Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1182734 > unrolled thread

[PATCH] Revert "perf tools: Allow to specify custom linker command"

Back to article view | Back to linux.kernel

Contents

  [PATCH] Revert "perf tools: Allow to specify custom linker command" Alexey Brodkin <Alexey.Brodkin@synopsys.com> - 2015-07-13 13:20 +0200
    Re: [PATCH] Revert "perf tools: Allow to specify custom linker  command" "acme@kernel.org" <acme@kernel.org> - 2015-07-14 16:50 +0200

#1182734 — [PATCH] Revert "perf tools: Allow to specify custom linker command"

This reverts commit 5ef7bbb09f7b
("perf tools: Allow to specify custom linker command").

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.

As for commit which is reverted here:
 [1] Usually for selection of non-default flavour of CPU core/options
     linker flags are used like "-mtune=xxx" or "-mMyCPUType" etc.

 [2] Still to implement ability to use "ld" that differs from
    "$(CROSS_COMPILE)ld" one will need to add new makefile variable like
    TARGET_LD and then check if $(TARGET_LD) is not specified on make
    invocation then use "$(CROSS_COMPILE)ld".

But for now to fix cross-building of perf this revert is enough.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Aaro Koskinen <aaro.koskinen@nokia.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: linux-kernel@vger.kernel.org
---
 tools/perf/Makefile.perf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 7a4b549..0e0938a 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -110,7 +110,7 @@ $(OUTPUT)PERF-VERSION-FILE: ../../.git/HEAD
 	$(Q)touch $(OUTPUT)PERF-VERSION-FILE
 
 CC = $(CROSS_COMPILE)gcc
-LD ?= $(CROSS_COMPILE)ld
+LD = $(CROSS_COMPILE)ld
 AR = $(CROSS_COMPILE)ar
 PKG_CONFIG = $(CROSS_COMPILE)pkg-config
 
-- 
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1183752 — Re: [PATCH] Revert "perf tools: Allow to specify custom linker command"

Em Tue, Jul 14, 2015 at 02:00:05PM +0000, Alexey Brodkin escreveu:
> On Tue, 2015-07-14 at 10:46 -0300, Arnaldo Carvalho de Melo wrote:
> > Em Mon, Jul 13, 2015 at 11:24:06PM +0300, Aaro Koskinen escreveu:
> > > > But for now to fix cross-building of perf this revert is enough.

> > > Hmm. You are probably right, my build system always exports LD with
> > > correct linker for cross builds so perhaps that's why I this "worked"
> > > for me when testing. Sorry.

> > So, I think this is an "Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>"
> > for the revert, right?

> > > I guess the correct fix would be [1], i.e. there should be some new
> > > variable to pass flags to ld command.

> > > Or maybe [2], could we use make "origin" function? If LD is "default",
> > > then use "$(CROSS_COMPILE)ld", otherwise use what the user passed?

> > When you guys get to some conclusion, please submit a new patch, for now
> > I am taking the revert with the (implied) Acked-by Aaro, ok?

> Please find my patch that both reverts initial Aaro's patch and implements
> proper handling of CC, AR and LD substitution here - https://lkml.org/lkml/2015/7/14/149

I saw it, will do.

- Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web