On Thu, Jul 05, 2018 at 08:00:08PM +0200, Peter Zijlstra wrote: > On Mon, Jul 02, 2018 at 01:30:14AM +0800, Guo Ren wrote: > > +#ifdef CONFIG_CPU_HAS_LDSTEX > > +ENTRY(csky_cmpxchg) > > + USPTOKSP > > + mfcr a3, epc > > + INCTRAP a3 > > + > > + subi sp, 8 > > + stw a3, (sp, 0) > > + mfcr a3, epsr > > + stw a3, (sp, 4) > > + > > + psrset ee > > +1: > > + ldex a3, (a2) > > + cmpne a0, a3 > > + bt16 2f > > + mov a3, a1 > > + stex a3, (a2) > > + bez a3, 1b > > +2: > > + sync.is > > + mvc a0 > > + ldw a3, (sp, 0) > > + mtcr a3, epc > > + ldw a3, (sp, 4) > > + mtcr a3, epsr > > + addi sp, 8 > > + KSPTOUSP > > + rte > > +END(csky_cmpxchg) > > +#else > > Please explain... if the CPU has LDEX/STEX, then _why_ do you need this? Our libc use csky_cmpxchg and we want it compatible. Of course, we'll also implement the ldex/stex atomic operations in libs in future. Guo Ren
