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[S390] Add dynamic size check for usercopy functions.

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Use a wrapper for copy_to/from_user to chose the best usercopy method.
The mvcos instruction is better for sizes greater than 256 bytes, if
mvcos is not available a page table walk is better for sizes greater
than 1024 bytes. Also removed the redundant copy_to/from_user_std_small
functions.

Signed-off-by: Gerald Schaefer <geraldsc@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Gerald Schaefer 2006-12-04 15:40:45 +01:00 committed by Martin Schwidefsky
parent d57de5a367
commit 59f35d53fd
4 changed files with 190 additions and 59 deletions
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2
arch/s390/lib/Makefile
View File

@ -4,7 +4,7 @@
EXTRA_AFLAGS := -traditional
lib-y += delay.o string.o uaccess_std.o
lib-y += delay.o string.o uaccess_std.o uaccess_pt.o
lib-$(CONFIG_32BIT) += div64.o
lib-$(CONFIG_64BIT) += uaccess_mvcos.o
lib-$(CONFIG_SMP) += spinlock.o

27
arch/s390/lib/uaccess_mvcos.c
View File

@ -27,6 +27,9 @@
#define SLR "slgr"
#endif
extern size_t copy_from_user_std(size_t, const void __user *, void *);
extern size_t copy_to_user_std(size_t, void __user *, const void *);
size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
{
register unsigned long reg0 asm("0") = 0x81UL;
@ -66,6 +69,13 @@ size_t copy_from_user_mvcos(size_t size, const void __user *ptr, void *x)
return size;
}
size_t copy_from_user_mvcos_check(size_t size, const void __user *ptr, void *x)
{
if (size <= 256)
return copy_from_user_std(size, ptr, x);
return copy_from_user_mvcos(size, ptr, x);
}
size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
{
register unsigned long reg0 asm("0") = 0x810000UL;
@ -95,6 +105,13 @@ size_t copy_to_user_mvcos(size_t size, void __user *ptr, const void *x)
return size;
}
size_t copy_to_user_mvcos_check(size_t size, void __user *ptr, const void *x)
{
if (size <= 256)
return copy_to_user_std(size, ptr, x);
return copy_to_user_mvcos(size, ptr, x);
}
size_t copy_in_user_mvcos(size_t size, void __user *to, const void __user *from)
{
register unsigned long reg0 asm("0") = 0x810081UL;
@ -145,18 +162,16 @@ size_t clear_user_mvcos(size_t size, void __user *to)
return size;
}
extern size_t copy_from_user_std_small(size_t, const void __user *, void *);
extern size_t copy_to_user_std_small(size_t, void __user *, const void *);
extern size_t strnlen_user_std(size_t, const char __user *);
extern size_t strncpy_from_user_std(size_t, const char __user *, char *);
extern int futex_atomic_op(int, int __user *, int, int *);
extern int futex_atomic_cmpxchg(int __user *, int, int);
struct uaccess_ops uaccess_mvcos = {
.copy_from_user = copy_from_user_mvcos,
.copy_from_user_small = copy_from_user_std_small,
.copy_to_user = copy_to_user_mvcos,
.copy_to_user_small = copy_to_user_std_small,
.copy_from_user = copy_from_user_mvcos_check,
.copy_from_user_small = copy_from_user_std,
.copy_to_user = copy_to_user_mvcos_check,
.copy_to_user_small = copy_to_user_std,
.copy_in_user = copy_in_user_mvcos,
.clear_user = clear_user_mvcos,
.strnlen_user = strnlen_user_std,

153
arch/s390/lib/uaccess_pt.c Normal file
View File

@ -0,0 +1,153 @@
/*
* arch/s390/lib/uaccess_pt.c
*
* User access functions based on page table walks.
*
* Copyright IBM Corp. 2006
* Author(s): Gerald Schaefer (gerald.schaefer@de.ibm.com)
*/
#include <linux/errno.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <asm/futex.h>
static inline int __handle_fault(struct mm_struct *mm, unsigned long address,
int write_access)
{
struct vm_area_struct *vma;
int ret = -EFAULT;
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (unlikely(!vma))
goto out;
if (unlikely(vma->vm_start > address)) {
if (!(vma->vm_flags & VM_GROWSDOWN))
goto out;
if (expand_stack(vma, address))
goto out;
}
if (!write_access) {
/* page not present, check vm flags */
if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
goto out;
} else {
if (!(vma->vm_flags & VM_WRITE))
goto out;
}
survive:
switch (handle_mm_fault(mm, vma, address, write_access)) {
case VM_FAULT_MINOR:
current->min_flt++;
break;
case VM_FAULT_MAJOR:
current->maj_flt++;
break;
case VM_FAULT_SIGBUS:
goto out_sigbus;
case VM_FAULT_OOM:
goto out_of_memory;
default:
BUG();
}
ret = 0;
out:
up_read(&mm->mmap_sem);
return ret;
out_of_memory:
up_read(&mm->mmap_sem);
if (current->pid == 1) {
yield();
goto survive;
}
printk("VM: killing process %s\n", current->comm);
return ret;
out_sigbus:
up_read(&mm->mmap_sem);
current->thread.prot_addr = address;
current->thread.trap_no = 0x11;
force_sig(SIGBUS, current);
return ret;
}
static 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;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
void *from, *to;
done = 0;
retry:
spin_lock(&mm->page_table_lock);
do {
pgd = pgd_offset(mm, uaddr);
if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
goto fault;
pmd = pmd_offset(pgd, uaddr);
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
goto fault;
pte = pte_offset_map(pmd, uaddr);
if (!pte || !pte_present(*pte) ||
(write_user && !pte_write(*pte)))
goto fault;
pfn = pte_pfn(*pte);
if (!pfn_valid(pfn))
goto out;
offset = uaddr & (PAGE_SIZE - 1);
size = min(n - done, PAGE_SIZE - offset);
if (write_user) {
to = (void *)((pfn << PAGE_SHIFT) + offset);
from = kptr + done;
} else {
from = (void *)((pfn << PAGE_SHIFT) + offset);
to = kptr + done;
}
memcpy(to, from, size);
done += size;
uaddr += size;
} while (done < n);
out:
spin_unlock(&mm->page_table_lock);
return n - done;
fault:
spin_unlock(&mm->page_table_lock);
if (__handle_fault(mm, uaddr, write_user))
return n - done;
goto retry;
}
size_t copy_from_user_pt(size_t n, const void __user *from, void *to)
{
size_t rc;
if (segment_eq(get_fs(), KERNEL_DS)) {
memcpy(to, (void __kernel __force *) from, n);
return 0;
}
rc = __user_copy_pt((unsigned long) from, to, n, 0);
if (unlikely(rc))
memset(to + n - rc, 0, rc);
return rc;
}
size_t copy_to_user_pt(size_t n, void __user *to, const void *from)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memcpy((void __kernel __force *) to, from, n);
return 0;
}
return __user_copy_pt((unsigned long) to, (void *) from, n, 1);
}

67
arch/s390/lib/uaccess_std.c
View File

@ -28,6 +28,9 @@
#define SLR "slgr"
#endif
extern size_t copy_from_user_pt(size_t n, const void __user *from, void *to);
extern size_t copy_to_user_pt(size_t n, void __user *to, const void *from);
size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
{
unsigned long tmp1, tmp2;
@ -69,34 +72,11 @@ size_t copy_from_user_std(size_t size, const void __user *ptr, void *x)
return size;
}
size_t copy_from_user_std_small(size_t size, const void __user *ptr, void *x)
size_t copy_from_user_std_check(size_t size, const void __user *ptr, void *x)
{
unsigned long tmp1, tmp2;
tmp1 = 0UL;
asm volatile(
"0: mvcp 0(%0,%2),0(%1),%3\n"
" "SLR" %0,%0\n"
" j 5f\n"
"1: la %4,255(%1)\n" /* %4 = ptr + 255 */
" "LHI" %3,-4096\n"
" nr %4,%3\n" /* %4 = (ptr + 255) & -4096 */
" "SLR" %4,%1\n"
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 5f\n"
"2: mvcp 0(%4,%2),0(%1),%3\n"
" "SLR" %0,%4\n"
" "ALR" %2,%4\n"
"3:"LHI" %4,-1\n"
" "ALR" %4,%0\n" /* copy remaining size, subtract 1 */
" bras %3,4f\n"
" xc 0(1,%2),0(%2)\n"
"4: ex %4,0(%3)\n"
"5:\n"
EX_TABLE(0b,1b) EX_TABLE(2b,3b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;
if (size <= 1024)
return copy_from_user_std(size, ptr, x);
return copy_from_user_pt(size, ptr, x);
}
size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
@ -130,28 +110,11 @@ size_t copy_to_user_std(size_t size, void __user *ptr, const void *x)
return size;
}
size_t copy_to_user_std_small(size_t size, void __user *ptr, const void *x)
size_t copy_to_user_std_check(size_t size, void __user *ptr, const void *x)
{
unsigned long tmp1, tmp2;
tmp1 = 0UL;
asm volatile(
"0: mvcs 0(%0,%1),0(%2),%3\n"
" "SLR" %0,%0\n"
" j 3f\n"
"1: la %4,255(%1)\n" /* ptr + 255 */
" "LHI" %3,-4096\n"
" nr %4,%3\n" /* (ptr + 255) & -4096UL */
" "SLR" %4,%1\n"
" "CLR" %0,%4\n" /* copy crosses next page boundary? */
" jnh 3f\n"
"2: mvcs 0(%4,%1),0(%2),%3\n"
" "SLR" %0,%4\n"
"3:\n"
EX_TABLE(0b,1b) EX_TABLE(2b,3b)
: "+a" (size), "+a" (ptr), "+a" (x), "+a" (tmp1), "=a" (tmp2)
: : "cc", "memory");
return size;
if (size <= 1024)
return copy_to_user_std(size, ptr, x);
return copy_to_user_pt(size, ptr, x);
}
size_t copy_in_user_std(size_t size, void __user *to, const void __user *from)
@ -343,10 +306,10 @@ int futex_atomic_cmpxchg(int __user *uaddr, int oldval, int newval)
}
struct uaccess_ops uaccess_std = {
.copy_from_user = copy_from_user_std,
.copy_from_user_small = copy_from_user_std_small,
.copy_to_user = copy_to_user_std,
.copy_to_user_small = copy_to_user_std_small,
.copy_from_user = copy_from_user_std_check,
.copy_from_user_small = copy_from_user_std,
.copy_to_user = copy_to_user_std_check,
.copy_to_user_small = copy_to_user_std,
.copy_in_user = copy_in_user_std,
.clear_user = clear_user_std,
.strnlen_user = strnlen_user_std,