> -----邮件原件----- > 发件人: Maciej W. Rozycki <macro@xxxxxxxxxxx> > 发送时间: 2021年3月29日 23:06 > 收件人: yunqiang.su@xxxxxxxxxxxxx > 抄送: 'YunQiang Su' <wzssyqa@xxxxxxxxx>; 'Thomas Bogendoerfer' > <tsbogend@xxxxxxxxxxxxxxxx>; 'linux-mips' <linux-mips@xxxxxxxxxxxxxxx>; > 'Jiaxun Yang' <jiaxun.yang@xxxxxxxxxxx>; 'Philippe Mathieu-Daudé' > <f4bug@xxxxxxxxx>; stable@xxxxxxxxxxxxxxx > 主题: Re: 回复: [PATCH v7 RESEND] MIPS: force use FR=0 or FRE for FPXX > binaries > > On Mon, 22 Mar 2021, yunqiang.su@xxxxxxxxxxxxx wrote: > > > > I don't know why Google choose not to have their runtime support > > > library (the Go library) as a dynamic shared object 20-something > > > years on, but it comes at a price. So you either have to relink > > > (recompile) all the > > affected > > > applications like in the old days or find a feasible workaround. > > > > > > > I also have no idea why (even hate). > > While there do be some program languages created in recently years, > > prefer static link. > > Hmm, lost wisdom, or an orchestrated effort? Or a false illusion that since > we're virtually fully open source now, we can always rebuild the world? Well, > indeed this is technically possible, but whether it is feasible is another matter. > Your case serves as a counterexample. > > > > As I noted in the discussion the use of FR=0 would be acceptable > > > for FPXX binaries as far as I am concerned for R2 through R5, but > > > not the FRE mode > > for > > > R6. > > > > There will no FPXX for r6. All of (if not mistake) R6 O32 is FP64. > > FRE here is only for compatible with pre-R6 objects. > > That doesn't seem like a good choice to me. > > While R6 programs are indeed best built as FP64, libraries are best built as > FPXX, so that users can link or load with whatever binary modules they have, > including pre-R6 ones. As much as we may dislike it sources will not always > be available or rebuilding them may be beyond the capabilities of whoever > has the binaries, so I think the system should be as permissive as possible. > So you may end up with running code that is largely R6 (libraries), and partly > pre-R6 (application code) that ends up linked as FPXX. > Yes. It is the situation we talk about R6 in early days. While after some talk, we decide to figure out pure R6 systems. And I agree with your concern, since the Android is such an example: 64bit is R6, and 32bit is R2. So, the compatible of R2 object on R6 CPU is some important. > And the kernel has to support it in the best way possible too and avoid slow > emulation where not necessary e.g. in R6 libm code used in the FPXX > arrangement, which the FRE mode will inevitably lead to. > Yes. > Maciej
