linux-kernel - [PATCH 14/18] ARC: mm: hack to allow 2 level build with 4 level code

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Date:   Tue, 10 Aug 2021 17:42:54 -0700
From:   Vineet Gupta <vgupta@...nel.org>
To:     linux-snps-arc@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Anshuman Khandual <anshuman.khandual@....com>,
        Mike Rapoport <rppt@...nel.org>,
        Vineet Gupta <vgupta@...nel.org>
Subject: [PATCH 14/18] ARC: mm: hack to allow 2 level build with 4 level code

PMD_SHIFT is mapped to PUD_SHIFT or PGD_SHIFT by asm-generic/pgtable-*
but only for !__ASSEMBLY__

tlbex.S asm code has PTRS_PER_PTE which uses PMD_SHIFT hence barfs
for CONFIG_PGTABLE_LEVEL={2,3} and works for 4.

So add a workaround local to tlbex.S - the proper fix is to change
asm-generic/pgtable-* headers to expose the defines for __ASSEMBLY__ too

Signed-off-by: Vineet Gupta <vgupta@...nel.org>
---
 arch/arc/mm/tlbex.S | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arc/mm/tlbex.S b/arch/arc/mm/tlbex.S
index 6b5872197005..d08bd09a0afc 100644
--- a/arch/arc/mm/tlbex.S
+++ b/arch/arc/mm/tlbex.S
@@ -145,6 +145,14 @@ ex_saved_reg1:
 ;TLB Miss handling Code
 ;============================================================================
 
+#ifndef PMD_SHIFT
+#define PMD_SHIFT PUD_SHIFT
+#endif
+
+#ifndef PUD_SHIFT
+#define PUD_SHIFT PGDIR_SHIFT
+#endif
+
 ;-----------------------------------------------------------------------------
 ; This macro does the page-table lookup for the faulting address.
 ; OUT: r0 = PTE faulted on, r1 = ptr to PTE, r2 = Faulting V-address
-- 
2.25.1