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

From: Sukadev Bhattiprolu
Date: Wed Oct 08 2014 - 13:17:29 EST


Anshuman Khandual [khandual@xxxxxxxxxxxxxxxxxx] wrote:
| On 08/28/2014 03:05 AM, Sukadev Bhattiprolu wrote:
| >
| > I see these in arch/powerpc/include/asm/processor.h
| >
| > #ifdef CONFIG_PPC64
| > unsigned long dscr;
| > int dscr_inherit;
| > unsigned long ppr; /* used to save/restore SMT priority */
| > #endif
| >
| > where there is an 'int' between ppr and dscr. So, should one of
| > the above sizeof(unsigned long) be changed to sizeof(int) ?
|
| Right, I understand that but strangely I get this compile time error
| when it is changed to sizeof(int).
|
| error: call to â__compiletime_assert_1350â declared with attribute error:
| BUILD_BUG_ON failed: TSO(dscr) + sizeof(unsigned long) + sizeof(int) != TSO(ppr)
| BUILD_BUG_ON(TSO(dscr) + sizeof(unsigned long) + sizeof(int) != TSO(ppr));
|
| 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

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