[PATCH] powerpc: add the missing required isync for the coherent icache flush

[Kevin Hao]

On Mon, Aug 19, 2013 at 01:37:17PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2013-08-19 at 13:36 +1000, Benjamin Herrenschmidt wrote:
> 
> > 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.
> 
> In fact, on P5 and later, I think we are supposed to do a single dummy
> icbi followed by sync and isync.

Do you mean something like this? But why?

diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
index d74fefb..8fcdec7 100644
--- a/arch/powerpc/kernel/misc_64.S
+++ b/arch/powerpc/kernel/misc_64.S
@@ -69,6 +69,8 @@ PPC64_CACHES:
 
 _KPROBE(flush_icache_range)
 BEGIN_FTR_SECTION
+	icbi	0,r3
+	sync
 	isync
 	blr
 END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
@@ -209,6 +211,8 @@ _GLOBAL(flush_inval_dcache_range)
  */
 _GLOBAL(__flush_dcache_icache)
 BEGIN_FTR_SECTION
+	icbi	0,r3
+	sync
 	isync
 	blr
 END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)

Thanks,
Kevin

> 
> Cheers,
> Ben.
> 
> > 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 at lists.ozlabs.org
> > > > https://lists.ozlabs.org/listinfo/linuxppc-dev
> > > 
> > 
> 
> 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 490 bytes
Desc: not available
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20130819/360fe2e0/attachment.sig>