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Subject[PATCH] arm64: ftrace: stop using kstop_machine to enable/disable tracing
Date
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.

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(-)

diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index c851be7..9669b33 100644
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -93,6 +93,11 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
return ftrace_modify_code(pc, old, new, true);
}

+void arch_ftrace_update_code(int command)
+{
+ ftrace_modify_all_code(command);
+}
+
int __init ftrace_dyn_arch_init(void)
{
return 0;
--
1.7.1


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