Skip to content

Commit

Permalink
---
Browse files Browse the repository at this point in the history 
yaml
---
r: 322995
b: refs/heads/master
c: 4db84d4
h: refs/heads/master
i:
  322993: efc9041
  322991: 6eba44b
v: v3
  • Loading branch information
Gerald Schaefer authored and Martin Schwidefsky committed Sep 17, 2012
1 parent dcef605 commit 8228bdf
Show file tree
Hide file tree
Showing 2 changed files with 64 additions and 80 deletions.
2 changes: 1 addition & 1 deletion [refs]
View file
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: db2e1f43e7b2320d0450fe34e5ac4ac4d8c7708d
refs/heads/master: 4db84d4f07b87c452c6000e0595dc9570ed21b41
142 changes: 63 additions & 79 deletions trunk/arch/s390/lib/uaccess_pt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2,69 +2,82 @@
* User access functions based on page table walks for enhanced
* system layout without hardware support.
*
* Copyright IBM Corp. 2006
* Copyright IBM Corp. 2006, 2012
* Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
*/

#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <asm/uaccess.h>
#include <asm/futex.h>
#include "uaccess.h"

static inline pte_t *follow_table(struct mm_struct *mm, unsigned long addr)

/*
* Returns kernel address for user virtual address. If the returned address is
* >= -4095 (IS_ERR_VALUE(x) returns true), a fault has occured and the address
* contains the (negative) exception code.
*/
static __always_inline unsigned long follow_table(struct mm_struct *mm,
unsigned long addr, int write)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *ptep;

pgd = pgd_offset(mm, addr);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
return (pte_t *) 0x3a;
return -0x3aUL;

pud = pud_offset(pgd, addr);
if (pud_none(*pud) || unlikely(pud_bad(*pud)))
return (pte_t *) 0x3b;
return -0x3bUL;

pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
return (pte_t *) 0x10;
if (pmd_none(*pmd))
return -0x10UL;
if (pmd_huge(*pmd)) {
if (write && (pmd_val(*pmd) & _SEGMENT_ENTRY_RO))
return -0x04UL;
return (pmd_val(*pmd) & HPAGE_MASK) + (addr & ~HPAGE_MASK);
}
if (unlikely(pmd_bad(*pmd)))
return -0x10UL;

ptep = pte_offset_map(pmd, addr);
if (!pte_present(*ptep))
return -0x11UL;
if (write && !pte_write(*ptep))
return -0x04UL;

return pte_offset_map(pmd, addr);
return (pte_val(*ptep) & PAGE_MASK) + (addr & ~PAGE_MASK);
}

static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
size_t n, int write_user)
{
struct mm_struct *mm = current->mm;
unsigned long offset, pfn, done, size;
pte_t *pte;
unsigned long offset, done, size, kaddr;
void *from, *to;

done = 0;
retry:
spin_lock(&mm->page_table_lock);
do {
pte = follow_table(mm, uaddr);
if ((unsigned long) pte < 0x1000)
kaddr = follow_table(mm, uaddr, write_user);
if (IS_ERR_VALUE(kaddr))
goto fault;
if (!pte_present(*pte)) {
pte = (pte_t *) 0x11;
goto fault;
} else if (write_user && !pte_write(*pte)) {
pte = (pte_t *) 0x04;
goto fault;
}

pfn = pte_pfn(*pte);
offset = uaddr & (PAGE_SIZE - 1);
offset = uaddr & ~PAGE_MASK;
size = min(n - done, PAGE_SIZE - offset);
if (write_user) {
to = (void *)((pfn << PAGE_SHIFT) + offset);
to = (void *) kaddr;
from = kptr + done;
} else {
from = (void *)((pfn << PAGE_SHIFT) + offset);
from = (void *) kaddr;
to = kptr + done;
}
memcpy(to, from, size);
Expand All @@ -75,7 +88,7 @@ static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
return n - done;
fault:
spin_unlock(&mm->page_table_lock);
if (__handle_fault(uaddr, (unsigned long) pte, write_user))
if (__handle_fault(uaddr, -kaddr, write_user))
return n - done;
goto retry;
}
Expand All @@ -84,27 +97,22 @@ static __always_inline size_t __user_copy_pt(unsigned long uaddr, void *kptr,
* Do DAT for user address by page table walk, return kernel address.
* This function needs to be called with current->mm->page_table_lock held.
*/
static __always_inline unsigned long __dat_user_addr(unsigned long uaddr)
static __always_inline unsigned long __dat_user_addr(unsigned long uaddr,
int write)
{
struct mm_struct *mm = current->mm;
unsigned long pfn;
pte_t *pte;
unsigned long kaddr;
int rc;

retry:
pte = follow_table(mm, uaddr);
if ((unsigned long) pte < 0x1000)
goto fault;
if (!pte_present(*pte)) {
pte = (pte_t *) 0x11;
kaddr = follow_table(mm, uaddr, write);
if (IS_ERR_VALUE(kaddr))
goto fault;
}

pfn = pte_pfn(*pte);
return (pfn << PAGE_SHIFT) + (uaddr & (PAGE_SIZE - 1));
return kaddr;
fault:
spin_unlock(&mm->page_table_lock);
rc = __handle_fault(uaddr, (unsigned long) pte, 0);
rc = __handle_fault(uaddr, -kaddr, write);
spin_lock(&mm->page_table_lock);
if (!rc)
goto retry;
Expand Down Expand Up @@ -159,11 +167,9 @@ static size_t clear_user_pt(size_t n, void __user *to)

static size_t strnlen_user_pt(size_t count, const char __user *src)
{
char *addr;
unsigned long uaddr = (unsigned long) src;
struct mm_struct *mm = current->mm;
unsigned long offset, pfn, done, len;
pte_t *pte;
unsigned long offset, done, len, kaddr;
size_t len_str;

if (segment_eq(get_fs(), KERNEL_DS))
Expand All @@ -172,27 +178,21 @@ static size_t strnlen_user_pt(size_t count, const char __user *src)
retry:
spin_lock(&mm->page_table_lock);
do {
pte = follow_table(mm, uaddr);
if ((unsigned long) pte < 0x1000)
goto fault;
if (!pte_present(*pte)) {
pte = (pte_t *) 0x11;
kaddr = follow_table(mm, uaddr, 0);
if (IS_ERR_VALUE(kaddr))
goto fault;
}

pfn = pte_pfn(*pte);
offset = uaddr & (PAGE_SIZE-1);
addr = (char *)(pfn << PAGE_SHIFT) + offset;
offset = uaddr & ~PAGE_MASK;
len = min(count - done, PAGE_SIZE - offset);
len_str = strnlen(addr, len);
len_str = strnlen((char *) kaddr, len);
done += len_str;
uaddr += len_str;
} while ((len_str == len) && (done < count));
spin_unlock(&mm->page_table_lock);
return done + 1;
fault:
spin_unlock(&mm->page_table_lock);
if (__handle_fault(uaddr, (unsigned long) pte, 0))
if (__handle_fault(uaddr, -kaddr, 0))
return 0;
goto retry;
}
Expand Down Expand Up @@ -225,11 +225,10 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
const void __user *from)
{
struct mm_struct *mm = current->mm;
unsigned long offset_from, offset_to, offset_max, pfn_from, pfn_to,
uaddr, done, size, error_code;
unsigned long offset_max, uaddr, done, size, error_code;
unsigned long uaddr_from = (unsigned long) from;
unsigned long uaddr_to = (unsigned long) to;
pte_t *pte_from, *pte_to;
unsigned long kaddr_to, kaddr_from;
int write_user;

if (segment_eq(get_fs(), KERNEL_DS)) {
Expand All @@ -242,38 +241,23 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
do {
write_user = 0;
uaddr = uaddr_from;
pte_from = follow_table(mm, uaddr_from);
error_code = (unsigned long) pte_from;
if (error_code < 0x1000)
goto fault;
if (!pte_present(*pte_from)) {
error_code = 0x11;
kaddr_from = follow_table(mm, uaddr_from, 0);
error_code = kaddr_from;
if (IS_ERR_VALUE(error_code))
goto fault;
}

write_user = 1;
uaddr = uaddr_to;
pte_to = follow_table(mm, uaddr_to);
error_code = (unsigned long) pte_to;
if (error_code < 0x1000)
goto fault;
if (!pte_present(*pte_to)) {
error_code = 0x11;
kaddr_to = follow_table(mm, uaddr_to, 1);
error_code = (unsigned long) kaddr_to;
if (IS_ERR_VALUE(error_code))
goto fault;
} else if (!pte_write(*pte_to)) {
error_code = 0x04;
goto fault;
}

pfn_from = pte_pfn(*pte_from);
pfn_to = pte_pfn(*pte_to);
offset_from = uaddr_from & (PAGE_SIZE-1);
offset_to = uaddr_from & (PAGE_SIZE-1);
offset_max = max(offset_from, offset_to);
offset_max = max(uaddr_from & ~PAGE_MASK,
uaddr_to & ~PAGE_MASK);
size = min(n - done, PAGE_SIZE - offset_max);

memcpy((void *)(pfn_to << PAGE_SHIFT) + offset_to,
(void *)(pfn_from << PAGE_SHIFT) + offset_from, size);
memcpy((void *) kaddr_to, (void *) kaddr_from, size);
done += size;
uaddr_from += size;
uaddr_to += size;
Expand All @@ -282,7 +266,7 @@ static size_t copy_in_user_pt(size_t n, void __user *to,
return n - done;
fault:
spin_unlock(&mm->page_table_lock);
if (__handle_fault(uaddr, error_code, write_user))
if (__handle_fault(uaddr, -error_code, write_user))
return n - done;
goto retry;
}
Expand Down Expand Up @@ -341,7 +325,7 @@ int futex_atomic_op_pt(int op, u32 __user *uaddr, int oparg, int *old)
return __futex_atomic_op_pt(op, uaddr, oparg, old);
spin_lock(&current->mm->page_table_lock);
uaddr = (u32 __force __user *)
__dat_user_addr((__force unsigned long) uaddr);
__dat_user_addr((__force unsigned long) uaddr, 1);
if (!uaddr) {
spin_unlock(&current->mm->page_table_lock);
return -EFAULT;
Expand Down Expand Up @@ -378,7 +362,7 @@ int futex_atomic_cmpxchg_pt(u32 *uval, u32 __user *uaddr,
return __futex_atomic_cmpxchg_pt(uval, uaddr, oldval, newval);
spin_lock(&current->mm->page_table_lock);
uaddr = (u32 __force __user *)
__dat_user_addr((__force unsigned long) uaddr);
__dat_user_addr((__force unsigned long) uaddr, 1);
if (!uaddr) {
spin_unlock(&current->mm->page_table_lock);
return -EFAULT;
Expand Down

0 comments on commit 8228bdf

Please sign in to comment.