This is the mail archive of the
ecos-discuss@sources.redhat.com
mailing list for the eCos project.
Re: Is Redboot run in supervisor mode?
- From: Jonathan Larmour <jifl at eCosCentric dot com>
- To: jameshq at liverpool dot ac dot uk
- Cc: ecos-discuss at sources dot redhat dot com
- Date: Sun, 02 Feb 2003 16:28:57 +0000
- Subject: Re: [ECOS] Is Redboot run in supervisor mode?
- References: <200302021335.h12DZYa08232@webmail2.liv.ac.uk>
jameshq@liverpool.ac.uk wrote:
Thank you very much Jonathan.
Could I ask 4 more questions about the ecos for arm. Thanks a lot in
advance.
I am on ARM target
Q1. When initializing a user thread (cyg_thread_create()), its mode
will be default to CPSR_SUPERVISOR_MODE.(HAL_THREAD_INIT_CONTEXT) then
the user thread will be loaded into supervisor mode rather than user
mode, is this correct?
Q2. if so why not use user mode to run the user created thread?
Q3. Is there any particular reason not using user mode for this?
Q4. So seems everything in ecos for ARM target are run in supervisor
mode correct(except exception)? no user mode at all.
Yes, as I said it's supervisor mode for everything. There is no
distinction between kernel and user programs in eCos as it's all fully
linked. User mode would just get in the way.
Jifl
-----Original Message-----
From: Jonathan Larmour [mailto:jifl@eCosCentric.com]
[snip]
I believe Qiang is on ARM in which case it's supervisor (SVC) mode for
everything. Even on interrupts we switch to SVC mode as soon as we
can.
--
eCosCentric http://www.eCosCentric.com/ <info@eCosCentric.com>
--[ "You can complain because roses have thorns, or you ]--
--[ can rejoice because thorns have roses." -Lincoln ]-- Opinions==mine
--
Before posting, please read the FAQ: http://sources.redhat.com/fom/ecos
and search the list archive: http://sources.redhat.com/ml/ecos-discuss