On Thu, 2006-12-14 at 14:58 -0500, Kyle McMartin wrote: > I posted a patch to Paul this week to fix this,
Hm, I didn't see it on linuxppc-dev. > Since ppc32 can't do a 64bit comparison on its own it seems, gcc > will generate a call to a helper function from libgcc. What other > arches do is link libgcc.a into libs-y, and export the symbol > they want from it. You still get to 'accidentally' do 64-bit arithmetic in-kernel that way though. Might be better just to provide __ucmpdi2, just as we have for the other functions which are required from libgcc It'd be better just to fix the compiler though -- which is in fact what they've done: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25724 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21237 I've applied this as a temporary hack to the Fedora kernel until the compiler is updated there... --- linux-2.6.19.ppc/arch/powerpc/kernel/misc_32.S~ 2006-11-29 21:57:37.000000000 +0000 +++ linux-2.6.19.ppc/arch/powerpc/kernel/misc_32.S 2006-12-17 12:19:48.000000000 +0000 @@ -728,6 +728,27 @@ _GLOBAL(__lshrdi3) or r4,r4,r7 # LSW |= t2 blr +/* + * __ucmpdi2: 64-bit comparison + * + * R3/R4 has 64 bit value A + * R5/R6 has 64 bit value B + * result in R3: 0 for A < B + * 1 for A == B + * 2 for A > B + */ +_GLOBAL(__ucmpdi2) + cmplw r7,r3,r5 # compare high words + li r3,0 + blt r7,2f # a < b ... return 0 + bgt r7,1f # a > b ... return 2 + cmplw r6,r4,r6 # compare low words + blt r6,2f # a < b ... return 0 + li r3,1 + ble r6,2f # a = b ... return 1 +1: li r3,2 +2: blr + _GLOBAL(abs) srawi r4,r3,31 xor r3,r3,r4 --- linux-2.6.19.ppc/arch/powerpc/kernel/ppc_ksyms.c~ 2006-12-15 17:19:56.000000000 +0000 +++ linux-2.6.19.ppc/arch/powerpc/kernel/ppc_ksyms.c 2006-12-17 12:16:54.000000000 +0000 @@ -161,9 +161,11 @@ EXPORT_SYMBOL(to_tm); long long __ashrdi3(long long, int); long long __ashldi3(long long, int); long long __lshrdi3(long long, int); +int __ucmpdi2(uint64_t, uint64_t); EXPORT_SYMBOL(__ashrdi3); EXPORT_SYMBOL(__ashldi3); EXPORT_SYMBOL(__lshrdi3); +EXPORT_SYMBOL(__ucmpdi2); #endif EXPORT_SYMBOL(memcpy); -- dwmw2 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
