Re: Kernel 4.7: PAGE_GUARDED and _PAGE_NO_CACHE

From: Michael Ellerman <mpe@ellerman.id.au>
To: Christian Zigotzky <chzigotzky@xenosoft.de>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	Darren Stevens <darren@stevens-zone.net>,
	 Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	linuxppc-dev@lists.ozlabs.org,
	Michael Ellerman <michaele@au1.ibm.com>,
	 Julian Margetson <runaway@candw.ms>,
	Adrian Cox <adrian@humboldt.co.uk>,
	"R.T.Dickinson" <rtd@a-eon.com>,
	"R.T.Dickinson" <rtd2@xtra.co.nz>, Pat Wall <pjwall@mac.com>,
	 Pat Wall <pjwall@me.com>,
	"contact@a-eon.com" <contact@a-eon.com>,
	Matthew Leaman <matthew@a-eon.biz>,
	 luigi burdo <intermediadc@hotmail.com>,
	Christian Zigotzky <info@xenosoft.de>
Subject: Re: Kernel 4.7: PAGE_GUARDED and _PAGE_NO_CACHE
Date: Thu, 09 Jun 2016 21:15:10 +1000	[thread overview]
Message-ID: <1465470910.31662.10.camel@ellerman.id.au> (raw)
In-Reply-To: <bab57839-0160-ae01-3cfb-6950067652c0@xenosoft.de>

On Thu, 2016-06-09 at 10:48 +0200, Christian Zigotzky wrote:

> Shall I modify the workaround? Is the workaround for lack of the device 
> tree the problem?

I don't think so.

You could try this patch to try and isolate it:

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 88a5ecaa157b..ae2f2705e8a0 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -251,7 +251,7 @@ extern unsigned long ioremap_bot;
  *  PHB_IO_BASE = ISA_IO_BASE + 64K to ISA_IO_BASE + 2G, PHB IO spaces
  * IOREMAP_BASE = ISA_IO_BASE + 2G to VMALLOC_START + PGTABLE_RANGE
  */
-#define KERN_IO_START	(KERN_VIRT_START + (KERN_VIRT_SIZE >> 1))
+#define KERN_IO_START	(H_KERN_VIRT_START + (H_KERN_VIRT_SIZE >> 1))
 #define FULL_IO_SIZE	0x80000000ul
 #define  ISA_IO_BASE	(KERN_IO_START)
 #define  ISA_IO_END	(KERN_IO_START + 0x10000ul)


cheers
