powerpc/hash64: Restrict page table lookup using init_mm with __flush_hash_table_range

This is only used with init_mm currently. Walking init_mm is much simpler
because we don't need to handle concurrent page table like other mm_context

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200505071729.54912-5-aneesh.kumar@linux.ibm.com

diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
index 64d02a704bcb596f146e95ebdff1343d459e4c20..3b95769739c7a01b98691c6897fa13f03398e3e4 100644 (file)
--- a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
@@ -113,8 +113,7 @@ static inline void hash__flush_tlb_kernel_range(unsigned long start,
 struct mmu_gather;
 extern void hash__tlb_flush(struct mmu_gather *tlb);
 /* Private function for use by PCI IO mapping code */
-extern void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
-                                    unsigned long end);
+extern void __flush_hash_table_range(unsigned long start, unsigned long end);
 extern void flush_tlb_pmd_range(struct mm_struct *mm, pmd_t *pmd,
                                unsigned long addr);
 #endif /*  _ASM_POWERPC_BOOK3S_64_TLBFLUSH_HASH_H */

diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
index f83d1f69b1dd837b1d098a46098d4f1b83fe3535..30d07fc79dd14ce5b739f77cfdc2445cb2ca9987 100644 (file)
--- a/arch/powerpc/kernel/pci_64.c
+++ b/arch/powerpc/kernel/pci_64.c
@@ -100,7 +100,7 @@ int pcibios_unmap_io_space(struct pci_bus *bus)
                         pci_name(bus->self));
 
 #ifdef CONFIG_PPC_BOOK3S_64
-               __flush_hash_table_range(&init_mm, res->start + _IO_BASE,
+               __flush_hash_table_range(res->start + _IO_BASE,
                                         res->end + _IO_BASE + 1);
 #endif
                return 0;

diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c
index 4a70d8dd39cd66eb0e536f9216ad0c67e516c9fa..1fa2173413b55bf391544426d363edd21c4b2e24 100644 (file)
--- a/arch/powerpc/mm/book3s64/hash_tlb.c
+++ b/arch/powerpc/mm/book3s64/hash_tlb.c
@@ -176,7 +176,6 @@ void hash__tlb_flush(struct mmu_gather *tlb)
  *                            from the hash table (and the TLB). But keeps
  *                            the linux PTEs intact.
  *
- * @mm         : mm_struct of the target address space (generally init_mm)
  * @start      : starting address
  * @end         : ending address (not included in the flush)
  *
@@ -189,17 +188,14 @@ void hash__tlb_flush(struct mmu_gather *tlb)
  * Because of that usage pattern, it is implemented for small size rather
  * than speed.
  */
-void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
-                             unsigned long end)
+void __flush_hash_table_range(unsigned long start, unsigned long end)
 {
-       bool is_thp;
        int hugepage_shift;
        unsigned long flags;
 
        start = _ALIGN_DOWN(start, PAGE_SIZE);
        end = _ALIGN_UP(end, PAGE_SIZE);
 
-       BUG_ON(!mm->pgd);
 
        /*
         * Note: Normally, we should only ever use a batch within a
@@ -212,21 +208,15 @@ void __flush_hash_table_range(struct mm_struct *mm, unsigned long start,
        local_irq_save(flags);
        arch_enter_lazy_mmu_mode();
        for (; start < end; start += PAGE_SIZE) {
-               pte_t *ptep = find_current_mm_pte(mm->pgd, start, &is_thp,
-                                                 &hugepage_shift);
+               pte_t *ptep = find_init_mm_pte(start, &hugepage_shift);
                unsigned long pte;
 
                if (ptep == NULL)
                        continue;
                pte = pte_val(*ptep);
-               if (is_thp)
-                       trace_hugepage_invalidate(start, pte);
                if (!(pte & H_PAGE_HASHPTE))
                        continue;
-               if (unlikely(is_thp))
-                       hpte_do_hugepage_flush(mm, start, (pmd_t *)ptep, pte);
-               else
-                       hpte_need_flush(mm, start, ptep, pte, hugepage_shift);
+               hpte_need_flush(&init_mm, start, ptep, pte, hugepage_shift);
        }
        arch_leave_lazy_mmu_mode();
        local_irq_restore(flags);