uml: add virt_to_pte
Turn um_virt_to_phys into virt_to_pte, cleaning up a horrid interface.
It's also made non-static and declared in pgtable.h because it'll be
needed when the stubs get a vma.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index d145565..05b41dbc 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -13,70 +13,60 @@
#include "kern_util.h"
#include "os.h"
-static void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
- pte_t *pte_out)
+pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
- pte_t *pte;
- pte_t ptent;
- if (task->mm == NULL)
- return ERR_PTR(-EINVAL);
- pgd = pgd_offset(task->mm, addr);
+ if (mm == NULL)
+ return NULL;
+
+ pgd = pgd_offset(mm, addr);
if (!pgd_present(*pgd))
- return ERR_PTR(-EINVAL);
+ return NULL;
pud = pud_offset(pgd, addr);
if (!pud_present(*pud))
- return ERR_PTR(-EINVAL);
+ return NULL;
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
- return ERR_PTR(-EINVAL);
+ return NULL;
- pte = pte_offset_kernel(pmd, addr);
- ptent = *pte;
- if (!pte_present(ptent))
- return ERR_PTR(-EINVAL);
-
- if (pte_out != NULL)
- *pte_out = ptent;
- return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
+ return pte_offset_kernel(pmd, addr);
}
-static unsigned long maybe_map(unsigned long virt, int is_write)
+static pte_t *maybe_map(unsigned long virt, int is_write)
{
- pte_t pte;
- int err;
+ pte_t *pte = virt_to_pte(current->mm, virt);
+ int err, dummy_code;
- void *phys = um_virt_to_phys(current, virt, &pte);
- int dummy_code;
-
- if (IS_ERR(phys) || (is_write && !pte_write(pte))) {
+ if ((pte == NULL) || !pte_present(*pte) ||
+ (is_write && !pte_write(*pte))) {
err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
if (err)
- return -1UL;
- phys = um_virt_to_phys(current, virt, NULL);
+ return NULL;
+ pte = virt_to_pte(current->mm, virt);
}
- if (IS_ERR(phys))
- phys = (void *) -1;
+ if (!pte_present(*pte))
+ pte = NULL;
- return (unsigned long) phys;
+ return pte;
}
static int do_op_one_page(unsigned long addr, int len, int is_write,
int (*op)(unsigned long addr, int len, void *arg), void *arg)
{
struct page *page;
+ pte_t *pte;
int n;
- addr = maybe_map(addr, is_write);
- if (addr == -1UL)
+ pte = maybe_map(addr, is_write);
+ if (pte == NULL)
return -1;
- page = phys_to_page(addr);
+ page = pte_page(*pte);
addr = (unsigned long) kmap_atomic(page, KM_UML_USERCOPY) +
(addr & ~PAGE_MASK);
diff --git a/include/asm-um/pgtable.h b/include/asm-um/pgtable.h
index 62ab94a..fb47777 100644
--- a/include/asm-um/pgtable.h
+++ b/include/asm-um/pgtable.h
@@ -323,6 +323,9 @@
#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)
+struct mm_struct;
+extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
+
#define update_mmu_cache(vma,address,pte) do ; while (0)
/* Encode and de-code a swap entry */