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Message-ID: <20071116214227.GA13877@c2.user-mode-linux.org>
Date: Fri, 16 Nov 2007 16:42:27 -0500
From: Jeff Dike <jdike@...toit.com>
To: Andrew Morton <akpm@...l.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
uml-devel <user-mode-linux-devel@...ts.sourceforge.net>
Subject: [PATCH 7/8] 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@...ux.intel.com>
---
arch/um/kernel/skas/uaccess.c | 56 +++++++++++++++++-------------------------
include/asm-um/pgtable.h | 3 ++
2 files changed, 26 insertions(+), 33 deletions(-)
Index: linux-2.6.22/arch/um/kernel/skas/uaccess.c
===================================================================
--- linux-2.6.22.orig/arch/um/kernel/skas/uaccess.c 2007-11-16 15:16:54.000000000 -0500
+++ linux-2.6.22/arch/um/kernel/skas/uaccess.c 2007-11-16 15:40:25.000000000 -0500
@@ -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);
-
- pte = pte_offset_kernel(pmd, addr);
- ptent = *pte;
- if (!pte_present(ptent))
- return ERR_PTR(-EINVAL);
+ return NULL;
- 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);
Index: linux-2.6.22/include/asm-um/pgtable.h
===================================================================
--- linux-2.6.22.orig/include/asm-um/pgtable.h 2007-11-16 15:35:38.000000000 -0500
+++ linux-2.6.22/include/asm-um/pgtable.h 2007-11-16 15:39:44.000000000 -0500
@@ -323,6 +323,9 @@ static inline pte_t pte_modify(pte_t pte
#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 */
-
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