On Tue, 28 Sep 2004, Matt Porter wrote:
> > > then you're an interesting spot. Can you trace it down to the exact > > > failure in __alloc_bootmem_core? > > I already did it. Can you please read > > http://ozlabs.org/pipermail/linuxppc-dev/2004-September/000104.html? I > > described there what weird things are happening in __alloc_bootmem_core. > > I see. Can you move the reset instruction to isolate the offending > instruction? > > BTW, it's not clear how you are guaranteeing that the processor has > bit 2 or 3 asserted before the dbcr0 load. If you preloaded r12 out of > the scope of the code fragments shown, it's clear that r12 is getting > clobbered in the subf instruction of the 2.6.8.1 fragment. My mistake. I thought I was putting immediate value 12 in DBCR0 using asm("mtspr 0x3f2, 12") in C code, but it's putting the value hold in the r12 register. I shoul read the manual correctly. So untill now we just had luck if our processor reset!? Look what I trie now. static void * __init 147 __alloc_bootmem_core(struct bootmem_data *bdata, unsigned long size, 148 unsigned long align, unsigned long goal) 149 { 150 unsigned long offset, remaining_size, areasize, preferred; 151 unsigned long i, start = 0, incr; 152 unsigned long eidx = bdata->node_low_pfn - (bdata->node_boot_start >> PAGE_SHIFT); 153 void *ret; 154 155 if(!size) { 156 printk("__alloc_bootmem_core(): zero-sized request\n"); 157 BUG(); 158 } 159 BUG_ON(align & (align-1)); 160 161 asm ("li 17, 12"); // <-- immediate value of 12 to r17 - bit 2:3 set 162 asm ("mtspr 0x3f2, 17"); // < write to DBCR0 what is in DOESN'T reset!!! r17 163 asm ("mtspr 0x3f2, 12"); // resets, but I don't know what is value of r12 asm code is: 23c: 3a 20 00 0c li r17,12 240: 7e 32 fb a6 mtdbcr0 r17 244: 7d 92 fb a6 mtdbcr0 r12 It is said in manual, that setting bits 2:3 in DBCR0 resets the processor. In my code it doesn't. :) > Is this a hobby project or a "for profit" project? If it's for profit, > then consider investing in a JTAG emulator (like BDI2000)...it'll pay > for itself many times over. I'm a trainee in some firm. They use 2.4.23 now in their boxes. Porting 2.6.8.1 to their board is my project. I was told that they have some hardware debbuger, but it doesn't work with virtual memory. Piotr Perak
