On 4/23/15 10:51, Steven Miao wrote: > On Wed, Apr 22, 2015 at 10:32 PM, Chen Gang <xili_gchen_5...@hotmail.com> > wrote: >> On 4/22/15 17:00, Steven Miao wrote: >>> Hi, >>> >>> On Thu, Apr 9, 2015 at 5:03 AM, Chen Gang <xili_gchen_5...@hotmail.com> >>> wrote: >>>> l1_text is at L1_CODE_START (e.g. for bf533, 0xff800000). If the kernel >>>> is too big, it may be overwritten, the related issue: >>>> >>>> LD init/built-in.o >>>> init/built-in.o: In function `do_early_param': >>>> init/main.c:(.init.text+0xe0): relocation truncated to fit: >>>> R_BFIN_PCREL24 against symbol `strcmp' defined in .l1.text section in >>>> arch/blackfin/lib/lib.a(strcmp.o) >>>> init/main.c:(.init.text+0x10e): relocation truncated to fit: >>>> R_BFIN_PCREL24 against symbol `strcmp' defined in .l1.text section in >>>> arch/blackfin/lib/lib.a(strcmp.o) >>> blackfin toolchain generate 24 bit pc-relative calls by default, with >>> a range of –16,777,216 through 16,777,214 (0xFF00 0000 to 0x00FF FFFE) >>> is available. >>> So call to l1_text should be ok. What do you mean the kernel is too big? >>> http://docs.blackfin.uclinux.org/doku.php?id=ism:call >>> >>> >> >> Excuse me, I am not quite familiar with what you said above, can we >> also treat 24-bit as 16MB size limitation for kernel size? I am not >> quite sure, could you provide more information about it?. >> >> And I checked "arch/blackfin/kernel/vmlinux.lds.S", for me, in current >> case: > The memory address on blackfin usually starts from 0, if pc = 0, the > pc relative call range is [0xFF00 0000 - 0xFFFFFFFF, 0 - 0x00FF > FFFE], it covers L1 space. > If the kernel is big than 16M, eg. pc = 0x100 0000, the pc relative > call range accordingly is [0x1 - 0x100 0000, 0x100 0000 - 0x 1FF FFFE > ], it cann't call to L1 space.
OK, thanks. I guess your meaning is: - If the kernel is too big, it may let the pc which wants to call L1 space fail. - So the kernel is too big to cause this issue, but it is nothing with 'overwritten' in my original patch comments. - We can treat it as environments limitation, then can use COMPILE_TEST for it. So this patch is still OK, except the related comments need be improved (at least need to remove 'overwritten'). >> >> - init section is the last section of kernel, l1.text is within init >> section, and it is in the fixed address. The other contents before >> l1.text are dynamic (depend on kernel size). >> I guess, what I said above is meaningless (although it is correct). >> - if kernel is too big, the contents before l1.text (the other contents >> in .init.text) will override it, so ld reports issues. I guess, what I said above is incorrect. Are all of I guesses correct? Thanks. -- Chen Gang Open, share, and attitude like air, water, and life which God blessed -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
