Oh man, sorry, those damn keyboard shortcuts, let me try again :-)
I wonder if anyone can help with some hints in this situation: here is a code fragment to illustrate the questions: if ((ai = kmalloc(sizeof(alloc_info_t) + 4 * szw, GFP_ATOMIC | GFP_DMA)) != NULL) { ai->src = FROM_KMALLOC; printk("\n%s:%d %p\n", __FUNCTION__, __LINE__, ai); basically, a block of contiguous memory is allocated. This block is needed to set up some DMA descriptors, so it needs to be uncached, and I thought this is what GFP_DMA flag is for. I stop execution using a JTAG probe right after the printk above, and examine the TLB matching the allocated address. This is what printk reports: sal_alloc:163 eee76000 And the TLB record for this memory is the default kernel 256M page: 61 : 00 e0000000 256MB V0 -> 0_20000000 U:0000 ---G- ---XWR Which is obviously cached (missing the I bit set). How is this supposed to work? Is this right to expect the address returned by kmalloc() to be mapped to uncached TLB in case GFP_DMA flag is passed in? What are the proper ways of setting up shared memory in this kernel? Any hints will be highly appreciated, TIA, Vadim _______________________________________________ Linuxppc-embedded mailing list Linuxppc-embedded@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-embedded