linux/scripts/Makefile.build, branch v4.20

x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support

2018-11-28T10:57:03Z

Since retpoline capable compilers are widely available, make CONFIG_RETPOLINE hard depend on the compiler capability. Break the build when CONFIG_RETPOLINE is enabled and the compiler does not support it. Emit an error message in that case: "arch/x86/Makefile:226: *** You are building kernel with non-retpoline compiler, please update your compiler.. Stop." [dwmw: Fail the build with non-retpoline compiler] Suggested-by: Peter Zijlstra Signed-off-by: Zhenzhong Duan Signed-off-by: Thomas Gleixner Cc: David Woodhouse Cc: Borislav Petkov Cc: Daniel Borkmann Cc: H. Peter Anvin Cc: Konrad Rzeszutek Wilk Cc: Andy Lutomirski Cc: Masahiro Yamada Cc: Michal Marek Cc: Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/cca0cb20-f9e2-4094-840b-fb0f8810cd34@default

Merge tag 'kbuild-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2018-10-28T20:22:35Z

Pull Kbuild updates from Masahiro Yamada: - optimize kallsyms slightly - remove check for old CFLAGS usage - add some compiler flags unconditionally instead of evaluating $(call cc-option,...) - fix variable shadowing in host tools - refactor scripts/mkmakefile - refactor various makefiles * tag 'kbuild-v4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: modpost: Create macro to avoid variable shadowing ASN.1: Remove unnecessary shadowed local variable kbuild: use 'else ifeq' for checksrc to improve readability kbuild: remove unneeded link_multi_deps kbuild: add -Wno-unused-but-set-variable flag unconditionally kbuild: add -Wdeclaration-after-statement flag unconditionally kbuild: add -Wno-pointer-sign flag unconditionally modpost: remove leftover symbol prefix handling for module device table kbuild: simplify command line creation in scripts/mkmakefile kbuild: do not pass $(objtree) to scripts/mkmakefile kbuild: remove user ID check in scripts/mkmakefile kbuild: remove VERSION and PATCHLEVEL from $(objtree)/Makefile kbuild: add --include-dir flag only for out-of-tree build kbuild: remove dead code in cmd_files calculation in top Makefile kbuild: hide most of targets when running config or mixed targets kbuild: remove old check for CFLAGS use kbuild: prefix Makefile.dtbinst path with $(srctree) unconditionally kallsyms: remove left-over Blackfin code kallsyms: reduce size a little on 64-bit

kbuild: use 'else ifeq' for checksrc to improve readability

2018-10-19T00:48:47Z

'ifeq ... else ifeq ... endif' notation is supported by GNU Make 3.81 or later, which is the requirement for building the kernel since commit 37d69ee30808 ("docs: bump minimal GNU Make version to 3.81"). Use it to improve the readability. Signed-off-by: Masahiro Yamada

kbuild: remove unneeded link_multi_deps

2018-10-19T00:47:46Z

Since commit c8589d1e9e01 ("kbuild: handle multi-objs dependency appropriately"), $^ really represents all the prerequisite of the composite object being built. Hence, $(filter %.o,$^) contains all the objects to link together, which is much simpler than link_multi_deps calculation. Please note $(filter-out FORCE,$^) does not work here. When a single object module is turned into a multi object module, $^ will contain header files that were previously included for building the single object, and recorded in the .*.cmd file. To filter out such headers, $(filter %.o,$^) should be used here. Signed-off-by: Masahiro Yamada

ftrace: Build with CPPFLAGS to get -Qunused-arguments

2018-09-19T14:53:54Z

When building to record the mcount locations the kernel uses KBUILD_CFLAGS but not KBUILD_CPPFLAGS. This means it lacks -Qunused-arguments when building with clang, resulting in a lot of noisy warnings. Signed-off-by: Joel Stanley Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada

kbuild: remove old check for CFLAGS use

2018-09-12T15:01:16Z

This check has been here for more than a decade since commit 0c53c8e6eb45 ("kbuild: check for wrong use of CFLAGS"). Enough time for migration has passed. Signed-off-by: Masahiro Yamada

objtool: Remove workaround for unreachable warnings from old GCC

2018-08-30T10:56:40Z

Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6") bumped the minimum GCC version to 4.6 for all architectures. This effectively reverts commit da541b20021c ("objtool: Skip unreachable warnings for GCC 4.4 and older"), which was a workaround for GCC 4.4 or older. Signed-off-by: Masahiro Yamada Signed-off-by: Thomas Gleixner Acked-by: Josh Poimboeuf Cc: Peter Zijlstra Cc: Michal Marek Cc: linux-kbuild@vger.kernel.org Link: https://lkml.kernel.org/r/1535341183-19994-1-git-send-email-yamada.masahiro@socionext.com

kbuild: rename LDFLAGS to KBUILD_LDFLAGS

2018-08-23T23:22:08Z

Commit a0f97e06a43c ("kbuild: enable 'make CFLAGS=...' to add additional options to CC") renamed CFLAGS to KBUILD_CFLAGS. Commit 222d394d30e7 ("kbuild: enable 'make AFLAGS=...' to add additional options to AS") renamed AFLAGS to KBUILD_AFLAGS. Commit 06c5040cdb13 ("kbuild: enable 'make CPPFLAGS=...' to add additional options to CPP") renamed CPPFLAGS to KBUILD_CPPFLAGS. For some reason, LDFLAGS was not renamed. Using a well-known variable like LDFLAGS may result in accidental override of the variable. Kbuild generally uses KBUILD_ prefixed variables for the internally appended options, so here is one more conversion to sanitize the naming convention. I did not touch Makefiles under tools/ since the tools build system is a different world. Signed-off-by: Masahiro Yamada Acked-by: Kirill A. Shutemov Reviewed-by: Palmer Dabbelt

kbuild: pass LDFLAGS to recordmcount.pl

2018-08-23T23:22:08Z

Since commit 0fbe9a245c60 ("microblaze: add endianness options to LDFLAGS instead of LD"), you cannot build the kernel for microblaze with CONFIG_DYNAMIC_FTRACE. Fixes: 0fbe9a245c60 ("microblaze: add endianness options to LDFLAGS instead of LD") Signed-off-by: Masahiro Yamada

Merge tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2018-08-21T01:32:00Z

Pull tracing updates from Steven Rostedt: - Restructure of lockdep and latency tracers This is the biggest change. Joel Fernandes restructured the hooks from irqs and preemption disabling and enabling. He got rid of a lot of the preprocessor #ifdef mess that they caused. He turned both lockdep and the latency tracers to use trace events inserted in the preempt/irqs disabling paths. But unfortunately, these started to cause issues in corner cases. Thus, parts of the code was reverted back to where lockdep and the latency tracers just get called directly (without using the trace events). But because the original change cleaned up the code very nicely we kept that, as well as the trace events for preempt and irqs disabling, but they are limited to not being called in NMIs. - Have trace events use SRCU for "rcu idle" calls. This was required for the preempt/irqs off trace events. But it also had to not allow them to be called in NMI context. Waiting till Paul makes an NMI safe SRCU API. - New notrace SRCU API to allow trace events to use SRCU. - Addition of mcount-nop option support - SPDX headers replacing GPL templates. - Various other fixes and clean ups. - Some fixes are marked for stable, but were not fully tested before the merge window opened. * tag 'trace-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (44 commits) tracing: Fix SPDX format headers to use C++ style comments tracing: Add SPDX License format tags to tracing files tracing: Add SPDX License format to bpf_trace.c blktrace: Add SPDX License format header s390/ftrace: Add -mfentry and -mnop-mcount support tracing: Add -mcount-nop option support tracing: Avoid calling cc-option -mrecord-mcount for every Makefile tracing: Handle CC_FLAGS_FTRACE more accurately Uprobe: Additional argument arch_uprobe to uprobe_write_opcode() Uprobes: Simplify uprobe_register() body tracepoints: Free early tracepoints after RCU is initialized uprobes: Use synchronize_rcu() not synchronize_sched() tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister() ftrace: Remove unused pointer ftrace_swapper_pid tracing: More reverting of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing/irqsoff: Handle preempt_count for different configs tracing: Partial revert of "tracing: Centralize preemptirq tracepoints and unify their usage" tracing: irqsoff: Account for additional preempt_disable trace: Use rcu_dereference_raw for hooks from trace-event subsystem tracing/kprobes: Fix within_notrace_func() to check only notrace functions ...