Patch "powerpc/mm: Fix lazy icache flush on pre-POWER5" has been added to the 4.8-stable tree

Patch "powerpc/mm: Fix lazy icache flush on pre-POWER5" has been added to the 4.8-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    powerpc/mm: Fix lazy icache flush on pre-POWER5

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-mm-fix-lazy-icache-flush-on-pre-power5.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From dd7b2f035ec41a409f7a7cec7aabc0ec0eacf476 Mon Sep 17 00:00:00 2001
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Tue, 29 Nov 2016 13:13:46 +1100
Subject: powerpc/mm: Fix lazy icache flush on pre-POWER5

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

commit dd7b2f035ec41a409f7a7cec7aabc0ec0eacf476 upstream.

On 64-bit CPUs with no-execute support and non-snooping icache, such as
970 or POWER4, we have a software mechanism to ensure coherency of the
cache (using exec faults when needed).

This was broken due to a logic error when the code was rewritten
from assembly to C, previously the assembly code did:

  BEGIN_FTR_SECTION
         mr      r4,r30
         mr      r5,r7
         bl      hash_page_do_lazy_icache
  END_FTR_SECTION(CPU_FTR_NOEXECUTE|CPU_FTR_COHERENT_ICACHE, CPU_FTR_NOEXECUTE)

Which tests that:
   (cpu_features & (NOEXECUTE | COHERENT_ICACHE)) == NOEXECUTE

Which says that the current cpu does have NOEXECUTE, but does not have
COHERENT_ICACHE.

Fixes: 91f1da99792a ("powerpc/mm: Convert 4k hash insert to C")
Fixes: 89ff725051d1 ("powerpc/mm: Convert __hash_page_64K to C")
Fixes: a43c0eb8364c ("powerpc/mm: Convert 4k insert from asm to C")
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[mpe: Change log verbosification]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/powerpc/mm/hash64_4k.c  |    2 +-
 arch/powerpc/mm/hash64_64k.c |    4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

--- a/arch/powerpc/mm/hash64_4k.c
+++ b/arch/powerpc/mm/hash64_4k.c
@@ -55,7 +55,7 @@ int __hash_page_4K(unsigned long ea, uns
 	 */
 	rflags = htab_convert_pte_flags(new_pte);
 
-	if (!cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
 	    !cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
 		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
 
--- a/arch/powerpc/mm/hash64_64k.c
+++ b/arch/powerpc/mm/hash64_64k.c
@@ -87,7 +87,7 @@ int __hash_page_4K(unsigned long ea, uns
 	subpg_pte = new_pte & ~subpg_prot;
 	rflags = htab_convert_pte_flags(subpg_pte);
 
-	if (!cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
 	    !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
 
 		/*
@@ -258,7 +258,7 @@ int __hash_page_64K(unsigned long ea, un
 
 	rflags = htab_convert_pte_flags(new_pte);
 
-	if (!cpu_has_feature(CPU_FTR_NOEXECUTE) &&
+	if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
 	    !cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
 		rflags = hash_page_do_lazy_icache(rflags, __pte(old_pte), trap);
 


Patches currently in stable-queue which might be from benh@kernel.crashing.org are

queue-4.8/powerpc-mm-fix-lazy-icache-flush-on-pre-power5.patch