Commit 18991197b4 added --build-id
linker option when toolchain supports it. ARM one does, but for some
reason places the section at 0 when linker script doesn't mention it
explicitly.
The 1e621a8e37 worked around the problem
removing this section from binary image with explicit objcopy options,
but it still exists in vmlinux, confusing tools like debuggers and perf.
This problem was discussed here:
http://lists.infradead.org/pipermail/linux-arm-kernel/2010-May/015994.htmlhttp://lists.infradead.org/pipermail/linux-arm-kernel/2010-May/015994.html
but the proposed changes to the linker script were substantial.
This patch simply places NOTES (36 bytes long, at least when compiled
with CodeSourcery toolchain) between data and bss, which seem to be
the right place (and suggested by the sample linker script in
include/asm-generic/vmlinux.lds.h).
It is enough to place it correctly in vmlinux (so debuggers are happy):
Section Headers:
[11] .data PROGBITS c07ce000 7ce000 020fc0 00 WA 0 0 32
[12] .notes NOTE c07eefc0 7eefc0 000024 00 AX 0 0 4
[13] .bss NOBITS c07ef000 7eefe4 01e628 00 WA 0 0 32
Program Headers:
LOAD 0x008000 0xc0008000 0xc0008000 0x7e6fe4 0x805628 RWE 0x8000
NOTE 0x7eefc0 0xc07eefc0 0xc07eefc0 0x00024 0x00024 R E 0x4
Section to Segment mapping:
Segment Sections...
00 <...> .data .notes .bss
01 .notes
and to get it exposed as /sys/kernel/notes used by perf tools.
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
dc810efb0c