* [PATCH v2 2/2] powerpc32: add support for csum_add() @ 2015-02-03 11:39 ` Christophe Leroy 0 siblings, 0 replies; 13+ messages in thread From: Christophe Leroy @ 2015-02-03 11:39 UTC (permalink / raw) To: Benjamin Herrenschmidt, Paul Mackerras, scottwood Cc: linux-kernel, linuxppc-dev, Joakim Tjernlund The C version of csum_add() as defined in include/net/checksum.h gives the following assembly: 0: 7c 04 1a 14 add r0,r4,r3 4: 7c 64 00 10 subfc r3,r4,r0 8: 7c 63 19 10 subfe r3,r3,r3 c: 7c 63 00 50 subf r3,r3,r0 include/net/checksum.h also offers the possibility to define an arch specific function. This patch provides a ppc32 specific csum_add() inline function. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- v2: changed constraints on the __asm__ arch/powerpc/include/asm/checksum.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h index cfe806a..1e48cc7 100644 --- a/arch/powerpc/include/asm/checksum.h +++ b/arch/powerpc/include/asm/checksum.h @@ -141,6 +141,18 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, { return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); } + +#define HAVE_ARCH_CSUM_ADD +static inline __wsum csum_add(__wsum csum, __wsum addend) +{ + __asm__("\n\ + addc %0,%0,%1 \n\ + addze %0,%0 \n\ + " + : "+r" (csum) : "r" (addend)); + return csum; +} + #endif #endif #endif /* __KERNEL__ */ -- 2.1.0 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* [PATCH v2 2/2] powerpc32: add support for csum_add() @ 2015-02-03 11:39 ` Christophe Leroy 0 siblings, 0 replies; 13+ messages in thread From: Christophe Leroy @ 2015-02-03 11:39 UTC (permalink / raw) To: Benjamin Herrenschmidt, Paul Mackerras, scottwood Cc: linuxppc-dev, linux-kernel The C version of csum_add() as defined in include/net/checksum.h gives the following assembly: 0: 7c 04 1a 14 add r0,r4,r3 4: 7c 64 00 10 subfc r3,r4,r0 8: 7c 63 19 10 subfe r3,r3,r3 c: 7c 63 00 50 subf r3,r3,r0 include/net/checksum.h also offers the possibility to define an arch specific function. This patch provides a ppc32 specific csum_add() inline function. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- v2: changed constraints on the __asm__ arch/powerpc/include/asm/checksum.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h index cfe806a..1e48cc7 100644 --- a/arch/powerpc/include/asm/checksum.h +++ b/arch/powerpc/include/asm/checksum.h @@ -141,6 +141,18 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, { return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); } + +#define HAVE_ARCH_CSUM_ADD +static inline __wsum csum_add(__wsum csum, __wsum addend) +{ + __asm__("\n\ + addc %0,%0,%1 \n\ + addze %0,%0 \n\ + " + : "+r" (csum) : "r" (addend)); + return csum; +} + #endif #endif #endif /* __KERNEL__ */ -- 2.1.0 ^ permalink raw reply related [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() 2015-02-03 11:39 ` Christophe Leroy @ 2015-03-25 1:30 ` Scott Wood -1 siblings, 0 replies; 13+ messages in thread From: Scott Wood @ 2015-03-25 1:30 UTC (permalink / raw) To: LEROY Christophe Cc: Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev, linux-kernel On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: > The C version of csum_add() as defined in include/net/checksum.h gives the > following assembly: > 0: 7c 04 1a 14 add r0,r4,r3 > 4: 7c 64 00 10 subfc r3,r4,r0 > 8: 7c 63 19 10 subfe r3,r3,r3 > c: 7c 63 00 50 subf r3,r3,r0 > > include/net/checksum.h also offers the possibility to define an arch specific > function. > This patch provides a ppc32 specific csum_add() inline function. What makes it 32-bit specific? -Scott ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() @ 2015-03-25 1:30 ` Scott Wood 0 siblings, 0 replies; 13+ messages in thread From: Scott Wood @ 2015-03-25 1:30 UTC (permalink / raw) To: LEROY Christophe; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: > The C version of csum_add() as defined in include/net/checksum.h gives the > following assembly: > 0: 7c 04 1a 14 add r0,r4,r3 > 4: 7c 64 00 10 subfc r3,r4,r0 > 8: 7c 63 19 10 subfe r3,r3,r3 > c: 7c 63 00 50 subf r3,r3,r0 > > include/net/checksum.h also offers the possibility to define an arch specific > function. > This patch provides a ppc32 specific csum_add() inline function. What makes it 32-bit specific? -Scott ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() 2015-03-25 1:30 ` Scott Wood (?) @ 2015-04-28 19:01 ` christophe leroy 2015-05-02 1:00 ` Scott Wood -1 siblings, 1 reply; 13+ messages in thread From: christophe leroy @ 2015-04-28 19:01 UTC (permalink / raw) To: Scott Wood; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel [-- Attachment #1: Type: text/plain, Size: 1278 bytes --] Le 25/03/2015 02:30, Scott Wood a écrit : > On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: >> The C version of csum_add() as defined in include/net/checksum.h gives the >> following assembly: >> 0: 7c 04 1a 14 add r0,r4,r3 >> 4: 7c 64 00 10 subfc r3,r4,r0 >> 8: 7c 63 19 10 subfe r3,r3,r3 >> c: 7c 63 00 50 subf r3,r3,r0 >> >> include/net/checksum.h also offers the possibility to define an arch specific >> function. >> This patch provides a ppc32 specific csum_add() inline function. > What makes it 32-bit specific? > > As far as I understand, the 64-bit will do a 64 bit addition, so we will have to handle differently the carry, can't just be an addze like in 32-bit. The generated code is most likely different on ppc64. I have no ppc64 compiler so I can't check what gcc generates for the following code: |__wsumcsum_add(__wsum csum, __wsum addend) { u32 res= (__force u32)csum; res+= (__force u32)addend; return (__force __wsum)(res+ (res< (__force u32)addend)); }| Can someone with a ppc64 compiler tell what we get ? Christophe --- L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast. http://www.avast.com [-- Attachment #2: Type: text/html, Size: 3353 bytes --] ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() 2015-04-28 19:01 ` christophe leroy @ 2015-05-02 1:00 ` Scott Wood 0 siblings, 0 replies; 13+ messages in thread From: Scott Wood @ 2015-05-02 1:00 UTC (permalink / raw) To: christophe leroy Cc: Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev, linux-kernel On Tue, 2015-04-28 at 21:01 +0200, christophe leroy wrote: > > > Le 25/03/2015 02:30, Scott Wood a écrit : > > > On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: > > > The C version of csum_add() as defined in include/net/checksum.h gives the > > > following assembly: > > > 0: 7c 04 1a 14 add r0,r4,r3 > > > 4: 7c 64 00 10 subfc r3,r4,r0 > > > 8: 7c 63 19 10 subfe r3,r3,r3 > > > c: 7c 63 00 50 subf r3,r3,r0 > > > > > > include/net/checksum.h also offers the possibility to define an arch specific > > > function. > > > This patch provides a ppc32 specific csum_add() inline function. > > What makes it 32-bit specific? > > > > > As far as I understand, the 64-bit will do a 64 bit addition, so we > will have to handle differently the carry, can't just be an addze like > in 32-bit. OK. Before I couldn't find where this was ifdeffed to 32-bit, but it's in patch 1/2. > The generated code is most likely different on ppc64. I have no ppc64 > compiler so I can't check what gcc generates for the following code: > > __wsum csum_add(__wsum csum, __wsum addend) > { > u32 res = (__force u32)csum; > res += (__force u32)addend; > return (__force __wsum)(res + (res < (__force u32)addend)); > } > > Can someone with a ppc64 compiler tell what we get ? With CONFIG_GENERIC_CPU: 0xc000000000001af8 <+0>: add r3,r3,r4 0xc000000000001afc <+4>: cmplw cr7,r3,r4 0xc000000000001b00 <+8>: mfcr r4 0xc000000000001b04 <+12>: rlwinm r4,r4,29,31,31 0xc000000000001b08 <+16>: add r3,r4,r3 0xc000000000001b0c <+20>: clrldi r3,r3,32 0xc000000000001b10 <+24>: blr The mfcr is particularly nasty, at least on our chips. With CONFIG_CPU_E6500: 0xc000000000001b30 <+0>: add r3,r3,r4 0xc000000000001b34 <+4>: cmplw cr7,r3,r4 0xc000000000001b38 <+8>: mfocrf r4,1 0xc000000000001b3c <+12>: rlwinm r4,r4,29,31,31 0xc000000000001b40 <+16>: add r3,r4,r3 0xc000000000001b44 <+20>: clrldi r3,r3,32 0xc000000000001b48 <+24>: blr Ideal (short of a 64-bit __wsum) would probably be something like (untested): add r3,r3,r4 srdi r5,r3,32 add r3,r3,r5 clrldi r3,r3,32 Or in C code (which would let the compiler schedule it better): static inline __wsum csum_add(__wsum csum, __wsum addend) { u64 res = (__force u64)csum; res += (__force u32)addend; return (__force __wsum)((u32)res + (res >> 32)); } -Scott ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() @ 2015-05-02 1:00 ` Scott Wood 0 siblings, 0 replies; 13+ messages in thread From: Scott Wood @ 2015-05-02 1:00 UTC (permalink / raw) To: christophe leroy; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel On Tue, 2015-04-28 at 21:01 +0200, christophe leroy wrote: > > > Le 25/03/2015 02:30, Scott Wood a écrit : > > > On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: > > > The C version of csum_add() as defined in include/net/checksum.h gives the > > > following assembly: > > > 0: 7c 04 1a 14 add r0,r4,r3 > > > 4: 7c 64 00 10 subfc r3,r4,r0 > > > 8: 7c 63 19 10 subfe r3,r3,r3 > > > c: 7c 63 00 50 subf r3,r3,r0 > > > > > > include/net/checksum.h also offers the possibility to define an arch specific > > > function. > > > This patch provides a ppc32 specific csum_add() inline function. > > What makes it 32-bit specific? > > > > > As far as I understand, the 64-bit will do a 64 bit addition, so we > will have to handle differently the carry, can't just be an addze like > in 32-bit. OK. Before I couldn't find where this was ifdeffed to 32-bit, but it's in patch 1/2. > The generated code is most likely different on ppc64. I have no ppc64 > compiler so I can't check what gcc generates for the following code: > > __wsum csum_add(__wsum csum, __wsum addend) > { > u32 res = (__force u32)csum; > res += (__force u32)addend; > return (__force __wsum)(res + (res < (__force u32)addend)); > } > > Can someone with a ppc64 compiler tell what we get ? With CONFIG_GENERIC_CPU: 0xc000000000001af8 <+0>: add r3,r3,r4 0xc000000000001afc <+4>: cmplw cr7,r3,r4 0xc000000000001b00 <+8>: mfcr r4 0xc000000000001b04 <+12>: rlwinm r4,r4,29,31,31 0xc000000000001b08 <+16>: add r3,r4,r3 0xc000000000001b0c <+20>: clrldi r3,r3,32 0xc000000000001b10 <+24>: blr The mfcr is particularly nasty, at least on our chips. With CONFIG_CPU_E6500: 0xc000000000001b30 <+0>: add r3,r3,r4 0xc000000000001b34 <+4>: cmplw cr7,r3,r4 0xc000000000001b38 <+8>: mfocrf r4,1 0xc000000000001b3c <+12>: rlwinm r4,r4,29,31,31 0xc000000000001b40 <+16>: add r3,r4,r3 0xc000000000001b44 <+20>: clrldi r3,r3,32 0xc000000000001b48 <+24>: blr Ideal (short of a 64-bit __wsum) would probably be something like (untested): add r3,r3,r4 srdi r5,r3,32 add r3,r3,r5 clrldi r3,r3,32 Or in C code (which would let the compiler schedule it better): static inline __wsum csum_add(__wsum csum, __wsum addend) { u64 res = (__force u64)csum; res += (__force u32)addend; return (__force __wsum)((u32)res + (res >> 32)); } -Scott ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() 2015-05-02 1:00 ` Scott Wood @ 2015-05-04 22:10 ` Segher Boessenkool -1 siblings, 0 replies; 13+ messages in thread From: Segher Boessenkool @ 2015-05-04 22:10 UTC (permalink / raw) To: Scott Wood; +Cc: christophe leroy, Paul Mackerras, linuxppc-dev, linux-kernel On Fri, May 01, 2015 at 08:00:14PM -0500, Scott Wood wrote: > On Tue, 2015-04-28 at 21:01 +0200, christophe leroy wrote: > > The generated code is most likely different on ppc64. I have no ppc64 > > compiler For reference: yes you do. Just add -m64. > Ideal (short of a 64-bit __wsum) would probably be something like (untested): > > add r3,r3,r4 > srdi r5,r3,32 > add r3,r3,r5 > clrldi r3,r3,32 > > Or in C code (which would let the compiler schedule it better): > > static inline __wsum csum_add(__wsum csum, __wsum addend) > { > u64 res = (__force u64)csum; > res += (__force u32)addend; > return (__force __wsum)((u32)res + (res >> 32)); > } Older GCC make exactly your asm code for that, in 64-bit; newer GCC get two adds (one as 32-bit, one as 64-bit, it does not see those are the same, grrr); and GCC 5 makes the perfect addc 3,4,3 ; addze 3,3 for this in 32-bit mode. You don't want to see what older GCC does with 32-bit though :-/ Segher ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() @ 2015-05-04 22:10 ` Segher Boessenkool 0 siblings, 0 replies; 13+ messages in thread From: Segher Boessenkool @ 2015-05-04 22:10 UTC (permalink / raw) To: Scott Wood; +Cc: linuxppc-dev, Paul Mackerras, linux-kernel On Fri, May 01, 2015 at 08:00:14PM -0500, Scott Wood wrote: > On Tue, 2015-04-28 at 21:01 +0200, christophe leroy wrote: > > The generated code is most likely different on ppc64. I have no ppc64 > > compiler For reference: yes you do. Just add -m64. > Ideal (short of a 64-bit __wsum) would probably be something like (untested): > > add r3,r3,r4 > srdi r5,r3,32 > add r3,r3,r5 > clrldi r3,r3,32 > > Or in C code (which would let the compiler schedule it better): > > static inline __wsum csum_add(__wsum csum, __wsum addend) > { > u64 res = (__force u64)csum; > res += (__force u32)addend; > return (__force __wsum)((u32)res + (res >> 32)); > } Older GCC make exactly your asm code for that, in 64-bit; newer GCC get two adds (one as 32-bit, one as 64-bit, it does not see those are the same, grrr); and GCC 5 makes the perfect addc 3,4,3 ; addze 3,3 for this in 32-bit mode. You don't want to see what older GCC does with 32-bit though :-/ Segher ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() 2015-05-04 22:10 ` Segher Boessenkool @ 2015-05-19 11:37 ` leroy christophe -1 siblings, 0 replies; 13+ messages in thread From: leroy christophe @ 2015-05-19 11:37 UTC (permalink / raw) To: Segher Boessenkool, Scott Wood; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel Le 05/05/2015 00:10, Segher Boessenkool a écrit : > On Fri, May 01, 2015 at 08:00:14PM -0500, Scott Wood wrote: >> On Tue, 2015-04-28 at 21:01 +0200, christophe leroy wrote: >>> The generated code is most likely different on ppc64. I have no ppc64 >>> compiler > For reference: yes you do. Just add -m64. [root@localhost knl]# LANG= ppc-linux-gcc -m64 test.c test.c:1:0: error: -m64 not supported in this configuration Christophe ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() @ 2015-05-19 11:37 ` leroy christophe 0 siblings, 0 replies; 13+ messages in thread From: leroy christophe @ 2015-05-19 11:37 UTC (permalink / raw) To: Segher Boessenkool, Scott Wood; +Cc: linuxppc-dev, Paul Mackerras, linux-kernel Le 05/05/2015 00:10, Segher Boessenkool a écrit : > On Fri, May 01, 2015 at 08:00:14PM -0500, Scott Wood wrote: >> On Tue, 2015-04-28 at 21:01 +0200, christophe leroy wrote: >>> The generated code is most likely different on ppc64. I have no ppc64 >>> compiler > For reference: yes you do. Just add -m64. [root@localhost knl]# LANG= ppc-linux-gcc -m64 test.c test.c:1:0: error: -m64 not supported in this configuration Christophe ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() 2015-02-03 11:39 ` Christophe Leroy @ 2015-03-31 3:14 ` Scott Wood -1 siblings, 0 replies; 13+ messages in thread From: Scott Wood @ 2015-03-31 3:14 UTC (permalink / raw) To: LEROY Christophe Cc: Benjamin Herrenschmidt, Paul Mackerras, linuxppc-dev, linux-kernel On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: > The C version of csum_add() as defined in include/net/checksum.h gives the > following assembly: > 0: 7c 04 1a 14 add r0,r4,r3 > 4: 7c 64 00 10 subfc r3,r4,r0 > 8: 7c 63 19 10 subfe r3,r3,r3 > c: 7c 63 00 50 subf r3,r3,r0 > > include/net/checksum.h also offers the possibility to define an arch specific > function. > This patch provides a ppc32 specific csum_add() inline function. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > --- > v2: changed constraints on the __asm__ > > arch/powerpc/include/asm/checksum.h | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h > index cfe806a..1e48cc7 100644 > --- a/arch/powerpc/include/asm/checksum.h > +++ b/arch/powerpc/include/asm/checksum.h > @@ -141,6 +141,18 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, > { > return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); > } > + > +#define HAVE_ARCH_CSUM_ADD > +static inline __wsum csum_add(__wsum csum, __wsum addend) > +{ > + __asm__("\n\ s/__asm__/asm/ Use tabs to indent > + addc %0,%0,%1 \n\ > + addze %0,%0 \n\ Use ; to separate asm statements instead of using \n Use string concatenation instead of \ -Scott ^ permalink raw reply [flat|nested] 13+ messages in thread
* Re: [v2,2/2] powerpc32: add support for csum_add() @ 2015-03-31 3:14 ` Scott Wood 0 siblings, 0 replies; 13+ messages in thread From: Scott Wood @ 2015-03-31 3:14 UTC (permalink / raw) To: LEROY Christophe; +Cc: Paul Mackerras, linuxppc-dev, linux-kernel On Tue, Feb 03, 2015 at 12:39:27PM +0100, LEROY Christophe wrote: > The C version of csum_add() as defined in include/net/checksum.h gives the > following assembly: > 0: 7c 04 1a 14 add r0,r4,r3 > 4: 7c 64 00 10 subfc r3,r4,r0 > 8: 7c 63 19 10 subfe r3,r3,r3 > c: 7c 63 00 50 subf r3,r3,r0 > > include/net/checksum.h also offers the possibility to define an arch specific > function. > This patch provides a ppc32 specific csum_add() inline function. > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> > --- > v2: changed constraints on the __asm__ > > arch/powerpc/include/asm/checksum.h | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/arch/powerpc/include/asm/checksum.h b/arch/powerpc/include/asm/checksum.h > index cfe806a..1e48cc7 100644 > --- a/arch/powerpc/include/asm/checksum.h > +++ b/arch/powerpc/include/asm/checksum.h > @@ -141,6 +141,18 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, > { > return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); > } > + > +#define HAVE_ARCH_CSUM_ADD > +static inline __wsum csum_add(__wsum csum, __wsum addend) > +{ > + __asm__("\n\ s/__asm__/asm/ Use tabs to indent > + addc %0,%0,%1 \n\ > + addze %0,%0 \n\ Use ; to separate asm statements instead of using \n Use string concatenation instead of \ -Scott ^ permalink raw reply [flat|nested] 13+ messages in thread
end of thread, other threads:[~2015-05-19 11:37 UTC | newest] Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-02-03 11:39 [PATCH v2 2/2] powerpc32: add support for csum_add() Christophe Leroy 2015-02-03 11:39 ` Christophe Leroy 2015-03-25 1:30 ` [v2,2/2] " Scott Wood 2015-03-25 1:30 ` Scott Wood 2015-04-28 19:01 ` christophe leroy 2015-05-02 1:00 ` Scott Wood 2015-05-02 1:00 ` Scott Wood 2015-05-04 22:10 ` Segher Boessenkool 2015-05-04 22:10 ` Segher Boessenkool 2015-05-19 11:37 ` leroy christophe 2015-05-19 11:37 ` leroy christophe 2015-03-31 3:14 ` Scott Wood 2015-03-31 3:14 ` Scott Wood
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