Hi All I am working on Intel IA32 platform on linux kernel 2.6.8. Primarily I am looking at Inter Processor Interrupts (IPI) on APIC. As per my understanding Linux supports Logical mode of IPI. I want to change it to physical mode (please don't ask why ??). Can anybody tell me what all things I need to change ? More explanation of problem: ====================== Intel architecture's APIC functionality supports IPI also, which are useful in SMP. For IPI functionality each processor's local APIC provides ICR register (Interrupt command register) and this is the basic register for controlling IPI mechanism. Setting destination mode field of ICR register can change the mode from physical to logical. As per my understanding Linux IPI mechanism work under logical mode only. There is no support for physical mode (however ppl may argue that it is not needed.. I agree.. But due to some reason I need it..) Search Till now and queries: ==================== Till this point of time I can figure out following changes : - 1. Need to change function __prepare_ICR (arch/asm-i386/kernel/smp.c) in case of destination shorthand is not used that is value of shortcut is 0. 2. Need to pass physical APIC_ID in __prepare_ICR2() function calls. - Here I am not sure how to get physical APIC_ID for the destination processor ? Is there any standard function available for this ? 3. Also If I change according to 2 then I think I need to change the code in kernel where Linux handles logical mode (that is look for DFR and LDR registers) - I am not able to figure out the location of the code in kernel. Can anybody let me know the location of code ? Also if somebody can suggest me what else needs to be change then it would be great help for me ? Any pointer in this regard will be useful. Finally correct me if somewhere my understanding is not correct OR I have mentioned something wrong. TIA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Deepak Kumar Gupta Project Leader System Software Group HCL Technologies Limited Noida UP Contributing to the World by creating indispensable value ! System Software CoE @ HCLT-Noida http://www.hcltechnologies.com Ph. : +91-120-2510701/702 Ext : 3159 FAX : +91-120-2510713 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
