Patch "powerpc/nohash: Fix use of mmu_has_feature() in setup_initial_memory_limit()" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    powerpc/nohash: Fix use of mmu_has_feature() in setup_initial_memory_limit()

to the 4.9-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-nohash-fix-use-of-mmu_has_feature-in-setup_initial_memory_limit.patch
and it can be found in the queue-4.9 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 foo@baz Sun Mar 18 16:55:33 CET 2018
From: Michael Ellerman <mpe@ellerman.id.au>
Date: Mon, 3 Apr 2017 12:05:55 +1000
Subject: powerpc/nohash: Fix use of mmu_has_feature() in setup_initial_memory_limit()

From: Michael Ellerman <mpe@ellerman.id.au>


[ Upstream commit 4868e3508d1934d28961f940ed6b9f1e347ab52c ]

setup_initial_memory_limit() is called from early_init_devtree(), which
runs prior to feature patching. If the kernel is built with CONFIG_JUMP_LABEL=y
and CONFIG_JUMP_LABEL_FEATURE_CHECKS=y then we will potentially get the
wrong value.

If we also have CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG=y we get a warning
and backtrace:

  Warning! mmu_has_feature() used prior to jump label init!
  CPU: 0 PID: 0 Comm: swapper Not tainted 4.11.0-rc4-gccN-next-20170331-g6af2434 #1
  Call Trace:
  [c000000000fc3d50] [c000000000a26c30] .dump_stack+0xa8/0xe8 (unreliable)
  [c000000000fc3de0] [c00000000002e6b8] .setup_initial_memory_limit+0xa4/0x104
  [c000000000fc3e60] [c000000000d5c23c] .early_init_devtree+0xd0/0x2f8
  [c000000000fc3f00] [c000000000d5d3b0] .early_setup+0x90/0x11c
  [c000000000fc3f90] [c000000000000520] start_here_multiplatform+0x68/0x80

Fix it by using early_mmu_has_feature().

Fixes: c12e6f24d413 ("powerpc: Add option to use jump label for mmu_has_feature()")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/powerpc/mm/tlb_nohash.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c
@@ -751,7 +751,7 @@ void setup_initial_memory_limit(phys_add
 	 * avoid going over total available memory just in case...
 	 */
 #ifdef CONFIG_PPC_FSL_BOOK3E
-	if (mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
+	if (early_mmu_has_feature(MMU_FTR_TYPE_FSL_E)) {
 		unsigned long linear_sz;
 		unsigned int num_cams;
 


Patches currently in stable-queue which might be from mpe@ellerman.id.au are

queue-4.9/powerpc-nohash-fix-use-of-mmu_has_feature-in-setup_initial_memory_limit.patch
queue-4.9/powerpc-avoid-taking-a-data-miss-on-every-userspace-instruction-miss.patch
queue-4.9/powerpc-modules-don-t-try-to-restore-r2-after-a-sibling-call.patch
queue-4.9/powerpc-xmon-fix-an-unexpected-xmon-on-off-state-change.patch
queue-4.9/powerpc-mm-hugetlb-filter-out-hugepage-size-not-supported-by-page-table-layout.patch