[PATCH] powerpc/32: Add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly

[PATCH] powerpc/32: Add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly

[Mathieu Malaterre]

When both `CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y` and `CONFIG_UBSAN=y`
are set, link step typically produce numberous warnings about orphan
section:

  + powerpc-linux-gnu-ld -EB -m elf32ppc -Bstatic --orphan-handling=warn --build-id --gc-sections -X -o .tmp_vmlinux1 -T ./arch/powerpc/kernel/vmlinux.lds --who
  le-archive built-in.a --no-whole-archive --start-group lib/lib.a --end-group
  powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_data393' from `init/main.o' being placed in section `.data..Lubsan_data393'.
  powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_data394' from `init/main.o' being placed in section `.data..Lubsan_data394'.
  ...
  powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_type11' from `init/main.o' being placed in section `.data..Lubsan_type11'.
  powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_type12' from `init/main.o' being placed in section `.data..Lubsan_type12'.
  ...

This commit remove those warnings produced at W=1.

Link: https://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg135407.html
Suggested-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Mathieu Malaterre <malat@debian.org>
---
 arch/powerpc/kernel/vmlinux.lds.S | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 434581bcd5b4..1148c3c60c3b 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -308,6 +308,10 @@ SECTIONS
 #ifdef CONFIG_PPC32
 	.data : AT(ADDR(.data) - LOAD_OFFSET) {
 		DATA_DATA
+#ifdef CONFIG_UBSAN
+		*(.data..Lubsan_data*)
+		*(.data..Lubsan_type*)
+#endif
 		*(.data.rel*)
 		*(SDATA_MAIN)
 		*(.sdata2)
-- 
2.11.0

Re: powerpc/32: Add .data..Lubsan_data*/.data..Lubsan_type* sections explicitly

[Michael Ellerman]

On Wed, 2018-10-31 at 12:31:56 UTC, Mathieu Malaterre wrote:
> When both `CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y` and `CONFIG_UBSAN=y`
> are set, link step typically produce numberous warnings about orphan
> section:
> 
>   + powerpc-linux-gnu-ld -EB -m elf32ppc -Bstatic --orphan-handling=warn --build-id --gc-sections -X -o .tmp_vmlinux1 -T ./arch/powerpc/kernel/vmlinux.lds --who
>   le-archive built-in.a --no-whole-archive --start-group lib/lib.a --end-group
>   powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_data393' from `init/main.o' being placed in section `.data..Lubsan_data393'.
>   powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_data394' from `init/main.o' being placed in section `.data..Lubsan_data394'.
>   ...
>   powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_type11' from `init/main.o' being placed in section `.data..Lubsan_type11'.
>   powerpc-linux-gnu-ld: warning: orphan section `.data..Lubsan_type12' from `init/main.o' being placed in section `.data..Lubsan_type12'.
>   ...
> 
> This commit remove those warnings produced at W=1.
> 
> Link: https://www.mail-archive.com/linuxppc-dev@lists.ozlabs.org/msg135407.html
> Suggested-by: Nicholas Piggin <npiggin@gmail.com>
> Signed-off-by: Mathieu Malaterre <malat@debian.org>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/beba24ac59133cb36ecd03f9af9ccb

cheers