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>
diff --git a/mm/memory.c b/mm/memory.c
index 1e8f0d3..79f28e3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2981,9 +2981,9 @@
#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 @@
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 @@
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 @@
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);