From mboxrd@z Thu Jan 1 00:00:00 1970 From: rabin@rab.in (Rabin Vincent) Date: Wed, 23 Nov 2011 20:25:09 +0530 Subject: [PATCH 4/4] ARM: add jump label support In-Reply-To: <20111122235041.GB24453@redhat.com> References: <1321888429-3519-1-git-send-email-rabin@rab.in> <1321888429-3519-4-git-send-email-rabin@rab.in> <20111122194213.GC9581@n2100.arm.linux.org.uk> <4ECC2A07.8050701@codeaurora.org> <20111122233949.GA24453@redhat.com> <20111122235041.GB24453@redhat.com> Message-ID: <20111123145509.GA4973@debian> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Nov 22, 2011 at 06:50:41PM -0500, Jason Baron wrote: > On Tue, Nov 22, 2011 at 06:39:50PM -0500, Jason Baron wrote: > > Right, for jump labels we have a script at: scripts/gcc-goto.sh, which > > basically just checks if we can compile 'asm goto' without error, so for > > %c, you could probably have some simple 'asm()' that uses %c, and see if > > it compiles. Although, I'm not sure if there's a arch specific dir, for > > such a thing? > > > > thanks, > > > > -Jason > > hmm...actually we could add it to the top level scripts/gcc-goto.sh, > that would be fine, I can take a look at that... Here's a patch. Atleast on MIPS %c means something else so I had to ifdef it for ARM: 8<---------------------------- >>From ea211ce77e0ea9c5b8cd32b99bfb24e0140f0068 Mon Sep 17 00:00:00 2001 From: Rabin Vincent Date: Wed, 23 Nov 2011 20:05:09 +0530 Subject: [PATCH] jump label: detect %c support for ARM Some versions of ARM GCC don't support the %c specifier fully, but do support asm goto. Since we need the %c to support jump labels on ARM, detect that too in the asm goto detection script to avoid build errors with these versions. http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637 Signed-off-by: Rabin Vincent --- scripts/gcc-goto.sh | 18 +++++++++++++++++- 1 files changed, 17 insertions(+), 1 deletions(-) diff --git a/scripts/gcc-goto.sh b/scripts/gcc-goto.sh index 98cffcb..9b744de 100644 --- a/scripts/gcc-goto.sh +++ b/scripts/gcc-goto.sh @@ -2,4 +2,20 @@ # Test for gcc 'asm goto' support # Copyright (C) 2010, Jason Baron -echo "int main(void) { entry: asm goto (\"\"::::entry); return 0; }" | $@ -x c - -c -o /dev/null >/dev/null 2>&1 && echo "y" +cat << "END" | $@ -x c - -c -o /dev/null >/dev/null 2>&1 && echo "y" +int main(void) +{ +#ifdef __arm__ + /* + * Not related to asm goto, but used by jump label + * and broken on some ARM GCC versions (see GCC Bug 48637). + */ + static struct { int dummy; int state; } tp; + asm ("@ %c0" :: "i" (&tp.state)); +#endif + +entry: + asm goto ("" :::: entry); + return 0; +} +END -- 1.7.7.3