From: Mathieu Malaterre <malat@debian.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>,
linux-arch@vger.kernel.org,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-kbuild <linux-kbuild@vger.kernel.org>
Subject: Re: [PATCH v2 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected
Date: Mon, 14 May 2018 08:06:43 +0200 [thread overview]
Message-ID: <CA+7wUswRCMQX3qrqCZYj73TDG4P1x_w6DTN-RNM0OQYQX=gm4A@mail.gmail.com> (raw)
In-Reply-To: <20180509130001.24276-5-npiggin@gmail.com>
On Wed, May 9, 2018 at 3:00 PM, Nicholas Piggin <npiggin@gmail.com> 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, the resulting
> kernel is almost 400kB smaller (and still boots):
>
> text data bss dec filename
> 11827621 4810490 1341080 17979191 vmlinux
> 11752437 4598858 1338776 17690071 vmlinux.dcde
>
> Mathieu's numbers for custom Mac Mini G4 config has almost 200kB
Technically this is an oldconfig from debian original config file
(debian official powerpc kernel package)... tested on a mac mini g4.
> saving. It also had some increase in vmlinux size for as-yet
> unknown reasons.
>
> text data bss dec filename
> 7461457 2475122 1428064 11364643 vmlinux
> 7386425 2364370 1425432 11176227 vmlinux.dcde
>
> Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> [8xx]
> Tested-by: Mathieu Malaterre <malat@debian.org> [32-bit powermac]
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> 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..52a93cdd04bc 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_MAIN .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
>
WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Malaterre <malat@debian.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-arch@vger.kernel.org,
Masahiro Yamada <yamada.masahiro@socionext.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-kbuild <linux-kbuild@vger.kernel.org>
Subject: Re: [PATCH v2 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected
Date: Mon, 14 May 2018 08:06:43 +0200 [thread overview]
Message-ID: <CA+7wUswRCMQX3qrqCZYj73TDG4P1x_w6DTN-RNM0OQYQX=gm4A@mail.gmail.com> (raw)
In-Reply-To: <20180509130001.24276-5-npiggin@gmail.com>
On Wed, May 9, 2018 at 3:00 PM, Nicholas Piggin <npiggin@gmail.com> 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, the resulting
> kernel is almost 400kB smaller (and still boots):
>
> text data bss dec filename
> 11827621 4810490 1341080 17979191 vmlinux
> 11752437 4598858 1338776 17690071 vmlinux.dcde
>
> Mathieu's numbers for custom Mac Mini G4 config has almost 200kB
Technically this is an oldconfig from debian original config file
(debian official powerpc kernel package)... tested on a mac mini g4.
> saving. It also had some increase in vmlinux size for as-yet
> unknown reasons.
>
> text data bss dec filename
> 7461457 2475122 1428064 11364643 vmlinux
> 7386425 2364370 1425432 11176227 vmlinux.dcde
>
> Tested-by: Christophe Leroy <christophe.leroy@c-s.fr> [8xx]
> Tested-by: Mathieu Malaterre <malat@debian.org> [32-bit powermac]
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
> 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..52a93cdd04bc 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_MAIN .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
>
next prev parent reply other threads:[~2018-05-14 6:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-09 12:59 [PATCH v2 0/4] LD_DEAD_CODE_DATA_ELIMINATION fixes and enabling for powerpc Nicholas Piggin
2018-05-09 12:59 ` Nicholas Piggin
2018-05-09 12:59 ` [PATCH v2 1/4] kbuild: Fix asm-generic/vmlinux.lds.h for LD_DEAD_CODE_DATA_ELIMINATION Nicholas Piggin
2018-05-09 12:59 ` Nicholas Piggin
2018-05-09 12:59 ` [PATCH v2 2/4] kbuild: LD_DEAD_CODE_DATA_ELIMINATION no -ffunction-sections/-fdata-sections for module build Nicholas Piggin
2018-05-09 12:59 ` Nicholas Piggin
2018-05-09 13:00 ` [PATCH v2 3/4] kbuild: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selectable if enabled Nicholas Piggin
2018-05-09 13:00 ` Nicholas Piggin
2018-05-09 13:00 ` [PATCH v2 4/4] powerpc: Allow LD_DEAD_CODE_DATA_ELIMINATION to be selected Nicholas Piggin
2018-05-09 13:00 ` Nicholas Piggin
2018-05-14 2:05 ` Michael Ellerman
2018-05-14 2:05 ` Michael Ellerman
2018-05-14 2:05 ` Michael Ellerman
2018-05-14 6:06 ` Mathieu Malaterre [this message]
2018-05-14 6:06 ` Mathieu Malaterre
2018-05-14 0:08 ` [PATCH v2 0/4] LD_DEAD_CODE_DATA_ELIMINATION fixes and enabling for powerpc Masahiro Yamada
2018-05-14 0:08 ` Masahiro Yamada
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CA+7wUswRCMQX3qrqCZYj73TDG4P1x_w6DTN-RNM0OQYQX=gm4A@mail.gmail.com' \
--to=malat@debian.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kbuild@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=npiggin@gmail.com \
--cc=yamada.masahiro@socionext.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.