Re: [PATCH V3 3/5] arch/powerpc/mm: Nest MMU workaround for mprotect RW upgrade.
flat view
From: Christoph Hellwig <hch@infradead.org>
Date: 2018-12-18 17:21:22
Also in:
linux-mm
On Wed, Dec 05, 2018 at 08:39:29AM +0530, Aneesh Kumar K.V wrote:
quoted hunk ↗ jump to hunk
+pte_t 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, 0); + + return __pte(pte_val); + +} +EXPORT_SYMBOL(ptep_modify_prot_start);
As far as I can tell this is only called from mm/memory.c, mm/mprotect.c and fs/proc/task_mmu.c, so there should be no need to export the function.