linux-kernel - [PATCH 5.6 111/126] sparc32: use PUD rather than PGD to get PMD in srmmu_nocache

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Date:   Tue, 26 May 2020 20:54:08 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, kbuild test robot <lkp@...el.com>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "David S. Miller" <davem@...emloft.net>,
        Anatoly Pugachev <matorola@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 5.6 111/126] sparc32: use PUD rather than PGD to get PMD in srmmu_nocache_init()

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

commit c2bc26f7ca1ff1165bb6669a7a4cccc20ffd2ced upstream.

The kbuild test robot reported the following warning:

  arch/sparc/mm/srmmu.c: In function 'srmmu_nocache_init': arch/sparc/mm/srmmu.c:300:9: error: variable 'pud' set but not used [-Werror=unused-but-set-variable]
  300 |  pud_t *pud;

This warning is caused by misprint in the page table traversal in
srmmu_nocache_init() function which accessed a PMD entry using PGD
rather than PUD.

Since sparc32 has only 3 page table levels, the PGD and PUD are
essentially the same and usage of __nocache_fix() removed the type
checking.

Use PUD for the consistency and to silence the compiler warning.

Fixes: 7235db268a2777bc38 ("sparc32: use pgtable-nopud instead of 4level-fixup")
Reported-by: kbuild test robot <lkp@...el.com>
Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Cc: David S. Miller <davem@...emloft.net>
Cc: Anatoly Pugachev <matorola@...il.com>
Cc: <stable@...r.kernel.org>
Link: http://lkml.kernel.org/r/20200520132005.GM1059226@linux.ibm.com
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/sparc/mm/srmmu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/sparc/mm/srmmu.c
+++ b/arch/sparc/mm/srmmu.c
@@ -333,7 +333,7 @@ static void __init srmmu_nocache_init(vo
 		pgd = pgd_offset_k(vaddr);
 		p4d = p4d_offset(__nocache_fix(pgd), vaddr);
 		pud = pud_offset(__nocache_fix(p4d), vaddr);
-		pmd = pmd_offset(__nocache_fix(pgd), vaddr);
+		pmd = pmd_offset(__nocache_fix(pud), vaddr);
 		pte = pte_offset_kernel(__nocache_fix(pmd), vaddr);

 		pteval = ((paddr >> 4) | SRMMU_ET_PTE | SRMMU_PRIV);