As the first eval expansion is used only to generate Makefile statements, messages should not be displayed at this stage, as for example conditional expressions are not evaluated. It can be seen for example in the output of feature detection for bpftool, where the number of detected features does not change, despite turning on the verbose mode (VF = 1) and there are additional features to display. Fix this issue by escaping the $ before $(info) statements, to ensure that messages are printed only when the function containing them is actually executed, and not when it is expanded. In addition, move the $(info) statement out of feature_print_status, due to the fact that is called both inside and outside an eval context, and place it to the caller so that the $ can be escaped when necessary. For symmetry, move the $(info) statement also out of feature_print_text, and place it to the caller. Force the TMP variable evaluation in verbose mode, to display the features in FEATURE_TESTS that are not in FEATURE_DISPLAY. Reorder perf feature detection messages (first non-verbose, then verbose ones) by moving the call to feature_display_entries earlier, before the VF environment variable check. Also, remove the newline from that function, as perf might display additional messages. Move the newline to perf Makefile, and display another one if displaying the detection result is not deferred as in the case of bpftool. Committer testing: Collecting the output from: $ make VF=1 -C tools/bpf/bpftool/ |& grep "Auto-detecting system features" -A20 $ diff -u before after --- before 2022-08-18 09:59:55.460529231 -0300 +++ after 2022-08-18 10:01:11.182517282 -0300 @@ -4,3 +4,5 @@ ... libbfd-liberty-z: [ on ] ... libcap: [ on ] ... clang-bpf-co-re: [ on ] +... disassembler-four-args: [ on ] +... disassembler-init-styled: [ OFF ] $ Fixes: 0afc5cad387db560 ("perf build: Separate feature make support into config/Makefile.feature") Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: bpf@vger.kernel.org Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Monnet <quentin@isovalent.com> Link: https://lore.kernel.org/r/20220818120957.319995-1-roberto.sassu@huaweicloud.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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