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Commit 3910a7f4 authored by Michael Ellerman's avatar Michael Ellerman
Browse files

powerpc/mm: Add pte_xchg() helper 



We have five locations in 64-bit hash MMU code that do a cmpxchg() of a
PTE. Currently doing it inline OK, but in a future patch we will be
converting the PTEs to __be64 in some configs. In that case we will need
casts at every cmpxchg() site in order to keep sparse happy.

So move the logic into a helper, this is a reasonably nice cleanup on
its own.

Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 4bece39b

arch/powerpc/include/asm/kvm_book3s_64.h

+1 −4
Original line number Diff line number Diff line
@@ -319,12 +319,9 @@ static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing) 
		if (writing && pte_write(old_pte))

			new_pte = pte_mkdirty(new_pte);



		if (pte_val(old_pte) == __cmpxchg_u64((unsigned long *)ptep,

						      pte_val(old_pte),

						      pte_val(new_pte))) {

		if (pte_xchg(ptep, old_pte, new_pte))

			break;

	}

	}

	return new_pte;

}

arch/powerpc/include/asm/pgtable-types.h

+12 −0
Original line number Diff line number Diff line
@@ -54,4 +54,16 @@ typedef struct { pte_t pte; unsigned long hidx; } real_pte_t; 
#else

typedef struct { pte_t pte; } real_pte_t;

#endif



#ifdef CONFIG_PPC_STD_MMU_64

#include <asm/cmpxchg.h>



static inline bool pte_xchg(pte_t *ptep, pte_t old, pte_t new)

{

	unsigned long *p = (unsigned long *)ptep;



	return pte_val(old) == __cmpxchg_u64(p, pte_val(old), pte_val(new));

}

#endif



#endif /* _ASM_POWERPC_PGTABLE_TYPES_H */

arch/powerpc/mm/hash64_4k.c

+2 −2
Original line number Diff line number Diff line
@@ -47,8 +47,8 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, 
		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;

		if (access & _PAGE_RW)

			new_pte |= _PAGE_DIRTY;

	} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,

					  old_pte, new_pte));

	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));



	/*

	 * PP bits. _PAGE_USER is already PP bit 0x2, so we only

	 * need to add in 0x1 if it's a read-only user page

arch/powerpc/mm/hash64_64k.c

+3 −4
Original line number Diff line number Diff line
@@ -79,8 +79,8 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, 
		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED | _PAGE_COMBO;

		if (access & _PAGE_RW)

			new_pte |= _PAGE_DIRTY;

	} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,

					  old_pte, new_pte));

	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));



	/*

	 * Handle the subpage protection bits

	 */
@@ -254,8 +254,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access, 
		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;

		if (access & _PAGE_RW)

			new_pte |= _PAGE_DIRTY;

	} while (old_pte != __cmpxchg_u64((unsigned long *)ptep,

					  old_pte, new_pte));

	} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));



	rflags = htab_convert_pte_flags(new_pte);

arch/powerpc/mm/hugetlbpage-hash64.c

+2 −2
Original line number Diff line number Diff line
@@ -57,8 +57,8 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, 
		new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;

		if (access & _PAGE_RW)

			new_pte |= _PAGE_DIRTY;

	} while(old_pte != __cmpxchg_u64((unsigned long *)ptep,

					 old_pte, new_pte));

	} while(!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));



	rflags = htab_convert_pte_flags(new_pte);



	sz = ((1UL) << shift);