linux-kernel - [tip:perf/urgent] perf tools: Really allow to specify custom CC, AR or LD

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <tip-3c71ba3f80bbd476bbfb2a008da9b676031cbd32@git.kernel.org>
Date:	Fri, 17 Jul 2015 20:22:05 -0700
From:	tip-bot for Alexey Brodkin <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	mingo@...nel.org, Alexey.Brodkin@...opsys.com, hpa@...or.com,
	tglx@...utronix.de, abrodkin@...opsys.com,
	linux-kernel@...r.kernel.org, aaro.koskinen@...ia.com,
	a.p.zijlstra@...llo.nl, acme@...hat.com,
	Vineet.Gupta1@...opsys.com, vgupta@...opsys.com, paulus@...ba.org,
	jolsa@...nel.org
Subject: [tip:perf/urgent] perf tools: Really allow to specify custom CC,
  AR or LD

Commit-ID:  3c71ba3f80bbd476bbfb2a008da9b676031cbd32
Gitweb:     http://git.kernel.org/tip/3c71ba3f80bbd476bbfb2a008da9b676031cbd32
Author:     Alexey Brodkin <Alexey.Brodkin@...opsys.com>
AuthorDate: Tue, 14 Jul 2015 12:05:20 +0300
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Wed, 15 Jul 2015 11:57:28 -0300

perf tools: Really allow to specify custom CC, AR or LD

Commit 5ef7bbb09f7b ("perf tools: Allow to specify custom linker
command") was meant to enable usage non $(CROSS_COMPILE)ld linker during
perf building.

But implementation didn't take into account the fact that LD is a
pre-defined variable in GNU Make. I.e. it is always defined.

Which means there's no point to check "LD ?= ..." because it will never
succeed.

And so LD will be either that explicitly passed to make like this:

 ------->8-------
 make LD=path_to_my_ld ...
 ------->8-------
 or default value, which is host's "ld".

Latter leads to failure of cross-linkage because instead of cross linker
"$(CROSS_COMPILE)ld" host's "ld" is used.

Fortunately there's a way to do correct substitution of $(CROSS_COMPILE)ld
with user defined LD on command-line.

As a reference was used implementation in "tools/lib/traceevent/Makefile".

Build tested for x86_64 and ARC.

Thanks Jiri for this hint.

Signed-off-by: Alexey Brodkin <abrodkin@...opsys.com>
Fixes: 5ef7bbb09f7b ("perf tools: Allow to specify custom linker command")
Cc: Aaro Koskinen <aaro.koskinen@...ia.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Vineet Gupta <Vineet.Gupta1@...opsys.com>
Cc: Vineet Gupta <vgupta@...opsys.com>
Cc: linux-arch@...r.kernel.org
Link: http://lkml.kernel.org/r/1436864720-26316-1-git-send-email-abrodkin@synopsys.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/Makefile.perf | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 7a4b549..bba3463 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -109,9 +109,22 @@ $(OUTPUT)PERF-VERSION-FILE: ../../.git/HEAD
 	$(Q)$(SHELL_PATH) util/PERF-VERSION-GEN $(OUTPUT)
 	$(Q)touch $(OUTPUT)PERF-VERSION-FILE
 
-CC = $(CROSS_COMPILE)gcc
-LD ?= $(CROSS_COMPILE)ld
-AR = $(CROSS_COMPILE)ar
+# Makefiles suck: This macro sets a default value of $(2) for the
+# variable named by $(1), unless the variable has been set by
+# environment or command line. This is necessary for CC and AR
+# because make sets default values, so the simpler ?= approach
+# won't work as expected.
+define allow-override
+  $(if $(or $(findstring environment,$(origin $(1))),\
+            $(findstring command line,$(origin $(1)))),,\
+    $(eval $(1) = $(2)))
+endef
+
+# Allow setting CC and AR and LD, or setting CROSS_COMPILE as a prefix.
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,AR,$(CROSS_COMPILE)ar)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+
 PKG_CONFIG = $(CROSS_COMPILE)pkg-config
 
 RM      = rm -f
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/