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Commit d87fe660 authored by venkatesh.pallipadi@intel.com's avatar venkatesh.pallipadi@intel.com Committed by H. Peter Anvin
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x86: PAT: modify follow_phys to return phys_addr prot and return value 



Impact: Changes and globalizes an existing static interface.

Follow_phys does similar things as follow_pfnmap_pte. Make a minor change
to follow_phys so that it can be used in place of follow_pfnmap_pte.
Physical address return value with 0 as error return does not work in
follow_phys as the actual physical address 0 mapping may exist in pte.

Signed-off-by: default avatarVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 6bd9cd50

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -804,6 +804,8 @@ int copy_page_range(struct mm_struct *dst, struct mm_struct *src, 
			struct vm_area_struct *vma);

void unmap_mapping_range(struct address_space *mapping,

		loff_t const holebegin, loff_t const holelen, int even_cows);

int follow_phys(struct vm_area_struct *vma, unsigned long address,

		unsigned int flags, unsigned long *prot, resource_size_t *phys);

int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,

			void *buf, int len, int write);

mm/memory.c

+14 −17
Original line number Diff line number Diff line
@@ -2981,9 +2981,9 @@ int in_gate_area_no_task(unsigned long addr) 
#endif	/* __HAVE_ARCH_GATE_AREA */



#ifdef CONFIG_HAVE_IOREMAP_PROT

static resource_size_t follow_phys(struct vm_area_struct *vma,

int follow_phys(struct vm_area_struct *vma,

		unsigned long address, unsigned int flags,

			unsigned long *prot)

		unsigned long *prot, resource_size_t *phys)

{

	pgd_t *pgd;

	pud_t *pud;
@@ -2992,24 +2992,26 @@ static resource_size_t follow_phys(struct vm_area_struct *vma, 
	spinlock_t *ptl;

	resource_size_t phys_addr = 0;

	struct mm_struct *mm = vma->vm_mm;

	int ret = -EINVAL;



	VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP)));

	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))

		goto out;



	pgd = pgd_offset(mm, address);

	if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))

		goto no_page_table;

		goto out;



	pud = pud_offset(pgd, address);

	if (pud_none(*pud) || unlikely(pud_bad(*pud)))

		goto no_page_table;

		goto out;



	pmd = pmd_offset(pud, address);

	if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))

		goto no_page_table;

		goto out;



	/* We cannot handle huge page PFN maps. Luckily they don't exist. */

	if (pmd_huge(*pmd))

		goto no_page_table;

		goto out;



	ptep = pte_offset_map_lock(mm, pmd, address, &ptl);

	if (!ptep)
@@ -3024,13 +3026,13 @@ static resource_size_t follow_phys(struct vm_area_struct *vma, 
	phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */



	*prot = pgprot_val(pte_pgprot(pte));

	*phys = phys_addr;

	ret = 0;



unlock:

	pte_unmap_unlock(ptep, ptl);

out:

	return phys_addr;

no_page_table:

	return 0;

	return ret;

}



int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
@@ -3041,12 +3043,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, 
	void *maddr;

	int offset = addr & (PAGE_SIZE-1);



	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))

		return -EINVAL;



	phys_addr = follow_phys(vma, addr, write, &prot);



	if (!phys_addr)

	if (follow_phys(vma, addr, write, &prot, &phys_addr))

		return -EINVAL;



	maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);