Hi Paul, On Tue, Jan 23, 2018 at 04:49:16PM +1100, Paul Mackerras wrote: > On Thu, Jan 11, 2018 at 06:11:17PM +0800, wei.guo.si...@gmail.com wrote: > > From: Simon Guo <wei.guo.si...@gmail.com> > > > > Currently _kvmppc_save/restore_tm() APIs can only be invoked from > > assembly function. This patch adds C function wrappers for them so > > that they can be safely called from C function. > > > > Signed-off-by: Simon Guo <wei.guo.si...@gmail.com> > > [snip] > > > --- a/arch/powerpc/include/asm/asm-prototypes.h > > +++ b/arch/powerpc/include/asm/asm-prototypes.h > > @@ -126,4 +126,11 @@ unsigned long __init prom_init(unsigned long r3, > > unsigned long r4, > > void _mcount(void); > > unsigned long prepare_ftrace_return(unsigned long parent, unsigned long > > ip); > > > > +#ifdef CONFIG_PPC_TRANSACTIONAL_MEM > > +/* Transaction memory related */ > > +struct kvm_vcpu; > > +void _kvmppc_restore_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr); > > +void _kvmppc_save_tm_pr(struct kvm_vcpu *vcpu, u64 guest_msr); > > +#endif > > It's not generally necessary to have ifdefs around function > declarations. If the function is never defined because the feature > is not configured in, that is fine. > Got it. Thanks.
> > @@ -149,6 +149,58 @@ _GLOBAL(kvmppc_save_tm) > > blr > > > > /* > > + * _kvmppc_save_tm() is a wrapper around __kvmppc_save_tm(), so that it can > > + * be invoked from C function by PR KVM only. > > + */ > > +_GLOBAL(_kvmppc_save_tm_pr) > > + mflr r5 > > + std r5, PPC_LR_STKOFF(r1) > > + stdu r1, -SWITCH_FRAME_SIZE(r1) > > + SAVE_NVGPRS(r1) > > + > > + /* save MSR since TM/math bits might be impacted > > + * by __kvmppc_save_tm(). > > + */ > > + mfmsr r5 > > + SAVE_GPR(5, r1) > > + > > + /* also save DSCR/CR so that it can be recovered later */ > > + mfspr r6, SPRN_DSCR > > + SAVE_GPR(6, r1) > > + > > + mfcr r7 > > + stw r7, _CCR(r1) > > + > > + /* allocate stack frame for __kvmppc_save_tm since > > + * it will save LR into its stackframe and we don't > > + * want to corrupt _kvmppc_save_tm_pr's. > > + */ > > + stdu r1, -PPC_MIN_STKFRM(r1) > > You don't need to do this. In the PowerPC ELF ABI, functions always > save their LR (i.e. their return address) in their *caller's* stack > frame, not their own. You have established a stack frame for > _kvmppc_save_tm_pr above, and that is sufficient. Same comment > applies for _kvmppc_restore_tm_pr. Ah..yes. I need remove that. Thanks, - Simon
