powerpc/mm: Move around testing of _PAGE_PRESENT in hash code
Instead of adding _PAGE_PRESENT to the access permission mask in each low level routine independently, we add it once from hash_page(). We also move the preliminary access check (the racy one before the PTE is locked) up so it applies to the huge page case. This duplicates code in __hash_page_huge() which we'll remove in a subsequent patch to fix a race in there. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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@ -68,9 +68,6 @@ _GLOBAL(__hash_page_4K)
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std r8,STK_PARM(r8)(r1)
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std r9,STK_PARM(r9)(r1)
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/* Add _PAGE_PRESENT to access */
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ori r4,r4,_PAGE_PRESENT
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/* Save non-volatile registers.
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* r31 will hold "old PTE"
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* r30 is "new PTE"
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@ -347,9 +344,6 @@ _GLOBAL(__hash_page_4K)
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std r8,STK_PARM(r8)(r1)
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std r9,STK_PARM(r9)(r1)
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/* Add _PAGE_PRESENT to access */
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ori r4,r4,_PAGE_PRESENT
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/* Save non-volatile registers.
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* r31 will hold "old PTE"
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* r30 is "new PTE"
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@ -687,9 +681,6 @@ _GLOBAL(__hash_page_64K)
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std r8,STK_PARM(r8)(r1)
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std r9,STK_PARM(r9)(r1)
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/* Add _PAGE_PRESENT to access */
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ori r4,r4,_PAGE_PRESENT
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/* Save non-volatile registers.
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* r31 will hold "old PTE"
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* r30 is "new PTE"
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@ -955,6 +955,17 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
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return 1;
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}
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/* Add _PAGE_PRESENT to the required access perm */
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access |= _PAGE_PRESENT;
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/* Pre-check access permissions (will be re-checked atomically
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* in __hash_page_XX but this pre-check is a fast path
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*/
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if (access & ~pte_val(*ptep)) {
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DBG_LOW(" no access !\n");
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return 1;
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}
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#ifdef CONFIG_HUGETLB_PAGE
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if (hugeshift)
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return __hash_page_huge(ea, access, vsid, ptep, trap, local,
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@ -967,14 +978,6 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
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DBG_LOW(" i-pte: %016lx %016lx\n", pte_val(*ptep),
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pte_val(*(ptep + PTRS_PER_PTE)));
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#endif
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/* Pre-check access permissions (will be re-checked atomically
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* in __hash_page_XX but this pre-check is a fast path
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*/
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if (access & ~pte_val(*ptep)) {
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DBG_LOW(" no access !\n");
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return 1;
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}
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/* Do actual hashing */
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#ifdef CONFIG_PPC_64K_PAGES
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/* If _PAGE_4K_PFN is set, make sure this is a 4k segment */
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