diff mbox series

[v2] kbuild: Strip runtime const RELA sections correctly

Message ID 20250113143222.1868692-2-ardb+git@google.com (mailing list archive)
State Superseded
Headers show
Series [v2] kbuild: Strip runtime const RELA sections correctly | expand

Commit Message

Ard Biesheuvel Jan. 13, 2025, 2:32 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
Link: https://lore.kernel.org/all/CAHk-=wjk3ynjomNvFN8jf9A1k=qSc=JFF591W00uXj-qqNUxPQ@mail.gmail.com/
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
v2: add missing include of scripts/Makefile.lib

 arch/riscv/Makefile.postlink | 10 ++--------
 arch/s390/Makefile.postlink  |  6 +-----
 arch/x86/Makefile.postlink   |  6 +-----
 scripts/Makefile.lib         |  3 +++
 4 files changed, 7 insertions(+), 18 deletions(-)

Comments

Ron Economos Jan. 13, 2025, 3:07 p.m. UTC | #1 
On 1/13/25 06:32, 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
> Link: https://lore.kernel.org/all/CAHk-=wjk3ynjomNvFN8jf9A1k=qSc=JFF591W00uXj-qqNUxPQ@mail.gmail.com/
> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> ---
> v2: add missing include of scripts/Makefile.lib
>
>   arch/riscv/Makefile.postlink | 10 ++--------
>   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
> @@ -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 = 							\
> @@ -19,13 +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
>   
>   vmlinux: FORCE
> @@ -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
>   # ---------------------------------------------------------------------------
>   

Fails on RISC-V with:

   LD      vmlinux
   NM      System.map
   SORTTAB vmlinux
arch/riscv/Makefile.postlink:41: *** missing 'endif'.  Stop.
make[2]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 2
make[2]: *** Deleting file 'vmlinux'
make[1]: *** [/home/ubuntu/xfer/linux/Makefile:1167: vmlinux] Error 2
make: *** [Makefile:224: __sub-make] Error 2
Command exited with non-zero status 2

I think you need to put that deleted "endif" back in.
Ard Biesheuvel Jan. 13, 2025, 3:09 p.m. UTC | #2 
On Mon, 13 Jan 2025 at 16:07, Ron Economos <re@w6rz.net> wrote:
>
> On 1/13/25 06:32, 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
> > Link: https://lore.kernel.org/all/CAHk-=wjk3ynjomNvFN8jf9A1k=qSc=JFF591W00uXj-qqNUxPQ@mail.gmail.com/
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > ---
> > v2: add missing include of scripts/Makefile.lib
> >
> >   arch/riscv/Makefile.postlink | 10 ++--------
> >   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
> > @@ -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 =                                                  \
> > @@ -19,13 +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
> >
> >   vmlinux: FORCE
> > @@ -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
> >   # ---------------------------------------------------------------------------
> >
>
> Fails on RISC-V with:
>
>    LD      vmlinux
>    NM      System.map
>    SORTTAB vmlinux
> arch/riscv/Makefile.postlink:41: *** missing 'endif'.  Stop.
> make[2]: *** [scripts/Makefile.vmlinux:34: vmlinux] Error 2
> make[2]: *** Deleting file 'vmlinux'
> make[1]: *** [/home/ubuntu/xfer/linux/Makefile:1167: vmlinux] Error 2
> make: *** [Makefile:224: __sub-make] Error 2
> Command exited with non-zero status 2
>
> I think you need to put that deleted "endif" back in.
>

Yeah, sorry about that, and thanks for testing.
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 = 							\
@@ -19,13 +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
 
 vmlinux: FORCE
@@ -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
 # ---------------------------------------------------------------------------