On Mon, 2013-08-19 at 03:24 +0000, Wang Dongsheng-B40534 wrote: > > > -----Original Message----- > > From: Linuxppc-dev [mailto:linuxppc-dev- > > bounces+b40534=freescale....@lists.ozlabs.org] On Behalf Of Kevin Hao > > Sent: Thursday, August 15, 2013 7:56 PM > > To: Benjamin Herrenschmidt > > Cc: linuxppc > > Subject: [PATCH] powerpc: add the missing required isync for the coherent > > icache flush > > > > Even we don't need to flush the dcache and invalidate the icache > > on the CPU which has coherent icache. But we do need an isync to > > discard the prefetched instructions in this case. > > > > Signed-off-by: Kevin Hao <haoke...@gmail.com> > > --- > > arch/powerpc/kernel/misc_32.S | 2 ++ > > arch/powerpc/kernel/misc_64.S | 1 + > > 2 files changed, 3 insertions(+) > > > > diff --git a/arch/powerpc/kernel/misc_32.S > > b/arch/powerpc/kernel/misc_32.S > > index 777d999..0b84c8d 100644 > > --- a/arch/powerpc/kernel/misc_32.S > > +++ b/arch/powerpc/kernel/misc_32.S > > @@ -433,6 +433,7 @@ _GLOBAL(invalidate_dcache_range) > > */ > > _GLOBAL(__flush_dcache_icache) > > BEGIN_FTR_SECTION > > + isync > There is not touch the icache, why need we to do this?
The semantic of this function is to make data executable. Even if the implementation has a snooping icache, it *still* needs to make sure prefetched code is tossed out of the pipeline which is what isync should provide. The architecture actually specifies that. Cheers, Ben. > > blr > > END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) > > rlwinm r3,r3,0,0,31-PAGE_SHIFT /* Get page base address > > */ > > @@ -474,6 +475,7 @@ END_MMU_FTR_SECTION_IFSET(MMU_FTR_TYPE_44x) > > */ > > _GLOBAL(__flush_dcache_icache_phys) > > BEGIN_FTR_SECTION > > + isync > > blr /* for 601, do nothing */ > > END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) > > mfmsr r10 > > diff --git a/arch/powerpc/kernel/misc_64.S > > b/arch/powerpc/kernel/misc_64.S > > index 992a78e..d74fefb 100644 > > --- a/arch/powerpc/kernel/misc_64.S > > +++ b/arch/powerpc/kernel/misc_64.S > > @@ -69,6 +69,7 @@ PPC64_CACHES: > > > > _KPROBE(flush_icache_range) > > BEGIN_FTR_SECTION > > + isync > > blr > > END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) > > /* > > -- > > 1.8.3.1 > > > > _______________________________________________ > > Linuxppc-dev mailing list > > Linuxppc-dev@lists.ozlabs.org > > https://lists.ozlabs.org/listinfo/linuxppc-dev > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
