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parisc: strip debug information when building compressed images

PATCH In review Sven Schnelle 3 participants 9 messages Jul 31, 2019 PA-RISC architecture

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Sven Schnelle

author
#0 lore raw

PATCH 1/1 parisc: strip debug information when building compressed images

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/compressed/Makefile:28: arch/parisc/boot/compressed/vmlinux] Error 1 make[2]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/Makefile:17: arch/parisc/boot/compressed/vmlinux] Error 2 make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

While this might also be fixed by adjusting the linker script, i think we should strip the debug information when generating the compressed image. This reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug information is enabled.

Signed-off-by Sven Schnelle <[email protected]>
---
 arch/parisc/boot/compressed/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
arch/parisc/boot/compressed/Makefile +4 -1
index 2da8624e5cf6..2a81997b1079 100644
@@ -55,8 +55,11 @@ $(obj)/misc.o: $(obj)/sizes.h
 CPPFLAGS_vmlinux.lds += -I$(objtree)/$(obj) -DBOOTLOADER
 $(obj)/vmlinux.lds: $(obj)/sizes.h
 
+quiet_cmd_objcopy_strip_debug = OBJCOPY_STRIP_DEBUG $@
+      cmd_objcopy_strip_debug = $(OBJCOPY) --strip-debug $< $@
+
 $(obj)/vmlinux.bin: vmlinux
-	$(call if_changed,objcopy)
+	$(call if_changed,objcopy_strip_debug)
 
 vmlinux.bin.all-y := $(obj)/vmlinux.bin
Signature · 1 line
2.20.1
maintainer
#1 lore raw

* Sven Schnelle <[email protected]>:

Quoted 11 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/compressed/Makefile:28: arch/parisc/boot/compressed/vmlinux] Error 1 make[2]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/Makefile:17: arch/parisc/boot/compressed/vmlinux] Error 2 make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

While this might also be fixed by adjusting the linker script, i think we should strip the debug information when generating the compressed image. This reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug information is enabled.

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Helge

------------------------
[PATCH] parisc: Allow building a compressed vmlinuz with CONFIG_DEBUG_INFO enabled.

Signed-off-by Helge Deller <[email protected]>
arch/parisc/boot/compressed/vmlinux.lds.S +3 -0
index bfd7872739a3..dac000ec3861 100644
@@ -49,7 +49,10 @@ SECTIONS
 	}
 
 	/* bootloader code and data starts behind area of extracted kernel */
+#if !defined(CONFIG_DEBUG_INFO)
+	/* ensure at least max address when compiled without debug info: */
 	. = (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START);
+#endif
 
 	/* align on next page boundary */
 	. = ALIGN(4096);
maintainer
#2 lore raw

* Helge Deller <[email protected]>:

Quoted 13 lines

* Sven Schnelle <[email protected]>:

Quoted 11 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/compressed/Makefile:28: arch/parisc/boot/compressed/vmlinux] Error 1 make[2]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/Makefile:17: arch/parisc/boot/compressed/vmlinux] Error 2 make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

While this might also be fixed by adjusting the linker script, i think we should strip the debug information when generating the compressed image. This reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug information is enabled.

Quoted 7 lines

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Here is an updated patch without ifdefs:
Helge

arch/parisc/boot/compressed/vmlinux.lds.S +2 -2
index bfd7872739a3..2ac3a643f2eb 100644
@@ -48,8 +48,8 @@ SECTIONS
 		*(.rodata.compressed)
 	}
 
-	/* bootloader code and data starts behind area of extracted kernel */
-	. = (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START);
+	/* bootloader code and data starts at least behind area of extracted kernel */
+	. = MAX(ABSOLUTE(.), (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
 
 	/* align on next page boundary */
 	. = ALIGN(4096);
author
#3 lore raw

Hi Helge,

Quoted 30 lines · Helge Deller

* Helge Deller <[email protected]>:

Quoted 13 lines

* Sven Schnelle <[email protected]>:

Quoted 11 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/compressed/Makefile:28: arch/parisc/boot/compressed/vmlinux] Error 1 make[2]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/Makefile:17: arch/parisc/boot/compressed/vmlinux] Error 2 make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

While this might also be fixed by adjusting the linker script, i think we should strip the debug information when generating the compressed image. This reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug information is enabled.

Quoted 7 lines

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Here is an updated patch without ifdefs:
Helge

arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
index bfd7872739a3..2ac3a643f2eb 100644

arch/parisc/boot/compressed/vmlinux.lds.S SECTIONS · line 55

Quoted 10 lines
arch/parisc/boot/compressed/vmlinux.lds.S +2 -2
@@ -48,8 +48,8 @@ SECTIONS
 		*(.rodata.compressed)
 	}
 
-	/* bootloader code and data starts behind area of extracted kernel */
-	. = (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START);
+	/* bootloader code and data starts at least behind area of extracted kernel */
+	. = MAX(ABSOLUTE(.), (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
 
 	/* align on next page boundary */
 	. = ALIGN(4096);

With full debug and a 64 Bit Build i get now (vmlinux is 128M):

  LD      vmlinux
  SORTEX  vmlinux
  SYSMAP  System.map

/sbin/palo -f ./palo.conf
palo version 2.00 http://www.parisc-linux.org - Mon, 01 Jan 2018 21:07:58 +0100
uncompressing Linux kernel................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ Decompression error:
uncompressed image too long - wouldn't fit into destination
vmlinuz is not a recognizable executable (ELF32 or ELF64)
make[1]: *** [arch/parisc/Makefile:130: lifimage] Error 2
make[1]: Leaving directory '/home/svens/parisc-linux/build64'
make: *** [Makefile:179: sub-make] Error 2

maintainer
#4 lore raw
Quoted 46 lines · Sven Schnelle

Hi Helge,

Quoted 30 lines · Helge Deller

* Helge Deller <[email protected]>:

Quoted 13 lines

* Sven Schnelle <[email protected]>:

Quoted 11 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/compressed/Makefile:28: arch/parisc/boot/compressed/vmlinux] Error 1 make[2]: *** [/home/svens/parisc-linux/src/arch/parisc/boot/Makefile:17: arch/parisc/boot/compressed/vmlinux] Error 2 make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

While this might also be fixed by adjusting the linker script, i think we should strip the debug information when generating the compressed image. This reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug information is enabled.

Quoted 7 lines

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Here is an updated patch without ifdefs:
Helge

arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
index bfd7872739a3..2ac3a643f2eb 100644

arch/parisc/boot/compressed/vmlinux.lds.S SECTIONS · line 55

Quoted 10 lines
arch/parisc/boot/compressed/vmlinux.lds.S +2 -2
@@ -48,8 +48,8 @@ SECTIONS
  		*(.rodata.compressed)
  	}
 
-	/* bootloader code and data starts behind area of extracted kernel */
-	. = (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START);
+	/* bootloader code and data starts at least behind area of extracted kernel */
+	. = MAX(ABSOLUTE(.), (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START));
 
  	/* align on next page boundary */
  	. = ALIGN(4096);

With full debug and a 64 Bit Build i get now (vmlinux is 128M):

Quoted 8 lines
   LD      vmlinux
   SORTEX  vmlinux
   SYSMAP  System.map

/sbin/palo -f ./palo.conf
palo version 2.00 http://www.parisc-linux.org - Mon, 01 Jan 2018 21:07:58 +0100
uncompressing Linux kernel................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................ Decompression error:
uncompressed image too long - wouldn't fit into destination

You are using the built-in palo gzip decompression function.
Please don't use it, it is an old (not bug-free) implementation which got replaced by the kernel self-decompressor.
My palo.conf in the build dir has:
--init-tape=lifimage
--recoverykernel=vmlinuz

and set
CONFIG_PARISC_SELF_EXTRACT=y
in .config.

Helge

author
#5 lore raw

Hi Helge,

Quoted 10 lines · Helge Deller
Quoted 1 line · Sven Schnelle

uncompressed image too long - wouldn't fit into destination

You are using the built-in palo gzip decompression function.
Please don't use it, it is an old (not bug-free) implementation which got replaced by the kernel self-decompressor.
My palo.conf in the build dir has:
--init-tape=lifimage
--recoverykernel=vmlinuz

Quoted 3 lines

and set
CONFIG_PARISC_SELF_EXTRACT=y
in .config.

Thanks. I had the palo option (probably because they are default), but missed the Kernel option. The lifimage is now 28MB in size, and your patch works for me.

Thanks!
Sven

maintainer
#6 lore raw
In reply to Helge Deller
Quoted 55 lines · Helge Deller

* Sven Schnelle <[email protected]>:

Quoted 15 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc- linux/src/arch/parisc/boot/compressed/Makefile:28:
arch/parisc/boot/compressed/vmlinux] Error 1
make[2]: *** [/home/svens/parisc- linux/src/arch/parisc/boot/Makefile:17:
arch/parisc/boot/compressed/vmlinux] Error 2
make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

Quoted 7 lines

While this might also be fixed by adjusting the linker script, i think we
should strip the debug information when generating the compressed image. This
reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug
information is enabled.

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end - SZparisc_kernel_start
+ KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Helge

------------------------
[PATCH] parisc: Allow building a compressed vmlinuz with CONFIG_DEBUG_INFO enabled.

Signed-off-by Helge Deller <[email protected]>
arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
index bfd7872739a3..dac000ec3861 100644
@@ -49,7 +49,10 @@ SECTIONS
 	}
 
 	/* bootloader code and data starts behind area of extracted

kernel */

arch/parisc/boot/compressed/vmlinux.lds.S +2 -0
+#if !defined(CONFIG_DEBUG_INFO)
+	/* ensure at least max address when compiled without debug
Quoted 4 lines

info: */
. = (SZ_end - SZparisc_kernel_start +
KERNEL_BINARY_TEXT_START);
+#endif

This would cause the kernel to be built in a single section for the !defined(CONFIG_DEBUG_INFO) case, meaning we'd always blow through the 0x00100000-end text hole we need to leave for the compressed kernel to decompress into.

James

maintainer
#7 lore raw
Quoted 52 lines · James Bottomley
Quoted 51 lines · Helge Deller

* Sven Schnelle <[email protected]>:

Quoted 15 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc- linux/src/arch/parisc/boot/compressed/Makefile:28:
arch/parisc/boot/compressed/vmlinux] Error 1
make[2]: *** [/home/svens/parisc- linux/src/arch/parisc/boot/Makefile:17:
arch/parisc/boot/compressed/vmlinux] Error 2
make[2]: Target 'arch/parisc/boot/bzImage' not remade because of errors.

Quoted 7 lines

While this might also be fixed by adjusting the linker script, i think we
should strip the debug information when generating the compressed image. This
reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full debug
information is enabled.

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end - SZparisc_kernel_start
+ KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Helge

------------------------
[PATCH] parisc: Allow building a compressed vmlinuz with CONFIG_DEBUG_INFO enabled.

Signed-off-by Helge Deller <[email protected]>
arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
index bfd7872739a3..dac000ec3861 100644
@@ -49,7 +49,10 @@ SECTIONS
  	}
Quoted 10 lines
Quoted 8 lines
arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
  	/* bootloader code and data starts behind area of extracted

kernel */

arch/parisc/boot/compressed/vmlinux.lds.S +2 -0
+#if !defined(CONFIG_DEBUG_INFO)
+	/* ensure at least max address when compiled without debug

info: */
. = (SZ_end - SZparisc_kernel_start +
KERNEL_BINARY_TEXT_START);
+#endif

This would cause the kernel to be built in a single section

Yes.

Quoted 4 lines

for the
!defined(CONFIG_DEBUG_INFO) case, meaning we'd always blow through the 0x00100000-end text hole we need to leave for the compressed kernel to decompress into.

The debug info occupied the memory (and more) in the 0x00100000-end text area, so we have the room to decompress to.
But the second patch I just sent is better anyway.

Helge

maintainer
#8 lore raw
Quoted 71 lines · Helge Deller
Quoted 57 lines · James Bottomley
Quoted 56 lines · Helge Deller

* Sven Schnelle <[email protected]>:

Quoted 16 lines

When compiling the kernel with debug information i got the following error:

hppa-linux-gnu-ld: section .text LMA [0000000000e78000,0000000000e7b41f] overlaps section .rodata.compressed LMA [00000000000e0078,00000000015ad43d] make[3]: *** [/home/svens/parisc- linux/src/arch/parisc/boot/compressed/Makefile:28:
arch/parisc/boot/compressed/vmlinux] Error 1 make[2]: *** [/home/svens/parisc- linux/src/arch/parisc/boot/Makefile:17:
arch/parisc/boot/compressed/vmlinux] Error 2 make[2]: Target 'arch/parisc/boot/bzImage' not remade because of
errors.

Quoted 10 lines

While this might also be fixed by adjusting the linker script, i
think we
should strip the debug information when generating the compressed
image. This
reduces the size of vmlinuz/lifimage from ~69MB to 6.6MB when full
debug
information is enabled.

I think keeping debug info is good.
Can you test this patch instead?
It converts a 141MB vmlinux boot file (with debug info) to a 32M vmlinuz for me.

Ideally I would prefer something like
. = MIN_OR_HIGHER_THAN_CURRENT_ADDR((SZ_end -
SZparisc_kernel_start
+ KERNEL_BINARY_TEXT_START));
to avoid the ifdef, but I'm missing the linker script expert knowledge...

Helge

------------------------
[PATCH] parisc: Allow building a compressed vmlinuz with CONFIG_DEBUG_INFO enabled.

Signed-off-by Helge Deller <[email protected]>
arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
index bfd7872739a3..dac000ec3861 100644
@@ -49,7 +49,10 @@ SECTIONS
  	}
Quoted 12 lines
Quoted 10 lines
arch/parisc/boot/compressed/vmlinux.lds.S +0 -0
  	/* bootloader code and data starts behind area of

extracted
kernel */

arch/parisc/boot/compressed/vmlinux.lds.S +2 -0
+#if !defined(CONFIG_DEBUG_INFO)
+	/* ensure at least max address when compiled without

debug
info: */
. = (SZ_end - SZparisc_kernel_start +
KERNEL_BINARY_TEXT_START);
+#endif

This would cause the kernel to be built in a single section

Quoted 8 lines

Yes.

Quoted 3 lines

for the !defined(CONFIG_DEBUG_INFO) case, meaning we'd always blow through the 0x00100000-end text hole we need to leave for the compressed kernel to decompress into.

The debug info occupied the memory (and more) in the 0x00100000-end text area, so we have the room to decompress to.

Only if the end of text in the compressed section occurs before 0x00100000. That was the bug that caused my decompression to fail. Even for a moderately configured kernel, the compressed text size is often bigger than the 128kb we have available between 0x000e0000 and 0x00100000.

James

Quoted 4 lines

But the second patch I just sent is better anyway.

Helge