linuxppc-dev.lists.ozlabs.org archive mirror
 help / color / mirror / Atom feed
From: Joel Stanley <joel@jms.id.au>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nick Desaulniers <ndesaulniers@google.com>
Subject: [PATCH] powerpc: Disable -Wbuiltin-requires-header when setjmp is used
Date: Mon, 17 Sep 2018 17:16:21 +0930	[thread overview]
Message-ID: <20180917074621.25066-1-joel@jms.id.au> (raw)

The powerpc kernel uses setjmp which causes a warning when building with
clang:

    CC      arch/powerpc/xmon/xmon.o
  In file included from arch/powerpc/xmon/xmon.c:51:
  ./arch/powerpc/include/asm/setjmp.h:15:13: error: declaration of
  built-in function 'setjmp' requires inclusion of the header <setjmp.h>
        [-Werror,-Wbuiltin-requires-header]
  extern long setjmp(long *);
              ^
  ./arch/powerpc/include/asm/setjmp.h:16:13: error: declaration of
  built-in function 'longjmp' requires inclusion of the header <setjmp.h>
        [-Werror,-Wbuiltin-requires-header]
  extern void longjmp(long *, long);
              ^

This *is* the header and we're not using the built-in setjump but
rather the one in arch/powerpc/kernel/misc.S. As the compiler warning
does not make sense, it for the files where setjmp is used.

Signed-off-by: Joel Stanley <joel@jms.id.au>
---
We could instead disable this for all of the kernel as I don't think the
warning is going to ever provide useful information for the kernel.

 arch/powerpc/kernel/Makefile | 3 +++
 arch/powerpc/xmon/Makefile   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 1e64cfe22a83..9845a94f5f68 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -7,6 +7,9 @@ CFLAGS_ptrace.o		+= -DUTS_MACHINE='"$(UTS_MACHINE)"'
 
 subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
 
+# Disable clang warning for using setjmp without setjmp.h header
+CFLAGS_crash.o		+= $(call cc-disable-warning, builtin-requires-header)
+
 ifdef CONFIG_PPC64
 CFLAGS_prom_init.o	+= $(NO_MINIMAL_TOC)
 endif
diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index 93cc1f1b8b61..a38db48f9f6d 100644
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -14,6 +14,9 @@ ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
 
 obj-y			+= xmon.o nonstdio.o spr_access.o
 
+# Disable clang warning for using setjmp without setjmp.h header
+subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header)
+
 ifdef CONFIG_XMON_DISASSEMBLY
 obj-y			+= ppc-dis.o ppc-opc.o
 obj-$(CONFIG_SPU_BASE)	+= spu-dis.o spu-opc.o
-- 
2.17.1

             reply	other threads:[~2018-09-17  7:46 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-17  7:46 Joel Stanley [this message]
2018-09-17 17:13 ` [PATCH] powerpc: Disable -Wbuiltin-requires-header when setjmp is used Nick Desaulniers
2018-10-15  4:01 ` Michael Ellerman

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20180917074621.25066-1-joel@jms.id.au \
    --to=joel@jms.id.au \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=ndesaulniers@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).