Date: Sat, 11 Nov 2006 22:37:40 -0800 From: Garrett Cooper <youshi10@u.washington.edu> To: freebsd-questions@freebsd.org Subject: Re: signal design questions Message-ID: <9EA5F6DB-1EB9-4092-A92D-DE452A13BF0B@u.washington.edu> In-Reply-To: <562718.15358.qm@web72013.mail.tp2.yahoo.com> References: <562718.15358.qm@web72013.mail.tp2.yahoo.com>
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On Nov 11, 2006, at 10:55 AM, Wenyen, Shih wrote: > Hi all, > I have some questions. > (1) I know how to delivery of a signal to a > process. > > 1. The kernel places a signal context on the > user's stack.(user level) > 2. The kernel places a signal-handler frame on > the user's stack.(kernel level) > 3. The user's signal handler returns to the > sigtramp() routine, which pops the signal-handler > context from the user's stack.(user level) > 4. The sigtramp() routine finishes by calling > the sigreturn system call. > > But, why don't implement signal handler routine > in kernel level? Are there having any ideas to > implement signal handler routine in kernel level? > > > (2) The system-call exit code first checks for a > posted signal and check to see whether any process has > a priority higher than that of the currently running > process. > But, I don't know the signal be checked when > returning from kernel mode to user mode. > > Anyone have any other methods to checked the > signal in the other occasion ? > > Thanks, > > Wenyen I would suggest asking this question on the freebsd-hackers list. -Garrett
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