* Re: [PATCH 4/4] ARM: add jump label support
[not found] ` <20111122235041.GB24453@redhat.com>
@ 2011-11-23 14:55 ` Rabin Vincent
2011-11-23 17:53 ` Russell King - ARM Linux
0 siblings, 1 reply; 3+ messages in thread
From: Rabin Vincent @ 2011-11-23 14:55 UTC (permalink / raw)
To: Jason Baron
Cc: Stephen Boyd, Russell King - ARM Linux, linux-arm-kernel, linux-kernel
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 <rabin@rab.in>
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 <rabin@rab.in>
---
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 <jbaron@redhat.com>
-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
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 4/4] ARM: add jump label support
2011-11-23 14:55 ` [PATCH 4/4] ARM: add jump label support Rabin Vincent
@ 2011-11-23 17:53 ` Russell King - ARM Linux
2011-11-28 17:04 ` Rabin Vincent
0 siblings, 1 reply; 3+ messages in thread
From: Russell King - ARM Linux @ 2011-11-23 17:53 UTC (permalink / raw)
To: Rabin Vincent; +Cc: Jason Baron, Stephen Boyd, linux-arm-kernel, linux-kernel
On Wed, Nov 23, 2011 at 08:25:09PM +0530, Rabin Vincent wrote:
> 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 <rabin@rab.in>
> 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 <rabin@rab.in>
> ---
> 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 <jbaron@redhat.com>
>
> -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
Is the presence of asm goto and %c something we want to test together or
separately? I suspect it's something we want to do separately.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 4/4] ARM: add jump label support
2011-11-23 17:53 ` Russell King - ARM Linux
@ 2011-11-28 17:04 ` Rabin Vincent
0 siblings, 0 replies; 3+ messages in thread
From: Rabin Vincent @ 2011-11-28 17:04 UTC (permalink / raw)
To: Russell King - ARM Linux
Cc: Jason Baron, Stephen Boyd, linux-arm-kernel, linux-kernel
On Wed, Nov 23, 2011 at 23:23, Russell King - ARM Linux
<linux@arm.linux.org.uk> wrote:
> On Wed, Nov 23, 2011 at 08:25:09PM +0530, Rabin Vincent wrote:
>> +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
>
> Is the presence of asm goto and %c something we want to test together or
> separately? I suspect it's something we want to do separately.
Why would we want to do it separately?
The only reason I see is because the results of this test are assigned
to a variable called CC_HAVE_ASM_GOTO and that is not an entirely
accurate name (on ARM) after the addition of this test. If that's the
concern, perhaps this variable could just be renamed?
^ permalink raw reply [flat|nested] 3+ messages in thread
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2011-11-23 14:55 ` [PATCH 4/4] ARM: add jump label support Rabin Vincent
2011-11-23 17:53 ` Russell King - ARM Linux
2011-11-28 17:04 ` Rabin Vincent
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