Hi I am trying to find out what the code written in arch/arm/kernel/entry-armv.S means. ( I am working on ARM ). The code there talks about proirities and other such stuff. I have an idea about how interrupts work, but I have not been able to figure out what exactly the table in that file conveys. I am posting the code which I am trying to understand with this mail. Regards Ramki. P.S: If this is specific to ARM, then please tell me. I will ask these questions in the ARM list and Sorry for the inconvenience. ----------------------------------------------------------------------- #include <linux/config.h> #include "entry-header.S" #ifdef IOC_BASE /* IOC / IOMD based hardware */ #include <asm/hardware/iomd.h> .equ ioc_base_high, IOC_BASE & 0xff000000 .equ ioc_base_low, IOC_BASE & 0x00ff0000 .macro disable_fiq mov r12, #ioc_base_high .if ioc_base_low orr r12, r12, #ioc_base_low .endif strb r12, [r12, #0x38] @ Disable FIQ register .endm .macro get_irqnr_and_base, irqnr, irqstat, base, tmp mov r4, #ioc_base_high @ point at IOC .if ioc_base_low orr r4, r4, #ioc_base_low .endif ldrb \irqstat, [r4, #IOMD_IRQREQB] @ get high priority first ldr \base, =irq_prio_h teq \irqstat, #0 #ifdef IOMD_BASE ldreqb \irqstat, [r4, #IOMD_DMAREQ] @ get dma addeq \base, \base, #256 @ irq_prio_h table size teqeq \irqstat, #0 bne 2406f #endif ldreqb \irqstat, [r4, #IOMD_IRQREQA] @ get low priority addeq \base, \base, #256 @ irq_prio_d table size teqeq \irqstat, #0 #ifdef IOMD_IRQREQC ldreqb \irqstat, [r4, #IOMD_IRQREQC] addeq \base, \base, #256 @ irq_prio_l table size teqeq \irqstat, #0 #endif #ifdef IOMD_IRQREQD ldreqb \irqstat, [r4, #IOMD_IRQREQD] addeq \base, \base, #256 @ irq_prio_lc table size teqeq \irqstat, #0 #endif 2406: ldrneb \irqnr, [\base, \irqstat] @ get IRQ number .endm /* * Interrupt table (incorporates priority). Please note that we * rely on the order of these tables (see above code). */ .macro irq_prio_table irq_prio_h: .byte 0, 8, 9, 8,10,10,10,10,11,11,11,11,10,10,10,10 .byte 12, 8, 9, 8,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 14,14,14,14,10,10,10,10,11,11,11,11,10,10,10,10 .byte 14,14,14,14,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10 .byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10 .byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 .byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10 #ifdef IOMD_BASE irq_prio_d: .byte 0,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 20,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 22,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 22,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 23,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 23,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 22,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 22,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 .byte 21,16,17,16,18,16,17,16,19,16,17,16,18,16,17,16 #endif irq_prio_l: .byte 0, 0, 1, 0, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 .byte 4, 0, 1, 0, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3 .byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 .byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 .byte 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, 3, 3, 3 .byte 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, 3, 3, 3 .byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 .byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 .byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 #ifdef IOMD_IRQREQC irq_prio_lc: .byte 24,24,25,24,26,26,26,26,27,27,27,27,27,27,27,27 .byte 28,24,25,24,26,26,26,26,27,27,27,27,27,27,27,27 .byte 29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29 .byte 29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29 .byte 30,30,30,30,30,30,30,30,27,27,27,27,27,27,27,27 .byte 30,30,30,30,30,30,30,30,27,27,27,27,27,27,27,27 .byte 29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29 .byte 29,29,29,29,29,29,29,29,29,29,29,29,29,29,29,29 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 .byte 31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31 #endif #ifdef IOMD_IRQREQD irq_prio_ld: .byte 40,40,41,40,42,42,42,42,43,43,43,43,43,43,43,43 .byte 44,40,41,40,42,42,42,42,43,43,43,43,43,43,43,43 .byte 45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45 .byte 45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45 .byte 46,46,46,46,46,46,46,46,43,43,43,43,43,43,43,43 .byte 46,46,46,46,46,46,46,46,43,43,43,43,43,43,43,43 .byte 45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45 .byte 45,45,45,45,45,45,45,45,45,45,45,45,45,45,45,45 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 .byte 47,47,47,47,47,47,47,47,47,47,47,47,47,47,47,47 #endif ----------------------------------------------------------------------------- On Wed, 4 Sep 2002, Jirka Kosina wrote: > On Tue, 3 Sep 2002, Ramakrishnan wrote: > > > Can someone direct me to some link or tell me how to write the interrupt > > table at the kernel level? I want to find out what exactly those table > > entries convey to the processor. > > I don't understand your question exactly, but anyway I would suggest > > - reading Pentium manual from Intel (I've it somewhere on my disk, if you > can't find it) > - see arch/i386/kernel/traps.c, especially functions as set_trap_gate(), > _set_gate(), etc. > - just be more specific. > > Your question could be answered shortly by two words: lidt instruction. > ;) > > -- > JiKos. > > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
