diff mbox series

[v5,4/8] linux-user: Split out preadv, pwritev, readv, writev, pread64, pwrite64

Message ID 20181219042113.7364-5-richard.henderson@linaro.org
State New
Headers show
Series linux-user: Split do_syscall | expand

Commit Message

Richard Henderson Dec. 19, 2018, 4:21 a.m. UTC
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 linux-user/syscall-defs.h     |  14 ++++
 linux-user/syscall-file.inc.c | 124 ++++++++++++++++++++++++++++++++++
 linux-user/syscall.c          |  93 -------------------------
 linux-user/strace.list        |  18 -----
 4 files changed, 138 insertions(+), 111 deletions(-)

-- 
2.17.2

Comments

Laurent Vivier Jan. 10, 2019, 3:17 p.m. UTC | #1
On 19/12/2018 05:21, Richard Henderson wrote:
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  linux-user/syscall-defs.h     |  14 ++++

>  linux-user/syscall-file.inc.c | 124 ++++++++++++++++++++++++++++++++++

>  linux-user/syscall.c          |  93 -------------------------

>  linux-user/strace.list        |  18 -----

>  4 files changed, 138 insertions(+), 111 deletions(-)

> 

...
> diff --git a/linux-user/syscall-file.inc.c b/linux-user/syscall-file.inc.c

> index 11e75044c1..410a763eee 100644

> --- a/linux-user/syscall-file.inc.c

> +++ b/linux-user/syscall-file.inc.c

> @@ -315,6 +315,104 @@ SYSCALL_IMPL(openat)

...
> +

> +/*

> + * Both preadv and pwritev merge args 4/5 into a 64-bit offset.

> + * Moreover, the parts are *always* in little-endian order.

> + */

> +#if TARGET_ABI_BITS == 32

> +SYSCALL_ARGS(preadv_pwritev)

> +{

> +    /* We have already assigned out[0-2].  */

> +    abi_ulong lo = in[3], hi = in[4];

> +    out[3] = ((hi << (TARGET_ABI_BITS - 1)) << 1) | lo;

> +    return def;

> +}

> +#else

> +#define args_preadv_pwritev NULL

> +#endif

> +

> +/* Perform the inverse operation for the host.  */

> +static inline void host_offset64_low_high(unsigned long *l, unsigned long *h,

> +                                          uint64_t off)

> +{

> +    *l = off;

> +    *h = (off >> (HOST_LONG_BITS - 1)) >> 1;

> +}



I have an error with preadv() on a 32bit target (powerpc, LTP test preadv02).

It works if I use:

static inline void host_offset64_low_high(unsigned long *hlow,
                                          unsigned long *hhigh,
                                          abi_ulong tlow,
                                          abi_ulong thigh)
{
    uint64_t off = tlow |
                   ((unsigned long long)thigh << TARGET_LONG_BITS / 2) <<
                   TARGET_LONG_BITS / 2;
    
    *hlow = off;
    *hhigh = (off >> HOST_LONG_BITS / 2) >> HOST_LONG_BITS / 2;
}



> +

> +SYSCALL_IMPL(preadv)

> +{

> +    struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 0);

> +    unsigned long lo, hi;

> +    abi_long ret;

> +

> +    if (vec == NULL) {

> +        return -host_to_target_errno(errno);

> +    }

> +

> +    host_offset64_low_high(&lo, &hi, arg4);

> +    ret = get_errno(safe_preadv(arg1, vec, arg3, lo, hi));

> +    unlock_iovec(vec, arg2, arg3, 1);

> +    return ret;

> +}

> +

> +SYSCALL_IMPL(pwritev)

> +{

> +    struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);

> +    unsigned long lo, hi;

> +    abi_long ret;

> +

> +    if (vec == NULL) {

> +        ret = -host_to_target_errno(errno);


           return -host_to_target_errno(errno);

> +    }

> +

> +    host_offset64_low_high(&lo, &hi, arg4);

> +    ret = get_errno(safe_pwritev(arg1, vec, arg3, lo, hi));

> +    unlock_iovec(vec, arg2, arg3, 0);

> +    return ret;

> +}

> +

>  SYSCALL_IMPL(read)

>  {

>      abi_long ret;
Richard Henderson Jan. 11, 2019, 9:31 p.m. UTC | #2
On 1/11/19 2:17 AM, Laurent Vivier wrote:
> On 19/12/2018 05:21, Richard Henderson wrote:

>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

>> ---

>>  linux-user/syscall-defs.h     |  14 ++++

>>  linux-user/syscall-file.inc.c | 124 ++++++++++++++++++++++++++++++++++

>>  linux-user/syscall.c          |  93 -------------------------

>>  linux-user/strace.list        |  18 -----

>>  4 files changed, 138 insertions(+), 111 deletions(-)

>>

> ...

>> diff --git a/linux-user/syscall-file.inc.c b/linux-user/syscall-file.inc.c

>> index 11e75044c1..410a763eee 100644

>> --- a/linux-user/syscall-file.inc.c

>> +++ b/linux-user/syscall-file.inc.c

>> @@ -315,6 +315,104 @@ SYSCALL_IMPL(openat)

> ...

>> +

>> +/*

>> + * Both preadv and pwritev merge args 4/5 into a 64-bit offset.

>> + * Moreover, the parts are *always* in little-endian order.

>> + */

>> +#if TARGET_ABI_BITS == 32

>> +SYSCALL_ARGS(preadv_pwritev)

>> +{

>> +    /* We have already assigned out[0-2].  */

>> +    abi_ulong lo = in[3], hi = in[4];

>> +    out[3] = ((hi << (TARGET_ABI_BITS - 1)) << 1) | lo;

>> +    return def;

>> +}

>> +#else

>> +#define args_preadv_pwritev NULL

>> +#endif

>> +

>> +/* Perform the inverse operation for the host.  */

>> +static inline void host_offset64_low_high(unsigned long *l, unsigned long *h,

>> +                                          uint64_t off)

>> +{

>> +    *l = off;

>> +    *h = (off >> (HOST_LONG_BITS - 1)) >> 1;

>> +}

> 

> 

> I have an error with preadv() on a 32bit target (powerpc, LTP test preadv02).

> 

> It works if I use:

> 

> static inline void host_offset64_low_high(unsigned long *hlow,

>                                           unsigned long *hhigh,

>                                           abi_ulong tlow,

>                                           abi_ulong thigh)

> {

>     uint64_t off = tlow |

>                    ((unsigned long long)thigh << TARGET_LONG_BITS / 2) <<

>                    TARGET_LONG_BITS / 2;

>     

>     *hlow = off;

>     *hhigh = (off >> HOST_LONG_BITS / 2) >> HOST_LONG_BITS / 2;

> }


This doesn't make any sense.  Where are "tlow" and "thigh" coming from?

I think the bug will be

 SYSCALL_ARGS(preadv_pwritev)
 {
     /* We have already assigned out[0-2].  */
     abi_ulong lo = in[3], hi = in[4];
-    out[3] = ((hi << (TARGET_ABI_BITS - 1)) << 1) | lo;
+    out[3] = (((uint64_t)hi << (TARGET_ABI_BITS - 1)) << 1) | lo;
     return def;
 }



r~
Laurent Vivier Jan. 14, 2019, 11:04 a.m. UTC | #3
On 11/01/2019 22:31, Richard Henderson wrote:
> On 1/11/19 2:17 AM, Laurent Vivier wrote:

>> On 19/12/2018 05:21, Richard Henderson wrote:

>>> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

>>> ---

>>>   linux-user/syscall-defs.h     |  14 ++++

>>>   linux-user/syscall-file.inc.c | 124 ++++++++++++++++++++++++++++++++++

>>>   linux-user/syscall.c          |  93 -------------------------

>>>   linux-user/strace.list        |  18 -----

>>>   4 files changed, 138 insertions(+), 111 deletions(-)

>>>

>> ...

>>> diff --git a/linux-user/syscall-file.inc.c b/linux-user/syscall-file.inc.c

>>> index 11e75044c1..410a763eee 100644

>>> --- a/linux-user/syscall-file.inc.c

>>> +++ b/linux-user/syscall-file.inc.c

>>> @@ -315,6 +315,104 @@ SYSCALL_IMPL(openat)

>> ...

>>> +

>>> +/*

>>> + * Both preadv and pwritev merge args 4/5 into a 64-bit offset.

>>> + * Moreover, the parts are *always* in little-endian order.

>>> + */

>>> +#if TARGET_ABI_BITS == 32

>>> +SYSCALL_ARGS(preadv_pwritev)

>>> +{

>>> +    /* We have already assigned out[0-2].  */

>>> +    abi_ulong lo = in[3], hi = in[4];

>>> +    out[3] = ((hi << (TARGET_ABI_BITS - 1)) << 1) | lo;

>>> +    return def;

>>> +}

>>> +#else

>>> +#define args_preadv_pwritev NULL

>>> +#endif

>>> +

>>> +/* Perform the inverse operation for the host.  */

>>> +static inline void host_offset64_low_high(unsigned long *l, unsigned long *h,

>>> +                                          uint64_t off)

>>> +{

>>> +    *l = off;

>>> +    *h = (off >> (HOST_LONG_BITS - 1)) >> 1;

>>> +}

>>

>>

>> I have an error with preadv() on a 32bit target (powerpc, LTP test preadv02).

>>

>> It works if I use:

>>

>> static inline void host_offset64_low_high(unsigned long *hlow,

>>                                            unsigned long *hhigh,

>>                                            abi_ulong tlow,

>>                                            abi_ulong thigh)

>> {

>>      uint64_t off = tlow |

>>                     ((unsigned long long)thigh << TARGET_LONG_BITS / 2) <<

>>                     TARGET_LONG_BITS / 2;

>>      

>>      *hlow = off;

>>      *hhigh = (off >> HOST_LONG_BITS / 2) >> HOST_LONG_BITS / 2;

>> }

> 

> This doesn't make any sense.  Where are "tlow" and "thigh" coming from?

> 

> I think the bug will be

> 

>   SYSCALL_ARGS(preadv_pwritev)

>   {

>       /* We have already assigned out[0-2].  */

>       abi_ulong lo = in[3], hi = in[4];

> -    out[3] = ((hi << (TARGET_ABI_BITS - 1)) << 1) | lo;

> +    out[3] = (((uint64_t)hi << (TARGET_ABI_BITS - 1)) << 1) | lo;

>       return def;

>   }


Yes, this change fixes the problem.

Thanks,
Laurent
diff mbox series

Patch

diff --git a/linux-user/syscall-defs.h b/linux-user/syscall-defs.h
index b031de1375..ae89be0e87 100644
--- a/linux-user/syscall-defs.h
+++ b/linux-user/syscall-defs.h
@@ -21,6 +21,18 @@  SYSCALL_DEF(close, ARG_DEC);
 SYSCALL_DEF(open, ARG_STR, ARG_OPENFLAG, ARG_MODEFLAG);
 #endif
 SYSCALL_DEF(openat, ARG_ATDIRFD, ARG_STR, ARG_OPENFLAG, ARG_MODEFLAG);
+SYSCALL_DEF_FULL(pread64, .impl = impl_pread64,
+                 .args = args_pread64_pwrite64,
+                 .arg_type = { ARG_DEC, ARG_PTR, ARG_DEC, ARG_DEC64 });
+SYSCALL_DEF_FULL(pwrite64, .impl = impl_pwrite64,
+                 .args = args_pread64_pwrite64,
+                 .arg_type = { ARG_DEC, ARG_PTR, ARG_DEC, ARG_DEC64 });
+SYSCALL_DEF_FULL(preadv, .impl = impl_preadv,
+                 .args = args_preadv_pwritev,
+                 .arg_type = { ARG_DEC, ARG_PTR, ARG_DEC, ARG_DEC64 });
+SYSCALL_DEF_FULL(pwritev, .impl = impl_pwritev,
+                 .args = args_preadv_pwritev,
+                 .arg_type = { ARG_DEC, ARG_PTR, ARG_DEC, ARG_DEC64 });
 SYSCALL_DEF(read, ARG_DEC, ARG_PTR, ARG_DEC);
 #ifdef TARGET_NR_readlink
 SYSCALL_DEF(readlink, ARG_STR, ARG_PTR, ARG_DEC);
@@ -28,4 +40,6 @@  SYSCALL_DEF(readlink, ARG_STR, ARG_PTR, ARG_DEC);
 #ifdef TARGET_NR_readlinkat
 SYSCALL_DEF(readlinkat, ARG_ATDIRFD, ARG_STR, ARG_PTR, ARG_DEC);
 #endif
+SYSCALL_DEF(readv, ARG_DEC, ARG_PTR, ARG_DEC);
 SYSCALL_DEF(write, ARG_DEC, ARG_PTR, ARG_DEC);
+SYSCALL_DEF(writev, ARG_DEC, ARG_PTR, ARG_DEC);
diff --git a/linux-user/syscall-file.inc.c b/linux-user/syscall-file.inc.c
index 11e75044c1..410a763eee 100644
--- a/linux-user/syscall-file.inc.c
+++ b/linux-user/syscall-file.inc.c
@@ -315,6 +315,104 @@  SYSCALL_IMPL(openat)
     return do_openat(cpu_env, arg1, arg2, arg3, arg4);
 }
 
+/*
+ * Both pread64 and pwrite64 merge args into a 64-bit offset,
+ * but the input registers and ordering are target specific.
+ */
+#if TARGET_ABI_BITS == 32
+SYSCALL_ARGS(pread64_pwrite64)
+{
+    /* We have already assigned out[0-2].  */
+    int off = regpairs_aligned(cpu_env, TARGET_NR_pread64);
+    out[3] = target_offset64(in[3 + off], in[4 + off]);
+    return def;
+}
+#else
+#define args_pread64_pwrite64 NULL
+#endif
+
+SYSCALL_IMPL(pread64)
+{
+    void *p = lock_user(VERIFY_WRITE, arg2, arg3, 0);
+    abi_long ret;
+
+    if (!p) {
+        return -TARGET_EFAULT;
+    }
+    ret = get_errno(pread64(arg1, p, arg3, arg4));
+    unlock_user(p, arg2, ret);
+    return ret;
+}
+
+SYSCALL_IMPL(pwrite64)
+{
+    void *p = lock_user(VERIFY_READ, arg2, arg3, 0);
+    abi_long ret;
+
+    if (!p) {
+        return -TARGET_EFAULT;
+    }
+    ret = get_errno(pwrite64(arg1, p, arg3, arg4));
+    unlock_user(p, arg2, 0);
+    return ret;
+}
+
+/*
+ * Both preadv and pwritev merge args 4/5 into a 64-bit offset.
+ * Moreover, the parts are *always* in little-endian order.
+ */
+#if TARGET_ABI_BITS == 32
+SYSCALL_ARGS(preadv_pwritev)
+{
+    /* We have already assigned out[0-2].  */
+    abi_ulong lo = in[3], hi = in[4];
+    out[3] = ((hi << (TARGET_ABI_BITS - 1)) << 1) | lo;
+    return def;
+}
+#else
+#define args_preadv_pwritev NULL
+#endif
+
+/* Perform the inverse operation for the host.  */
+static inline void host_offset64_low_high(unsigned long *l, unsigned long *h,
+                                          uint64_t off)
+{
+    *l = off;
+    *h = (off >> (HOST_LONG_BITS - 1)) >> 1;
+}
+
+SYSCALL_IMPL(preadv)
+{
+    struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 0);
+    unsigned long lo, hi;
+    abi_long ret;
+
+    if (vec == NULL) {
+        return -host_to_target_errno(errno);
+    }
+
+    host_offset64_low_high(&lo, &hi, arg4);
+    ret = get_errno(safe_preadv(arg1, vec, arg3, lo, hi));
+    unlock_iovec(vec, arg2, arg3, 1);
+    return ret;
+}
+
+SYSCALL_IMPL(pwritev)
+{
+    struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);
+    unsigned long lo, hi;
+    abi_long ret;
+
+    if (vec == NULL) {
+        ret = -host_to_target_errno(errno);
+    }
+
+    host_offset64_low_high(&lo, &hi, arg4);
+    ret = get_errno(safe_pwritev(arg1, vec, arg3, lo, hi));
+    unlock_iovec(vec, arg2, arg3, 0);
+    return ret;
+}
+
 SYSCALL_IMPL(read)
 {
     abi_long ret;
@@ -403,6 +501,19 @@  SYSCALL_IMPL(readlinkat)
 }
 #endif
 
+SYSCALL_IMPL(readv)
+{
+    struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 0);
+    abi_long ret;
+
+    if (vec == NULL) {
+        return -host_to_target_errno(errno);
+    }
+    ret = get_errno(safe_readv(arg1, vec, arg3));
+    unlock_iovec(vec, arg2, arg3, 1);
+    return ret;
+}
+
 SYSCALL_IMPL(write)
 {
     TargetFdDataFunc trans;
@@ -431,3 +542,16 @@  SYSCALL_IMPL(write)
     unlock_user(p, arg2, 0);
     return ret;
 }
+
+SYSCALL_IMPL(writev)
+{
+    struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);
+    abi_long ret;
+
+    if (vec == NULL) {
+        return -host_to_target_errno(errno);
+    }
+    ret = get_errno(safe_writev(arg1, vec, arg3));
+    unlock_iovec(vec, arg2, arg3, 0);
+    return ret;
+}
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index d4c11c3e93..9a9b6c543c 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2364,23 +2364,6 @@  static abi_long do_getsockopt(int sockfd, int level, int optname,
     return ret;
 }
 
-/* Convert target low/high pair representing file offset into the host
- * low/high pair. This function doesn't handle offsets bigger than 64 bits
- * as the kernel doesn't handle them either.
- */
-static void target_to_host_low_high(abi_ulong tlow,
-                                    abi_ulong thigh,
-                                    unsigned long *hlow,
-                                    unsigned long *hhigh)
-{
-    uint64_t off = tlow |
-        ((unsigned long long)thigh << TARGET_LONG_BITS / 2) <<
-        TARGET_LONG_BITS / 2;
-
-    *hlow = off;
-    *hhigh = (off >> HOST_LONG_BITS / 2) >> HOST_LONG_BITS / 2;
-}
-
 static struct iovec *lock_iovec(int type, abi_ulong target_addr,
                                 abi_ulong count, int copy)
 {
@@ -8910,60 +8893,6 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         /* NOTE: the flock constant seems to be the same for every
            Linux platform */
         return get_errno(safe_flock(arg1, arg2));
-    case TARGET_NR_readv:
-        {
-            struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 0);
-            if (vec != NULL) {
-                ret = get_errno(safe_readv(arg1, vec, arg3));
-                unlock_iovec(vec, arg2, arg3, 1);
-            } else {
-                ret = -host_to_target_errno(errno);
-            }
-        }
-        return ret;
-    case TARGET_NR_writev:
-        {
-            struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);
-            if (vec != NULL) {
-                ret = get_errno(safe_writev(arg1, vec, arg3));
-                unlock_iovec(vec, arg2, arg3, 0);
-            } else {
-                ret = -host_to_target_errno(errno);
-            }
-        }
-        return ret;
-#if defined(TARGET_NR_preadv)
-    case TARGET_NR_preadv:
-        {
-            struct iovec *vec = lock_iovec(VERIFY_WRITE, arg2, arg3, 0);
-            if (vec != NULL) {
-                unsigned long low, high;
-
-                target_to_host_low_high(arg4, arg5, &low, &high);
-                ret = get_errno(safe_preadv(arg1, vec, arg3, low, high));
-                unlock_iovec(vec, arg2, arg3, 1);
-            } else {
-                ret = -host_to_target_errno(errno);
-           }
-        }
-        return ret;
-#endif
-#if defined(TARGET_NR_pwritev)
-    case TARGET_NR_pwritev:
-        {
-            struct iovec *vec = lock_iovec(VERIFY_READ, arg2, arg3, 1);
-            if (vec != NULL) {
-                unsigned long low, high;
-
-                target_to_host_low_high(arg4, arg5, &low, &high);
-                ret = get_errno(safe_pwritev(arg1, vec, arg3, low, high));
-                unlock_iovec(vec, arg2, arg3, 0);
-            } else {
-                ret = -host_to_target_errno(errno);
-           }
-        }
-        return ret;
-#endif
     case TARGET_NR_getsid:
         return get_errno(getsid(arg1));
 #if defined(TARGET_NR_fdatasync) /* Not on alpha (osf_datasync ?) */
@@ -9295,28 +9224,6 @@  static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 #else
 #error unreachable
 #endif
-#endif
-#ifdef TARGET_NR_pread64
-    case TARGET_NR_pread64:
-        if (regpairs_aligned(cpu_env, num)) {
-            arg4 = arg5;
-            arg5 = arg6;
-        }
-        if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0)))
-            return -TARGET_EFAULT;
-        ret = get_errno(pread64(arg1, p, arg3, target_offset64(arg4, arg5)));
-        unlock_user(p, arg2, ret);
-        return ret;
-    case TARGET_NR_pwrite64:
-        if (regpairs_aligned(cpu_env, num)) {
-            arg4 = arg5;
-            arg5 = arg6;
-        }
-        if (!(p = lock_user(VERIFY_READ, arg2, arg3, 1)))
-            return -TARGET_EFAULT;
-        ret = get_errno(pwrite64(arg1, p, arg3, target_offset64(arg4, arg5)));
-        unlock_user(p, arg2, 0);
-        return ret;
 #endif
     case TARGET_NR_getcwd:
         if (!(p = lock_user(VERIFY_WRITE, arg1, arg2, 0)))
diff --git a/linux-user/strace.list b/linux-user/strace.list
index ff8bb19f5f..8f96b7a105 100644
--- a/linux-user/strace.list
+++ b/linux-user/strace.list
@@ -1034,12 +1034,6 @@ 
 #ifdef TARGET_NR_prctl
 { TARGET_NR_prctl, "prctl" , NULL, NULL, NULL },
 #endif
-#ifdef TARGET_NR_pread64
-{ TARGET_NR_pread64, "pread64" , NULL, NULL, NULL },
-#endif
-#ifdef TARGET_NR_preadv
-{ TARGET_NR_preadv, "preadv" , NULL, NULL, NULL },
-#endif
 #ifdef TARGET_NR_prlimit64
 { TARGET_NR_prlimit64, "prlimit64" , NULL, NULL, NULL },
 #endif
@@ -1064,12 +1058,6 @@ 
 #ifdef TARGET_NR_putpmsg
 { TARGET_NR_putpmsg, "putpmsg" , NULL, NULL, NULL },
 #endif
-#ifdef TARGET_NR_pwrite64
-{ TARGET_NR_pwrite64, "pwrite64" , NULL, NULL, NULL },
-#endif
-#ifdef TARGET_NR_pwritev
-{ TARGET_NR_pwritev, "pwritev" , NULL, NULL, NULL },
-#endif
 #ifdef TARGET_NR_query_module
 { TARGET_NR_query_module, "query_module" , NULL, NULL, NULL },
 #endif
@@ -1091,9 +1079,6 @@ 
 #ifdef TARGET_NR_readlinkat
 { TARGET_NR_readlinkat, "readlinkat" , NULL, print_readlinkat, NULL },
 #endif
-#ifdef TARGET_NR_readv
-{ TARGET_NR_readv, "readv" , NULL, NULL, NULL },
-#endif
 #ifdef TARGET_NR_reboot
 { TARGET_NR_reboot, "reboot" , NULL, NULL, NULL },
 #endif
@@ -1629,9 +1614,6 @@ 
 #ifdef TARGET_NR_write
 { TARGET_NR_write, "write" , "%s(%d,%#x,%d)", NULL, NULL },
 #endif
-#ifdef TARGET_NR_writev
-{ TARGET_NR_writev, "writev" , "%s(%d,%p,%#x)", NULL, NULL },
-#endif
 #ifdef TARGET_NR_utimensat
 { TARGET_NR_utimensat, "utimensat", NULL, print_utimensat, NULL },
 #endif