[PATCH] powerpc/vdso: Don't discard rela sections

After building the VDSO, there is a verification that it contains
no dynamic relocation, see commit aff69273af61 ("vdso: Improve
cmd_vdso_check to check all dynamic relocations").

This verification uses readelf -r and doesn't work if rela sections
are discarded.

Fixes: 8ad57add77d3 ("powerpc/build: vdso linker warning for orphan sections")
Signed-off-by: Christophe Leroy <redacted>
---
Was part of series "Wire up getrandom() vDSO implementation on powerpc" but
it is not directly related and should be fixed independantly as it may happen
already, for instance if the compiler wants rest_gpr30 instead of rest_gpr31.
---
 arch/powerpc/kernel/vdso/vdso32.lds.S | 4 +++-
 arch/powerpc/kernel/vdso/vdso64.lds.S | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 426e1ccc6971..8f57107000a2 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S

@@ -74,6 +74,8 @@ SECTIONS
 	.got		: { *(.got) }			:text
 	.plt		: { *(.plt) }
 
+	.rela.dyn	: { *(.rela .rela*) }
+
 	_end = .;
 	__end = .;
 	PROVIDE(end = .);

@@ -87,7 +89,7 @@ SECTIONS
 		*(.branch_lt)
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
 		*(.bss .sbss .dynbss .dynsbss)
-		*(.got1 .glink .iplt .rela*)
+		*(.got1 .glink .iplt)
 	}
 }
 

diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index bda6c8cdd459..400819258c06 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S

@@ -69,7 +69,7 @@ SECTIONS
 	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
 	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
 	.gcc_except_table : { *(.gcc_except_table) }
-	.rela.dyn ALIGN(8) : { *(.rela.dyn) }
+	.rela.dyn ALIGN(8) : { *(.rela .rela*) }
 
 	.got ALIGN(8)	: { *(.got .toc) }
 

@@ -86,7 +86,7 @@ SECTIONS
 		*(.data .data.* .gnu.linkonce.d.* .sdata*)
 		*(.bss .sbss .dynbss .dynsbss)
 		*(.opd)
-		*(.glink .iplt .plt .rela*)
+		*(.glink .iplt .plt)
 	}
 }
 

-- 
2.44.0

On Tue, 20 Aug 2024 13:28:07 +0200, Christophe Leroy wrote:

After building the VDSO, there is a verification that it contains
no dynamic relocation, see commit aff69273af61 ("vdso: Improve
cmd_vdso_check to check all dynamic relocations").

This verification uses readelf -r and doesn't work if rela sections
are discarded.

[...]

Applied to powerpc/fixes.

[1/1] powerpc/vdso: Don't discard rela sections
      https://git.kernel.org/powerpc/c/6114139c3bdde992f4a19264e4f9bfc100d8d776

cheers