Date: Sun, 8 May 2011 10:10:43 -0400 From: Attilio Rao <attilio@freebsd.org> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r221614 - projects/largeSMP/sys/powerpc/include Message-ID: <BANLkTi=mnZc6fy8TGpLMsMLDV8UpK5J-Gw@mail.gmail.com> In-Reply-To: <20110508202725.K1192@besplex.bde.org> References: <201105080039.p480doiZ021493@svn.freebsd.org> <20110508202725.K1192@besplex.bde.org>
next in thread | previous in thread | raw e-mail | index | archive | help
2011/5/8 Bruce Evans <brde@optusnet.com.au>: > On Sun, 8 May 2011, Attilio Rao wrote: > >> Log: >> =C2=A0All architectures define the size-bounded types (uint32_t, uint64_= t, >> etc.) >> =C2=A0starting from base C types (int, long, etc). >> =C2=A0That is also reflected when building atomic operations, as the >> =C2=A0size-bounded types are built from the base C types. >> >> =C2=A0However, powerpc does the inverse thing, leading to a serie of nas= ty > > I think you mean that it does the inverse thing for atomic ops only. > >> =C2=A0bugs. >> =C2=A0Cleanup the atomic implementation by defining as base the base C t= ype >> =C2=A0version and depending on them, appropriately. > > I think that it is mostly the other arches that are backwards here, > except for plain ints. =C2=A0MI code cannot use atomic ops for anything > except plain ints, since no other type is guaranteed to be supported > by the MD code. =C2=A0For example, sparc64 doesn't support any 8-bit or > 16-bit types, and i386 doesn't support any 64-bit types (until recently; > it now uses cmpxchg8b on some CPUs and a hack on other CPUs to support > 64, bit types), and my version of i386 doesn't support any 8-bit or > 16-bit types or long since these types are unusable in MI code and > unused in MD code (long is misused in some MI code but I don't use > such broken code). > > At least one type must be supported, and to keep things sane, int must > be supported. =C2=A0The type could be int32_t instead, but then you would= have > a hard-coded assumption that int is int32_t instead of a hard-coded > assumption that int can be an atomic type. =C2=A0The latter is a better > assumption for MI code. =C2=A0But MD code can make the former assumption > except of course on arches where it is false, but there are none of > those yet. =C2=A0This gives the following structure in atomic.h: > > o basic definitions in terms of uint8/16/32/64_t. =C2=A0But don't define = the > =C2=A08/16/64 bit ones unless they are actually used in MD code, which is > =C2=A0rare. =C2=A0MI code cannot use these. > o assume that u_int is uint32_t and #define all the atomic_foo_int() > =C2=A0interfaces as atomic_foo_32. =C2=A0Similarly for pointers, except u= se > =C2=A0atomic_foo_64 in some cases. > o do something for long. =C2=A0MI code cannot use atomic ops on longs, bu= t does. > =C2=A0Correctly-sized longs are usually fundamentally non-atomic since th= ey > =C2=A0are twice as long as the register width and the register width is u= sually > =C2=A0the same as the bus width and atomicness for widths wider than the = bus is > =C2=A0unnatural and/or inefficient. =C2=A0But no supported arch has corre= ctly-sized > =C2=A0longs. So the thing is that we define the uintXX_t type from int,long,etc and then we should really expect to follow the same pattern for atomic instructions. >> Modified: projects/largeSMP/sys/powerpc/include/atomic.h >> >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D >> --- projects/largeSMP/sys/powerpc/include/atomic.h =C2=A0 =C2=A0 =C2=A0S= at May =C2=A07 >> 23:34:14 2011 =C2=A0 =C2=A0 =C2=A0 =C2=A0(r221613) >> +++ projects/largeSMP/sys/powerpc/include/atomic.h =C2=A0 =C2=A0 =C2=A0S= un May =C2=A08 >> 00:39:49 2011 =C2=A0 =C2=A0 =C2=A0 =C2=A0(r221614) >> @@ -48,13 +48,7 @@ >> =C2=A0* { *p +=3D v; } >> =C2=A0*/ >> >> -#define __ATOMIC_ADD_8(p, v, t) =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A08-bit atomic_add not implemented >> - >> -#define __ATOMIC_ADD_16(p, v, t) =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> - =C2=A0 =C2=A016-bit atomic_add not implemented >> - > > Already correctly left out except for bogusly #defining it and #undefinin= g > it. =C2=A0Now not bogusly #defined either. I don't see the point to have something like that, also because is never used in the kernel. >> -#define __ATOMIC_ADD_32(p, v, t) =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> +#define __atomic_add_int(p, v, t) =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> =C2=A0 =C2=A0__asm __volatile( =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0"1: =C2=A0 =C2=A0 lwarx =C2=A0 %0, 0, %2\n" = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0\ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0" =C2=A0 =C2=A0 =C2=A0 add =C2=A0 =C2=A0 %0, = %3, %0\n" =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> @@ -63,10 +57,10 @@ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0: "=3D&r" (t), "=3Dm" (*p) =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0: "r" (p), "r" (v), "m" (*p) =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0\ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0: "cc", "memory") =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> - =C2=A0 =C2=A0/* __ATOMIC_ADD_32 */ >> + =C2=A0 =C2=A0/* __atomic_add_int */ > > No type problems at this level. Yes, but I also want uniformity in the implementation, thus try to give a common pattern. >> #ifdef __powerpc64__ >> -#define __ATOMIC_ADD_64(p, v, t) =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> +#define __atomic_add_long(p, v, t) =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> =C2=A0 =C2=A0__asm __volatile( =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0"1: =C2=A0 =C2=A0 ldarx =C2=A0 %0, 0, %2\n" = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0\ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0" =C2=A0 =C2=A0 =C2=A0 add =C2=A0 =C2=A0 %0, = %3, %0\n" =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> @@ -75,69 +69,78 @@ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0: "=3D&r" (t), "=3Dm" (*p) =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0: "r" (p), "r" (v), "m" (*p) =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0\ >> =C2=A0 =C2=A0 =C2=A0 =C2=A0: "cc", "memory") =C2=A0 =C2=A0 =C2=A0 =C2=A0= =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> - =C2=A0 =C2=A0/* __ATOMIC_ADD_64 */ >> + =C2=A0 =C2=A0/* __atomic_add_long */ >> #else >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0__ATOMIC_ADD_64(p, v, t) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A064-bit atomic_add not implemented > > Now correctly left out when it is not supported. See below, for non powerpc64 case it must not be used. >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0__atomic_add_long(p, v, t) =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0long atomic_add not implemented >> #endif > > atomic_add_long() should never be supported, but it is (mis)used in > standard kernel files so not having it will break more than just LINT. > But the above is not atomic_add_long()...hacks are used below to make > that sort of work. In which sense "should never be supported"? If you are on a 64 bit arch and you want and atomic operation for long you are supposed to use 64-bit version directly? I don't get the point. >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_acq_64 =C2=A0 =C2=A0 =C2= =A0 atomic_add_acq_long >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_rel_64 =C2=A0 =C2=A0 =C2= =A0 atomic_add_rel_long >> + >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_ptr(p, v) =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_long((volatile u_long *)(p), (u_long)(= v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_acq_ptr(p, v) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_acq_long((volatile u_long *)(p), (u_lo= ng)(v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_rel_ptr(p, v) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_rel_long((volatile u_long *)(p), (u_lo= ng)(v)) > > This uses bogus casts to break warnings. =C2=A0amd64 is still missing thi= s bug. > Someone added this bug to i386 after reviewers objected to it. =C2=A0Even= i386 > only has this bug for accesses to pointers. =C2=A0For char/short/long, it= uses > type-safe code with separate functions/#defines like the ones for int. I'll probabilly may have get from the i386 version, I'll verify, thanks. > The casts for pointers break jhb's intentions that: > - atomic accesses to pointers should be rare > - when they are needed, the caller must cast > > I don't know why we don't have separate functions/#defines for pointers, > but like not having the bloat for it. Nice history, I didn't know that explicitly, but I'll check that later along with the cast thing. >> +#else >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_long(p, v) =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_int((volatile u_int *)(p), (u_int)(v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_acq_long(p, v) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_acq_int((volatile u_int *)(p), (u_int)= (v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_rel_long(p, v) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_rel_int((volatile u_int *)(p), (u_int)= (v)) >> + >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_ptr(p, v) =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_int((volatile u_int *)(p), (u_int)(v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_acq_ptr(p, v) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_acq_int((volatile u_int *)(p), (u_int)= (v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_add_rel_ptr(p, v) =C2=A0 =C2= =A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_add_rel_int((volatile u_int *)(p), (u_int)= (v)) >> +#endif > > Now you need the bogus casts for the longs, since although atomic > accesses to longs should be rarer than ones to pointers (never on MI code= ), > it is not intended that the caller must bogusly cast for them, especially > since the bogus casts are MD. > > The bogus casts for the pointers should have no effect except to break > warnings in new code, since at least old MI code must already have the > casts in callers else it wouldn't compile on amd64. > >> [... often I snip bits without noting this as here] >> -#if 0 >> -_ATOMIC_CLEAR(8, 8, uint8_t) >> -_ATOMIC_CLEAR(8, char, u_char) >> -_ATOMIC_CLEAR(16, 16, uint16_t) >> -_ATOMIC_CLEAR(16, short, u_short) >> -#endif >> -_ATOMIC_CLEAR(32, 32, uint32_t) >> -_ATOMIC_CLEAR(32, int, u_int) >> -#ifdef __powerpc64__ >> -_ATOMIC_CLEAR(64, 64, uint64_t) >> -_ATOMIC_CLEAR(64, long, u_long) >> -_ATOMIC_CLEAR(64, ptr, uintptr_t) >> -#else >> -_ATOMIC_CLEAR(32, long, u_long) >> -_ATOMIC_CLEAR(32, ptr, uintptr_t) >> -#endif > > Seems a better way, and still used on amd64 and i386, to generate > separate type-safe code for each type supported. =C2=A0Here the only erro= r > relative to amd64 and i386 seems to have been to generate from long > to a 32/64 suffix and #define from that back to a long suffix, instead > of to generate from long to a long suffix and #define from that to a > 32/64 suffix. I'm a bit confused on what you are stating here exactly... are in favor of this change or not? >> ... >> @@ -622,39 +638,59 @@ atomic_cmpset_rel_long(volatile u_long * >> =C2=A0 =C2=A0 =C2=A0 =C2=A0return (atomic_cmpset_long(p, cmpval, newval)= ); >> } >> >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_int =C2=A0 atomic_= cmpset_acq_32 >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_int =C2=A0 atomic_= cmpset_rel_32 >> - >> -#ifdef __powerpc64__ >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_ptr(dst, old, new)= =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A0atomic_cmpset_acq_long((volatile u_long *)(dst), (u_long)= (old), >> (u_long)(new)) >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_ptr(dst, old, new)= =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A0atomic_cmpset_rel_long((volatile u_long *)(dst), (u_long)= (old), >> (u_long)(new)) >> -#else >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_ptr(dst, old, new)= =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A0atomic_cmpset_acq_32((volatile u_int *)(dst), (u_int)(old= ), >> (u_int)(new)) >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_ptr(dst, old, new)= =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A0atomic_cmpset_rel_32((volatile u_int *)(dst), (u_int)(old= ), >> (u_int)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_64 =C2=A0 =C2=A0 =C2= =A0 =C2=A0atomic_cmpset_long >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_64 =C2=A0 =C2=A0at= omic_cmpset_acq_long >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_64 =C2=A0 =C2=A0at= omic_cmpset_rel_long >> + >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_ptr(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0\ > > No bogus casts for these now. > >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_long((volatile u_long *)(dst), (u_l= ong)(old), =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_long)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_ptr(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_acq_long((volatile u_long *)(dst), = (u_long)(old), \ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_long)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_ptr(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_rel_long((volatile u_long *)(dst), = (u_long)(old), \ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_long)(new)) > > These bogus casts seem more bogus than before -- they seem to do nothing > except break type safety, since you already have functions with the right > suffixes and types (except the suffix says `long' but only u_longs are > supported). > >> +#else >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_long(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_int((volatile u_int *)(dst), (u_int= )(old), =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_int)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_long(dst, old, new= ) >> =C2=A0 =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_acq_int((volatile u_int *)(dst), (u= _int)(old), =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_int)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_long(dst, old, new= ) >> =C2=A0 =C2=A0 =C2=A0 \ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_rel_int((volatile u_int *)(dst), (u= _int)(old), =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_int)(new)) > > Usual bogus casts to type-pun from long to int in the 32-bit case. =C2=A0= Even > here, the ones on the non-pointer args have no useful effect. > >> + >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_ptr(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_int((volatile u_int *)(dst), (u_int= )(old), =C2=A0 =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_int)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_acq_ptr(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_acq_int((volatile u_int *)(dst), (u= _int)(old), =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_int)(new)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_cmpset_rel_ptr(dst, old, new) >> =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 atomic_cmpset_rel_int((volatile u_int *)(dst), (u= _int)(old), =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 (u_int)(new)) >> #endif > > Usual bogus casts for the pointer case. > >> #ifdef __powerpc64__ >> -static __inline uint64_t >> -atomic_fetchadd_64(volatile uint64_t *p, uint64_t v) >> +static __inline u_long >> +atomic_fetchadd_long(volatile u_long *p, u_long v) >> { >> - =C2=A0 =C2=A0 =C2=A0 uint64_t value; >> + =C2=A0 =C2=A0 =C2=A0 u_long value; >> >> =C2=A0 =C2=A0 =C2=A0 =C2=A0do { >> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value =3D *p; >> @@ -662,10 +698,10 @@ atomic_fetchadd_64(volatile uint64_t *p, >> =C2=A0 =C2=A0 =C2=A0 =C2=A0return (value); >> } >> >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_fetchadd_long =C2=A0 =C2=A0at= omic_fetchadd_64 >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_fetchadd_64 =C2=A0 =C2=A0 =C2= =A0atomic_fetchadd_long >> #else >> -#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_fetchadd_long(p, v) =C2=A0 = =C2=A0 =C2=A0\ >> - =C2=A0 =C2=A0(u_long)atomic_fetchadd_32((volatile u_int *)(p), (u_int)= (v)) >> +#define =C2=A0 =C2=A0 =C2=A0 =C2=A0atomic_fetchadd_long(p, v) >> =C2=A0 =C2=A0 =C2=A0\ >> + =C2=A0 =C2=A0 =C2=A0 (u_long)atomic_fetchadd_int((volatile u_int *)(p)= , (u_int)(v)) > > i386 uses a function to type-pun from fetchadd_long to fetchadd_int(). > This has minor technical advantages. =C2=A0Why be different? I'm not entirely sure what you mean with 'function to type-pun' but will look at that as well, thanks. Attilio --=20 Peace can only be achieved by understanding - A. Einstein
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?BANLkTi=mnZc6fy8TGpLMsMLDV8UpK5J-Gw>