From: irfan_hamid@softhome.net
To: linux-kernel@vger.kernel.org
Subject: cli()/sti() clarification
Date: Thu, 18 Jul 2002 00:27:40 -0600 [thread overview]
Message-ID: <courier.3D365FDC.0000712F@softhome.net> (raw)
Hi,
I added two system calls, blockintr() and unblockintr() to give cli()/sti()
control to userland programs (yes I know its not advisable) but I only want
to do it as a test. My test program looks like this:
blockintr();
/* Some long calculations */
unblockintr();
The problem is that if I press Ctrl+C during the calculation, the program
terminates. So I checked the _syscallN() and __syscall_return() macros to
see if they explicitly call sti() before returning to userspace, but they
dont.
Reading the lkml archives, I found that cli() disables only the interrupts,
exceptions are allowed, so it makes sense that the SIGINT was delivered, but
if thats the case, then how come the SIGINT was delivered from the Ctrl+C?
Doesnt this mean that the SIGINT signal was generated as a result of the
keyboard interrupt?
I know I am missing something here, would appreciate if someone could point
me in the right direction.
Regards,
Irfan Hamid.
next reply other threads:[~2002-07-18 6:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-18 6:27 irfan_hamid [this message]
2002-07-18 6:58 ` cli()/sti() clarification george anzinger
2002-07-18 9:33 ` Kasper Dupont
2002-07-18 14:52 ` Marco Colombo
-- strict thread matches above, loose matches on Subject: below --
2002-07-22 7:20 irfan_hamid
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