* [PATCH net-next] sh: add missing fpscr_values
@ 2014-04-02 2:54 Alexei Starovoitov
2014-04-02 7:04 ` Daniel Borkmann
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Alexei Starovoitov @ 2014-04-02 2:54 UTC (permalink / raw)
To: David S. Miller
Cc: Nobuhiro Iwamatsu, Daniel Borkmann, Paul Mundt, Fengguang Wu,
linux-sh, netdev
GCC on SuperH for the following program:
int foo(int i)
{
static const void *table[2] = {
[0] = &&label1,
[1] = &&label2,
};
goto *table[i & 1];
label1:
return 1;
label2:
return 2;
}
generates code:
mov.l .L9,r1
mov #1,r0
rts
lds.l @r1+,fpscr
.L9:
.long __fpscr_values+4
so kernel has to provide body of fpscr_values just like glibc does
Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
---
kernel modules can hit the same problem, so export it
arch/sh/lib/Makefile | 2 +-
arch/sh/lib/fpscr_values.c | 4 ++++
2 files changed, 5 insertions(+), 1 deletion(-)
create mode 100644 arch/sh/lib/fpscr_values.c
diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile
index 3baff31e58cf..0d0c7ae21cfe 100644
--- a/arch/sh/lib/Makefile
+++ b/arch/sh/lib/Makefile
@@ -8,7 +8,7 @@ lib-y = delay.o memmove.o memchr.o \
# Extracted from libgcc
obj-y += movmem.o ashldi3.o ashrdi3.o lshrdi3.o \
ashlsi3.o ashrsi3.o ashiftrt.o lshrsi3.o \
- udiv_qrnnd.o
+ udiv_qrnnd.o fpscr_values.o
udivsi3-y := udivsi3_i4i-Os.o
diff --git a/arch/sh/lib/fpscr_values.c b/arch/sh/lib/fpscr_values.c
new file mode 100644
index 000000000000..58153272aba1
--- /dev/null
+++ b/arch/sh/lib/fpscr_values.c
@@ -0,0 +1,4 @@
+#include <linux/module.h>
+
+long __fpscr_values[2] = { 0L, 0x80000L };
+EXPORT_SYMBOL(__fpscr_values);
--
1.7.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] sh: add missing fpscr_values
2014-04-02 2:54 [PATCH net-next] sh: add missing fpscr_values Alexei Starovoitov
@ 2014-04-02 7:04 ` Daniel Borkmann
2014-04-02 7:38 ` Geert Uytterhoeven
2014-04-02 12:47 ` David Miller
2 siblings, 0 replies; 6+ messages in thread
From: Daniel Borkmann @ 2014-04-02 7:04 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: David S. Miller, Nobuhiro Iwamatsu, Paul Mundt, Fengguang Wu,
linux-sh, netdev
On 04/02/2014 04:54 AM, Alexei Starovoitov wrote:
> GCC on SuperH for the following program:
> int foo(int i)
> {
> static const void *table[2] = {
> [0] = &&label1,
> [1] = &&label2,
> };
> goto *table[i & 1];
>
> label1:
> return 1;
> label2:
> return 2;
> }
> generates code:
> mov.l .L9,r1
> mov #1,r0
> rts
> lds.l @r1+,fpscr
> .L9:
> .long __fpscr_values+4
>
> so kernel has to provide body of fpscr_values just like glibc does
>
> Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] sh: add missing fpscr_values
2014-04-02 2:54 [PATCH net-next] sh: add missing fpscr_values Alexei Starovoitov
2014-04-02 7:04 ` Daniel Borkmann
@ 2014-04-02 7:38 ` Geert Uytterhoeven
2014-04-02 10:52 ` Geert Uytterhoeven
2014-04-02 12:47 ` David Miller
2 siblings, 1 reply; 6+ messages in thread
From: Geert Uytterhoeven @ 2014-04-02 7:38 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: David S. Miller, Nobuhiro Iwamatsu, Daniel Borkmann, Paul Mundt,
Fengguang Wu, Linux-sh list, netdev@vger.kernel.org
On Wed, Apr 2, 2014 at 4:54 AM, Alexei Starovoitov <ast@plumgrid.com> wrote:
> GCC on SuperH for the following program:
> int foo(int i)
> {
> static const void *table[2] = {
> [0] = &&label1,
> [1] = &&label2,
> };
> goto *table[i & 1];
>
> label1:
> return 1;
> label2:
> return 2;
> }
> generates code:
> mov.l .L9,r1
> mov #1,r0
> rts
> lds.l @r1+,fpscr
> .L9:
> .long __fpscr_values+4
>
> so kernel has to provide body of fpscr_values just like glibc does
>
> Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> ---
>
> kernel modules can hit the same problem, so export it
>
> arch/sh/lib/Makefile | 2 +-
> arch/sh/lib/fpscr_values.c | 4 ++++
> 2 files changed, 5 insertions(+), 1 deletion(-)
> create mode 100644 arch/sh/lib/fpscr_values.c
>
> diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile
> index 3baff31e58cf..0d0c7ae21cfe 100644
> --- a/arch/sh/lib/Makefile
> +++ b/arch/sh/lib/Makefile
> @@ -8,7 +8,7 @@ lib-y = delay.o memmove.o memchr.o \
> # Extracted from libgcc
> obj-y += movmem.o ashldi3.o ashrdi3.o lshrdi3.o \
> ashlsi3.o ashrsi3.o ashiftrt.o lshrsi3.o \
> - udiv_qrnnd.o
> + udiv_qrnnd.o fpscr_values.o
>
> udivsi3-y := udivsi3_i4i-Os.o
>
> diff --git a/arch/sh/lib/fpscr_values.c b/arch/sh/lib/fpscr_values.c
> new file mode 100644
> index 000000000000..58153272aba1
> --- /dev/null
> +++ b/arch/sh/lib/fpscr_values.c
> @@ -0,0 +1,4 @@
> +#include <linux/module.h>
> +
> +long __fpscr_values[2] = { 0L, 0x80000L };
> +EXPORT_SYMBOL(__fpscr_values);
Pardon my ignorance, but according to
http://www.sourceware.org/ml/libc-alpha/2003-06/msg00027.html
__fpscr_values is needed for FPU support only.
The kernel is built with -m4-nofpu. If this option is used, gcc doesn't generate
the reference to __fpscr_values?
Why do we need symbols for userspace FPU support in the kernel?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] sh: add missing fpscr_values
2014-04-02 7:38 ` Geert Uytterhoeven
@ 2014-04-02 10:52 ` Geert Uytterhoeven
0 siblings, 0 replies; 6+ messages in thread
From: Geert Uytterhoeven @ 2014-04-02 10:52 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: David S. Miller, Nobuhiro Iwamatsu, Daniel Borkmann, Paul Mundt,
Fengguang Wu, Linux-sh list, netdev@vger.kernel.org, Linux-Next
On Wed, Apr 2, 2014 at 9:38 AM, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> On Wed, Apr 2, 2014 at 4:54 AM, Alexei Starovoitov <ast@plumgrid.com> wrote:
>> GCC on SuperH for the following program:
>> int foo(int i)
>> {
>> static const void *table[2] = {
>> [0] = &&label1,
>> [1] = &&label2,
>> };
>> goto *table[i & 1];
>>
>> label1:
>> return 1;
>> label2:
>> return 2;
>> }
>> generates code:
>> mov.l .L9,r1
>> mov #1,r0
>> rts
>> lds.l @r1+,fpscr
>> .L9:
>> .long __fpscr_values+4
>>
>> so kernel has to provide body of fpscr_values just like glibc does
>>
>> Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
>> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
>> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
>> Cc: Daniel Borkmann <dborkman@redhat.com>
>> ---
>>
>> kernel modules can hit the same problem, so export it
>>
>> arch/sh/lib/Makefile | 2 +-
>> arch/sh/lib/fpscr_values.c | 4 ++++
>> 2 files changed, 5 insertions(+), 1 deletion(-)
>> create mode 100644 arch/sh/lib/fpscr_values.c
>>
>> diff --git a/arch/sh/lib/Makefile b/arch/sh/lib/Makefile
>> index 3baff31e58cf..0d0c7ae21cfe 100644
>> --- a/arch/sh/lib/Makefile
>> +++ b/arch/sh/lib/Makefile
>> @@ -8,7 +8,7 @@ lib-y = delay.o memmove.o memchr.o \
>> # Extracted from libgcc
>> obj-y += movmem.o ashldi3.o ashrdi3.o lshrdi3.o \
>> ashlsi3.o ashrsi3.o ashiftrt.o lshrsi3.o \
>> - udiv_qrnnd.o
>> + udiv_qrnnd.o fpscr_values.o
>>
>> udivsi3-y := udivsi3_i4i-Os.o
>>
>> diff --git a/arch/sh/lib/fpscr_values.c b/arch/sh/lib/fpscr_values.c
>> new file mode 100644
>> index 000000000000..58153272aba1
>> --- /dev/null
>> +++ b/arch/sh/lib/fpscr_values.c
>> @@ -0,0 +1,4 @@
>> +#include <linux/module.h>
>> +
>> +long __fpscr_values[2] = { 0L, 0x80000L };
>> +EXPORT_SYMBOL(__fpscr_values);
>
> Pardon my ignorance, but according to
> http://www.sourceware.org/ml/libc-alpha/2003-06/msg00027.html
> __fpscr_values is needed for FPU support only.
>
> The kernel is built with -m4-nofpu. If this option is used, gcc doesn't generate
> the reference to __fpscr_values?
>
> Why do we need symbols for userspace FPU support in the kernel?
Ah, so this comes from these build failures in -next:
http://kisskb.ellerman.id.au/kisskb/buildresult/10875446/
http://kisskb.ellerman.id.au/kisskb/buildresult/10875446/
Indeed, SH2A-targets fail when built with a sh4-linux toolchain, as
sh4-linux-gcc doesn't understand -m2a-nofpu, so it's left out:
arch/sh/Makefile:
cflags-$(CONFIG_CPU_SH2A) += $(call cc-option,-m2a,) \
$(call cc-option,-m2a-nofpu,)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] sh: add missing fpscr_values
2014-04-02 2:54 [PATCH net-next] sh: add missing fpscr_values Alexei Starovoitov
2014-04-02 7:04 ` Daniel Borkmann
2014-04-02 7:38 ` Geert Uytterhoeven
@ 2014-04-02 12:47 ` David Miller
2014-04-02 16:09 ` Alexei Starovoitov
2 siblings, 1 reply; 6+ messages in thread
From: David Miller @ 2014-04-02 12:47 UTC (permalink / raw)
To: ast; +Cc: nobuhiro.iwamatsu.yj, dborkman, lethal, fengguang.wu, linux-sh,
netdev
From: Alexei Starovoitov <ast@plumgrid.com>
Date: Tue, 1 Apr 2014 19:54:04 -0700
> GCC on SuperH for the following program:
> int foo(int i)
> {
> static const void *table[2] = {
> [0] = &&label1,
> [1] = &&label2,
> };
> goto *table[i & 1];
>
> label1:
> return 1;
> label2:
> return 2;
> }
> generates code:
> mov.l .L9,r1
> mov #1,r0
> rts
> lds.l @r1+,fpscr
> .L9:
> .long __fpscr_values+4
>
> so kernel has to provide body of fpscr_values just like glibc does
>
> Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
You guys really need to just fix the compiler, sorry.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net-next] sh: add missing fpscr_values
2014-04-02 12:47 ` David Miller
@ 2014-04-02 16:09 ` Alexei Starovoitov
0 siblings, 0 replies; 6+ messages in thread
From: Alexei Starovoitov @ 2014-04-02 16:09 UTC (permalink / raw)
To: David Miller
Cc: Nobuhiro Iwamatsu, Daniel Borkmann, Paul Mundt, kbuild test robot,
linux-sh, Network Development, Kaz Kojima, Geert Uytterhoeven,
linux-next
On Wed, Apr 2, 2014 at 5:47 AM, David Miller <davem@davemloft.net> wrote:
> From: Alexei Starovoitov <ast@plumgrid.com>
> Date: Tue, 1 Apr 2014 19:54:04 -0700
>
>> GCC on SuperH for the following program:
>> int foo(int i)
>> {
>> static const void *table[2] = {
>> [0] = &&label1,
>> [1] = &&label2,
>> };
>> goto *table[i & 1];
>>
>> label1:
>> return 1;
>> label2:
>> return 2;
>> }
>> generates code:
>> mov.l .L9,r1
>> mov #1,r0
>> rts
>> lds.l @r1+,fpscr
>> .L9:
>> .long __fpscr_values+4
>>
>> so kernel has to provide body of fpscr_values just like glibc does
>>
>> Fixes: bd4cf0ed331a ("net: filter: rework/optimize internal BPF interpreter's instruction set")
>> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
>> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
>
> You guys really need to just fix the compiler, sorry.
agree.
To summarize:
according to Kaz:
"For sh2a, configuring gcc with --with-multilib-list=m2a,m2a-nofpu
and specifying -m2a-nofpu during compiling kernel would work."
and as Geert pointed out we already have:
arch/sh/Makefile:
cflags-$(CONFIG_CPU_SH2A) += $(call cc-option,-m2a,) \
$(call cc-option,-m2a-nofpu,)
so no kernel changes needed and gcc just needs to be reconfigured.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-04-02 16:09 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2014-04-02 2:54 [PATCH net-next] sh: add missing fpscr_values Alexei Starovoitov
2014-04-02 7:04 ` Daniel Borkmann
2014-04-02 7:38 ` Geert Uytterhoeven
2014-04-02 10:52 ` Geert Uytterhoeven
2014-04-02 12:47 ` David Miller
2014-04-02 16:09 ` Alexei Starovoitov
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