Commit 9157f90f authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

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: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent b8bec829

arch/um/kernel/ksyms.c

+0 −1
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ 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);

arch/um/kernel/process.c

+0 −43
Original line number Diff line number Diff line
@@ -255,49 +255,6 @@ 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

}



void dump_thread(struct pt_regs *regs, struct user *u)

{

}

arch/um/kernel/skas/uaccess.c

+32 −2
Original line number Diff line number Diff line
@@ -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)

{

include/asm-um/pgtable.h

+0 −3
Original line number Diff line number Diff line
@@ -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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE