=return-typeOlaf Hering1-1/+1
Catch errors which at least gcc tolerates by default: warning: 'return' with no value, in function returning non-void [-Wreturn-type] Signed-off-by: Olaf Hering <olaf@aepfle.de> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-11Linux 5.9Linus Torvalds1-1/+1
2020-10-12scripts: remove namespace.plJacob Keller1-5/+1
namespace.pl is intended to help locate symbols which are defined but are not used externally. The goal is to avoid bloat of the namespace in the resulting kernel image. The script relies on object data, and only finds unused symbols for the configuration used to generate that object data. This results in a lot of false positive warnings such as symbols only used by a single architecture, or symbols which are used externally only under certain configurations. Running namespace.pl using allyesconfig, allmodconfig, and x86_64_defconfig yields the following results: * allmodconfig * 11122 unique symbol names with no external reference * 1194 symbols listed as multiply defined * 214 symbols it can't resolve * allyesconfig * 10997 unique symbol names with no external reference * 1194 symbols listed as multiply defined * 214 symbols it can't resolve * x86_64_defconfig * 5757 unique symbol names with no external reference * 528 symbols listed as multiply defined * 154 symbols it can't resolve The script also has no way to easily limit the scope of the checks to a given subset of the kernel, such as only checking for symbols defined within a module or subsystem. Discussion on public mailing lists seems to indicate that many view the tool output as suspect or not very useful (see discussions at [1] and [2] for further context). As described by Masahiro Yamada at [2], namespace.pl provides 3 types of checks: listing multiply defined symbols, resolving external symbols, and warnings about symbols with no reference. The first category of issues is easily caught by the linker as any set of multiply defined symbols should fail to link. The second category of issues is also caught by linking, as undefined symbols would cause issues. Even with modules, these types of issues where a module relies on an external symbol are caught by modpost. The remaining category of issues reported is the list of symbols with no external reference, and is the primary motivation of this script. However, it ought to be clear from the above examples that the output is difficult to sort through. Even allyesconfig has ~10000 entries. The current submit-checklist indicates that patches ought to go through namespacecheck and fix any new issues arising. But that itself presents problems. As described at [1], many cases of reports are due to configuration where a function is used externally by some configuration settings. Prominent maintainers appear to dislike changes modify code such that symbols become static based on CONFIG_* flags ([3], and [4]) One possible solution is to adjust the advice and indicate that we only care about the output of namespacecheck on allyesconfig or allmodconfig builds... However, given the discussion at [2], I suspect that few people are actively using this tool. It doesn't have a maintainer in the MAINTAINERS flie, and it produces so many warnings for unused symbols that it is difficult to use effectively. Thus, I propose we simply remove it. [1] https://lore.kernel.org/netdev/20200708164812.384ae8ea@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/ [2] https://lore.kernel.org/lkml/20190129204319.15238-1-jacob.e.keller@intel.com/ [3] https://lore.kernel.org/netdev/20190828.154744.2058157956381129672.davem@davemloft.net/ [4] https://lore.kernel.org/netdev/20190827210928.576c5fef@cakuba.netronome.com/ Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-09kbuild: explicitly specify the build id styleBill Wendling1-2/+2
ld's --build-id defaults to "sha1" style, while lld defaults to "fast". The build IDs are very different between the two, which may confuse programs that reference them. Signed-off-by: Bill Wendling <morbo@google.com> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller1-1/+1
Rejecting non-native endian BTF overlapped with the addition of support for it. The rest were more simple overlapping changes, except the renesas ravb binding update, which had to follow a file move as well as a YAML conversion. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-10-04Linux 5.9-rc8Linus Torvalds1-1/+1
2020-09-27Linux 5.9-rc7Linus Torvalds1-1/+1
2020-09-25kbuild: remove cc-option test of -Werror=date-timeMasahiro Yamada1-1/+1
The minimal compiler versions, GCC 4.9 and Clang 10 support this flag. Here is the godbolt: https://godbolt.org/z/xvjcMa Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Will Deacon <will@kernel.org>
2020-09-25kbuild: remove cc-option test of -fno-stack-checkMasahiro Yamada1-1/+1
The minimal compiler version, GCC 4.9 supports this flag. Nathan Chancellor pointed out: "This flag is technically ignored by clang (see commit 05b0798916f01690b5903302e51f3136274e291f) but that obviously does not matter for the sake of this." Here is the godbolt: https://godbolt.org/z/59cK6o Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
2020-09-25kbuild: remove cc-option test of -fno-strict-overflowMasahiro Yamada1-1/+1
The minimal compiler versions, GCC 4.9 and Clang 10 support this flag. Here is the godbolt: https://godbolt.org/z/odq8h9 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Acked-by: Will Deacon <will@kernel.org>
2020-09-25kbuild: move CFLAGS_{KASAN,UBSAN,KCSAN} exports to relevant MakefilesMasahiro Yamada1-1/+0
Move CFLAGS_KASAN*, CFLAGS_UBSAN, CFLAGS_KCSAN to Makefile.kasan, Makefile.ubsan, Makefile.kcsan, respectively. This commit also avoids the same -fsanitize=* flags being added to CFLAGS_UBSAN multiple times. Prior to this commit, the ubsan flags were appended by the '+=' operator, without any initialization. Some build targets such as 'make bindeb-pkg' recurses to the top Makefile, and ended up with adding the same flags to CFLAGS_UBSAN twice. Clear CFLAGS_UBSAN with ':=' to make it a simply expanded variable. This is better than a recursively expanded variable, which evaluates $(call cc-option, ...) multiple times before Kbuild starts descending to subdirectories. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Marco Elver <elver@google.com>
2020-09-25kbuild: do not create built-in objects for external module buildsMasahiro Yamada1-1/+2
'make M=/path/to/your/external/module' creates a pointless built-in.a in the top of the external module directory because KBUILD_BUILTIN is set to 1. Clear KBUILD_BUILTIN when we are building external modules so that 'make M=...' and 'make M=... modules' work equivalently. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-09-25kbuild: preprocess module linker scriptMasahiro Yamada1-4/+6
There was a request to preprocess the module linker script like we do for the vmlinux one. (https://lkml.org/lkml/2020/8/21/512) The difference between vmlinux.lds and module.lds is that the latter is needed for external module builds, thus must be cleaned up by 'make mrproper' instead of 'make clean'. Also, it must be created by 'make modules_prepare'. You cannot put it in arch/$(SRCARCH)/kernel/, which is cleaned up by 'make clean'. I moved arch/$(SRCARCH)/kernel/module.lds to arch/$(SRCARCH)/include/asm/module.lds.h, which is included from scripts/module.lds.S. scripts/module.lds is fine because 'make clean' keeps all the build artifacts under scripts/. You can add arch-specific sections in <asm/module.lds.h>. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Jessica Yu <jeyu@kernel.org> Acked-by: Will Deacon <will@kernel.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Jessica Yu <jeyu@kernel.org>
2020-09-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller1-1/+3
Alexei Starovoitov says: ==================== pull-request: bpf-next 2020-09-23 The following pull-request contains BPF updates for your *net-next* tree. We've added 95 non-merge commits during the last 22 day(s) which contain a total of 124 files changed, 4211 insertions(+), 2040 deletions(-). The main changes are: 1) Full multi function support in libbpf, from Andrii. 2) Refactoring of function argument checks, from Lorenz. 3) Make bpf_tail_call compatible with functions (subprograms), from Maciej. 4) Program metadata support, from YiFei. 5) bpf iterator optimizations, from Yonghong. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-09-23bpf: Check CONFIG_BPF option for resolve_btfidsJiri Olsa1-1/+3
Currently all the resolve_btfids 'users' are under CONFIG_BPF code, so if we have CONFIG_BPF disabled, resolve_btfids will fail, because there's no data to resolve. Disabling resolve_btfids if there's CONFIG_BPF disabled, so we won't fail such builds. Suggested-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200923185735.3048198-1-jolsa@kernel.org
2020-09-20Linux 5.9-rc6Linus Torvalds1-1/+1
2020-09-13Linux 5.9-rc5Linus Torvalds1-1/+1
2020-09-08Merge tag 'livepatching-for-5.9-rc5' of ↵Linus Torvalds1-4/+0
git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching Pull livepatching fix from Petr Mladek: "Workaround for 'unreachable instruction' objtool warnings that happen with some compiler versions" * tag 'livepatching-for-5.9-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching: Revert "kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled"
2020-09-06Linux 5.9-rc4Linus Torvalds1-1/+1
2020-09-03Revert "kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled"Josh Poimboeuf1-4/+0
Use of the new -flive-patching flag was introduced with the following commit: 43bd3a95c98e ("kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled") This flag has several drawbacks: - It disables some optimizations, so it can have a negative effect on performance. - According to the GCC documentation it's not compatible with LTO, which will become a compatibility issue as LTO support gets upstreamed in the kernel. - It was intended to be used for source-based patch generation tooling, as opposed to binary-based patch generation tooling (e.g., kpatch-build). It probably should have at least been behind a separate config option so as not to negatively affect other livepatch users. - Clang doesn't have the flag, so as far as I can tell, this method of generating patches is incompatible with Clang, which like LTO is becoming more mainstream. - It breaks GCC's implicit noreturn detection for local functions. This is the cause of several "unreachable instruction" objtool warnings. - The broken noreturn detection is an obvious GCC regression, but we haven't yet gotten GCC developers to acknowledge that, which doesn't inspire confidence in their willingness to keep the feature working as optimizations are added or changed going forward. - While there *is* a distro which relies on this flag for their distro livepatch module builds, there's not a publicly documented way to create safe livepatch modules with it. Its use seems to be based on tribal knowledge. It serves no benefit to those who don't know how to use it. (In fact, I believe the current livepatch documentation and samples are misleading and dangerous, and should be corrected. Or at least amended with a disclaimer. But I don't feel qualified to make such changes.) Also, we have an idea for using objtool to detect function changes, which could potentially obsolete the need for this flag anyway. At this point the flag has no benefits for upstream which would counteract the above drawbacks. Revert it until it becomes more ready. This reverts commit 43bd3a95c98e1a86b8b55d97f745c224ecff02b9. Fixes: 43bd3a95c98e ("kbuild: use -flive-patching when CONFIG_LIVEPATCH is enabled") Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/696262e997359666afa053fe7d1a9fb2bb373964.1595010490.git.jpoimboe@redhat.com
2020-08-30Linux 5.9-rc3Linus Torvalds1-1/+1
2020-08-27Makefile: Add clang-tidy and static analyzer support to makefileNathan Huckleberry1-2/+18
This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-27kbuild: wire up the build rule of compile_commands.json to MakefileMasahiro Yamada1-4/+25
Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-27kbuild: hide commands to run Kconfig, and show short log for syncconfigMasahiro Yamada1-1/+4
Some targets (localyesconfig, localmodconfig, defconfig) hide the command running, but the others do not. Users know which Kconfig flavor they are running, so it is OK to hide the command. Add $(Q) to all commands consistently. If you want to see the full command running, pass V=1 from the command line. syncconfig is the exceptional case, which occurs without explicit command invocation by the user. Display the Kbuild-style log for it. The ugly bare log will go away. [Before] scripts/kconfig/conf --syncconfig Kconfig [After] SYNC include/config/auto.conf Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-27kbuild: Simplify DEBUG_INFO Kconfig handlingSedat Dilek1-1/+5
While playing with [1] I saw that the handling of CONFIG_DEBUG_INFO can be simplified. [1] https://patchwork.kernel.org/patch/11716107/ Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-23Linux 5.9-rc2Linus Torvalds1-1/+1
2020-08-18kbuild: remove redundant patterns in filter/filter-outMasahiro Yamada1-3/+2
The '%' in filter/filter-out matches to any number of any characters, including empty string. So, '%config' matches to 'config', and '%install' to 'install'. Drop the redundant patterns. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-16Linux 5.9-rc1Linus Torvalds1-2/+2
2020-08-12./Makefile: add debug option to enable function aligned on 32 bytesFeng Tang1-0/+4
Recently 0day reported many strange performance changes (regression or improvement), in which there was no obvious relation between the culprit commit and the benchmark at the first look, and it causes people to doubt the test itself is wrong. Upon further check, many of these cases are caused by the change to the alignment of kernel text or data, as whole text/data of kernel are linked together, change in one domain may affect alignments of other domains. gcc has an option '-falign-functions=n' to force text aligned, and with that option enabled, some of those performance changes will be gone, like [1][2][3]. Add this option so that developers and 0day can easily find performance bump caused by text alignment change, as tracking these strange bump is quite time consuming. Though it can't help in other cases like data alignment changes like [4]. Following is some size data for v5.7 kernel built with a RHEL config used in 0day: text data bss dec filename 19738771 13292906 5554236 38585913 vmlinux.noalign 19758591 13297002 5529660 38585253 vmlinux.align32 Raw vmlinux size in bytes: v5.7 v5.7+align32 253950832 254018000 +0.02% Some benchmark data, most of them have no big change: * hackbench: [ -1.8%, +0.5%] * fsmark: [ -3.2%, +3.4%] # ext4/xfs/btrfs * kbuild: [ -2.0%, +0.9%] * will-it-scale: [ -0.5%, +1.8%] # mmap1/pagefault3 * netperf: - TCP_CRR [+16.6%, +97.4%] - TCP_RR [-18.5%, -1.8%] - TCP_STREAM [ -1.1%, +1.9%] [1] https://lore.kernel.org/lkml/20200114085637.GA29297@shao2-debian/ [2] https://lore.kernel.org/lkml/20200330011254.GA14393@feng-iot/ [3] https://lore.kernel.org/lkml/1d98d1f0-fe84-6df7-f5bd-f4cb2cdb7f45@intel.com/ [4] https://lore.kernel.org/lkml/20200205123216.GO12867@shao2-debian/ Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Andy Shevchenko <andriy.shevchenko@intel.com> Link: http://lkml.kernel.org/r/1595475001-90945-1-git-send-email-feng.tang@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-09Merge tag 'kbuild-v5.9' of ↵Linus Torvalds1-11/+15
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - run the checker (e.g. sparse) after the compiler - remove unneeded cc-option tests for old compiler flags - fix tar-pkg to install dtbs - introduce ccflags-remove-y and asflags-remove-y syntax - allow to trace functions in sub-directories of lib/ - introduce hostprogs-always-y and userprogs-always-y syntax - various Makefile cleanups * tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled kbuild: introduce hostprogs-always-y and userprogs-always-y kbuild: sort hostprogs before passing it to ifneq kbuild: move host .so build rules to scripts/gcc-plugins/Makefile kbuild: Replace HTTP links with HTTPS ones kbuild: trace functions in subdirectories of lib/ kbuild: introduce ccflags-remove-y and asflags-remove-y kbuild: do not export LDFLAGS_vmlinux kbuild: always create directories of targets powerpc/boot: add DTB to 'targets' kbuild: buildtar: add dtbs support kbuild: remove cc-option test of -ffreestanding kbuild: remove cc-option test of -fno-stack-protector Revert "kbuild: Create directory for target DTB" kbuild: run the checker after the compiler
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