[PATCH 01/15] mips: define pud_index() regardless of page table folding

[Huacai Chen <chenhc@lemote.com>]

From: Mike Rapoport <rppt@linux.ibm.com>

Commit 31168f033e37 ("mips: drop __pXd_offset() macros that duplicate
pXd_index() ones") is correct that pud_index() & __pud_offset() are the
same when pud_index() is actually provided, however it does not take into
account the __PAGETABLE_PUD_FOLDED case. This has broken MIPS KVM
compilation because it relied on availability of pud_index().

Define pud_index() regardless of page table folded. It will evaluate to
actual index for 4-level pagetables and to 0 for folded PUD level.

Link: https://lore.kernel.org/lkml/20200331154749.5457-1-pbonzini@redhat.com
Tested-by: Bibo Mao <maobibo@loongson.cn>
Tested-by: Huacai Chen <chenhc@lemote.com>
Reported-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
[Huacai: Add Tested-by and take this patch into my series, because my
         series can't build an available kernel if without this patch.]
Signed-off-by: Huacai Chen <chenhc@lemote.com>
---
 arch/mips/include/asm/pgtable-64.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
index f92716c..ee5dc0c 100644
--- a/arch/mips/include/asm/pgtable-64.h
+++ b/arch/mips/include/asm/pgtable-64.h
@@ -172,6 +172,8 @@
 
 extern pte_t invalid_pte_table[PTRS_PER_PTE];
 
+#define pud_index(address)	(((address) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
+
 #ifndef __PAGETABLE_PUD_FOLDED
 /*
  * For 4-level pagetables we defines these ourselves, for 3-level the
@@ -210,8 +212,6 @@ static inline void p4d_clear(p4d_t *p4dp)
 	p4d_val(*p4dp) = (unsigned long)invalid_pud_table;
 }
 
-#define pud_index(address)	(((address) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
-
 static inline unsigned long p4d_page_vaddr(p4d_t p4d)
 {
 	return p4d_val(p4d);
-- 
2.7.0