"Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com> writes:
> Benjamin Herrenschmidt <b...@kernel.crashing.org> writes: > >> On Wed, 2016-04-27 at 11:00 +1000, Balbir Singh wrote: >>> Just basic testing across CPUs with various mm features >>> enabled/disabled. Just for sanity >> >> I still don't think it's worth scattering the change. Either the jump >> label works or it doesn't ... The only problem is make sure we identify >> all the pre-boot ones but that's about it. >> > > There are two ways to do this. One is to follow the approach listed > below done by Kevin, which is to do the jump_label_init early during boot and > switch both cpu and mmu feature check to plain jump label. > > http://mid.gmane.org/1440415228-8006-1-git-send-email-haoke...@gmail.com > > I already found one use case of cpu_has_feature before that > jump_label_init. In this approach we need to carefully audit all the > cpu/mmu_has_feature calls to make sure they don't get called before > jump_label_init. A missed conversion mean we miss a cpu/mmu feature > check. > > > Other option is to follow the patch I posted above, with the simple > change of renaming mmu_feature_enabled to mmu_has_feature. So we can > use it in early boot without really worrying about when we init jump > label. > > What do you suggest we follow ? > Something simple as below ? diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h index 696b7c5cc31f..0835a8f9904b 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu.h +++ b/arch/powerpc/include/asm/book3s/64/mmu.h @@ -23,7 +23,7 @@ struct mmu_psize_def { }; extern struct mmu_psize_def mmu_psize_defs[MMU_PAGE_COUNT]; -#define radix_enabled() mmu_feature_enabled(MMU_FTR_RADIX) +#define radix_enabled() mmu_has_feature(MMU_FTR_RADIX) #endif /* __ASSEMBLY__ */ diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h index fdb70dc218e5..d4b726f5bd4a 100644 --- a/arch/powerpc/include/asm/mmu.h +++ b/arch/powerpc/include/asm/mmu.h @@ -115,7 +115,7 @@ DECLARE_PER_CPU(int, next_tlbcam_idx); #endif -static inline int mmu_has_feature(unsigned long feature) +static inline int __mmu_has_feature(unsigned long feature) { return (cur_cpu_spec->mmu_features & feature); } @@ -145,7 +145,7 @@ static inline void assert_pte_locked(struct mm_struct *mm, unsigned long addr) #endif /* !CONFIG_DEBUG_VM */ #ifdef HAVE_JUMP_LABEL -static __always_inline bool mmu_feature_enabled(unsigned long feature) +static __always_inline bool mmu_has_feature(unsigned long feature) { asm_volatile_goto("1:\n\t" ".pushsection __mmu_ftr_fixup_c, \"a\"\n\t" @@ -155,7 +155,7 @@ static __always_inline bool mmu_feature_enabled(unsigned long feature) JUMP_ENTRY_TYPE "%l[l_false]\n\t" ".popsection\n\t" : : "i"(feature) : : l_true, l_false); - if (mmu_has_feature(feature)) + if (__mmu_has_feature(feature)) l_true: return true; l_false: _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
