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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
This commit is contained in:
Aneesh Kumar K.V 2020-05-05 12:47:11 +05:30 committed by Michael Ellerman
parent ec4abf1e70
commit 7900757ce1
3 changed files with 5 additions and 16 deletions
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3
arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
View File

@ -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 */

2
arch/powerpc/kernel/pci_64.c
View File

@ -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;

16
arch/powerpc/mm/book3s64/hash_tlb.c
View File

@ -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);