Subject: [PATCH v2 1/2] powerpc/vdso: Remove unused ENTRY in linker scripts

From: Nathan Chancellor <[email-masked]>
Date: Wed, 11 May 2022 11:50:00 -0700

When linking vdso{32,64}.so.dbg with ld.lld, there is a warning about
not finding _start for the starting address:

  ld.lld: warning: cannot find entry symbol _start; not setting start address
  ld.lld: warning: cannot find entry symbol _start; not setting start address

Looking at GCC + GNU ld, the entry point address is 0x0:

  $ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
  File: vdso32.so.dbg
    Entry point address:               0x0
  File: vdso64.so.dbg
    Entry point address:               0x0

This matches what ld.lld emits:

  $ powerpc64le-linux-gnu-readelf -p .comment vdso{32,64}.so.dbg

  File: vdso32.so.dbg

  String dump of section '.comment':
    [     0]  Linker: LLD 14.0.0
    [    14]  clang version 14.0.0 (Fedora 14.0.0-1.fc37)

  File: vdso64.so.dbg

  String dump of section '.comment':
    [     0]  Linker: LLD 14.0.0
    [    14]  clang version 14.0.0 (Fedora 14.0.0-1.fc37)

  $ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
  File: vdso32.so.dbg
    Entry point address:               0x0
  File: vdso64.so.dbg
    Entry point address:               0x0

Remove ENTRY to remove the warning, as it is unnecessary for the vDSO to
function correctly.

Reviewed-by: Nick Desaulniers <[email-masked]>
Reviewed-by: Alexey Kardashevskiy <[email-masked]>
Tested-by: Alexey Kardashevskiy <[email-masked]>
Signed-off-by: Nathan Chancellor <[email-masked]>
---
 arch/powerpc/kernel/vdso/vdso32.lds.S | 1 -
 arch/powerpc/kernel/vdso/vdso64.lds.S | 1 -
 2 files changed, 2 deletions(-)

diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 58e0099f70f4..e0d19d74455f 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -13,7 +13,6 @@ OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle")
 OUTPUT_FORMAT("elf32-powerpc", "elf32-powerpc", "elf32-powerpc")
 #endif
 OUTPUT_ARCH(powerpc:common)
-ENTRY(_start)
 
 SECTIONS
 {
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index 0288cad428b0..1a4a7bc4c815 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -13,7 +13,6 @@ OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle")
 OUTPUT_FORMAT("elf64-powerpc", "elf64-powerpc", "elf64-powerpc")
 #endif
 OUTPUT_ARCH(powerpc:common64)
-ENTRY(_start)
 
 SECTIONS
 {
-- 
2.36.1