Messages in this thread Patch in this message | | | Date | Tue, 05 May 2020 15:16:35 +0200 | From | Thomas Gleixner <> | Subject | [patch V4 part 1 33/36] x86,tracing: Robustify ftrace_nmi_enter() |
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From: Peter Zijlstra <peterz@infradead.org>
ftrace_nmi_enter() trace_hwlat_callback() trace_clock_local() sched_clock() paravirt_sched_clock() native_sched_clock()
All must not be traced or kprobed, it will be called from do_debug() before the kprobe handler.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> --- arch/x86/include/asm/paravirt.h | 2 +- arch/x86/kernel/tsc.c | 4 ++-- include/linux/ftrace_irq.h | 4 ++-- kernel/trace/trace_clock.c | 3 ++- kernel/trace/trace_hwlat.c | 2 +- 5 files changed, 8 insertions(+), 7 deletions(-)
--- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -17,7 +17,7 @@ #include <linux/cpumask.h> #include <asm/frame.h> -static inline unsigned long long paravirt_sched_clock(void) +static __always_inline unsigned long long paravirt_sched_clock(void) { return PVOP_CALL0(unsigned long long, time.sched_clock); } --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -207,7 +207,7 @@ static void __init cyc2ns_init_secondary /* * Scheduler clock - returns current time in nanosec units. */ -u64 native_sched_clock(void) +noinstr u64 native_sched_clock(void) { if (static_branch_likely(&__use_tsc)) { u64 tsc_now = rdtsc(); @@ -240,7 +240,7 @@ u64 native_sched_clock_from_tsc(u64 tsc) /* We need to define a real function for sched_clock, to override the weak default version */ #ifdef CONFIG_PARAVIRT -unsigned long long sched_clock(void) +noinstr unsigned long long sched_clock(void) { return paravirt_sched_clock(); } --- a/include/linux/ftrace_irq.h +++ b/include/linux/ftrace_irq.h @@ -7,7 +7,7 @@ extern bool trace_hwlat_callback_enabled extern void trace_hwlat_callback(bool enter); #endif -static inline void ftrace_nmi_enter(void) +static __always_inline void ftrace_nmi_enter(void) { #ifdef CONFIG_HWLAT_TRACER if (trace_hwlat_callback_enabled) @@ -15,7 +15,7 @@ static inline void ftrace_nmi_enter(void #endif } -static inline void ftrace_nmi_exit(void) +static __always_inline void ftrace_nmi_exit(void) { #ifdef CONFIG_HWLAT_TRACER if (trace_hwlat_callback_enabled) --- a/kernel/trace/trace_clock.c +++ b/kernel/trace/trace_clock.c @@ -22,6 +22,7 @@ #include <linux/sched/clock.h> #include <linux/ktime.h> #include <linux/trace_clock.h> +#include <linux/kprobes.h> /* * trace_clock_local(): the simplest and least coherent tracing clock. @@ -29,7 +30,7 @@ * Useful for tracing that does not cross to other CPUs nor * does it go through idle events. */ -u64 notrace trace_clock_local(void) +u64 noinstr trace_clock_local(void) { u64 clock; --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -139,7 +139,7 @@ static void trace_hwlat_sample(struct hw #define init_time(a, b) (a = b) #define time_u64(a) a -void trace_hwlat_callback(bool enter) +noinstr void trace_hwlat_callback(bool enter) { if (smp_processor_id() != nmi_cpu) return;
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