On Sat, Oct 9, 2010 at 4:10 PM, Albert ARIBAUD <[email protected]> wrote: > Le 09/10/2010 09:53, Lei Wen a écrit : >> >> Hi Albert, >> >> On Sat, Oct 9, 2010 at 3:43 PM, Albert ARIBAUD<[email protected]> >> wrote: >>> >>> Le 09/10/2010 07:50, Lei Wen a écrit : >>>> >>>> Hi, >>>> >>>> I recently try to port our board code to new uboot, which has been >>>> changed to use new relocation scheme. >>>> But I found a very strange thing, that is if the uboot is loaded to >>>> the TEXT_BASE address, it could run without >>>> problem. But if it is loaded to a different place, it fail to boot up... >>>> >>>> I check the code, and found that in the board_init_f, it calls the >>>> init_sequence which is stored as a data sector >>>> in the u-boot.bin file. While the new scheme use the fPIC, the code >>>> could locate the GOT table correctly, >>>> and it seem to forgot what the GOT table stores is context that is >>>> meaningful in TEXT_BASE, not the loaded base. >>>> That is to say, if the TEXT_BASE is 0xf00000, and loaded base is >>>> 0x500000, I found the GOT table also filled >>>> with 0xf0****, not the 0x50****. This leads the cpu loading wrong >>>> function address in the init_sequence table, and >>>> cause pc become invalid... >>>> >>>> Am I missing something to switch to the new relocation scheme? >>>> >>>> Thanks, >>>> Lei >>> >>> Can you indicate which hardware (architecture, cpu, SoC, etc) you're >>> running this code on? >>> >> I am running the code on Marvell aspen soc, which is arm926ejs compatible >> core. > > For arm926, TEXT_BASE should be the FLASH location (if booting from NOR) or > a location in DRAM (for NAND and other methods).
Yeah, got that. The TEXT_BASE of 0xf00000 in my case is the exactly what I want to uboot run during its run time. > > I have had little difficulty in running the .got relocation code in a > Marvell oront5x (arm926ejs too), except for some functions called from > board_init_f which did not respect the general rule that code run before > relocation should only access gd; one place in orion5x wrote to global > variables, which always was a no-no and only happened to work because the > arm926ejs init sequence did not run in proper order. Have you tried load the uboot to different place with tftp or something else? When I load the uboot to the TEXT_BASE and run, there is also no issue... > > However, .got relocation has shortcomings of its own; mainly, it requires > manual fixups in many places within the code. I have provided patches which > replace .got relocation with ELF relocation (look up [ELF-RELOC] tags in the > posts), which eliminates the need for any manual fixup; you may want to try > this, as it might eventually replace the .got patches. Glad to hear this. :-) But my problem is before relocating, the new scheme call the init_sequence in board_init_f, while the TEXT_BASE keep the function entry as static value during compile time. Does the ELF relocation could bring us a relative jump when call the init_sequence table? Thanks, Lei _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
