From: Jesus Villena <j.villena@ecler.com>
To: "xenomai@lists.linux.dev" <xenomai@lists.linux.dev>
Subject: [EVL] Problems writing to physical memory with mmap on oob context
Date: Tue, 26 Sep 2023 11:21:04 +0000 [thread overview]
Message-ID: <DB8PR10MB370698CF0BAFEAE2198D24A3F9C3A@DB8PR10MB3706.EURPRD10.PROD.OUTLOOK.COM> (raw)
Hello,
We are using an ARM64 based platform which includes a small Cortex M4 processor to run some algorithms, and both subsystems use an internal shared SRAM memory to implement the inter-processor communication.
In mainline Linux, we open a "/dev/mem" file in the ARM64 core to get access to physical memory, and mmap the shared area to read and write directly to the SRAM from userland.
With EVL, it doesn't work: after opening the file and doing mmap, we call evl_attach_self to switch to the oob context, and then, reading on the shared area works, but writing aborts the program with the message:
EVL: evl_test switching in-band [pid=363, excpt=0, user_pc=0x404b5c]
oop...
CPU time limit exceeded
I don't understand why EVL is switching to in-band context.
Do you know where is the problem? Why does reading work but writing doesn't?
Regards.
Jesus Villena
next reply other threads:[~2023-09-26 11:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-26 11:21 Jesus Villena [this message]
2023-09-26 14:15 ` [EVL] Problems writing to physical memory with mmap on oob context Philippe Gerum
2023-09-26 15:40 ` Jesus Villena
2023-09-26 15:46 ` Philippe Gerum
2023-09-26 16:04 ` Jesus Villena
2023-09-27 6:51 ` Philippe Gerum
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