Re: [PATCH v2] mips: delete __cpuinit/__CPUINIT usage from MIPS code

[David Daney <ddaney.cavm@gmail.com>]

On 06/18/2013 07:38 AM, Paul Gortmaker wrote:
> The __cpuinit type of throwaway sections might have made sense
> some time ago when RAM was more constrained, but now the savings
> do not offset the cost and complications.  For example, the fix in
> commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time")
> is a good example of the nasty type of bugs that can be created
> with improper use of the various __init prefixes.
>
> After a discussion on LKML[1] it was decided that cpuinit should go
> the way of devinit and be phased out.  Once all the users are gone,
> we can then finally remove the macros themselves from linux/init.h.
>
> Note that some harmless section mismatch warnings may result, since
> notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c)
> and are flagged as __cpuinit  -- so if we remove the __cpuinit from
> the arch specific callers, we will also get section mismatch warnings.
> As an intermediate step, we intend to turn the linux/init.h cpuinit
> related content into no-ops as early as possible, since that will get
> rid of these warnings.  In any case, they are temporary and harmless.
>
> Here, we remove all the MIPS __cpuinit from C code and __CPUINIT
> from asm files.  MIPS is interesting in this respect, because there
> are also uasm users hiding behind their own renamed versions of the
> __cpuinit macros.
>
> [1] https://lkml.org/lkml/2013/5/20/589
>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

I get:


WARNING: vmlinux.o(.text+0x18640): Section mismatch in reference from 
the function register_cavium_notifier() to the variable 
.cpuinit.data:octeon_cpu_callback_nb.37045
The function register_cavium_notifier() references
the variable __cpuinitdata octeon_cpu_callback_nb.37045.
This is often because register_cavium_notifier lacks a __cpuinitdata
annotation or the annotation of octeon_cpu_callback_nb.37045 is wrong.

WARNING: vmlinux.o(.text+0x18650): Section mismatch in reference from 
the function register_cavium_notifier() to the variable 
.cpuinit.data:octeon_cpu_callback_nb.37045
The function register_cavium_notifier() references
the variable __cpuinitdata octeon_cpu_callback_nb.37045.
This is often because register_cavium_notifier lacks a __cpuinitdata
annotation or the annotation of octeon_cpu_callback_nb.37045 is wrong.

WARNING: vmlinux.o(.text+0x24778): Section mismatch in reference from 
the function start_secondary() to the function 
.cpuinit.text:calibrate_delay()
The function start_secondary() references
the function __cpuinit calibrate_delay().
This is often because start_secondary lacks a __cpuinit
annotation or the annotation of calibrate_delay is wrong.

WARNING: vmlinux.o(.text+0x247b4): Section mismatch in reference from 
the function start_secondary() to the function 
.cpuinit.text:notify_cpu_starting()
The function start_secondary() references
the function __cpuinit notify_cpu_starting().
This is often because start_secondary lacks a __cpuinit
annotation or the annotation of notify_cpu_starting is wrong.



So I think an alternate approach is required.

Really I think we need to leave all existing __cpuinitdata and __cpuinit 
annotations in place.

Instead we would first change the definitions of these two to be empyt:

#define __cpuinit
#define __cpuinitdata

Once that is working, we would make a second pass and remove the symbols 
themselves.

David Daney