Messages in this thread | | | From | "ZCane, Ed (Test Purposes)" <> | Subject | Problem with bootmem/mmap | Date | Tue, 10 Jun 2003 17:49:43 +0100 |
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Dear all,
I'm allocating a large buffer at boot time (for later DMA purposes) using:
buf=alloc_bootmem_low_pages(1024*1024*500);
If I printk here, from init/main.c, I get: buf=0xc1e14000 __va(buf)=0x81e14000 __pa(buf)=0x1e14000
Now, in user-space, I'm trying to get access to my buffer (as root), by doing the following:
memfd=open("/dev/mem", O_RDWR); my_buf=mmap(0, 1024*1024*501, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, memfd, OFFSET);
I've tried all those addresses above, as the OFFSET, but it either generates an illegal instruction, or a segfault. Bit of a beginner, but learning fast, and I'd be _really_ greatful, if anyone could help me!
Many thanks, Ed
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