RE: [PATCH 1/1] x86/vdso: use the right GDT_ENTRY_CPUNODE for 32-bit getcpu() on 64-bit kernel

[Li, Xin3]

> > I think I'd much rather if we define all of the GDT_ENTRY_* macros in
> > *one* place, then make that *one* place depend on BUILD_VDSO32_64.
> 
> Sounds a better way, let me try.

Hi Dave,

I tried the following patch, and it works:

diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 794f69625780..9d6411c65920 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -56,7 +56,7 @@

 #define GDT_ENTRY_INVALID_SEG  0

-#ifdef CONFIG_X86_32
+#if defined(CONFIG_X86_32) && !defined(BUILD_VDSO32_64)
 /*
  * The layout of the per-CPU GDT under Linux:
  *


It's simpler and looks reasonable to me. Is it what you suggested?

Thanks!
  Xin


> 
> > Also, about the *silent* failure...  Do we not have a selftest for this
> somewhere?
> 
> When lsl is used, we should check ZF which indicates whether the segment limit is
> loaded successfully.  Seems we need to refactor vdso_read_cpunode() a bit.
> 
>   Xin