Re: [PATCH 1/2] uprobes: Pass probed vaddr to arch_uprobe_analyze_insn()

* Oleg Nesterov [off-list ref] [2012-06-06 17:08:48]:

On 06/06, Ananth N Mavinakayanahalli wrote:

quoted

From: Ananth N Mavinakayanahalli <redacted>

On RISC architectures like powerpc, instructions are fixed size.
Instruction analysis on such platforms is just a matter of (insn % 4).
Pass the vaddr at which the uprobe is to be inserted so that
arch_uprobe_analyze_insn() can flag misaligned registration requests.

And the next patch checks "vaddr & 0x03".

But why do you need this new arg? arch_uprobe_analyze_insn() could
check "container_of(auprobe, struct uprobe, arch)->offset & 0x3" with
the same effect, no? vm_start/vm_pgoff are obviously page-aligned.

We cant use container_of because we moved the definition for struct
uprobe to kernel/events/uprobe.c. This was possible before when struct
uprobe definition was in include/uprobes.h 

-- 
Thanks and Regards
Srikar