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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: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
venkatesh.pallipadi@intel.com 2008-12-19 13:47:27 -08:00 committed by H. Peter Anvin
parent 6bd9cd50c8
commit d87fe6607c
2 changed files with 16 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/mm.h
View File

@ -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);

31
mm/memory.c
View File

@ -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,
unsigned long address, unsigned int flags,
unsigned long *prot)
int follow_phys(struct vm_area_struct *vma,
unsigned long address, unsigned int flags,
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);