2015-01-20 15:05 GMT+01:00 Kirill A. Shutemov [off-list ref]:

Russell King - ARM Linux wrote:

quoted

On Tue, Jan 20, 2015 at 02:16:43AM +0200, Kirill A. Shutemov wrote:

quoted

Better option would be converting 2-lvl ARM configuration to
<asm-generic/pgtable-nopmd.h>, but I'm not sure if it's possible.

Well, IMHO the folded approach in asm-generic was done the wrong way
which barred ARM from ever using it.

Okay, I see.

Regarding the topic bug. Completely untested patch is below. Could anybody
check if it helps?

From 34b9182d08ef2b541829e305fcc91ef1d26b27ea Mon Sep 17 00:00:00 2001
From: "Kirill A. Shutemov" <redacted>
Date: Tue, 20 Jan 2015 15:47:22 +0200
Subject: [PATCH] arm: define __PAGETABLE_PMD_FOLDED for !LPAE

ARM uses custom implementation of PMD folding in 2-level page table case.
Generic code expects to see __PAGETABLE_PMD_FOLDED to be defined if PMD is
folded, but ARM doesn't do this. Let's fix it.

Defining __PAGETABLE_PMD_FOLDED will drop out unused __pmd_alloc().
It also fixes problems with recently-introduced pmd accounting on ARM
without LPAE.

Signed-off-by: Kirill A. Shutemov <redacted>
Reported-by: Nishanth Menon <nm@ti.com>
---
 arch/arm/include/asm/pgtable-2level.h | 2 ++
 1 file changed, 2 insertions(+)

Helps for this issue on Exynos 4412 (Trats2) and Exynos 5420 (Arndale Octa):
Tested-by: Krzysztof Kozlowski <redacted>

Off-topic: "Using smp_processor_id() in preemptible" still screams [1]

[1] https://lkml.org/lkml/2015/1/20/162

Best regards,
Krzysztof