Messages in this thread | | | Subject | Re: [PATCH] ARM: ftrace: Ensure code modifications are synchronised across all cpus | From | "Jon Medhurst (Tixy)" <> | Date | Mon, 10 Dec 2012 11:04:05 +0000 |
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On Fri, 2012-12-07 at 19:02 +0000, Will Deacon wrote: > For ARMv7, there are small subsets of instructions for ARM and Thumb which > are guaranteed to be atomic wrt concurrent modification and execution of > the instruction stream between different processors: > > Thumb: The 16-bit encodings of the B, NOP, BKPT, and SVC instructions. > ARM: The B, BL, NOP, BKPT, SVC, HVC, and SMC instructions. >
So this means for things like kprobes which can modify arbitrary kernel code we are going to need to continue to always use some form of stop_the_whole_system() function?
Also, kprobes currently uses patch_text() which only uses stop_machine for Thumb2 instructions which straddle a word boundary, so this needs changing?
-- Tixy
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