On Mon, 2014-01-20 at 00:03 -0600, Wang Dongsheng-B40534 wrote: > > > > > + /* > > > > > + * Need to save float-point registers if MSR[FP] = 1. > > > > > + */ > > > > > + mfmsr r12 > > > > > + andi. r12, r12, MSR_FP > > > > > + beq 1f > > > > > + do_sr_fpr_regs(save) > > > > > > > > C code should have already ensured that MSR[FP] is not 1 (and thus the > > > > FP > > > > context has been saved). > > > > > > > > > > Yes, right. But I mean if the FP still use in core save flow, we need to > > > save > > it. > > > In this process, i don't care what other code do, we need to focus on not > > losing > > > valuable data. > > > > It is not allowed to use FP at that point. > > > If MSR[FP] not active, that is FP not allowed to use. > But here is a normal judgment, if MSR[FP] is active, this means that the > floating > point module is being used. I offer is a function of the interface, we don't > know > where is the function will be called. Just because we call this function in > the > context of uncertainty, we need this judgment to ensure that no data is lost.
The whole point of calling enable_kernel_fp() in C code before suspending is to ensure that the FP state gets saved. If FP is used after that point it is a bug. If you're worried about such bugs, then clear MSR[FP] after calling enable_kernel_fp(), rather than adding redundant state saving. -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
