Hi,

I've been trying to install the FIQ handler from the MontaVista 2.4 kernel. Currently without much success. When the first gpio interrupt occurs I get a data abort, as show below:

<2>Bad mode in data abort handler detected: mode FIQ_32 Internal error: Oops - bad mode: 0 [#1] Modules linked in: at76c505_rfmd2958 at76c503 at76_usbdfu CPU: 0 PC is at 0xffff0028 LR is at serial8250_startup+0x384/0x488 pc : [<ffff0028>] lr : [<c016571c>] Not tainted sp : c1941d78 ip : 00000002 fp : c1941dec r10: c0309ecc r9 : 00000000 r8 : c0309c44 r7 : 60000013 r6 : 00000288 r5 : c030a2b4 r4 : 00000000 r3 : eb000000 r2 : 00000002 r1 : 00000005 r0 : c030a2b4 Flags: nZCv IRQs off FIQs off Mode FIQ_32 Segment user Control: 317F Table: 11B34000 DAC: 00000015 Process microcom (pid: 73, stack limit = 0xc1940194) Stack: (0xc1941d78 to 0xc1942000) 1d60: c030a2b4 00000005 1d80: 00000002 eb000000 00000000 c030a2b4 00000288 60000013 c0309c44 00000000 1da0: c0309ecc c1941dec 00000002 c1941d78 c016571c ffff0028 600000d1 ffffffff 1dc0: c0309ecc c030a2b4 c1b26d20 c1e76f08 00000000 00000000 c15fe2c0 00000002 1de0: c1941e10 c1941df0 c01612e8 c01653a8 00000000 c1e76f08 c1b30000 c02aa1e4 1e00: c1940000 c1941e6c c1941e14 c01632f0 c0161260 c003b4c4 c1941e6c c1941e28 1e20: c014b6c0 c014a784 00000000 00000000 c1e60fc4 c1b26f20 c1e60fb4 c1b26a20 1e40: c1941e6c 00000000 c15fe2c0 c02a688c 00000000 00400041 c15fe2c0 00000002 1e60: c1941e9c c1941e70 c014c8dc c0163074 c1b30000 00000001 00000000 c1e77e04 1e80: c1940000 c1925cc4 00000001 00000000 c1941ecc c1941ea0 c0084f08 c014c6c0 1ea0: 00000001 c15fe2c0 00000000 c1925cc4 c0084d34 00000001 c1a4daa8 c0372220 1ec0: c1941ef8 c1941ed0 c00798b0 c0084d44 c15fe2c0 c1941f14 00000003 00000005 1ee0: c0023e04 c1940000 c15b5000 c1941f10 c1941efc c0079a2c c007977c 00000000 1f00: 00000002 c1941f6c c1941f14 c0079a80 c0079a08 c1a4daa8 c0372220 00000000 1f20: 00000003 c03803c8 00000101 00000001 00000000 c1940000 c15b5000 c1941f6c 1f40: c1941f4c c0079c88 c003a300 00000003 00000000 c15fe2c0 00000002 00000000 1f60: c1941f94 c1941f70 c0079dcc c0079a50 00000002 be82af8a be82aed4 00000005 1f80: c0023e04 400721fc c1941fa4 c1941f98 c0079e68 c0079d98 00000000 c1941fa8 1fa0: c0023c80 c0079e68 00000002 be82af8a 000137f8 00000002 00000000 00000002 1fc0: 00000002 be82af8a be82aed4 00000002 0000893c 00000002 400721fc 00008dc0 1fe0: 4005f5ec be82ad20 00008f0c 4005f610 60000010 000137f8 00000000 00000000 Backtrace: [<c0165398>] (serial8250_startup+0x0/0x488) from [<c01612e8>] (uart_startup+0x98/0x1f0) [<c0161250>] (uart_startup+0x0/0x1f0) from [<c01632f0>] (uart_open+0x28c/0x624) r8 = C1940000 r7 = C02AA1E4 r6 = C1B30000 r5 = C1E76F08 r4 = 00000000 [<c0163064>] (uart_open+0x0/0x624) from [<c014c8dc>] (tty_open+0x22c/0x398) [<c014c6b0>] (tty_open+0x0/0x398) from [<c0084f08>] (chrdev_open+0x1d4/0x1f4) [<c0084d34>] (chrdev_open+0x0/0x1f4) from [<c00798b0>] (__dentry_open+0x144/0x28c) [<c007976c>] (__dentry_open+0x0/0x28c) from [<c0079a2c>] (nameidata_to_filp+0x34/0x48) [<c00799f8>] (nameidata_to_filp+0x0/0x48) from [<c0079a80>] (filp_open+0x40/0x48) r4 = 00000002 [<c0079a40>] (filp_open+0x0/0x48) from [<c0079dcc>] (do_sys_open+0x44/0xd0) r5 = 00000000 r4 = 00000002 [<c0079d88>] (do_sys_open+0x0/0xd0) from [<c0079e68>] (sys_open+0x10/0x14) [<c0079e58>] (sys_open+0x0/0x14) from [<c0023c80>] (ret_fast_syscall+0x0/0x2c) Code: ea000078 e3a0c4ff e38cc8fe e38ccccb (e59cb014)

From what I can make of this, the FIQ handler is being executed (PC is at 0xffff0028), so if look at the FIQ code (which is at 0xffff001c), I see

fff001c: e3a0c4ff mov r12, #-16777216 ; 0xff000000 fff0020: e38cc8fe orr r12, r12, #16646144 ; 0xfe0000 fff0024: e38ccccb orr r12, r12, #51968 ; 0xcb00 fff0028: e59cb014 ldr r11, [r12, #20] fff002c: e589b030 str r11, [r9, #48] fff0030: e3a0c4ff mov r12, #-16777216 ; 0xff000000 fff0034: e38cc73f orr r12, r12, #16515072 ; 0xfc0000 fff0038: e38cca0e orr r12, r12, #57344 ; 0xe000 fff003c: e599a044 ldr r10, [r9, #68] fff0040: e28aa001 add r10, r10, #1 ; 0x1 fff0044: e589a044 str r10, [r9, #68]

So, at 0xfff0028, it's trying to load r11 with the contents of 0xfffecb14, which is the SIR_FIQ_CODE register. How can that be causing a data abort?

Matt