Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-05-14 Thread Mathieu Malaterre 
On Wed, May 2, 2018 at 2:24 PM, Nicholas Piggin  wrote:
> On Wed, 2 May 2018 11:17:52 +0200
> Mathieu Malaterre  wrote:
>
>> Nick,
>>
>> On Sat, Apr 21, 2018 at 4:48 AM, Nicholas Piggin  wrote:
>> > On Fri, 20 Apr 2018 22:08:27 +0200
>> > Mathieu Malaterre  wrote:
>> >
>> >> On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin  
>> >> wrote:
>> >> > On Fri, 20 Apr 2018 12:00:49 +0200
>> >> > Mathieu Malaterre  wrote:
>> >> >
>> >> >> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  
>> >> >> wrote:
>> >> >> > This requires further changes to linker script to KEEP some tables
>> >> >> > and wildcard compiler generated sections into the right place. This
>> >> >> > includes pp32 modifications from Christophe Leroy.
>> >> >> >
>> >> >> > When compiling powernv_defconfig with this option:
>> >> >> >
>> >> >> > text   data  bss   decfilename
>> >> >> > 11827621   4810490   1341080   17979191   vmlinux
>> >> >> > 11752437   4598858   1338776   17690071   vmlinux.dcde
>> >> >> >
>> >> >> > Resulting kernel is almost 400kB smaller (and still boots).
>> >> >> >
>> >> >> > [ppc32 numbers here]
>> >> >>
>> >> >> ^^^
>> >> >>
>> >> >> Do you want somebody else to provide those numbers ?
>> >> >
>> >> > If you have a booting kernel, yes some more numbers would be good.
>> >>
>> >> I've used /boot/config-4.15.0-2-powerpc from my current debian
>> >> package. Rebuild master with and without option, boot ok, load/unload
>> >> module ok.
>> >>
>> >> $ size nick/vmlinux.with*
>> >>textdata bss dec hex filename
>> >> 7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
>> >> 7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without
>> >>
>> >> This is not clear why with option the size of kernel is slightly bigger:
>> >>
>> >> $ du -sk nick/vmlinux.with*
>> >> 124488 nick/vmlinux.with
>> >> 124004 nick/vmlinux.without
>> >
>> > Not sure. readelf -S vmlinux may show something.
>> >
>> > To really get lots of detail, you can add to the top level Makefile:
>> >
>> > LDFLAGS_vmlinux += -M
>>
>> Here is what I did:
>>
>> $ git diff
>> diff --git a/Makefile b/Makefile
>> index 619a85ad716b..1a2e3d142a59 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -4,6 +4,7 @@ PATCHLEVEL = 17
>>  SUBLEVEL = 0
>>  EXTRAVERSION = -rc3
>>  NAME = Fearless Coyote
>> +LDFLAGS_vmlinux += -M
>
> That'll get overwritten further down. Put it down with another line
> that starts with LDFLAGS_vmlinux +=

Sorry about that, I was not paying attention :(

Anyway I cannot make sense of the output with -M.

Here is a quick summary if needed (with option / without option).

$ ./scripts/bloat-o-meter nick/vmlinux.without nick/vmlinux.with | head
add/remove: 0/647 grow/shrink: 852/1846 up/down: 11276/-95033 (-83757)
Function old new   delta
SiSInitPtr  22122600+388
xmon_core.isra  75407900+360
ata_attach_transport 8401032+192
via_pmu_interrupt   28283004+176
matroxfb_init   30003156+156
fbcon_scroll30923248+156
__do_adjtimex   17161868+152
fbcon_event_notify  20442184+140
$ ./scripts/bloat-o-meter nick/vmlinux.without nick/vmlinux.with | tail
aty_set_pll18818 540   --540
sel_ib_pkey_sid  556   --556
pci_dev_acs_enabled  608   --608
aa_label_find_merge  752   --752
drmem_update_dt  796   --796
powerpc_macros  1176   -   -1176
ima_restore_measurement_list1224   -   -1224
rtas_os_term_buf2048   -   -2048
vle_opcodes 8200   -   -8200
Total: Before=9927171, After=9843414, chg -0.84%


> Thanks,
> Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-05-07 Thread Nicholas Piggin 
On Mon, 7 May 2018 09:46:43 +0900
Masahiro Yamada  wrote:

> Hi Nicholas,
> 
> 2018-04-20 19:41 GMT+09:00 Nicholas Piggin :
> > On Fri, 20 Apr 2018 12:00:49 +0200
> > Mathieu Malaterre  wrote:
> >  
> >> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  
> >> wrote:  
> >> > This requires further changes to linker script to KEEP some tables
> >> > and wildcard compiler generated sections into the right place. This
> >> > includes pp32 modifications from Christophe Leroy.
> >> >
> >> > When compiling powernv_defconfig with this option:
> >> >
> >> > text   data  bss   decfilename
> >> > 11827621   4810490   1341080   17979191   vmlinux
> >> > 11752437   4598858   1338776   17690071   vmlinux.dcde
> >> >
> >> > Resulting kernel is almost 400kB smaller (and still boots).
> >> >
> >> > [ppc32 numbers here]  
> >>
> >> ^^^
> >>
> >> Do you want somebody else to provide those numbers ?  
> >
> > If you have a booting kernel, yes some more numbers would be good.
> >
> > Thanks,
> > Nick  
> 
> 
> 
> I applied this series because I want it to be more tested in linux-next.

Thank you.


> Some requests:
> 
>  - Could you provide information to replace '[ppc32 numbers here]'?
>(or just remove it)

Yes there were some numbers reported, I can give you an updated
changelog.

>  - V2 is welcome if you have code improvement.
>(I thought so from your comments)

I'll see where it ended up and send you updated patches if necessary.

Thanks,
Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-05-06 Thread Masahiro Yamada 
Hi Nicholas,

2018-04-20 19:41 GMT+09:00 Nicholas Piggin :
> On Fri, 20 Apr 2018 12:00:49 +0200
> Mathieu Malaterre  wrote:
>
>> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  wrote:
>> > This requires further changes to linker script to KEEP some tables
>> > and wildcard compiler generated sections into the right place. This
>> > includes pp32 modifications from Christophe Leroy.
>> >
>> > When compiling powernv_defconfig with this option:
>> >
>> > text   data  bss   decfilename
>> > 11827621   4810490   1341080   17979191   vmlinux
>> > 11752437   4598858   1338776   17690071   vmlinux.dcde
>> >
>> > Resulting kernel is almost 400kB smaller (and still boots).
>> >
>> > [ppc32 numbers here]
>>
>> ^^^
>>
>> Do you want somebody else to provide those numbers ?
>
> If you have a booting kernel, yes some more numbers would be good.
>
> Thanks,
> Nick



I applied this series because I want it to be more tested in linux-next.


Some requests:

 - Could you provide information to replace '[ppc32 numbers here]'?
   (or just remove it)

 - V2 is welcome if you have code improvement.
   (I thought so from your comments)

Thanks.


-- 
Best Regards
Masahiro Yamada

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-05-02 Thread Nicholas Piggin 
On Wed, 2 May 2018 11:17:52 +0200
Mathieu Malaterre  wrote:

> Nick,
> 
> On Sat, Apr 21, 2018 at 4:48 AM, Nicholas Piggin  wrote:
> > On Fri, 20 Apr 2018 22:08:27 +0200
> > Mathieu Malaterre  wrote:
> >  
> >> On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin  
> >> wrote:  
> >> > On Fri, 20 Apr 2018 12:00:49 +0200
> >> > Mathieu Malaterre  wrote:
> >> >  
> >> >> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  
> >> >> wrote:  
> >> >> > This requires further changes to linker script to KEEP some tables
> >> >> > and wildcard compiler generated sections into the right place. This
> >> >> > includes pp32 modifications from Christophe Leroy.
> >> >> >
> >> >> > When compiling powernv_defconfig with this option:
> >> >> >
> >> >> > text   data  bss   decfilename
> >> >> > 11827621   4810490   1341080   17979191   vmlinux
> >> >> > 11752437   4598858   1338776   17690071   vmlinux.dcde
> >> >> >
> >> >> > Resulting kernel is almost 400kB smaller (and still boots).
> >> >> >
> >> >> > [ppc32 numbers here]  
> >> >>
> >> >> ^^^
> >> >>
> >> >> Do you want somebody else to provide those numbers ?  
> >> >
> >> > If you have a booting kernel, yes some more numbers would be good.  
> >>
> >> I've used /boot/config-4.15.0-2-powerpc from my current debian
> >> package. Rebuild master with and without option, boot ok, load/unload
> >> module ok.
> >>
> >> $ size nick/vmlinux.with*
> >>textdata bss dec hex filename
> >> 7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
> >> 7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without
> >>
> >> This is not clear why with option the size of kernel is slightly bigger:
> >>
> >> $ du -sk nick/vmlinux.with*
> >> 124488 nick/vmlinux.with
> >> 124004 nick/vmlinux.without  
> >
> > Not sure. readelf -S vmlinux may show something.
> >
> > To really get lots of detail, you can add to the top level Makefile:
> >
> > LDFLAGS_vmlinux += -M  
> 
> Here is what I did:
> 
> $ git diff
> diff --git a/Makefile b/Makefile
> index 619a85ad716b..1a2e3d142a59 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -4,6 +4,7 @@ PATCHLEVEL = 17
>  SUBLEVEL = 0
>  EXTRAVERSION = -rc3
>  NAME = Fearless Coyote
> +LDFLAGS_vmlinux += -M

That'll get overwritten further down. Put it down with another line
that starts with LDFLAGS_vmlinux +=

Thanks,
Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-05-02 Thread Mathieu Malaterre 
Nick,

On Sat, Apr 21, 2018 at 4:48 AM, Nicholas Piggin  wrote:
> On Fri, 20 Apr 2018 22:08:27 +0200
> Mathieu Malaterre  wrote:
>
>> On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin  wrote:
>> > On Fri, 20 Apr 2018 12:00:49 +0200
>> > Mathieu Malaterre  wrote:
>> >
>> >> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  
>> >> wrote:
>> >> > This requires further changes to linker script to KEEP some tables
>> >> > and wildcard compiler generated sections into the right place. This
>> >> > includes pp32 modifications from Christophe Leroy.
>> >> >
>> >> > When compiling powernv_defconfig with this option:
>> >> >
>> >> > text   data  bss   decfilename
>> >> > 11827621   4810490   1341080   17979191   vmlinux
>> >> > 11752437   4598858   1338776   17690071   vmlinux.dcde
>> >> >
>> >> > Resulting kernel is almost 400kB smaller (and still boots).
>> >> >
>> >> > [ppc32 numbers here]
>> >>
>> >> ^^^
>> >>
>> >> Do you want somebody else to provide those numbers ?
>> >
>> > If you have a booting kernel, yes some more numbers would be good.
>>
>> I've used /boot/config-4.15.0-2-powerpc from my current debian
>> package. Rebuild master with and without option, boot ok, load/unload
>> module ok.
>>
>> $ size nick/vmlinux.with*
>>textdata bss dec hex filename
>> 7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
>> 7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without
>>
>> This is not clear why with option the size of kernel is slightly bigger:
>>
>> $ du -sk nick/vmlinux.with*
>> 124488 nick/vmlinux.with
>> 124004 nick/vmlinux.without
>
> Not sure. readelf -S vmlinux may show something.
>
> To really get lots of detail, you can add to the top level Makefile:
>
> LDFLAGS_vmlinux += -M

Here is what I did:

$ git diff
diff --git a/Makefile b/Makefile
index 619a85ad716b..1a2e3d142a59 100644
--- a/Makefile
+++ b/Makefile
@@ -4,6 +4,7 @@ PATCHLEVEL = 17
 SUBLEVEL = 0
 EXTRAVERSION = -rc3
 NAME = Fearless Coyote
+LDFLAGS_vmlinux += -M

 # *DOCUMENTATION*
 # To see a list of typical targets execute "make help"

Then:

$ rm ppc32/arch/powerpc/kernel/vmlinux.lds
$ make O=ppc32 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- W=1 V=1

-> I did not see anything specific. I must be missing one step, but I
don't see which one.


> Then it will print the link map for you and other details. Actually
> it will output several times because we link vmlinux 2-3 times, so
> just take the last one. There is a lot of data there.
>

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-23 Thread Mathieu Malaterre 
Christophe,

On Sat, Apr 21, 2018 at 9:16 AM, christophe leroy
 wrote:
>
>
> Le 20/04/2018 à 22:08, Mathieu Malaterre a écrit :
>>
>> On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin 
>> wrote:
>>>
>>> On Fri, 20 Apr 2018 12:00:49 +0200
>>> Mathieu Malaterre  wrote:
>>>
 On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin 
 wrote:
>
> This requires further changes to linker script to KEEP some tables
> and wildcard compiler generated sections into the right place. This
> includes pp32 modifications from Christophe Leroy.
>
> When compiling powernv_defconfig with this option:
>
> text   data  bss   decfilename
> 11827621   4810490   1341080   17979191   vmlinux
> 11752437   4598858   1338776   17690071   vmlinux.dcde
>
> Resulting kernel is almost 400kB smaller (and still boots).
>
> [ppc32 numbers here]


 ^^^

 Do you want somebody else to provide those numbers ?
>>>
>>>
>>> If you have a booting kernel, yes some more numbers would be good.
>>
>>
>> I've used /boot/config-4.15.0-2-powerpc from my current debian
>> package. Rebuild master with and without option, boot ok, load/unload
>> module ok.
>>
>> $ size nick/vmlinux.with*
>> textdata bss dec hex filename
>> 7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
>> 7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without
>>
>> This is not clear why with option the size of kernel is slightly bigger:
>
>
> The file contains also debug symbols, which might differ.
> Only the LOAD part of the file is interesting, that's the part you get when
> doing ppc-linux-objcopy vmlinux vmlinux.bin -O binary
>
> You can see it with readelf -l vmlinux

Here is what I see:

$ diff -u <(readelf -l nick/vmlinux.with) <(readelf -l nick/vmlinux.without)
--- /proc/self/fd/11 2018-04-23 12:59:52.413101612 +0200
+++ /proc/self/fd/12 2018-04-23 12:59:52.417101567 +0200
@@ -5,9 +5,9 @@

 Program Headers:
   Type   Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg Align
-  LOAD   0x01 0xc000 0x 0x950f34 0xaad018 RWE 0x1
-  NOTE   0x867640 0xc0857640 0x00857640 0x00024 0x00024 0x4
-  NOTE   0x867664 0xc0857664 0x00857664 0xc 0xc 0x1
+  LOAD   0x01 0xc000 0x 0x97ef34 0xadba68 RWE 0x1
+  NOTE   0x87f640 0xc086f640 0x0086f640 0x00024 0x00024 0x4
+  NOTE   0x87f664 0xc086f664 0x0086f664 0xc 0xc 0x1

  Section to Segment mapping:
   Segment Sections...


> Christophe
>
>>
>> $ du -sk nick/vmlinux.with*
>> 124488 nick/vmlinux.with
>> 124004 nick/vmlinux.without
>>
>>
>>> Thanks,
>>> Nick
>
>
> ---
> L'absence de virus dans ce courrier électronique a été vérifiée par le
> logiciel antivirus Avast.
> https://www.avast.com/antivirus
>

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-21 Thread christophe leroy 



Le 20/04/2018 à 22:08, Mathieu Malaterre a écrit :

On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin  wrote:

On Fri, 20 Apr 2018 12:00:49 +0200
Mathieu Malaterre  wrote:


On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  wrote:

This requires further changes to linker script to KEEP some tables
and wildcard compiler generated sections into the right place. This
includes pp32 modifications from Christophe Leroy.

When compiling powernv_defconfig with this option:

text   data  bss   decfilename
11827621   4810490   1341080   17979191   vmlinux
11752437   4598858   1338776   17690071   vmlinux.dcde

Resulting kernel is almost 400kB smaller (and still boots).

[ppc32 numbers here]


^^^

Do you want somebody else to provide those numbers ?


If you have a booting kernel, yes some more numbers would be good.


I've used /boot/config-4.15.0-2-powerpc from my current debian
package. Rebuild master with and without option, boot ok, load/unload
module ok.

$ size nick/vmlinux.with*
textdata bss dec hex filename
7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without

This is not clear why with option the size of kernel is slightly bigger:


The file contains also debug symbols, which might differ.
Only the LOAD part of the file is interesting, that's the part you get 
when doing ppc-linux-objcopy vmlinux vmlinux.bin -O binary


You can see it with readelf -l vmlinux

Christophe



$ du -sk nick/vmlinux.with*
124488 nick/vmlinux.with
124004 nick/vmlinux.without



Thanks,
Nick


---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel 
antivirus Avast.
https://www.avast.com/antivirus

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Nicholas Piggin 
On Fri, 20 Apr 2018 22:08:27 +0200
Mathieu Malaterre  wrote:

> On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin  wrote:
> > On Fri, 20 Apr 2018 12:00:49 +0200
> > Mathieu Malaterre  wrote:
> >  
> >> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  
> >> wrote:  
> >> > This requires further changes to linker script to KEEP some tables
> >> > and wildcard compiler generated sections into the right place. This
> >> > includes pp32 modifications from Christophe Leroy.
> >> >
> >> > When compiling powernv_defconfig with this option:
> >> >
> >> > text   data  bss   decfilename
> >> > 11827621   4810490   1341080   17979191   vmlinux
> >> > 11752437   4598858   1338776   17690071   vmlinux.dcde
> >> >
> >> > Resulting kernel is almost 400kB smaller (and still boots).
> >> >
> >> > [ppc32 numbers here]  
> >>
> >> ^^^
> >>
> >> Do you want somebody else to provide those numbers ?  
> >
> > If you have a booting kernel, yes some more numbers would be good.  
> 
> I've used /boot/config-4.15.0-2-powerpc from my current debian
> package. Rebuild master with and without option, boot ok, load/unload
> module ok.
> 
> $ size nick/vmlinux.with*
>textdata bss dec hex filename
> 7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
> 7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without
> 
> This is not clear why with option the size of kernel is slightly bigger:
> 
> $ du -sk nick/vmlinux.with*
> 124488 nick/vmlinux.with
> 124004 nick/vmlinux.without

Not sure. readelf -S vmlinux may show something.

To really get lots of detail, you can add to the top level Makefile:

LDFLAGS_vmlinux += -M

Then it will print the link map for you and other details. Actually
it will output several times because we link vmlinux 2-3 times, so
just take the last one. There is a lot of data there.

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Mathieu Malaterre 
On Fri, Apr 20, 2018 at 12:41 PM, Nicholas Piggin  wrote:
> On Fri, 20 Apr 2018 12:00:49 +0200
> Mathieu Malaterre  wrote:
>
>> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  wrote:
>> > This requires further changes to linker script to KEEP some tables
>> > and wildcard compiler generated sections into the right place. This
>> > includes pp32 modifications from Christophe Leroy.
>> >
>> > When compiling powernv_defconfig with this option:
>> >
>> > text   data  bss   decfilename
>> > 11827621   4810490   1341080   17979191   vmlinux
>> > 11752437   4598858   1338776   17690071   vmlinux.dcde
>> >
>> > Resulting kernel is almost 400kB smaller (and still boots).
>> >
>> > [ppc32 numbers here]
>>
>> ^^^
>>
>> Do you want somebody else to provide those numbers ?
>
> If you have a booting kernel, yes some more numbers would be good.

I've used /boot/config-4.15.0-2-powerpc from my current debian
package. Rebuild master with and without option, boot ok, load/unload
module ok.

$ size nick/vmlinux.with*
   textdata bss dec hex filename
7386425 2364370 1425432 11176227 aa8923 nick/vmlinux.with
7461457 2475122 1428064 11364643 ad6923 nick/vmlinux.without

This is not clear why with option the size of kernel is slightly bigger:

$ du -sk nick/vmlinux.with*
124488 nick/vmlinux.with
124004 nick/vmlinux.without


> Thanks,
> Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Christophe LEROY 



Le 20/04/2018 à 12:36, Nicholas Piggin a écrit :

On Fri, 20 Apr 2018 12:01:34 +0200
Christophe LEROY  wrote:


Le 20/04/2018 à 09:34, Nicholas Piggin a écrit :

This requires further changes to linker script to KEEP some tables
and wildcard compiler generated sections into the right place. This
includes pp32 modifications from Christophe Leroy.

When compiling powernv_defconfig with this option:

text   data  bss   decfilename
11827621   4810490   1341080   17979191   vmlinux
11752437   4598858   1338776   17690071   vmlinux.dcde

Resulting kernel is almost 400kB smaller (and still boots).

[ppc32 numbers here]


Here a few results, obtained with readelf -l vmlinux | grep LOAD

First val is filesz, second is memsz, for each config you get the size 
before and after activation of LD_DCDE, and the difference between the two.


mpc83xx_defconfig:
Before: 0x5ecfe0 0x60b69c
After:  0x5d2fe0 0x5f04a4
Diff:   0x01a000 0x01b4c8

mpc83xx_defconfig without CONFIG_MODULE:
Before: 0x5c1040 0x5e0614
After:  0x55f040 0x57d314
Diff:   0x062000 0x063300

mpc885_ads_defconfig:
Before: 0x36eda4 0x38da04
After:  0x316da4 0x333764
Diff:   0x058000 0x05a2a0

Custom mpc885 config:
Before: 0x719948 0x78bc34
After:  0x6b9948 0x72a99c
Diff:   0x06 0x061298

Custom mpc8321 config:
Before: 0x70f714 0x7d766c
After:  0x6af714 0x7763ec
Diff:   0x06 0x061280





Signed-off-by: Nicholas Piggin 
---
   arch/powerpc/Kconfig  |  1 +
   arch/powerpc/kernel/vmlinux.lds.S | 22 +++---
   2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ee6dbe2efc8b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -205,6 +205,7 @@ config PPC
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
+   select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH   if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
diff --git a/arch/powerpc/kernel/vmlinux.lds.S 
b/arch/powerpc/kernel/vmlinux.lds.S
index c8af90ff49f0..89381dc959ce 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -89,7 +89,7 @@ SECTIONS
 */
.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
   #ifdef CONFIG_LD_HEAD_STUB_CATCH
-   *(.linker_stub_catch);
+   KEEP(*(.linker_stub_catch));
. = . ;
   #endif
   
@@ -98,7 +98,7 @@ SECTIONS

ALIGN_FUNCTION();
   #endif
/* careful! __ftr_alt_* sections need to be close to .text */
-   *(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* 
.ref.text);
+   *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup 
.text.unlikely .fixup __ftr_alt_* .ref.text);


Why not use TEXT_MAIN here instead of .text .text.[0-9a-zA-Z_]* ?


It's from my early patch before we added those in the generic linker
script. Yes your version looks nicer.

Thanks,
Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Nicholas Piggin 
On Fri, 20 Apr 2018 12:00:49 +0200
Mathieu Malaterre  wrote:

> On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  wrote:
> > This requires further changes to linker script to KEEP some tables
> > and wildcard compiler generated sections into the right place. This
> > includes pp32 modifications from Christophe Leroy.
> >
> > When compiling powernv_defconfig with this option:
> >
> > text   data  bss   decfilename
> > 11827621   4810490   1341080   17979191   vmlinux
> > 11752437   4598858   1338776   17690071   vmlinux.dcde
> >
> > Resulting kernel is almost 400kB smaller (and still boots).
> >
> > [ppc32 numbers here]  
> 
> ^^^
> 
> Do you want somebody else to provide those numbers ?

If you have a booting kernel, yes some more numbers would be good.

Thanks,
Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Christophe LEROY 



Le 20/04/2018 à 09:34, Nicholas Piggin a écrit :

This requires further changes to linker script to KEEP some tables
and wildcard compiler generated sections into the right place. This
includes pp32 modifications from Christophe Leroy.

When compiling powernv_defconfig with this option:

text   data  bss   decfilename
11827621   4810490   1341080   17979191   vmlinux
11752437   4598858   1338776   17690071   vmlinux.dcde

Resulting kernel is almost 400kB smaller (and still boots).

[ppc32 numbers here]

Signed-off-by: Nicholas Piggin 


Tested-by: Christophe Leroy 

Tested on MPC885 and MPC8321E, CONFIG_MODULE unset.

Christophe


---
  arch/powerpc/Kconfig  |  1 +
  arch/powerpc/kernel/vmlinux.lds.S | 22 +++---
  2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ee6dbe2efc8b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -205,6 +205,7 @@ config PPC
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
+   select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH   if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
diff --git a/arch/powerpc/kernel/vmlinux.lds.S 
b/arch/powerpc/kernel/vmlinux.lds.S
index c8af90ff49f0..89381dc959ce 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -89,7 +89,7 @@ SECTIONS
 */
.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
  #ifdef CONFIG_LD_HEAD_STUB_CATCH
-   *(.linker_stub_catch);
+   KEEP(*(.linker_stub_catch));
. = . ;
  #endif
  
@@ -98,7 +98,7 @@ SECTIONS

ALIGN_FUNCTION();
  #endif
/* careful! __ftr_alt_* sections need to be close to .text */
-   *(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* 
.ref.text);
+   *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup 
.text.unlikely .fixup __ftr_alt_* .ref.text);
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
@@ -170,10 +170,10 @@ SECTIONS
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
INIT_DATA
__vtop_table_begin = .;
-   *(.vtop_fixup);
+   KEEP(*(.vtop_fixup));
__vtop_table_end = .;
__ptov_table_begin = .;
-   *(.ptov_fixup);
+   KEEP(*(.ptov_fixup));
__ptov_table_end = .;
}
  
@@ -194,26 +194,26 @@ SECTIONS

. = ALIGN(8);
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
__start___ftr_fixup = .;
-   *(__ftr_fixup)
+   KEEP(*(__ftr_fixup))
__stop___ftr_fixup = .;
}
. = ALIGN(8);
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
__start___mmu_ftr_fixup = .;
-   *(__mmu_ftr_fixup)
+   KEEP(*(__mmu_ftr_fixup))
__stop___mmu_ftr_fixup = .;
}
. = ALIGN(8);
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
__start___lwsync_fixup = .;
-   *(__lwsync_fixup)
+   KEEP(*(__lwsync_fixup))
__stop___lwsync_fixup = .;
}
  #ifdef CONFIG_PPC64
. = ALIGN(8);
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
__start___fw_ftr_fixup = .;
-   *(__fw_ftr_fixup)
+   KEEP(*(__fw_ftr_fixup))
__stop___fw_ftr_fixup = .;
}
  #endif
@@ -226,7 +226,7 @@ SECTIONS
. = ALIGN(8);
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
__machine_desc_start = . ;
-   *(.machine.desc)
+   KEEP(*(.machine.desc))
__machine_desc_end = . ;
}
  #ifdef CONFIG_RELOCATABLE
@@ -274,7 +274,7 @@ SECTIONS
.data : AT(ADDR(.data) - LOAD_OFFSET) {
DATA_DATA
*(.data.rel*)
-   *(.sdata)
+   *(SDATA_MAIN)
*(.sdata2)
*(.got.plt) *(.got)
*(.plt)
@@ -289,7 +289,7 @@ SECTIONS
  
  	.opd : AT(ADDR(.opd) - LOAD_OFFSET) {

__start_opd = .;
-   *(.opd)
+   KEEP(*(.opd))
__end_opd = .;
}

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Nicholas Piggin 
On Fri, 20 Apr 2018 12:01:34 +0200
Christophe LEROY  wrote:

> Le 20/04/2018 à 09:34, Nicholas Piggin a écrit :
> > This requires further changes to linker script to KEEP some tables
> > and wildcard compiler generated sections into the right place. This
> > includes pp32 modifications from Christophe Leroy.
> > 
> > When compiling powernv_defconfig with this option:
> > 
> > text   data  bss   decfilename
> > 11827621   4810490   1341080   17979191   vmlinux
> > 11752437   4598858   1338776   17690071   vmlinux.dcde
> > 
> > Resulting kernel is almost 400kB smaller (and still boots).
> > 
> > [ppc32 numbers here]
> > 
> > Signed-off-by: Nicholas Piggin 
> > ---
> >   arch/powerpc/Kconfig  |  1 +
> >   arch/powerpc/kernel/vmlinux.lds.S | 22 +++---
> >   2 files changed, 12 insertions(+), 11 deletions(-)
> > 
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index c32a181a7cbb..ee6dbe2efc8b 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -205,6 +205,7 @@ config PPC
> > select HAVE_KPROBES
> > select HAVE_KPROBES_ON_FTRACE
> > select HAVE_KRETPROBES
> > +   select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
> > select HAVE_LIVEPATCH   if HAVE_DYNAMIC_FTRACE_WITH_REGS
> > select HAVE_MEMBLOCK
> > select HAVE_MEMBLOCK_NODE_MAP
> > diff --git a/arch/powerpc/kernel/vmlinux.lds.S 
> > b/arch/powerpc/kernel/vmlinux.lds.S
> > index c8af90ff49f0..89381dc959ce 100644
> > --- a/arch/powerpc/kernel/vmlinux.lds.S
> > +++ b/arch/powerpc/kernel/vmlinux.lds.S
> > @@ -89,7 +89,7 @@ SECTIONS
> >  */
> > .text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
> >   #ifdef CONFIG_LD_HEAD_STUB_CATCH
> > -   *(.linker_stub_catch);
> > +   KEEP(*(.linker_stub_catch));
> > . = . ;
> >   #endif
> >   
> > @@ -98,7 +98,7 @@ SECTIONS
> > ALIGN_FUNCTION();
> >   #endif
> > /* careful! __ftr_alt_* sections need to be close to .text */
> > -   *(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* 
> > .ref.text);
> > +   *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup 
> > .text.unlikely .fixup __ftr_alt_* .ref.text);  
> 
> Why not use TEXT_MAIN here instead of .text .text.[0-9a-zA-Z_]* ?

It's from my early patch before we added those in the generic linker
script. Yes your version looks nicer.

Thanks,
Nick

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Christophe LEROY 



Le 20/04/2018 à 09:34, Nicholas Piggin a écrit :

This requires further changes to linker script to KEEP some tables
and wildcard compiler generated sections into the right place. This
includes pp32 modifications from Christophe Leroy.

When compiling powernv_defconfig with this option:

text   data  bss   decfilename
11827621   4810490   1341080   17979191   vmlinux
11752437   4598858   1338776   17690071   vmlinux.dcde

Resulting kernel is almost 400kB smaller (and still boots).

[ppc32 numbers here]

Signed-off-by: Nicholas Piggin 
---
  arch/powerpc/Kconfig  |  1 +
  arch/powerpc/kernel/vmlinux.lds.S | 22 +++---
  2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ee6dbe2efc8b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -205,6 +205,7 @@ config PPC
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
+   select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH   if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
diff --git a/arch/powerpc/kernel/vmlinux.lds.S 
b/arch/powerpc/kernel/vmlinux.lds.S
index c8af90ff49f0..89381dc959ce 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -89,7 +89,7 @@ SECTIONS
 */
.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
  #ifdef CONFIG_LD_HEAD_STUB_CATCH
-   *(.linker_stub_catch);
+   KEEP(*(.linker_stub_catch));
. = . ;
  #endif
  
@@ -98,7 +98,7 @@ SECTIONS

ALIGN_FUNCTION();
  #endif
/* careful! __ftr_alt_* sections need to be close to .text */
-   *(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* 
.ref.text);
+   *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup 
.text.unlikely .fixup __ftr_alt_* .ref.text);


Why not use TEXT_MAIN here instead of .text .text.[0-9a-zA-Z_]* ?

Christophe


SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
@@ -170,10 +170,10 @@ SECTIONS
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
INIT_DATA
__vtop_table_begin = .;
-   *(.vtop_fixup);
+   KEEP(*(.vtop_fixup));
__vtop_table_end = .;
__ptov_table_begin = .;
-   *(.ptov_fixup);
+   KEEP(*(.ptov_fixup));
__ptov_table_end = .;
}
  
@@ -194,26 +194,26 @@ SECTIONS

. = ALIGN(8);
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
__start___ftr_fixup = .;
-   *(__ftr_fixup)
+   KEEP(*(__ftr_fixup))
__stop___ftr_fixup = .;
}
. = ALIGN(8);
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
__start___mmu_ftr_fixup = .;
-   *(__mmu_ftr_fixup)
+   KEEP(*(__mmu_ftr_fixup))
__stop___mmu_ftr_fixup = .;
}
. = ALIGN(8);
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
__start___lwsync_fixup = .;
-   *(__lwsync_fixup)
+   KEEP(*(__lwsync_fixup))
__stop___lwsync_fixup = .;
}
  #ifdef CONFIG_PPC64
. = ALIGN(8);
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
__start___fw_ftr_fixup = .;
-   *(__fw_ftr_fixup)
+   KEEP(*(__fw_ftr_fixup))
__stop___fw_ftr_fixup = .;
}
  #endif
@@ -226,7 +226,7 @@ SECTIONS
. = ALIGN(8);
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
__machine_desc_start = . ;
-   *(.machine.desc)
+   KEEP(*(.machine.desc))
__machine_desc_end = . ;
}
  #ifdef CONFIG_RELOCATABLE
@@ -274,7 +274,7 @@ SECTIONS
.data : AT(ADDR(.data) - LOAD_OFFSET) {
DATA_DATA
*(.data.rel*)
-   *(.sdata)
+   *(SDATA_MAIN)
*(.sdata2)
*(.got.plt) *(.got)
*(.plt)
@@ -289,7 +289,7 @@ SECTIONS
  
  	.opd : AT(ADDR(.opd) - LOAD_OFFSET) {

__start_opd = .;
-   *(.opd)
+   KEEP(*(.opd))
__end_opd = .;
}

Re: [PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Mathieu Malaterre 
On Fri, Apr 20, 2018 at 9:34 AM, Nicholas Piggin  wrote:
> This requires further changes to linker script to KEEP some tables
> and wildcard compiler generated sections into the right place. This
> includes pp32 modifications from Christophe Leroy.
>
> When compiling powernv_defconfig with this option:
>
> text   data  bss   decfilename
> 11827621   4810490   1341080   17979191   vmlinux
> 11752437   4598858   1338776   17690071   vmlinux.dcde
>
> Resulting kernel is almost 400kB smaller (and still boots).
>
> [ppc32 numbers here]

^^^

Do you want somebody else to provide those numbers ?

> Signed-off-by: Nicholas Piggin 
> ---
>  arch/powerpc/Kconfig  |  1 +
>  arch/powerpc/kernel/vmlinux.lds.S | 22 +++---
>  2 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index c32a181a7cbb..ee6dbe2efc8b 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -205,6 +205,7 @@ config PPC
> select HAVE_KPROBES
> select HAVE_KPROBES_ON_FTRACE
> select HAVE_KRETPROBES
> +   select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
> select HAVE_LIVEPATCH   if 
> HAVE_DYNAMIC_FTRACE_WITH_REGS
> select HAVE_MEMBLOCK
> select HAVE_MEMBLOCK_NODE_MAP
> diff --git a/arch/powerpc/kernel/vmlinux.lds.S 
> b/arch/powerpc/kernel/vmlinux.lds.S
> index c8af90ff49f0..89381dc959ce 100644
> --- a/arch/powerpc/kernel/vmlinux.lds.S
> +++ b/arch/powerpc/kernel/vmlinux.lds.S
> @@ -89,7 +89,7 @@ SECTIONS
>  */
> .text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
>  #ifdef CONFIG_LD_HEAD_STUB_CATCH
> -   *(.linker_stub_catch);
> +   KEEP(*(.linker_stub_catch));
> . = . ;
>  #endif
>
> @@ -98,7 +98,7 @@ SECTIONS
> ALIGN_FUNCTION();
>  #endif
> /* careful! __ftr_alt_* sections need to be close to .text */
> -   *(.text.hot .text .text.fixup .text.unlikely .fixup 
> __ftr_alt_* .ref.text);
> +   *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup 
> .text.unlikely .fixup __ftr_alt_* .ref.text);
> SCHED_TEXT
> CPUIDLE_TEXT
> LOCK_TEXT
> @@ -170,10 +170,10 @@ SECTIONS
> .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
> INIT_DATA
> __vtop_table_begin = .;
> -   *(.vtop_fixup);
> +   KEEP(*(.vtop_fixup));
> __vtop_table_end = .;
> __ptov_table_begin = .;
> -   *(.ptov_fixup);
> +   KEEP(*(.ptov_fixup));
> __ptov_table_end = .;
> }
>
> @@ -194,26 +194,26 @@ SECTIONS
> . = ALIGN(8);
> __ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
> __start___ftr_fixup = .;
> -   *(__ftr_fixup)
> +   KEEP(*(__ftr_fixup))
> __stop___ftr_fixup = .;
> }
> . = ALIGN(8);
> __mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
> __start___mmu_ftr_fixup = .;
> -   *(__mmu_ftr_fixup)
> +   KEEP(*(__mmu_ftr_fixup))
> __stop___mmu_ftr_fixup = .;
> }
> . = ALIGN(8);
> __lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
> __start___lwsync_fixup = .;
> -   *(__lwsync_fixup)
> +   KEEP(*(__lwsync_fixup))
> __stop___lwsync_fixup = .;
> }
>  #ifdef CONFIG_PPC64
> . = ALIGN(8);
> __fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
> __start___fw_ftr_fixup = .;
> -   *(__fw_ftr_fixup)
> +   KEEP(*(__fw_ftr_fixup))
> __stop___fw_ftr_fixup = .;
> }
>  #endif
> @@ -226,7 +226,7 @@ SECTIONS
> . = ALIGN(8);
> .machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
> __machine_desc_start = . ;
> -   *(.machine.desc)
> +   KEEP(*(.machine.desc))
> __machine_desc_end = . ;
> }
>  #ifdef CONFIG_RELOCATABLE
> @@ -274,7 +274,7 @@ SECTIONS
> .data : AT(ADDR(.data) - LOAD_OFFSET) {
> DATA_DATA
> *(.data.rel*)
> -   *(.sdata)
> +   *(SDATA_MAIN)
> *(.sdata2)
> *(.got.plt) *(.got)
> *(.plt)
> @@ -289,7 +289,7 @@ SECTIONS
>
> .opd : AT(ADDR(.opd) - LOAD_OFFSET) {
> __start_opd = .;
> -   *(.opd)
> +   KEEP(*(.opd))
> __end_opd = .;
> }
>
> --
> 2.17.0
>

[PATCH 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected

2018-04-20 Thread Nicholas Piggin 
This requires further changes to linker script to KEEP some tables
and wildcard compiler generated sections into the right place. This
includes pp32 modifications from Christophe Leroy.

When compiling powernv_defconfig with this option:

text   data  bss   decfilename
11827621   4810490   1341080   17979191   vmlinux
11752437   4598858   1338776   17690071   vmlinux.dcde

Resulting kernel is almost 400kB smaller (and still boots).

[ppc32 numbers here]

Signed-off-by: Nicholas Piggin 
---
 arch/powerpc/Kconfig  |  1 +
 arch/powerpc/kernel/vmlinux.lds.S | 22 +++---
 2 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ee6dbe2efc8b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -205,6 +205,7 @@ config PPC
select HAVE_KPROBES
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
+   select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
select HAVE_LIVEPATCH   if HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_MEMBLOCK
select HAVE_MEMBLOCK_NODE_MAP
diff --git a/arch/powerpc/kernel/vmlinux.lds.S 
b/arch/powerpc/kernel/vmlinux.lds.S
index c8af90ff49f0..89381dc959ce 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -89,7 +89,7 @@ SECTIONS
 */
.text BLOCK(0) : AT(ADDR(.text) - LOAD_OFFSET) {
 #ifdef CONFIG_LD_HEAD_STUB_CATCH
-   *(.linker_stub_catch);
+   KEEP(*(.linker_stub_catch));
. = . ;
 #endif
 
@@ -98,7 +98,7 @@ SECTIONS
ALIGN_FUNCTION();
 #endif
/* careful! __ftr_alt_* sections need to be close to .text */
-   *(.text.hot .text .text.fixup .text.unlikely .fixup __ftr_alt_* 
.ref.text);
+   *(.text.hot .text .text.[0-9a-zA-Z_]* .text.fixup 
.text.unlikely .fixup __ftr_alt_* .ref.text);
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
@@ -170,10 +170,10 @@ SECTIONS
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
INIT_DATA
__vtop_table_begin = .;
-   *(.vtop_fixup);
+   KEEP(*(.vtop_fixup));
__vtop_table_end = .;
__ptov_table_begin = .;
-   *(.ptov_fixup);
+   KEEP(*(.ptov_fixup));
__ptov_table_end = .;
}
 
@@ -194,26 +194,26 @@ SECTIONS
. = ALIGN(8);
__ftr_fixup : AT(ADDR(__ftr_fixup) - LOAD_OFFSET) {
__start___ftr_fixup = .;
-   *(__ftr_fixup)
+   KEEP(*(__ftr_fixup))
__stop___ftr_fixup = .;
}
. = ALIGN(8);
__mmu_ftr_fixup : AT(ADDR(__mmu_ftr_fixup) - LOAD_OFFSET) {
__start___mmu_ftr_fixup = .;
-   *(__mmu_ftr_fixup)
+   KEEP(*(__mmu_ftr_fixup))
__stop___mmu_ftr_fixup = .;
}
. = ALIGN(8);
__lwsync_fixup : AT(ADDR(__lwsync_fixup) - LOAD_OFFSET) {
__start___lwsync_fixup = .;
-   *(__lwsync_fixup)
+   KEEP(*(__lwsync_fixup))
__stop___lwsync_fixup = .;
}
 #ifdef CONFIG_PPC64
. = ALIGN(8);
__fw_ftr_fixup : AT(ADDR(__fw_ftr_fixup) - LOAD_OFFSET) {
__start___fw_ftr_fixup = .;
-   *(__fw_ftr_fixup)
+   KEEP(*(__fw_ftr_fixup))
__stop___fw_ftr_fixup = .;
}
 #endif
@@ -226,7 +226,7 @@ SECTIONS
. = ALIGN(8);
.machine.desc : AT(ADDR(.machine.desc) - LOAD_OFFSET) {
__machine_desc_start = . ;
-   *(.machine.desc)
+   KEEP(*(.machine.desc))
__machine_desc_end = . ;
}
 #ifdef CONFIG_RELOCATABLE
@@ -274,7 +274,7 @@ SECTIONS
.data : AT(ADDR(.data) - LOAD_OFFSET) {
DATA_DATA
*(.data.rel*)
-   *(.sdata)
+   *(SDATA_MAIN)
*(.sdata2)
*(.got.plt) *(.got)
*(.plt)
@@ -289,7 +289,7 @@ SECTIONS
 
.opd : AT(ADDR(.opd) - LOAD_OFFSET) {
__start_opd = .;
-   *(.opd)
+   KEEP(*(.opd))
__end_opd = .;
}
 
-- 
2.17.0