2020-08-03 05:50:53

by Pingfan Liu

[permalink] [raw]
Subject: [PATCHv2] x86/purgatory: don't generate debug info for purgatory.ro

Purgatory.ro is a standalone binary that is not linked against the rest of
the kernel. Its image is copied into an array that is linked to the
kernel, and from there kexec relocates it wherever it desires.

Unlike the debug info for vmlinux, which can be used for analyzing crash
such info is useless in purgatory.ro. And discarding them can save about
200K space.

Original:
259080 kexec-purgatory.o
Stripped debug info:
29152 kexec-purgatory.o

Signed-off-by: Pingfan Liu <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Hans de Goede <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Arvind Sankar <[email protected]>
Cc: Steve Wahl <[email protected]>
Cc: [email protected]
Cc: [email protected]
To: [email protected]
---
arch/x86/purgatory/Makefile | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 088bd76..d24b43a 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -32,7 +32,7 @@ KCOV_INSTRUMENT := n
# make up the standalone purgatory.ro

PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
-PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
+PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector)

@@ -64,6 +64,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_string.o += $(PURGATORY_CFLAGS)

+AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
+AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
+
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)

--
2.7.5


2020-08-03 17:13:16

by Nick Desaulniers

[permalink] [raw]
Subject: Re: [PATCHv2] x86/purgatory: don't generate debug info for purgatory.ro

On Sun, Aug 2, 2020 at 10:50 PM Pingfan Liu <[email protected]> wrote:
>
> Purgatory.ro is a standalone binary that is not linked against the rest of
> the kernel. Its image is copied into an array that is linked to the
> kernel, and from there kexec relocates it wherever it desires.
>
> Unlike the debug info for vmlinux, which can be used for analyzing crash
> such info is useless in purgatory.ro. And discarding them can save about
> 200K space.
>
> Original:
> 259080 kexec-purgatory.o
> Stripped debug info:
> 29152 kexec-purgatory.o
>
> Signed-off-by: Pingfan Liu <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: Hans de Goede <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Arvind Sankar <[email protected]>
> Cc: Steve Wahl <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> To: [email protected]

Reviewed-by: Nick Desaulniers <[email protected]>

> ---

Thanks for the patch! One thing that can be handy for reviewers (but
isn't strictly necessary) is to put a comment about what changed since
the previous version below the above^ `---` line. By putting comments
"below the fold" you can pass along information to the reviewers that
won't wind up in `git log` when committed. Not strictly necessary,
and less so for smaller patches, but hope this helps. (No need for a
v3 over that).

> arch/x86/purgatory/Makefile | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 088bd76..d24b43a 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -32,7 +32,7 @@ KCOV_INSTRUMENT := n
> # make up the standalone purgatory.ro
>
> PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
> -PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
> +PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
> PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
> PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector)
>
> @@ -64,6 +64,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
> CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
> CFLAGS_string.o += $(PURGATORY_CFLAGS)
>
> +AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
> +AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
> +
> $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
> $(call if_changed,ld)
>
> --
> 2.7.5
>


--
Thanks,
~Nick Desaulniers

2020-08-03 17:16:54

by Steve Wahl

[permalink] [raw]
Subject: Re: [PATCHv2] x86/purgatory: don't generate debug info for purgatory.ro

Reviewed-by: Steve Wahl <[email protected]>

On Mon, Aug 03, 2020 at 01:49:48PM +0800, Pingfan Liu wrote:
> Purgatory.ro is a standalone binary that is not linked against the rest of
> the kernel. Its image is copied into an array that is linked to the
> kernel, and from there kexec relocates it wherever it desires.
>
> Unlike the debug info for vmlinux, which can be used for analyzing crash
> such info is useless in purgatory.ro. And discarding them can save about
> 200K space.
>
> Original:
> 259080 kexec-purgatory.o
> Stripped debug info:
> 29152 kexec-purgatory.o
>
> Signed-off-by: Pingfan Liu <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: Hans de Goede <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Arvind Sankar <[email protected]>
> Cc: Steve Wahl <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> To: [email protected]
> ---
> arch/x86/purgatory/Makefile | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 088bd76..d24b43a 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -32,7 +32,7 @@ KCOV_INSTRUMENT := n
> # make up the standalone purgatory.ro
>
> PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
> -PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
> +PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
> PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
> PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector)
>
> @@ -64,6 +64,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
> CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
> CFLAGS_string.o += $(PURGATORY_CFLAGS)
>
> +AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
> +AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
> +
> $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
> $(call if_changed,ld)
>
> --
> 2.7.5
>

2020-08-06 17:12:33

by Dave Young

[permalink] [raw]
Subject: Re: [PATCHv2] x86/purgatory: don't generate debug info for purgatory.ro

On 08/03/20 at 01:49pm, Pingfan Liu wrote:
> Purgatory.ro is a standalone binary that is not linked against the rest of
> the kernel. Its image is copied into an array that is linked to the
> kernel, and from there kexec relocates it wherever it desires.
>
> Unlike the debug info for vmlinux, which can be used for analyzing crash
> such info is useless in purgatory.ro. And discarding them can save about
> 200K space.
>
> Original:
> 259080 kexec-purgatory.o
> Stripped debug info:
> 29152 kexec-purgatory.o
>
> Signed-off-by: Pingfan Liu <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: Hans de Goede <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Arvind Sankar <[email protected]>
> Cc: Steve Wahl <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> To: [email protected]
> ---
> arch/x86/purgatory/Makefile | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 088bd76..d24b43a 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -32,7 +32,7 @@ KCOV_INSTRUMENT := n
> # make up the standalone purgatory.ro
>
> PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
> -PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
> +PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
> PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
> PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector)
>
> @@ -64,6 +64,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
> CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
> CFLAGS_string.o += $(PURGATORY_CFLAGS)
>
> +AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
> +AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
> +
> $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
> $(call if_changed,ld)
>
> --
> 2.7.5
>
>
> _______________________________________________
> kexec mailing list
> [email protected]
> http://lists.infradead.org/mailman/listinfo/kexec
>

Hi Pingfan,

Looks good, thanks for the patch.

Acked-by: Dave Young <[email protected]>

Thanks
Dave

2020-08-06 17:12:47

by tip-bot2 for Jacob Pan

[permalink] [raw]
Subject: [tip: x86/urgent] x86/purgatory: Don't generate debug info for purgatory.ro

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: b031cf7752a82fefa6818a788d906d14f533afa9
Gitweb: https://git.kernel.org/tip/b031cf7752a82fefa6818a788d906d14f533afa9
Author: Pingfan Liu <[email protected]>
AuthorDate: Mon, 03 Aug 2020 13:49:48 +08:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Thu, 06 Aug 2020 15:29:25 +02:00

x86/purgatory: Don't generate debug info for purgatory.ro

Purgatory.ro is a standalone binary that is not linked against the rest of
the kernel. Its image is copied into an array that is linked to the
kernel, and from there kexec relocates it wherever it desires.

Unlike the debug info for vmlinux, which can be used for analyzing crash
such info is useless in purgatory.ro. And discarding them can save about
200K space.

Original:
259080 kexec-purgatory.o
Stripped debug info:
29152 kexec-purgatory.o

Signed-off-by: Pingfan Liu <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Reviewed-by: Steve Wahl <[email protected]>
Acked-by: Dave Young <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/purgatory/Makefile | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 088bd76..d24b43a 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -32,7 +32,7 @@ KCOV_INSTRUMENT := n
# make up the standalone purgatory.ro

PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
-PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
+PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector)

@@ -64,6 +64,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_string.o += $(PURGATORY_CFLAGS)

+AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
+AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
+
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)

2020-08-06 23:44:23

by tip-bot2 for Jacob Pan

[permalink] [raw]
Subject: [tip: x86/urgent] x86/purgatory: Don't generate debug info for purgatory.ro

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 52416ffcf823ee11aa19792715664ab94757f111
Gitweb: https://git.kernel.org/tip/52416ffcf823ee11aa19792715664ab94757f111
Author: Pingfan Liu <[email protected]>
AuthorDate: Mon, 03 Aug 2020 13:49:48 +08:00
Committer: Ingo Molnar <[email protected]>
CommitterDate: Fri, 07 Aug 2020 01:32:00 +02:00

x86/purgatory: Don't generate debug info for purgatory.ro

Purgatory.ro is a standalone binary that is not linked against the rest of
the kernel. Its image is copied into an array that is linked to the
kernel, and from there kexec relocates it wherever it desires.

Unlike the debug info for vmlinux, which can be used for analyzing crash
such info is useless in purgatory.ro. And discarding them can save about
200K space.

Original:
259080 kexec-purgatory.o
Stripped debug info:
29152 kexec-purgatory.o

Signed-off-by: Pingfan Liu <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Reviewed-by: Steve Wahl <[email protected]>
Acked-by: Dave Young <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/x86/purgatory/Makefile | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 088bd76..d24b43a 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -32,7 +32,7 @@ KCOV_INSTRUMENT := n
# make up the standalone purgatory.ro

PURGATORY_CFLAGS_REMOVE := -mcmodel=kernel
-PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss
+PURGATORY_CFLAGS := -mcmodel=large -ffreestanding -fno-zero-initialized-in-bss -g0
PURGATORY_CFLAGS += $(DISABLE_STACKLEAK_PLUGIN) -DDISABLE_BRANCH_PROFILING
PURGATORY_CFLAGS += $(call cc-option,-fno-stack-protector)

@@ -64,6 +64,9 @@ CFLAGS_sha256.o += $(PURGATORY_CFLAGS)
CFLAGS_REMOVE_string.o += $(PURGATORY_CFLAGS_REMOVE)
CFLAGS_string.o += $(PURGATORY_CFLAGS)

+AFLAGS_REMOVE_setup-x86_$(BITS).o += -Wa,-gdwarf-2
+AFLAGS_REMOVE_entry64.o += -Wa,-gdwarf-2
+
$(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
$(call if_changed,ld)