Re: [PATCH] powerpc/vdso: Fix build of VDSO32 with pcrel

[Christophe Leroy]

Hi Maddy,

ping ?

Christophe

Le 12/05/2025 à 20:14, Christophe Leroy a écrit :

Building vdso32 on power10 with pcrel leads to following errors:

          VDSO32A arch/powerpc/kernel/vdso/gettimeofday-32.o
        arch/powerpc/kernel/vdso/gettimeofday.S: Assembler messages:
        arch/powerpc/kernel/vdso/gettimeofday.S:40: Error: syntax error; found 
`@', expected `,'
        arch/powerpc/kernel/vdso/gettimeofday.S:71:  Info: macro invoked from 
here
        arch/powerpc/kernel/vdso/gettimeofday.S:40: Error: junk at end of line: 
`@notoc'
        arch/powerpc/kernel/vdso/gettimeofday.S:71:  Info: macro invoked from 
here
         ...
        make[2]: *** [arch/powerpc/kernel/vdso/Makefile:85: 
arch/powerpc/kernel/vdso/gettimeofday-32.o] Error 1
        make[1]: *** [arch/powerpc/Makefile:388: vdso_prepare] Error 2

Once the above is fixed, the following happens:

          VDSO32C arch/powerpc/kernel/vdso/vgettimeofday-32.o
        cc1: error: '-mpcrel' requires '-mcmodel=medium'
        make[2]: *** [arch/powerpc/kernel/vdso/Makefile:89: 
arch/powerpc/kernel/vdso/vgettimeofday-32.o] Error 1
        make[1]: *** [arch/powerpc/Makefile:388: vdso_prepare] Error 2
        make: *** [Makefile:251: __sub-make] Error 2

Make sure pcrel version of CFUNC() macro is used only for powerpc64
builds and remove -mpcrel for powerpc32 builds.

Fixes: 7e3a68be42e1 ("powerpc/64: vmlinux support building with PCREL 
addresing")
Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
---
  arch/powerpc/include/asm/ppc_asm.h | 2 +-
  arch/powerpc/kernel/vdso/Makefile  | 2 +-
  2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/ppc_asm.h 
b/arch/powerpc/include/asm/ppc_asm.h
index 02897f4b0dbf..b891910fce8a 100644
--- a/arch/powerpc/include/asm/ppc_asm.h
+++ b/arch/powerpc/include/asm/ppc_asm.h
@@ -183,7 +183,7 @@
  /*
   * Used to name C functions called from asm
   */
-#ifdef CONFIG_PPC_KERNEL_PCREL
+#if defined(__powerpc64__) && defined(CONFIG_PPC_KERNEL_PCREL)
  #define CFUNC(name) name@notoc
  #else
  #define CFUNC(name) name
diff --git a/arch/powerpc/kernel/vdso/Makefile 
b/arch/powerpc/kernel/vdso/Makefile
index e8824f933326..8834dfe9d727 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -53,7 +53,7 @@ ldflags-$(CONFIG_LD_ORPHAN_WARN) += 
-Wl,--orphan-handling=$(CONFIG_LD_ORPHAN_WAR
  ldflags-y += $(filter-out $(CC_AUTO_VAR_INIT_ZERO_ENABLER) $(CC_FLAGS_FTRACE) 
-Wa$(comma)%, $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS))

CC32FLAGS := -m32

-CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc
+CC32FLAGSREMOVE := -mcmodel=medium -mabi=elfv1 -mabi=elfv2 -mcall-aixdesc 
-mpcrel
  ifdef CONFIG_CC_IS_CLANG
  # This flag is supported by clang for 64-bit but not 32-bit so it will cause
  # an unused command line flag warning for this file.