Commit 8ef5cbde authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Linus Torvalds
Browse files

arch/powerpc/mm/hugetlb: NestMMU workaround for hugetlb mprotect RW upgrade 

NestMMU requires us to mark the pte invalid and flush the tlb when we do
a RW upgrade of pte.  We fixed a variant of this in the fault path in
bd5050e3 ("powerpc/mm/radix: Change pte relax sequence to handle
nest MMU hang").

Link: http://lkml.kernel.org/r/20190116085035.29729-6-aneesh.kumar@linux.ibm.com


Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 023bdd00

arch/powerpc/include/asm/book3s/64/hugetlb.h

+12 −0
Original line number Diff line number Diff line
@@ -13,6 +13,10 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 
				unsigned long len, unsigned long pgoff,

				unsigned long flags);



extern void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,

						unsigned long addr, pte_t *ptep,

						pte_t old_pte, pte_t pte);



static inline int hstate_get_psize(struct hstate *hstate)

{

	unsigned long shift;
@@ -42,4 +46,12 @@ static inline bool gigantic_page_supported(void) 
/* hugepd entry valid bit */

#define HUGEPD_VAL_BITS		(0x8000000000000000UL)



#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start

extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,

					 unsigned long addr, pte_t *ptep);



#define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit

extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,

					 unsigned long addr, pte_t *ptep,

					 pte_t old_pte, pte_t new_pte);

#endif

arch/powerpc/mm/hugetlbpage-hash64.c

+25 −0
Original line number Diff line number Diff line
@@ -121,3 +121,28 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, 
	*ptep = __pte(new_pte & ~H_PAGE_BUSY);

	return 0;

}



pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,

				  unsigned long addr, pte_t *ptep)

{

	unsigned long pte_val;

	/*

	 * Clear the _PAGE_PRESENT so that no hardware parallel update is

	 * possible. Also keep the pte_present true so that we don't take

	 * wrong fault.

	 */

	pte_val = pte_update(vma->vm_mm, addr, ptep,

			     _PAGE_PRESENT, _PAGE_INVALID, 1);



	return __pte(pte_val);

}



void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,

				  pte_t *ptep, pte_t old_pte, pte_t pte)

{



	if (radix_enabled())

		return radix__huge_ptep_modify_prot_commit(vma, addr, ptep,

							   old_pte, pte);

	set_huge_pte_at(vma->vm_mm, addr, ptep, pte);

}

arch/powerpc/mm/hugetlbpage-radix.c

+17 −0
Original line number Diff line number Diff line
@@ -90,3 +90,20 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 


	return vm_unmapped_area(&info);

}



void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,

					 unsigned long addr, pte_t *ptep,

					 pte_t old_pte, pte_t pte)

{

	struct mm_struct *mm = vma->vm_mm;



	/*

	 * To avoid NMMU hang while relaxing access we need to flush the tlb before

	 * we set the new value.

	 */

	if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) &&

	    (atomic_read(&mm->context.copros) > 0))

		radix__flush_hugetlb_page(vma, addr);



	set_huge_pte_at(vma->vm_mm, addr, ptep, pte);

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE