Messages in this thread | | | Date | Sat, 28 Nov 2015 10:58:19 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH] arm64: ftrace: stop using kstop_machine to enable/disable tracing |
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On Sat, 28 Nov 2015 15:50:09 +0800 Li Bin <huawei.libin@huawei.com> wrote:
> On arm64, kstop_machine which is hugely disruptive to a running > system is not needed to convert nops to ftrace calls or back, > because that modifed code is a single 32bit instructions which > is impossible to cross cache (or page) boundaries, and the used str > instruction is single-copy atomic.
Is this really true? I thought that arm (and then perhaps arm64) has some 2 byte instructions. If that's the case it is very well possible that a 4 byte instruction can cross cache lines.
-- Steve
> > Cc: <stable@vger.kernel.org> # 3.18+ > Signed-off-by: Li Bin <huawei.libin@huawei.com> > --- > arch/arm64/kernel/ftrace.c | 5 +++++ > 1 files changed, 5 insertions(+), 0 deletions(-)
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