Re: [PATCH V3 3/3] powerpc, ptrace: Enable support for miscellaneous registers

[Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>]

Anshuman Khandual [khandual@linux.vnet.ibm.com] wrote:
| On 08/28/2014 03:05 AM, Sukadev Bhattiprolu wrote:
| >=20
| > I see these in  arch/powerpc/include/asm/processor.h
| >=20
| > #ifdef CONFIG_PPC64
| >         unsigned long   dscr;
| >         int             dscr_inherit;
| >         unsigned long   ppr;    /* used to save/restore SMT priority */
| > #endif
| >=20
| > where there is an 'int' between ppr and dscr. So, should one of
| > the above sizeof(unsigned long) be changed to sizeof(int) ?
|=20
| Right, I understand that but strangely I get this compile time error
| when it is changed to sizeof(int).
|=20
|  error: call to =E2=80=98__compiletime_assert_1350=E2=80=99 declared with=
 attribute error:
|   BUILD_BUG_ON failed: TSO(dscr) + sizeof(unsigned long) + sizeof(int) !=
=3D TSO(ppr)
|   BUILD_BUG_ON(TSO(dscr) + sizeof(unsigned long) + sizeof(int) !=3D TSO(p=
pr));
|=20
| may be I am missing something here.

I guess there is a 4-byte padding after dscr_inherit. We could make that
explicit by adding a field or just go with the sizeof(unsigned long).

Thanks,

Sukadev