On Sat, 28 Jul 2007 22:16:04 +0200, Roland McGrath wrote:
> Are you sure that changing _bfd_elf_make_section_from_phdr is the right way
> to fix gdb?
> 
> It is in a certain sense accurate to split the one segment into two
> sections, a leading SEC_LOAD one and a trailing one without SEC_LOAD.

The core files with `p_filesz == 0' were working before.
_bfd_elf_make_section_from_phdr() can create the sections as two parts, with
the second problematic one emulating the former `p_filesz == 0' core segments.
No new memory structure layout was introduced.  [attached]

Another issue would be changing the sections layout as currently the original
p_memsz is still lost.  Going to post later an add-on incompatible change using
SEC_NEVER_LOAD so that the p_memsz is retained for the bfd library applications
+ across objcopy.


> What does your change do to e.g. objcopy on a core file?

(the previous version was stripping the `load1b' part), thanks for finding it.



Best Regards,
Jan


Patched bfd version with the new `p_filesz == 4096' kernel core file:
	CVS HEAD gdb `info files':
		0x0000000000400000 - 0x0000000000401000 is load1a
		0x0000000000401000 - 0x0000000000401000 is load1b
		0x00000000006b1000 - 0x00000000006bb000 is load2
	objcopy:
	Section Headers:
	[Nr] Name                 Type         Addr             Off      Size     ES Flags Lk Inf Al
	[ 5] load1a               PROGBITS     0000000000400000 00001000 00001000  0 AX     0   0 4096
	[ 6] load1b               PROGBITS     0000000000401000 00002000 00000000  0 AX     0   0 4096
	[ 7] load2                PROGBITS     00000000006b1000 00002000 0000a000  0 WA     0   0 4096

Former bfd version with the former `p_filesz == 0' kernel core file:
	CVS HEAD gdb `info files':
		0x0000000000400000 - 0x0000000000400000 is load1
		0x00000000006b1000 - 0x00000000006bb000 is load2
	objcopy:
	Section Headers:
	[ 5] load1                PROGBITS     0000000000400000 00001000 00000000  0 AX     0   0 4096
	[ 6] load2                PROGBITS     00000000006b1000 00001000 0000a000  0 WA     0   0 4096