RE: newlib-2.2.0/libgloss/mips/crt0.S:161: undefined reference to `hardware_hazard_hook'

[Matthew Fortune <Matthew.Fortune@imgtec.com>]

Zhangwen (Esan) <zwzhangwen.zhang@huawei.com> writes:
> >It looks like you have not specified any form of linker script and MIPS
> crt0.S in newlib only works in conjunction with a linker script as it is
> dependent on external symbols that are not provided by the C library or
> ordinary modules:
> >
> >1) MIPS uses _start as the entry point not __start
> >2) The various init hooks are normally defined weak via the linker
> >  script
> >
> >3) The stack must be defined somewhere using the __stack symbol
> >   which is normally set to a valid address via the linker script.
> >
> >See mti32.ld as an example linker script although I doubt it will be
> suitable for your environment as it is designed around an older boot
> monitor. Mti32.ld will however create you an executable that you can run
> using the GNUSIM simulator provided with GDB.
> >
> >Hope that helps.
> >
> >Thanks,
> >Matthew
> It's a great help for me and thanks very much. After I rewrote a new
> linker script and add the definition of most symbols, there was only one
> symbol undefined:
> newlib-2.2.0/libgloss/mips/crt0.S:195: undefined reference to
> `get_mem_info'
> I found it in the source code:
> libgloss/mips/jmr3904-io.c:100:get_mem_info (mem)
> libgloss/mips/dvemon.c:79:get_mem_info (mem)
> libgloss/mips/cfe_mem.c:126:get_mem_info (struct s_mem *meminfo)
> libgloss/mips/cygmon.c:78:get_mem_info (mem) Then I search the .c files
> in building log, but no the corresponding files. Maybe .c files can not
> be compiled in building newlib, so the symbol " get_mem_info " is
> undefined when linking.
> But I have two problems:
> 1) How can .c file with the definition " get_mem_info " be compiled?

You probably need to provide your own get_mem_info unless one of the existing
implementations is suitable for your runtime environment. What gets included
in your build depends on the triple you use to configure newlib. See
libgloss/mips/configure[.in]. You may want libnullmon.a which has a fairly
basic version of get_mem_info.

> 2) How can crt0.o file be linked default when excuting mips-*-ld? Now I
> need to add the crt0.o manually.

The crt0.o file is often listed in the linker script using a START(crt0.o)
Which means you don't need to list crt0.o on the command line. You do
however have to use a linker script always as the default (built-in) link
scripts that come with BFD are for GNU/Linux environments and are not
suitable for bare metal systems.

> I have no experience on mips compile, so the low problems are more than
> others.

I'm sorry to say that for some of these issues you just have to keep
working through the issues until you get there. Don't be surprised/afraid
if you have to write your own function(s) to make everything work for your
board/sim/environment as it is unlikely to be supported with existing code.

Matthew