uml: move um_virt_to_phys
This patchset makes UML build and run with three-level page tables on
32-bit hosts. This is an uncommon use case, but the code here needed
fixing and cleaning up, so 32-bit three-level pages tables were tested
to make sure the changes are good.
Patch 1 - code movement
Patch 2 - header untangling
Patch 3 - style fixups in files affected so far
Patch 4 - clean up use of current.h
Patch 5 - fix sizes of types that are different between 2 and 3-level
page tables - three-level page table support should build at
this point
Patch 6 - tidy (i.e. eliminate much of) the code that figures out how
big the address space is
Patch 7 - change um_virt_to_phys into virt_to_pte, clean its
interface, and clean its (so far) one caller
Patch 8 - the stub pages are covered with a VMA, allowing some nasty
code to be thrown out - three-level page tables now work
This patch:
um_virt_to_phys only has one user, so it can be moved to the same file
and made static. Its declarations in pgtable.h and ksyms.c are also
gone.
current_cmd was another apparent user, but it itself isn't used, so it
is deleted.
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 1d8b119..302425b 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -12,8 +12,38 @@
#include "kern_util.h"
#include "os.h"
-extern void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
- pte_t *pte_out);
+static void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
+ pte_t *pte_out)
+{
+ 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 (!pgd_present(*pgd))
+ return ERR_PTR(-EINVAL);
+
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud))
+ return ERR_PTR(-EINVAL);
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ return ERR_PTR(-EINVAL);
+
+ 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);
+}
static unsigned long maybe_map(unsigned long virt, int is_write)
{