hi as i have already mentioned in a mail the scenario where i would need to asynchronously notify from kernel to user, i have taken a stand of sending a signal SIGIO to one process and any unsed signal to the other process. Can anyone tell me if it is possible to send any signals through kill_fasync. most drivers in linux source code which i have come across used only SIGIO for this kind of notification..i am not very much sure if signals like SIGUSR1 or SIGUSR2 can also be used ? I am sure SIGUSR1 or SIGUSR2 are not used anywhere. can anyone plz clear this doubt ?? thanks in advance Regards, Vijay Ram.C On Fri, 15 Jul 2005, Aggarwal, Vikas (OFT) wrote: > I am porting a driver (2.6.x ) kernel. It uses "send_sig" to notify > user process. The "send_sig" is called from the tasklet. > http://lxr.linux.no/source/kernel/signal.c#L1249 > > Don't know if this the best or only way. > > Thanks > -vikas > > > -------------------------------------------------------- > This e-mail, including any attachments, may be confidential, privileged or otherwise legally protected. It is intended only for the addressee. If you received this e-mail in error or from someone who was not authorized to send it to you, do not disseminate, copy or otherwise use this e-mail or its attachments. Please notify the sender immediately by reply e-mail and delete the e-mail from your system. > > > -----Original Message----- > > From: kernelnewbies-bounce@xxxxxxxxxxxx > [mailto:kernelnewbies-bounce@xxxxxxxxxxxx] On Behalf Of Vijay Ram > Chitrapu (RCVIJAYD) > Sent: Friday, July 15, 2005 3:43 AM > To: Thomas Petazzoni > Cc: Vijay Ram Chitrapu (RCVIJAYD); kernelnewbies@xxxxxxxxxxxx > Subject: Re: help regarding software interrupts > > > > Hi Robert > > Thanks for the info.. > i was under an idea that software interrupts can be used to send > some kind of signals to the user space asynchronously. Is it possible > for a driver running in the kernel to generate a software interrupt > asynchronously to the user such that the user is informed of some change > > in the kernel the driver is involved with? I am well aware of the fasync > > method of asynchronous notification..but want to know if this way of > signalling is feasible or not? > > Regards, > Vijay Ram.C > > > On Fri, 15 Jul 2005, Thomas Petazzoni wrote: > > > Hello, > > > > Vijay Ram Chitrapu (RCVIJAYD) wrote: > > > > > Can anyone help me understand what Software Interrupts are? > > > Any links or examples are welcomed.. > > > > Basically, on x86 architecture, you can have three sources of > interruption : > > > > - the processor himself, that generates "exceptions", such as Page > > Fault, General Protection Fault, Divide by Zero and so on. On IA32 > > architecture, there are 32 exceptions ; > > > > - the hardware, such as network cards, sound cards, hard drives and > > much more generates IRQs to signal an event (arrival of a network > > packet, acknowledgment of a DMA transfer, etc.) ; > > > > - the software which, using the <int> instruction, explicitly > > generates a so-called <software interrupt>. > > > > So, the software interrupts are interrupts that are generated > explicitly > > by the code running on the processor. The typical usage of such > > interrupts is to implement syscalls : when the code is running in user > > > (non privileged) mode, it cannot call kernel code directly. In order > to > > switch to kernel (privileged) mode, a software interrupt is used (at > > least on x86). > > > > Don't hesitate to ask for more details. Others, don't hesitate to > > correct me if I'm wrong. > > > > Sincerly, > > > > Thomas > > > > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > -- > Kernelnewbies: Help each other learn about the Linux kernel. > Archive: http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
