From: Vincentius Robby (vincentius_at_umich_dot_edu)
Date: Wed Sep 03 2008 - 10:38:53 PDT
Hello Paul,
Apologies, regarding the directory I forgot to add the CR_ARCH32
option because I was working on a 64-bit sparc machine for testing this.
While my question regarding the fetch and add still stands, I am
playing around with the syscall handlers now. Currently the errors I
am encountering are:
then mv -f ".deps/libcr_la-cr_syscall.Tpo"
".deps/libcr_la-cr_syscall.Plo"; else rm -f
".deps/libcr_la-cr_syscall.Tpo"; exit 1; fi
gcc -DHAVE_CONFIG_H -I. -I../../libcr -I.. -D_GNU_SOURCE
-D_REENTRANT -I../include -I../../include -I../../libcr/arch/sparc/
-Wall -Wno-unused-function -fno-stack-protector -g -O2 -MT
libcr_la-cr_syscall.lo -MD -MP -MF .deps/libcr_la-cr_syscall.Tpo -c
../../libcr/cr_syscall.c -fPIC -DPIC -o .libs/libcr_la-cr_syscall.o
../../libcr/cr_syscall.c:169: error: expected ')' before 'int'
../../libcr/cr_syscall.c:170: error: expected ')' before 'const'
../../libcr/cr_syscall.c:171: error: expected ')' before 'int'
../../libcr/cr_syscall.c: In function '__cri_sched_yield':
../../libcr/cr_syscall.c:172: warning: initialization makes integer
from pointer without a cast
../../libcr/cr_syscall.c:172: error: expected string literal before 'string'
../../libcr/cr_syscall.c:172: warning: statement with no effect
../../libcr/cr_syscall.c: At top level:
../../libcr/cr_syscall.c:173: error: expected ')' before 'const'
../../libcr/cr_syscall.c:174: error: expected ')' before 'int'
../../libcr/cr_syscall.c:176: error: expected ')' before 'int'
../../libcr/cr_syscall.c:183: error: expected ')' before 'int'
../../libcr/cr_syscall.c:189: error: expected ')' before 'int'
make[2]: *** [libcr_la-cr_syscall.lo] Error 1
make[2]: Leaving directory `/opt/blcr-0.7.3_vincent/builddir/libcr'
and this is what the beginning of libcr/arch/sparc/cr_arch.h looks like:
#define cri_syscall_cleanup(res,errno_p) \
__asm__ volatile ("" ::: "memory", "cc", "cx", "dx");\
if ((unsigned long)res >= (unsigned long)(-4096)) { \
if (errno_p != NULL) { *errno_p = -res; } \
res = -1; \
}
#define cri_syscall0(type,name,nr) \
type name(int *errno_p) \
{ \
register long __o0 __asm__ ("o0"); \
register long __g1 __asm__ ("g1") = name; \
__asm __volatile (string : "=r" (__g1), "=r" (__o0) : \
"0" (__g1) : \
__SYSCALL_CLOBBERS); \
__o0; \
cri_syscall_cleanup(__g1, errno_p); \
}
#define cri_syscall1(type,name,nr,arg1) \
type name(type1 arg1,int *errno_p) \
{ \
register long __o0 __asm__ ("o0") = (long)(arg1); \
register long __g1 __asm__ ("g1") = name; \
__asm __volatile (string : "=r" (__g1), "=r" (__o0) : \
"0" (__g1), "1" (__o0) : \
__SYSCALL_CLOBBERS); \
__o0; \
cri_syscall_cleanup(__g1, errno_p); \
}
One question I have is where it is written __asm __volatile (string :,
is the string to be replaced by 'type'? Originally the inline_syscall
has arguments (string,name) so I assumed I had to change the 'string'
to 'type' in the __asm __volatile arguments but after these errors I
changed it back, but either way it was not a solution to the errors.
Is this what you mentioned for the inclusion syscall_cleanup routine
as well?
Thank you.
--
Vincentius Robby
Quoting "Paul H. Hargrove" <PHHargrove_at_lbl_dot_gov>:
> My best guess is that the -I options are not quite right to include
> the libcr/arch/sparc directory. Take a look at the full command
> line that make executes for a file in libcr. For example, on a i686
> I see:
>
> /bin/sh ../libtool --tag=CC --mode=compile gcc -DHAVE_CONFIG_H -I.
> -I.. -I../../libcr -D_GNU_SOURCE -D_REENTRANT -I../include
> -I../../include -I../../libcr/arch/i386/ -Wall
> -Wno-unused-function -fno-stack-protector -g -O2 -MT
> libcr_la-cr_async.lo -MD -MP -MF .deps/libcr_la-cr_async.Tpo -c -o
> libcr_la-cr_async.lo `test -f 'cr_async.c' || echo
> '../../libcr/'`cr_async.c
>
> Notice the -I../../libcr/arch/i386/ part. My best guess is that
> your says -I../../libcr/arch/sparc64/, rather than
> -I../../libcr/arch/sparc/ as you are expecting (note the ../.. is
> based on where my build dir is located in relation to my source dir,
> your -I's may differ). If this is the case, then you should
> consider sparc and sparc64 dirs with the same relation as the
> existing ppc and ppc64 dirs (64 includes the 32bit code).
>
> As for the inc and dec-and-test, you can implement them using the following:
>
> CR_INLINE unsigned int
> __cri_atomic_add_fetch(cri_atomic_t *p, unsigned int op)
> {
> unsigned long oldval, newval;
> do {
> oldval = cri_atomic_read(p);
> newval = oldval + op;
> } while (!cri_cmp_swap(p, oldval, newval));
> return newval;
> }
>
> CR_INLINE void
> cri_atomic_inc(cri_atomic_t *p)
> {
> (void)__cri_atomic_add_fetch(p, 1);
> }
>
> CR_INLINE int
> cri_atomic_dec_and_test(cri_atomic_t *p)
> {
> return (__cri_atomic_add_fetch(p, -1) == 0);
> }
>
>
> These should be considered the "reference" implementations and would
> appear in a porting guide if I had written one.
>
> However, I think the following would be the (nearly) "optimal"
> __cri_atomic_add_fetch() for UltraSPARC and newer:
>
> CR_INLINE unsigned int
> __cri_atomic_add_fetch(cri_atomic_t *p, unsigned int op)
> {
> register unsigned int oldval, newval;
> __asm__ __volatile__ (
> "ld [%4],%0 \n\t" /* oldval = *addr; */
> "0: \t"
> "add %0,%3,%1 \n\t" /* newval = oldval + op; */
> "cas [%4],%0,%1 \n\t" /* if (*addr == oldval)
> SWAP(*addr,newval); else newval = *addr; */
> "cmp %0, %1 \n\t" /* check if newval == oldval (swap
> succeeded) */
> "bne,a,pn %%icc, 0b \n\t" /* otherwise, retry (,pn ==
> predict not taken; ,a == annul) */
> " mov %1, %0 " /* oldval = newval; (branch delay
> slot, annulled if not taken) */
> : "=&r"(oldval), "=&r"(newval), "=m"(*p)
> : "rn"(op), "r"(p), "m"(*p) );
> return newval;
> }
>
>
> If I got that right (based on a different SPARC atomics project I
> worked on), the generated asm for atomic inc and dec-and-test will
> use immediate +1 and -1 arguments to the add instruction.
>
> I'll need to think about whether you need any memory barriers to
> make this 100% correct on the SPARC architecture. Have you
> considered that for the cri_cmp_swap()?
>
> The syscall code is found in glibc. For instance in
> glibc-2.6/sysdeps/unix/sysv/linux/sparc/sysdep.h, where you'll want
> to use guts of the inline_syscall0() through inline_syscall5()
> macros, combined with the errno handling as seen in
> blcr/libcr/arch/i386/cr_arch.h:cri_syscall_cleanup().
>
> Just to be 100% proper about this code I've included here:
> Signed-off-by: Paul H. Hargrove <PHHargrove_at_lbl_dot_gov>
>
> -Paul
>
> Vincentius Robby wrote:
>> Thank you Paul,
>>
>> Now even after I put the cr_arch.h and cr_atomic.h under
>> libcr/arch/sparc, the following errors appear:
>> In file included from ../../libcr/cr_async.c:37:
>> ../../libcr/cr_private.h:63:23: error: cr_atomic.h: No such file or
>> directory
>> In file included from ../../libcr/cr_private.h:65,
>> from ../../libcr/cr_async.c:37:
>> [some more errors]
>> ../../libcr/cr_private.h:66:21: error: cr_arch.h: No such file or directory
>>
>> Do I have to change something else for blcr to realize the files' existence?
>> Also, would you be able to point me to some other resources for the
>> assembly codes? For cr_atomic.h, I understood how to implement
>> compare_and_swap but I am not able to infer the atomic increment
>> and decrement and test from the glibc source codes as well as the
>> source for other architectures. For the syscall functions, would
>> you know of where can I look into? Should the glibc have these?
>>
>> Thank you very much for the help, I've been slowly looking into
>> these for a while, but my inexperience hinders me from advancing as
>> quick.
>>
>
>
> --
> Paul H. Hargrove PHHargrove_at_lbl_dot_gov
> Future Technologies Group HPC Research Department
> Tel: +1-510-495-2352
> Lawrence Berkeley National Laboratory Fax: +1-510-486-6900
>
>
>
>