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Message-ID: <20071116214224.GA13847@c2.user-mode-linux.org>
Date: Fri, 16 Nov 2007 16:42:24 -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 1/8] 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@...ux.intel.com>
---
arch/um/kernel/ksyms.c | 1
arch/um/kernel/process.c | 43 ------------------------------------------
arch/um/kernel/skas/uaccess.c | 34 +++++++++++++++++++++++++++++++--
include/asm-um/pgtable.h | 3 --
4 files changed, 32 insertions(+), 49 deletions(-)
Index: linux-2.6.22/arch/um/kernel/process.c
===================================================================
--- linux-2.6.22.orig/arch/um/kernel/process.c 2007-11-15 16:34:14.000000000 -0500
+++ linux-2.6.22/arch/um/kernel/process.c 2007-11-16 13:14:41.000000000 -0500
@@ -256,49 +256,6 @@ void cpu_idle(void)
default_idle();
}
-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);
-}
-
-char *current_cmd(void)
-{
-#if defined(CONFIG_SMP) || defined(CONFIG_HIGHMEM)
- return "(Unknown)";
-#else
- void *addr = um_virt_to_phys(current, current->mm->arg_start, NULL);
- return IS_ERR(addr) ? "(Unknown)": __va((unsigned long) addr);
-#endif
-}
-
int __cant_sleep(void) {
return in_atomic() || irqs_disabled() || in_interrupt();
/* Is in_interrupt() really needed? */
Index: linux-2.6.22/arch/um/kernel/skas/uaccess.c
===================================================================
--- linux-2.6.22.orig/arch/um/kernel/skas/uaccess.c 2007-11-15 16:34:14.000000000 -0500
+++ linux-2.6.22/arch/um/kernel/skas/uaccess.c 2007-11-16 13:14:41.000000000 -0500
@@ -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)
{
Index: linux-2.6.22/include/asm-um/pgtable.h
===================================================================
--- linux-2.6.22.orig/include/asm-um/pgtable.h 2007-11-15 16:34:14.000000000 -0500
+++ linux-2.6.22/include/asm-um/pgtable.h 2007-11-16 13:14:41.000000000 -0500
@@ -31,9 +31,6 @@
extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
-extern void *um_virt_to_phys(struct task_struct *task, unsigned long virt,
- pte_t *pte_out);
-
/* zero page used for uninitialized stuff */
extern unsigned long *empty_zero_page;
Index: linux-2.6.22/arch/um/kernel/ksyms.c
===================================================================
--- linux-2.6.22.orig/arch/um/kernel/ksyms.c 2007-11-15 16:34:14.000000000 -0500
+++ linux-2.6.22/arch/um/kernel/ksyms.c 2007-11-16 13:14:39.000000000 -0500
@@ -25,7 +25,6 @@ EXPORT_SYMBOL(get_kmem_end);
EXPORT_SYMBOL(high_physmem);
EXPORT_SYMBOL(empty_zero_page);
-EXPORT_SYMBOL(um_virt_to_phys);
EXPORT_SYMBOL(handle_page_fault);
EXPORT_SYMBOL(find_iomem);
-
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