From: Oded Gabbay <ogabbay@advaoptical.com>
To: xenomai@xenomai.org
Subject: [Xenomai] Problem with rtdm_mmap_to_user
Date: Thu, 25 Oct 2012 21:58:44 +0200 [thread overview]
Message-ID: <508999F4.6060802@advaoptical.com> (raw)
Hi,
I'm using Xenomai 2.6.1 and kernel 2.6.33 on mpc8309 (powerpc) processor.
I'm trying to map a kernel memory area to user space memory.
The call to rtdm_mmap_to_user inside the rt driver works but when I read
the memory in the user space thread (rt thread), the contents of the
memory area are wrong.
Here is the code in the driver:
ret = rtdm_mmap_to_user(user_info, skb, sizeof(struct rtskb),
PROT_READ|PROT_WRITE,
(void **)&msg->msg_iov[1].iov_base,
NULL, NULL);
msg->msg_iov[1].iov_base is a void* which points to NULL before the call
to rtdm_mmap_to_user.
The result is in msg->msg_iov[1].iov_base. The address seems good, as it
in the range of the addresses of other variables in my user space thread.
In the user-space thread I do:
void *tmp;
tmp = msg->msg_iov[1].iov_base;
printf("tmp = %p:%x\n", tmp, *(int *)tmp);
The results is that tmp points to the same address I got at
rtdm_mmap_to_user, but the contents of tmp are wrong.
Please help me...
Thanks,
Oded
reply other threads:[~2012-10-25 19:58 UTC|newest]
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