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linux/scripts/gcc-goto.sh

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jump label: Base patch for jump label base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-09-17 08:09:00 -07:00
#!/bin/sh
scripts/gcc-goto.sh: fix a typo ("suport") Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-06-15 15:17:46 -07:00
# Test for gcc 'asm goto' support
jump label: Base patch for jump label base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-09-17 08:09:00 -07:00
# Copyright (C) 2010, Jason Baron <jbaron@redhat.com>
ARM: 7333/2: jump label: detect %c support for ARM Some versions of ARM GCC which do support asm goto, do not support the %c specifier. 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 Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-02-24 09:06:20 -07:00
cat << "END" | $@ -x c - -c -o /dev/null >/dev/null 2>&1 && echo "y"
int main(void)
{
arm64, jump label: detect %c support for ARM64 As commit a9468f30b5eac6 "ARM: 7333/2: jump label: detect %c support for ARM", this patch detects the same thing for ARM64 because some ARM64 GCC versions have the same issue. Some versions of ARM64 GCC which do support asm goto, do not support the %c specifier. Since we need the %c to support jump labels on ARM64, detect that too in the asm goto detection script to avoid build errors with these versions. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jiang Liu <liuj97@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-01-07 07:17:12 -07:00
#if defined(__arm__) || defined(__aarch64__)
ARM: 7333/2: jump label: detect %c support for ARM Some versions of ARM GCC which do support asm goto, do not support the %c specifier. 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 Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-02-24 09:06:20 -07:00
/*
* 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 (".long %c0" :: "i" (&tp.state));
#endif
entry:
asm goto ("" :::: entry);
return 0;
}
END
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