From: Arun Sharma <arun.sharma@intel.com>
To: Andrew Morton <akpm@osdl.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
"David S. Miller" <davem@redhat.com>,
linux-arch@vger.kernel.org
Subject: Re: sys getdents64 needs compat wrapper ?
Date: Thu, 17 Jun 2004 15:28:39 -0700 [thread overview]
Message-ID: <40D21B17.4060603@intel.com> (raw)
In-Reply-To: <40CDEB59.3040203@intel.com>
[-- Attachment #1: Type: text/plain, Size: 813 bytes --]
On 6/14/2004 11:15 AM, Arun Sharma wrote:
>> I just realized your code is broken on big-endian architectures, so
>> we should either get back to __copy_to_user or find the optimal solution
>> now.
>>
>> How about a {__,}{get,put}_user_unaligned() that gets defined per
>> architecture in one of these two ways:
>
>
> We'll go for the optimal solution now. We'll provide an
> <asm-generic/uaccess.h> that does __copy_to_user and a
> <asm-ia64/uaccess.h> that's optimized for ia64. Archs which don't care
> about alignment can override appropriately.
>
> Should have the patch tested by tomorrow.
It took us a bit longer :) But here's the promised patch. Using __put_user_unaligned() on ia64 may still cause unaligned faults, but we chose to optimize for the common case, where it's 4 byte aligned.
-Arun
[-- Attachment #2: __get_put_user_unaligned.patch --]
[-- Type: text/plain, Size: 8037 bytes --]
(1) Fix compat_filldir64() which is broken on big-endian machines.
(2) Introduce new APIs __{get,put}_user_unaligned.
(3) Optimize __{get,put}_user_unaligned for ia64.
Signed-off-by: Gordon Jin <gordon.jin@intel.com>
Signed-off-by: Arun Sharma <arun.sharma@intel.com>
---
fs/compat.c | 14 ++++----------
include/asm-generic/uaccess.h | 25 +++++++++++++++++++++++++
include/asm-ia64/uaccess.h | 36 ++++++++++++++++++++++++++++++++++++
include/asm-mips/uaccess.h | 1 +
include/asm-ppc64/uaccess.h | 1 +
include/asm-s390/uaccess.h | 1 +
include/asm-sparc64/uaccess.h | 1 +
include/asm-x86_64/uaccess.h | 1 +
8 files changed, 70 insertions(+), 10 deletions(-)
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/fs/compat.c linux-2.6.7-rc3-getdents-user_unaligned/fs/compat.c
--- linux-2.6.7-rc3-getdents/fs/compat.c 2004-06-16 22:13:46.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/fs/compat.c 2004-06-17 14:51:42.019623885 +0800
@@ -979,19 +979,14 @@ static int compat_filldir64(void * __buf
dirent = buf->previous;
if (dirent) {
- if (__put_user(offset, (u32 __user *)&dirent->d_off))
- goto efault;
- if (__put_user(offset >> 32,
- ((u32 __user *)&dirent->d_off) + 1))
+ if (__put_user_unaligned(offset, &dirent->d_off))
goto efault;
}
dirent = buf->current_dir;
- if ((__put_user(ino, (u32 __user *)&dirent->d_ino))
- || (__put_user(ino >> 32, ((u32 __user *)&dirent->d_ino) + 1)))
+ if (__put_user_unaligned(ino, &dirent->d_ino))
goto efault;
off = 0;
- if ((__put_user(off, (u32 __user *)&dirent->d_off))
- || (__put_user(off >> 32, ((u32 __user *)&dirent->d_off) + 1)))
+ if (__put_user_unaligned(off, &dirent->d_off))
goto efault;
if (__put_user(reclen, &dirent->d_reclen))
goto efault;
@@ -1040,8 +1035,7 @@ asmlinkage long compat_sys_getdents64(un
lastdirent = buf.previous;
if (lastdirent) {
typeof(lastdirent->d_off) d_off = file->f_pos;
- __put_user(d_off, (u32 __user *)&lastdirent->d_off);
- __put_user(d_off >> 32, ((u32 __user *)&lastdirent->d_off) + 1);
+ __put_user_unaligned(d_off, &lastdirent->d_off);
error = count - buf.count;
}
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-generic/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-generic/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-generic/uaccess.h 1970-01-01 08:00:00.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-generic/uaccess.h 2004-06-17 15:06:28.391683339 +0800
@@ -0,0 +1,25 @@
+#ifndef _ASM_GENERIC_UACCESS_H_
+#define _ASM_GENERIC_UACCESS_H_
+
+/*
+ * This macro should be used instead of __get_user() when accessing
+ * values at locations that are unknown to be aligned.
+ */
+#define __get_user_unaligned(x, ptr) \
+({ \
+ __typeof__ (*(ptr)) __x = (x); \
+ copy_from_user(&__x, (ptr), sizeof(*(ptr))) ? -EFAULT : 0; \
+})
+
+
+/*
+ * This macro should be used instead of __put_user() when accessing
+ * values at locations that are unknown to be aligned.
+ */
+#define __put_user_unaligned(x, ptr) \
+({ \
+ __typeof__ (*(ptr)) __x = (x); \
+ copy_to_user((ptr), &__x, sizeof(*(ptr))) ? -EFAULT : 0; \
+})
+
+#endif /* _ASM_GENERIC_UACCESS_H */
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-ia64/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-ia64/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-ia64/uaccess.h 2004-06-16 22:13:46.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-ia64/uaccess.h 2004-06-17 15:13:34.646560930 +0800
@@ -91,6 +91,42 @@ verify_area (int type, const void *addr,
#define __put_user(x, ptr) __put_user_nocheck((__typeof__(*(ptr))) (x), (ptr), sizeof(*(ptr)))
#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
+extern long __put_user_unaligned_unknown (void);
+
+#define __put_user_unaligned(x, ptr) \
+({ \
+ long __ret; \
+ switch (sizeof(*(ptr))) { \
+ case 1: __ret = __put_user((x), (ptr)); break; \
+ case 2: __ret = (__put_user((x), (u8 __user *)(ptr))) \
+ || (__put_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \
+ case 4: __ret = (__put_user((x), (u16 __user *)(ptr))) \
+ || (__put_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \
+ case 8: __ret = (__put_user((x), (u32 __user *)(ptr))) \
+ || (__put_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \
+ default: __ret = __put_user_unaligned_unknown(); \
+ } \
+ __ret; \
+})
+
+extern long __get_user_unaligned_unknown (void);
+
+#define __get_user_unaligned(x, ptr) \
+({ \
+ long __ret; \
+ switch (sizeof(*(ptr))) { \
+ case 1: __ret = __get_user((x), (ptr)); break; \
+ case 2: __ret = (__get_user((x), (u8 __user *)(ptr))) \
+ || (__get_user((x) >> 8, ((u8 __user *)(ptr) + 1))); break; \
+ case 4: __ret = (__get_user((x), (u16 __user *)(ptr))) \
+ || (__get_user((x) >> 16, ((u16 __user *)(ptr) + 1))); break; \
+ case 8: __ret = (__get_user((x), (u32 __user *)(ptr))) \
+ || (__get_user((x) >> 32, ((u32 __user *)(ptr) + 1))); break; \
+ default: __ret = __get_user_unaligned_unknown(); \
+ } \
+ __ret; \
+})
+
#ifdef ASM_SUPPORTED
struct __large_struct { unsigned long buf[100]; };
# define __m(x) (*(struct __large_struct *)(x))
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-mips/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-mips/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-mips/uaccess.h 2004-06-15 13:41:35.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-mips/uaccess.h 2004-06-17 14:51:42.020600447 +0800
@@ -13,6 +13,7 @@
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/thread_info.h>
+#include <asm-generic/uaccess.h>
/*
* The fs value determines whether argument validity checking should be
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-ppc64/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-ppc64/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-ppc64/uaccess.h 2004-06-15 13:41:35.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-ppc64/uaccess.h 2004-06-17 14:51:42.020600447 +0800
@@ -12,6 +12,7 @@
#include <linux/sched.h>
#include <linux/errno.h>
#include <asm/processor.h>
+#include <asm-generic/uaccess.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-s390/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-s390/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-s390/uaccess.h 2004-06-15 13:41:39.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-s390/uaccess.h 2004-06-17 14:51:42.021577010 +0800
@@ -16,6 +16,7 @@
*/
#include <linux/sched.h>
#include <linux/errno.h>
+#include <asm-generic/uaccess.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-sparc64/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-sparc64/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-sparc64/uaccess.h 2004-06-15 13:41:39.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-sparc64/uaccess.h 2004-06-17 14:51:42.021577010 +0800
@@ -14,6 +14,7 @@
#include <asm/asi.h>
#include <asm/system.h>
#include <asm/spitfire.h>
+#include <asm-generic/uaccess.h>
#endif
#ifndef __ASSEMBLY__
diff -purN -X dontdiff linux-2.6.7-rc3-getdents/include/asm-x86_64/uaccess.h linux-2.6.7-rc3-getdents-user_unaligned/include/asm-x86_64/uaccess.h
--- linux-2.6.7-rc3-getdents/include/asm-x86_64/uaccess.h 2004-06-15 13:41:34.000000000 +0800
+++ linux-2.6.7-rc3-getdents-user_unaligned/include/asm-x86_64/uaccess.h 2004-06-17 14:51:42.022553572 +0800
@@ -10,6 +10,7 @@
#include <linux/sched.h>
#include <linux/prefetch.h>
#include <asm/page.h>
+#include <asm-generic/uaccess.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
next prev parent reply other threads:[~2004-06-17 22:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-20 21:06 =?iso-8859-1?Q?Re:_sys_getdents64_needs_compat_wrapper_??= Arnd Bergmann
2004-06-05 0:16 ` =?iso-8859-1?Q?Re:_sys_getdents64_needs_compat_wrapper_??= Arun Sharma
2004-06-05 0:28 ` sys getdents64 needs compat wrapper ? David S. Miller
2004-06-07 21:13 ` Arun Sharma
2004-06-07 21:58 ` David S. Miller
2004-06-11 15:09 ` Arnd Bergmann
2004-06-14 18:15 ` Arun Sharma
2004-06-17 22:28 ` Arun Sharma [this message]
2004-06-17 23:36 ` Arnd Bergmann
2004-06-18 0:56 ` Arun Sharma
2004-06-18 17:05 ` Arun Sharma
2004-06-20 21:50 ` Arnd Bergmann
2004-06-22 18:21 ` Arun Sharma
-- strict thread matches above, loose matches on Subject: below --
2004-06-05 14:52 =?iso-8859-1?Q?Re:_Re:_Re:_sys_getdents64_needs_compat_wrapper_??= Arnd Bergmann
2004-06-05 18:41 ` sys getdents64 needs compat wrapper ? Andrew Morton
2004-06-05 19:31 ` David S. Miller
2004-05-20 18:32 sys_getdents64 " Arun Sharma
2004-05-20 20:58 ` David S. Miller
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