To fully isolate #DB and #BP from instrumentable code it's necessary to avoid invoking the hardware latency tracer on nmi_enter/exit().
Provide nmi_enter/exit() variants which are not invoking the hardware latency tracer. That allows to put calls explicitely into the call sites outside of the kprobe handling. Signed-off-by: Thomas Gleixner <[email protected]> --- V5: New patch --- include/linux/hardirq.h | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -77,28 +77,38 @@ extern void irq_exit(void); /* * nmi_enter() can nest up to 15 times; see NMI_BITS. */ -#define nmi_enter() \ +#define nmi_enter_notrace() \ do { \ arch_nmi_enter(); \ printk_nmi_enter(); \ lockdep_off(); \ - ftrace_nmi_enter(); \ BUG_ON(in_nmi() == NMI_MASK); \ __preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \ rcu_nmi_enter(); \ lockdep_hardirq_enter(); \ } while (0) -#define nmi_exit() \ +#define nmi_enter() \ + do { \ + nmi_enter_notrace(); \ + ftrace_nmi_enter(); \ + } while (0) + +#define nmi_exit_notrace() \ do { \ lockdep_hardirq_exit(); \ rcu_nmi_exit(); \ BUG_ON(!in_nmi()); \ __preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET); \ - ftrace_nmi_exit(); \ lockdep_on(); \ printk_nmi_exit(); \ arch_nmi_exit(); \ } while (0) +#define nmi_exit() \ + do { \ + ftrace_nmi_exit(); \ + nmi_exit_notrace(); \ + } while (0) + #endif /* LINUX_HARDIRQ_H */
