diff mbox series

[v3] kbuild: Strip runtime const RELA sections correctly

Message ID 20250113155306.1922992-2-ardb+git@google.com (mailing list archive)
State New
Headers show
Series [v3] kbuild: Strip runtime const RELA sections correctly | expand

Commit Message

Ard Biesheuvel Jan. 13, 2025, 3:53 p.m. UTC 
From: Ard Biesheuvel <ardb@kernel.org>

Due to the fact that runtime const ELF sections are named without a
leading period or double underscore, the RSTRIP logic that removes the
static RELA sections from vmlinux fails to identify them. This results
in a situation like below, where some sections that were supposed to get
removed are left behind.

  [Nr] Name                              Type            Address          Off     Size   ES Flg Lk Inf Al

  [58] runtime_shift_d_hash_shift        PROGBITS        ffffffff83500f50 2900f50 000014 00   A  0   0  1
  [59] .relaruntime_shift_d_hash_shift   RELA            0000000000000000 55b6f00 000078 18   I 70  58  8
  [60] runtime_ptr_dentry_hashtable      PROGBITS        ffffffff83500f68 2900f68 000014 00   A  0   0  1
  [61] .relaruntime_ptr_dentry_hashtable RELA            0000000000000000 55b6f78 000078 18   I 70  60  8
  [62] runtime_ptr_USER_PTR_MAX          PROGBITS        ffffffff83500f80 2900f80 000238 00   A  0   0  1
  [63] .relaruntime_ptr_USER_PTR_MAX     RELA            0000000000000000 55b6ff0 000d50 18   I 70  62  8

So tweak the match expression to strip all sections starting with .rel.
While at it, consolidate the logic used by RISC-V, s390 and x86 into a
single shared Makefile library command.

Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-riscv@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Ron Economos <re@w6rz.net>
Link: https://lore.kernel.org/all/CAHk-=wjk3ynjomNvFN8jf9A1k=qSc=JFF591W00uXj-qqNUxPQ@mail.gmail.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
v3: put back missing 'endif' to fix the RISC-V build
v2: add missing include of scripts/Makefile.lib

 arch/riscv/Makefile.postlink |  8 ++------
 arch/s390/Makefile.postlink  |  6 +-----
 arch/x86/Makefile.postlink   |  6 +-----
 scripts/Makefile.lib         |  3 +++
 4 files changed, 7 insertions(+), 18 deletions(-)

Comments

Charlie Jenkins Jan. 16, 2025, 10:02 p.m. UTC | #1 
On Mon, Jan 13, 2025 at 04:53:07PM +0100, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
> 
> Due to the fact that runtime const ELF sections are named without a
> leading period or double underscore, the RSTRIP logic that removes the
> static RELA sections from vmlinux fails to identify them. This results
> in a situation like below, where some sections that were supposed to get
> removed are left behind.
> 
>   [Nr] Name                              Type            Address          Off     Size   ES Flg Lk Inf Al
> 
>   [58] runtime_shift_d_hash_shift        PROGBITS        ffffffff83500f50 2900f50 000014 00   A  0   0  1
>   [59] .relaruntime_shift_d_hash_shift   RELA            0000000000000000 55b6f00 000078 18   I 70  58  8
>   [60] runtime_ptr_dentry_hashtable      PROGBITS        ffffffff83500f68 2900f68 000014 00   A  0   0  1
>   [61] .relaruntime_ptr_dentry_hashtable RELA            0000000000000000 55b6f78 000078 18   I 70  60  8
>   [62] runtime_ptr_USER_PTR_MAX          PROGBITS        ffffffff83500f80 2900f80 000238 00   A  0   0  1
>   [63] .relaruntime_ptr_USER_PTR_MAX     RELA            0000000000000000 55b6ff0 000d50 18   I 70  62  8
> 
> So tweak the match expression to strip all sections starting with .rel.
> While at it, consolidate the logic used by RISC-V, s390 and x86 into a
> single shared Makefile library command.
> 
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-s390@vger.kernel.org
> Cc: Ron Economos <re@w6rz.net>
> Link: https://lore.kernel.org/all/CAHk-=wjk3ynjomNvFN8jf9A1k=qSc=JFF591W00uXj-qqNUxPQ@mail.gmail.com/
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
> v3: put back missing 'endif' to fix the RISC-V build
> v2: add missing include of scripts/Makefile.lib
> 
>  arch/riscv/Makefile.postlink |  8 ++------
>  arch/s390/Makefile.postlink  |  6 +-----
>  arch/x86/Makefile.postlink   |  6 +-----
>  scripts/Makefile.lib         |  3 +++
>  4 files changed, 7 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/riscv/Makefile.postlink b/arch/riscv/Makefile.postlink
> index 829b9abc91f6..750d2784f69e 100644
> --- a/arch/riscv/Makefile.postlink
> +++ b/arch/riscv/Makefile.postlink

When I compile x86 as relocatable I see the problem that you are fixing
here, but I don't see it on riscv. It's probably better to keep around
this code for riscv, but I don't think it even needs this stripping? I
am adding Alex since he added this for riscv.

Anyways this works as expected:

Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Tested-by: Charlie Jenkins <charlie@rivosinc.com>

> @@ -10,6 +10,7 @@ __archpost:
>  
>  -include include/config/auto.conf
>  include $(srctree)/scripts/Kbuild.include
> +include $(srctree)/scripts/Makefile.lib
>  
>  quiet_cmd_relocs_check = CHKREL  $@
>  cmd_relocs_check = 							\
> @@ -19,11 +20,6 @@ ifdef CONFIG_RELOCATABLE
>  quiet_cmd_cp_vmlinux_relocs = CPREL   vmlinux.relocs
>  cmd_cp_vmlinux_relocs = cp vmlinux vmlinux.relocs
>  
> -quiet_cmd_relocs_strip = STRIPREL $@
> -cmd_relocs_strip = $(OBJCOPY)   --remove-section='.rel.*'       \
> -                                --remove-section='.rel__*'      \
> -                                --remove-section='.rela.*'      \
> -                                --remove-section='.rela__*' $@
>  endif
>  
>  # `@true` prevents complaint when there is nothing to be done
> @@ -33,7 +27,7 @@ vmlinux: FORCE
>  ifdef CONFIG_RELOCATABLE
>  	$(call if_changed,relocs_check)
>  	$(call if_changed,cp_vmlinux_relocs)
> -	$(call if_changed,relocs_strip)
> +	$(call if_changed,strip_relocs)
>  endif
>  
>  clean:
> diff --git a/arch/s390/Makefile.postlink b/arch/s390/Makefile.postlink
> index df82f5410769..1ae5478cd6ac 100644
> --- a/arch/s390/Makefile.postlink
> +++ b/arch/s390/Makefile.postlink
> @@ -11,6 +11,7 @@ __archpost:
>  
>  -include include/config/auto.conf
>  include $(srctree)/scripts/Kbuild.include
> +include $(srctree)/scripts/Makefile.lib
>  
>  CMD_RELOCS=arch/s390/tools/relocs
>  OUT_RELOCS = arch/s390/boot
> @@ -19,11 +20,6 @@ quiet_cmd_relocs = RELOCS  $(OUT_RELOCS)/relocs.S
>  	mkdir -p $(OUT_RELOCS); \
>  	$(CMD_RELOCS) $@ > $(OUT_RELOCS)/relocs.S
>  
> -quiet_cmd_strip_relocs = RSTRIP  $@
> -      cmd_strip_relocs = \
> -	$(OBJCOPY) --remove-section='.rel.*' --remove-section='.rel__*' \
> -		   --remove-section='.rela.*' --remove-section='.rela__*' $@
> -
>  vmlinux: FORCE
>  	$(call cmd,relocs)
>  	$(call cmd,strip_relocs)
> diff --git a/arch/x86/Makefile.postlink b/arch/x86/Makefile.postlink
> index fef2e977cc7d..8b8a68162c94 100644
> --- a/arch/x86/Makefile.postlink
> +++ b/arch/x86/Makefile.postlink
> @@ -11,6 +11,7 @@ __archpost:
>  
>  -include include/config/auto.conf
>  include $(srctree)/scripts/Kbuild.include
> +include $(srctree)/scripts/Makefile.lib
>  
>  CMD_RELOCS = arch/x86/tools/relocs
>  OUT_RELOCS = arch/x86/boot/compressed
> @@ -20,11 +21,6 @@ quiet_cmd_relocs = RELOCS  $(OUT_RELOCS)/$@.relocs
>  	$(CMD_RELOCS) $@ > $(OUT_RELOCS)/$@.relocs; \
>  	$(CMD_RELOCS) --abs-relocs $@
>  
> -quiet_cmd_strip_relocs = RSTRIP  $@
> -      cmd_strip_relocs = \
> -	$(OBJCOPY) --remove-section='.rel.*' --remove-section='.rel__*' \
> -		   --remove-section='.rela.*' --remove-section='.rela__*' $@
> -
>  # `@true` prevents complaint when there is nothing to be done
>  
>  vmlinux: FORCE
> diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
> index 7395200538da..f604f51d23ca 100644
> --- a/scripts/Makefile.lib
> +++ b/scripts/Makefile.lib
> @@ -374,6 +374,9 @@ quiet_cmd_ar = AR      $@
>  quiet_cmd_objcopy = OBJCOPY $@
>  cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
>  
> +quiet_cmd_strip_relocs = RSTRIP  $@
> +cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' $@
> +
>  # Gzip
>  # ---------------------------------------------------------------------------
>  
> -- 
> 2.47.1.688.g23fc6f90ad-goog
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Ard Biesheuvel Jan. 19, 2025, 5:15 p.m. UTC | #2 
On Thu, 16 Jan 2025 at 23:02, Charlie Jenkins <charlie@rivosinc.com> wrote:
>
> On Mon, Jan 13, 2025 at 04:53:07PM +0100, Ard Biesheuvel wrote:
> > From: Ard Biesheuvel <ardb@kernel.org>
> >
> > Due to the fact that runtime const ELF sections are named without a
> > leading period or double underscore, the RSTRIP logic that removes the
> > static RELA sections from vmlinux fails to identify them. This results
> > in a situation like below, where some sections that were supposed to get
> > removed are left behind.
> >
> >   [Nr] Name                              Type            Address          Off     Size   ES Flg Lk Inf Al
> >
> >   [58] runtime_shift_d_hash_shift        PROGBITS        ffffffff83500f50 2900f50 000014 00   A  0   0  1
> >   [59] .relaruntime_shift_d_hash_shift   RELA            0000000000000000 55b6f00 000078 18   I 70  58  8
> >   [60] runtime_ptr_dentry_hashtable      PROGBITS        ffffffff83500f68 2900f68 000014 00   A  0   0  1
> >   [61] .relaruntime_ptr_dentry_hashtable RELA            0000000000000000 55b6f78 000078 18   I 70  60  8
> >   [62] runtime_ptr_USER_PTR_MAX          PROGBITS        ffffffff83500f80 2900f80 000238 00   A  0   0  1
> >   [63] .relaruntime_ptr_USER_PTR_MAX     RELA            0000000000000000 55b6ff0 000d50 18   I 70  62  8
> >
> > So tweak the match expression to strip all sections starting with .rel.
> > While at it, consolidate the logic used by RISC-V, s390 and x86 into a
> > single shared Makefile library command.
> >
> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
> > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > Cc: linux-riscv@lists.infradead.org
> > Cc: linux-s390@vger.kernel.org
> > Cc: Ron Economos <re@w6rz.net>
> > Link: https://lore.kernel.org/all/CAHk-=wjk3ynjomNvFN8jf9A1k=qSc=JFF591W00uXj-qqNUxPQ@mail.gmail.com/
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > ---
> > v3: put back missing 'endif' to fix the RISC-V build
> > v2: add missing include of scripts/Makefile.lib
> >
> >  arch/riscv/Makefile.postlink |  8 ++------
> >  arch/s390/Makefile.postlink  |  6 +-----
> >  arch/x86/Makefile.postlink   |  6 +-----
> >  scripts/Makefile.lib         |  3 +++
> >  4 files changed, 7 insertions(+), 18 deletions(-)
> >
> > diff --git a/arch/riscv/Makefile.postlink b/arch/riscv/Makefile.postlink
> > index 829b9abc91f6..750d2784f69e 100644
> > --- a/arch/riscv/Makefile.postlink
> > +++ b/arch/riscv/Makefile.postlink
>
> When I compile x86 as relocatable I see the problem that you are fixing
> here, but I don't see it on riscv.

That is because riscv does not yet support optimized runtime
constants. Only arm64, s390 and x86 implement this today but I'd
expect other architectures to follow suit.

> It's probably better to keep around
> this code for riscv, but I don't think it even needs this stripping? I
> am adding Alex since he added this for riscv.
>

If vmlinux is linked with --emit-relocs, the stripping is probably
necessary, or you get a lot of metadata in vmlinux that is not needed
for debugging.

> Anyways this works as expected:
>
> Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
> Tested-by: Charlie Jenkins <charlie@rivosinc.com>
>

Thanks.
Alexander Gordeev Jan. 22, 2025, 4:49 p.m. UTC | #3 
On Mon, Jan 13, 2025 at 04:53:07PM +0100, Ard Biesheuvel wrote:

Hi Ard,

> Due to the fact that runtime const ELF sections are named without a
> leading period or double underscore, the RSTRIP logic that removes the
> static RELA sections from vmlinux fails to identify them. This results
> in a situation like below, where some sections that were supposed to get
> removed are left behind.
> 
>   [Nr] Name                              Type            Address          Off     Size   ES Flg Lk Inf Al
> 
>   [58] runtime_shift_d_hash_shift        PROGBITS        ffffffff83500f50 2900f50 000014 00   A  0   0  1
>   [59] .relaruntime_shift_d_hash_shift   RELA            0000000000000000 55b6f00 000078 18   I 70  58  8
>   [60] runtime_ptr_dentry_hashtable      PROGBITS        ffffffff83500f68 2900f68 000014 00   A  0   0  1
>   [61] .relaruntime_ptr_dentry_hashtable RELA            0000000000000000 55b6f78 000078 18   I 70  60  8
>   [62] runtime_ptr_USER_PTR_MAX          PROGBITS        ffffffff83500f80 2900f80 000238 00   A  0   0  1
>   [63] .relaruntime_ptr_USER_PTR_MAX     RELA            0000000000000000 55b6ff0 000d50 18   I 70  62  8
> 
> So tweak the match expression to strip all sections starting with .rel.
> While at it, consolidate the logic used by RISC-V, s390 and x86 into a
> single shared Makefile library command.

On s390 this is before:

  [32] .relaruntime[...] RELA             0000000000000000  13b3fe20
  [34] .relaruntime[...] RELA             0000000000000000  13b3fe98

This is after:

  [ 2] .rela.text        RELA             0000000000000000  13b3fe20
  [ 4] .rela.rodata      RELA             0000000000000000  142cf588
  [ 6] .rela__ksymtab    RELA             0000000000000000  142ece08
  [ 8] .rela__ksymt[...] RELA             0000000000000000  1433f200
  [13] .rela__param      RELA             0000000000000000  14432d40
  [15] .rela__modver     RELA             0000000000000000  14436358
  [17] .rela__ex_table   RELA             0000000000000000  14436538
  [20] .rela.data..[...] RELA             0000000000000000  14446228
  [22] .rela.data.rel.ro RELA             0000000000000000  144d9240
  [25] .rela.data        RELA             0000000000000000  14559148
  [27] .rela__bug_table  RELA             0000000000000000  145b4ae0
  [29] .rela.data.rel    RELA             0000000000000000  1461aab0
  [32] .rela.amode3[...] RELA             0000000000000000  146eb280
  [34] .rela.init.text   RELA             0000000000000000  146eb430
  [36] .rela.exit.text   RELA             0000000000000000  14750c20
  [38] .rela.altins[...] RELA             0000000000000000  14753d28
  [41] .rela.nospec[...] RELA             0000000000000000  1484ca58
  [43] .rela.nospec[...] RELA             0000000000000000  1487ef90
  [46] .rela.amode3[...] RELA             0000000000000000  14a0d168
  [48] .rela.amode3[...] RELA             0000000000000000  14a0d270
  [51] .rela.init.data   RELA             0000000000000000  14a0d330
  [53] .relaruntime[...] RELA             0000000000000000  14b5d6f0
  [55] .relaruntime[...] RELA             0000000000000000  14b5d768
  [57] .rela.data..[...] RELA             0000000000000000  14b5d7e0
  [61] .rela.debug_[...] RELA             0000000000000000  14b5d918
  [63] .rela.debug_info  RELA             0000000000000000  14b80478
  [66] .rela.debug_line  RELA             0000000000000000  250ef010
  [68] .rela.debug_frame RELA             0000000000000000  25123060
  [71] .rela.debug_loc   RELA             0000000000000000  253bb1a0
  [73] .rela.debug_[...] RELA             0000000000000000  298eb5a8

Thanks!
Alexander Gordeev Jan. 22, 2025, 5:22 p.m. UTC | #4 
On Wed, Jan 22, 2025 at 05:49:53PM +0100, Alexander Gordeev wrote:
> On Mon, Jan 13, 2025 at 04:53:07PM +0100, Ard Biesheuvel wrote:
> 
> Hi Ard,
> 
> > Due to the fact that runtime const ELF sections are named without a
> > leading period or double underscore, the RSTRIP logic that removes the
> > static RELA sections from vmlinux fails to identify them. This results
> > in a situation like below, where some sections that were supposed to get
> > removed are left behind.
> > 
> >   [Nr] Name                              Type            Address          Off     Size   ES Flg Lk Inf Al
> > 
> >   [58] runtime_shift_d_hash_shift        PROGBITS        ffffffff83500f50 2900f50 000014 00   A  0   0  1
> >   [59] .relaruntime_shift_d_hash_shift   RELA            0000000000000000 55b6f00 000078 18   I 70  58  8
> >   [60] runtime_ptr_dentry_hashtable      PROGBITS        ffffffff83500f68 2900f68 000014 00   A  0   0  1
> >   [61] .relaruntime_ptr_dentry_hashtable RELA            0000000000000000 55b6f78 000078 18   I 70  60  8
> >   [62] runtime_ptr_USER_PTR_MAX          PROGBITS        ffffffff83500f80 2900f80 000238 00   A  0   0  1
> >   [63] .relaruntime_ptr_USER_PTR_MAX     RELA            0000000000000000 55b6ff0 000d50 18   I 70  62  8
> > 
> > So tweak the match expression to strip all sections starting with .rel.
> > While at it, consolidate the logic used by RISC-V, s390 and x86 into a
> > single shared Makefile library command.
> 
> On s390 this is before:
> 
>   [32] .relaruntime[...] RELA             0000000000000000  13b3fe20
>   [34] .relaruntime[...] RELA             0000000000000000  13b3fe98
> 
> This is after:
> 
>   [ 2] .rela.text        RELA             0000000000000000  13b3fe20
...
>   [73] .rela.debug_[...] RELA             0000000000000000  298eb5a8

Sorry, I checked the wrong version. It works as expected.

Tested-by: Alexander Gordeev <agordeev@linux.ibm.com>
diff mbox series

Patch

diff --git a/arch/riscv/Makefile.postlink b/arch/riscv/Makefile.postlink
index 829b9abc91f6..750d2784f69e 100644
--- a/arch/riscv/Makefile.postlink
+++ b/arch/riscv/Makefile.postlink
@@ -10,6 +10,7 @@  __archpost:
 
 -include include/config/auto.conf
 include $(srctree)/scripts/Kbuild.include
+include $(srctree)/scripts/Makefile.lib
 
 quiet_cmd_relocs_check = CHKREL  $@
 cmd_relocs_check = 							\
@@ -19,11 +20,6 @@  ifdef CONFIG_RELOCATABLE
 quiet_cmd_cp_vmlinux_relocs = CPREL   vmlinux.relocs
 cmd_cp_vmlinux_relocs = cp vmlinux vmlinux.relocs
 
-quiet_cmd_relocs_strip = STRIPREL $@
-cmd_relocs_strip = $(OBJCOPY)   --remove-section='.rel.*'       \
-                                --remove-section='.rel__*'      \
-                                --remove-section='.rela.*'      \
-                                --remove-section='.rela__*' $@
 endif
 
 # `@true` prevents complaint when there is nothing to be done
@@ -33,7 +27,7 @@  vmlinux: FORCE
 ifdef CONFIG_RELOCATABLE
 	$(call if_changed,relocs_check)
 	$(call if_changed,cp_vmlinux_relocs)
-	$(call if_changed,relocs_strip)
+	$(call if_changed,strip_relocs)
 endif
 
 clean:
diff --git a/arch/s390/Makefile.postlink b/arch/s390/Makefile.postlink
index df82f5410769..1ae5478cd6ac 100644
--- a/arch/s390/Makefile.postlink
+++ b/arch/s390/Makefile.postlink
@@ -11,6 +11,7 @@  __archpost:
 
 -include include/config/auto.conf
 include $(srctree)/scripts/Kbuild.include
+include $(srctree)/scripts/Makefile.lib
 
 CMD_RELOCS=arch/s390/tools/relocs
 OUT_RELOCS = arch/s390/boot
@@ -19,11 +20,6 @@  quiet_cmd_relocs = RELOCS  $(OUT_RELOCS)/relocs.S
 	mkdir -p $(OUT_RELOCS); \
 	$(CMD_RELOCS) $@ > $(OUT_RELOCS)/relocs.S
 
-quiet_cmd_strip_relocs = RSTRIP  $@
-      cmd_strip_relocs = \
-	$(OBJCOPY) --remove-section='.rel.*' --remove-section='.rel__*' \
-		   --remove-section='.rela.*' --remove-section='.rela__*' $@
-
 vmlinux: FORCE
 	$(call cmd,relocs)
 	$(call cmd,strip_relocs)
diff --git a/arch/x86/Makefile.postlink b/arch/x86/Makefile.postlink
index fef2e977cc7d..8b8a68162c94 100644
--- a/arch/x86/Makefile.postlink
+++ b/arch/x86/Makefile.postlink
@@ -11,6 +11,7 @@  __archpost:
 
 -include include/config/auto.conf
 include $(srctree)/scripts/Kbuild.include
+include $(srctree)/scripts/Makefile.lib
 
 CMD_RELOCS = arch/x86/tools/relocs
 OUT_RELOCS = arch/x86/boot/compressed
@@ -20,11 +21,6 @@  quiet_cmd_relocs = RELOCS  $(OUT_RELOCS)/$@.relocs
 	$(CMD_RELOCS) $@ > $(OUT_RELOCS)/$@.relocs; \
 	$(CMD_RELOCS) --abs-relocs $@
 
-quiet_cmd_strip_relocs = RSTRIP  $@
-      cmd_strip_relocs = \
-	$(OBJCOPY) --remove-section='.rel.*' --remove-section='.rel__*' \
-		   --remove-section='.rela.*' --remove-section='.rela__*' $@
-
 # `@true` prevents complaint when there is nothing to be done
 
 vmlinux: FORCE
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 7395200538da..f604f51d23ca 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -374,6 +374,9 @@  quiet_cmd_ar = AR      $@
 quiet_cmd_objcopy = OBJCOPY $@
 cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
 
+quiet_cmd_strip_relocs = RSTRIP  $@
+cmd_strip_relocs = $(OBJCOPY) --remove-section='.rel*' $@
+
 # Gzip
 # ---------------------------------------------------------------------------