Re: [PATCH v4 2/2] powerpc: Uprobes port to powerpc

[Benjamin Herrenschmidt]

On Thu, 2012-08-23 at 11:02 +0530, Srikar Dronamraju wrote:
> > 
> 
> insn is updated/accessed in the arch independent code. Size of
> uprobe_opcode_t could be different for different archs.
> uprobe_opcode_t
> represents the size of the smallest breakpoint instruction for an
> arch.
> 
> Hence u8 works out the best. I know we could still use uprobe_opcode_t
> and achieve the same. In which case, we would have to interpret
> MAX_UINSN_BYTES differently. Do you see any advantages of using
> uprobe_opcode_t instead of u8 across archs?

But don't you actively rely on the fact that on powerpc, unlike x86, you
-can- atomically replace an instruction with a single 32-bit store ?

If you don't you should consider it, and that makes defining this as a
u8 array non-sensical (as is using memcpy)

Ben.


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