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Diffstat (limited to 'arch/s390/lib/uaccess_pt.c')
-rw-r--r--arch/s390/lib/uaccess_pt.c142
1 files changed, 63 insertions, 79 deletions
diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 60ee2b88379..2d37bb861fa 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -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);
@@ -75,7 +88,7 @@ retry:
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;
}
@@ -84,27 +97,22 @@ fault:
* 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;
@@ -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))
@@ -172,19 +178,13 @@ 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));
@@ -192,7 +192,7 @@ retry:
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;
}
@@ -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)) {
@@ -242,38 +241,23 @@ retry:
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;
@@ -282,7 +266,7 @@ retry:
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;
}
@@ -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;
@@ -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;
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 00:27:43 +0000