ARM: fix uaccess_with_memcpy() with SW_DOMAIN_PAN
The uaccess_with_memcpy() code is currently incompatible with the SW
PAN code: it takes locks within the region that we've changed the DACR,
potentially sleeping as a result. As we do not save and restore the
DACR across co-operative sleep events, can lead to an incorrect DACR
value later in this code path.
Reported-by: Peter Rosin <peda@axentia.se>
Tested-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index 8cc85a4..35c9db8 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -510,10 +510,14 @@
static inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
+#ifndef CONFIG_UACCESS_WITH_MEMCPY
unsigned int __ua_flags = uaccess_save_and_enable();
n = arm_copy_to_user(to, from, n);
uaccess_restore(__ua_flags);
return n;
+#else
+ return arm_copy_to_user(to, from, n);
+#endif
}
extern unsigned long __must_check
diff --git a/arch/arm/lib/uaccess_with_memcpy.c b/arch/arm/lib/uaccess_with_memcpy.c
index d72b909..588bbc2 100644
--- a/arch/arm/lib/uaccess_with_memcpy.c
+++ b/arch/arm/lib/uaccess_with_memcpy.c
@@ -88,6 +88,7 @@
static unsigned long noinline
__copy_to_user_memcpy(void __user *to, const void *from, unsigned long n)
{
+ unsigned long ua_flags;
int atomic;
if (unlikely(segment_eq(get_fs(), KERNEL_DS))) {
@@ -118,7 +119,9 @@
if (tocopy > n)
tocopy = n;
+ ua_flags = uaccess_save_and_enable();
memcpy((void *)to, from, tocopy);
+ uaccess_restore(ua_flags);
to += tocopy;
from += tocopy;
n -= tocopy;
@@ -145,14 +148,21 @@
* With frame pointer disabled, tail call optimization kicks in
* as well making this test almost invisible.
*/
- if (n < 64)
- return __copy_to_user_std(to, from, n);
- return __copy_to_user_memcpy(to, from, n);
+ if (n < 64) {
+ unsigned long ua_flags = uaccess_save_and_enable();
+ n = __copy_to_user_std(to, from, n);
+ uaccess_restore(ua_flags);
+ } else {
+ n = __copy_to_user_memcpy(to, from, n);
+ }
+ return n;
}
static unsigned long noinline
__clear_user_memset(void __user *addr, unsigned long n)
{
+ unsigned long ua_flags;
+
if (unlikely(segment_eq(get_fs(), KERNEL_DS))) {
memset((void *)addr, 0, n);
return 0;
@@ -175,7 +185,9 @@
if (tocopy > n)
tocopy = n;
+ ua_flags = uaccess_save_and_enable();
memset((void *)addr, 0, tocopy);
+ uaccess_restore(ua_flags);
addr += tocopy;
n -= tocopy;
@@ -193,9 +205,14 @@
unsigned long arm_clear_user(void __user *addr, unsigned long n)
{
/* See rational for this in __copy_to_user() above. */
- if (n < 64)
- return __clear_user_std(addr, n);
- return __clear_user_memset(addr, n);
+ if (n < 64) {
+ unsigned long ua_flags = uaccess_save_and_enable();
+ n = __clear_user_std(addr, n);
+ uaccess_restore(ua_flags);
+ } else {
+ n = __clear_user_memset(addr, n);
+ }
+ return n;
}
#if 0