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MIPS: do not call flush_tlb_all when setting pmd entry

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Function set_pmd_at is to set pmd entry, if tlb entry need to be flushed,
there exists pmdp_huge_clear_flush alike function before set_pmd_at is
called.  So it is not necessary to call flush_tlb_all in this function.

In these scenarios, tlb for the pmd range needs to be flushed:

 - privilege degrade such as wrprotect is set on the pmd entry

 - pmd entry is cleared

 - there is exception if set_pmd_at is issued by dup_mmap, since
   flush_tlb_mm is called for parent process, it is not necessary to
   flush tlb in function copy_huge_pmd.

Link: http://lkml.kernel.org/r/1592990792-1923-3-git-send-email-maobibo@loongson.cn
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Daniel Silsby <dansilsby@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Bibo Mao 2021-02-24 12:06:46 -08:00 committed by Linus Torvalds
parent fca40573e0
commit aba677f94b
2 changed files with 0 additions and 2 deletions
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1
arch/mips/mm/pgtable-32.c
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@ -45,7 +45,6 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd) pmd_t *pmdp, pmd_t pmd)
{ {
*pmdp = pmd; *pmdp = pmd;
flush_tlb_all();
} }
#endif /* defined(CONFIG_TRANSPARENT_HUGEPAGE) */ #endif /* defined(CONFIG_TRANSPARENT_HUGEPAGE) */

1
arch/mips/mm/pgtable-64.c
View File

@ -100,7 +100,6 @@ void set_pmd_at(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp, pmd_t pmd) pmd_t *pmdp, pmd_t pmd)
{ {
*pmdp = pmd; *pmdp = pmd;
flush_tlb_all();
} }
void __init pagetable_init(void) void __init pagetable_init(void)