[Qemu-devel] [PATCH for 4.1 v2 7/7] linux-user: Add support for semtimedop() syscall

Aleksandar Markovic posted 7 patches 6 years, 3 months ago
Maintainers: Riku Voipio <riku.voipio@iki.fi>, Laurent Vivier <laurent@vivier.eu>
There is a newer version of this series
[Qemu-devel] [PATCH for 4.1 v2 7/7] linux-user: Add support for semtimedop() syscall
Posted by Aleksandar Markovic 6 years, 3 months ago
From: Aleksandar Rikalo <arikalo@wavecomp.com>

Add support for semtimedop() emulation. It is based on invocation
of safe_semtimedop().

Conversion is left out of safe_semtimedop(), since other safe_xxx()
usually don't contain similar conversions.

Signed-off-by: Aleksandar Rikalo <arikalo@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
---
 linux-user/syscall.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ee80175..c7b08f5 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -6650,7 +6650,39 @@ static inline abi_long host_to_target_statx(struct target_statx *host_stx,
     return 0;
 }
 #endif
+#ifdef TARGET_NR_semtimedop
+static inline abi_long do_semtimedop(int semid, abi_long ptr, unsigned nsops,
+                                     abi_long timeout)
+{
+    struct sembuf *sops;
+    struct timespec ts, *pts;
+    abi_long ret;
+
+    if (timeout) {
+        pts = &ts;
+        if (target_to_host_timespec(pts, timeout)) {
+            return -TARGET_EFAULT;
+        }
+    } else {
+        pts = NULL;
+    }
 
+    sops = g_malloc(sizeof(struct sembuf) * nsops);
+    if (sops == NULL) {
+        return -TARGET_EFAULT;
+    }
+
+    if (target_to_host_sembuf(sops, ptr, nsops)) {
+        g_free(sops);
+        return -TARGET_EFAULT;
+    }
+
+    ret = get_errno(safe_semtimedop(semid, sops, nsops, pts));
+    g_free(sops);
+
+    return ret;
+}
+#endif
 
 /* ??? Using host futex calls even when target atomic operations
    are not really atomic probably breaks things.  However implementing
@@ -9194,6 +9226,10 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
     case TARGET_NR_semop:
         return do_semop(arg1, arg2, arg3);
 #endif
+#ifdef TARGET_NR_semtimedop
+    case TARGET_NR_semtimedop:
+        return do_semtimedop(arg1, arg2, arg3, arg4);
+#endif
 #ifdef TARGET_NR_semctl
     case TARGET_NR_semctl:
         return do_semctl(arg1, arg2, arg3, arg4);
-- 
2.7.4


Re: [Qemu-devel] [PATCH for 4.1 v2 7/7] linux-user: Add support for semtimedop() syscall
Posted by Aleksandar Markovic 6 years, 3 months ago
On Mon, Jul 29, 2019 at 3:11 PM Aleksandar Markovic <
aleksandar.markovic@rt-rk.com> wrote:

> From: Aleksandar Rikalo <arikalo@wavecomp.com>
>
> Add support for semtimedop() emulation. It is based on invocation
> of safe_semtimedop().
>
> Conversion is left out of safe_semtimedop(), since other safe_xxx()
> usually don't contain similar conversions.
>
> Signed-off-by: Aleksandar Rikalo <arikalo@wavecomp.com>
> Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
> ---
>

Aleksandar R., Laurent,

Please note that I just rebased the patch compared to its last incarnation
- no code change.

Laurent's hints were as follows last time:

"To avoid duplicate code (and cleanup the stack allocation), you should

remove do_semop()  and call do_semtimedop(..., NULL) from IPCOP_semop
and TARGET_NR_semop.

Thanks, Laurent"

 I guess they are still valid.

Thanks,
Aleksandar



>  linux-user/syscall.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
>
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index ee80175..c7b08f5 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6650,7 +6650,39 @@ static inline abi_long host_to_target_statx(struct
> target_statx *host_stx,
>      return 0;
>  }
>  #endif
> +#ifdef TARGET_NR_semtimedop
> +static inline abi_long do_semtimedop(int semid, abi_long ptr, unsigned
> nsops,
> +                                     abi_long timeout)
> +{
> +    struct sembuf *sops;
> +    struct timespec ts, *pts;
> +    abi_long ret;
> +
> +    if (timeout) {
> +        pts = &ts;
> +        if (target_to_host_timespec(pts, timeout)) {
> +            return -TARGET_EFAULT;
> +        }
> +    } else {
> +        pts = NULL;
> +    }
>
> +    sops = g_malloc(sizeof(struct sembuf) * nsops);
> +    if (sops == NULL) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    if (target_to_host_sembuf(sops, ptr, nsops)) {
> +        g_free(sops);
> +        return -TARGET_EFAULT;
> +    }
> +
> +    ret = get_errno(safe_semtimedop(semid, sops, nsops, pts));
> +    g_free(sops);
> +
> +    return ret;
> +}
> +#endif
>
>  /* ??? Using host futex calls even when target atomic operations
>     are not really atomic probably breaks things.  However implementing
> @@ -9194,6 +9226,10 @@ static abi_long do_syscall1(void *cpu_env, int num,
> abi_long arg1,
>      case TARGET_NR_semop:
>          return do_semop(arg1, arg2, arg3);
>  #endif
> +#ifdef TARGET_NR_semtimedop
> +    case TARGET_NR_semtimedop:
> +        return do_semtimedop(arg1, arg2, arg3, arg4);
> +#endif
>  #ifdef TARGET_NR_semctl
>      case TARGET_NR_semctl:
>          return do_semctl(arg1, arg2, arg3, arg4);
> --
> 2.7.4
>
>
>
Re: [Qemu-devel] [PATCH for 4.1 v2 7/7] linux-user: Add support for semtimedop() syscall
Posted by Laurent Vivier 6 years, 3 months ago
Le 29/07/2019 à 15:26, Aleksandar Markovic a écrit :
> 
> 
> On Mon, Jul 29, 2019 at 3:11 PM Aleksandar Markovic
> <aleksandar.markovic@rt-rk.com <mailto:aleksandar.markovic@rt-rk.com>>
> wrote:
> 
>     From: Aleksandar Rikalo <arikalo@wavecomp.com
>     <mailto:arikalo@wavecomp.com>>
> 
>     Add support for semtimedop() emulation. It is based on invocation
>     of safe_semtimedop().
> 
>     Conversion is left out of safe_semtimedop(), since other safe_xxx()
>     usually don't contain similar conversions.
> 
>     Signed-off-by: Aleksandar Rikalo <arikalo@wavecomp.com
>     <mailto:arikalo@wavecomp.com>>
>     Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com
>     <mailto:amarkovic@wavecomp.com>>
>     ---
> 
> 
> Aleksandar R., Laurent,
> 
> Please note that I just rebased the patch compared to its last
> incarnation - no code change.
> 
> Laurent's hints were as follows last time:
> 
> "To avoid duplicate code (and cleanup the stack allocation), you should
> 
> remove do_semop()  and call do_semtimedop(..., NULL) from IPCOP_semop
> and TARGET_NR_semop.
> 
> Thanks, Laurent"
> 
>  I guess they are still valid.

Yes, I didn't remember my comment and do the same again...

Thanks,
Laurent


Re: [Qemu-devel] [PATCH for 4.1 v2 7/7] linux-user: Add support for semtimedop() syscall
Posted by Laurent Vivier 6 years, 3 months ago
Le 29/07/2019 à 15:09, Aleksandar Markovic a écrit :
> From: Aleksandar Rikalo <arikalo@wavecomp.com>
> 
> Add support for semtimedop() emulation. It is based on invocation
> of safe_semtimedop().
> 
> Conversion is left out of safe_semtimedop(), since other safe_xxx()
> usually don't contain similar conversions.
> 
> Signed-off-by: Aleksandar Rikalo <arikalo@wavecomp.com>
> Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
> ---
>  linux-user/syscall.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index ee80175..c7b08f5 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -6650,7 +6650,39 @@ static inline abi_long host_to_target_statx(struct target_statx *host_stx,
>      return 0;
>  }
>  #endif
> +#ifdef TARGET_NR_semtimedop
> +static inline abi_long do_semtimedop(int semid, abi_long ptr, unsigned nsops,
> +                                     abi_long timeout)
> +{
> +    struct sembuf *sops;
> +    struct timespec ts, *pts;
> +    abi_long ret;
> +
> +    if (timeout) {
> +        pts = &ts;
> +        if (target_to_host_timespec(pts, timeout)) {
> +            return -TARGET_EFAULT;
> +        }
> +    } else {
> +        pts = NULL;
> +    }
>  
> +    sops = g_malloc(sizeof(struct sembuf) * nsops);
> +    if (sops == NULL) {
> +        return -TARGET_EFAULT;
> +    }
> +
> +    if (target_to_host_sembuf(sops, ptr, nsops)) {
> +        g_free(sops);
> +        return -TARGET_EFAULT;
> +    }
> +
> +    ret = get_errno(safe_semtimedop(semid, sops, nsops, pts));
> +    g_free(sops);
> +
> +    return ret;
> +}
> +#endif

As we have a "#ifdef__NR_semtimedop" around the definition of
safe_semtimedop() you need the same #ifdef around its use:
perhaps you can update the existing do_semop() to implement do_semtimedop().

>  
>  /* ??? Using host futex calls even when target atomic operations
>     are not really atomic probably breaks things.  However implementing
> @@ -9194,6 +9226,10 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
>      case TARGET_NR_semop:
>          return do_semop(arg1, arg2, arg3);
>  #endif
> +#ifdef TARGET_NR_semtimedop
> +    case TARGET_NR_semtimedop:
> +        return do_semtimedop(arg1, arg2, arg3, arg4);
> +#endif
>  #ifdef TARGET_NR_semctl
>      case TARGET_NR_semctl:
>          return do_semctl(arg1, arg2, arg3, arg4);
> 

You should also implement in do_ipc() the IPCOP_semtimedop operation.

Thanks,
Laurent