Hi , Reply Inline . --- "Thekkedath, Gopakumar" <Gopakumar.Thekkedath@xxxxxxx> wrote: > > > > > >Is there a way to find the PHYSICAL ADDRESSES of > all > >the devices used in a Computer ? > > does cat /proc/iomem serves the purpose ? > Well , if /proc/iomem gives the PHYSICAL address range of devices , then why is the System RAM split into 3 different address ranges as seen below (marked by arrows ) ? Is it bcoz the Motherboard is designed in this manner ? ~> cat /proc/iomem 00000000-0009fbff : System RAM <--- 1 0009fc00-0009ffff : reserved 000a0000-000bffff : Video RAM area 000c0000-000c7fff : Video ROM 000e0000-000effff : Extension ROM 000f0000-000fffff : System ROM 00100000-1fecffff : System RAM <---- 2 00100000-0028dadf : Kernel code 0028dae0-00324f63 : Kernel data 1fed0000-1feeffff : ACPI Non-volatile Storage 1fef0000-1fefffff : System RAM <---- 3 40000000-40000fff : Intel Corp. 82801BA/BAM/CA/CAM Ethernet Controller 40000000-40000fff : eepro100 40300000-4037ffff : Intel Corp. 82815 CGC [Chipset Graphics Controller] 44000000-47ffffff : Intel Corp. 82815 CGC [Chipset Graphics Controller] feea0000-ffffffff : reserved Are these memory address ranges dynamically determined ? Which kernel code file does this ? Also , does /proc/ioports represent IO-mapped PHYSICAL memory addresses , similar to the the Memory-mapped PHYSICAL memory addresses in /proc/iomem ? ~> cat /proc/ioports 0000-001f : dma1 0020-003f : pic1 0040-005f : timer 0060-006f : keyboard 0070-007f : rtc 0080-008f : dma page reg 00a0-00bf : pic2 00c0-00df : dma2 00f0-00ff : fpu 0170-0177 : ide1 01f0-01f7 : ide0 02f8-02ff : serial(auto) 0376-0376 : ide1 03c0-03df : vga+ 03f6-03f6 : ide0 03f8-03ff : serial(auto) 0cf8-0cff : PCI conf1 1000-103f : Intel Corp. 82801BA/BAM/CA/CAM Ethernet Controller 1000-103f : eepro100 2000-20ff : Intel Corp. 82801BA/BAM AC'97 Audio 2000-20ff : Intel 82801BA-ICH2 - AC'97 2400-243f : Intel Corp. 82801BA/BAM AC'97 Audio 2400-243f : Intel 82801BA-ICH2 - Controller 2440-245f : Intel Corp. 82801BA/BAM USB (Hub #2) 2440-245f : usb-uhci 2460-246f : Intel Corp. 82801BA IDE U100 2460-2467 : ide0 2468-246f : ide1 > >Also , does the VM in linux translate the memory > >address of programs into actual Physical addresses > >of RAM , or is it that Hardware does the actual > >translation to Physical addresses ( since the RAM > >addresses would differ across different Computers > >depending on the amount of RAM & also the > Motherboard > >design ) . > > Most of the processors will require the OS to setup > page directories/tables > which it will refer > to convert the virtual address to physical address. > You are right that the > RAM addresses differ across > systems, In one of the boards i worked, the SDRAM > physical start address was > 0xc4000000, so the kernel page > tables were set such that, virtual address 0xc000 > 0000 was mapped to > physical address 0xc400 0000 and so on. > So you mean to say the Page tables being setup during initialization at boot up would take care of this dynamically or would this require a kernel code change ( which file )? TIA . Cheers ! > -- > Kernelnewbies: Help each other learn about the Linux > kernel. > Archive: > http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > _______________________________ Do you Yahoo!? Declare Yourself - Register online to vote today! http://vote.yahoo.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
