5.15-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt (VMware) rostedt@goodmis.org
[ Upstream commit 91ebe8bcbff9d2ff21303e73bf7434f39a98b255 ]
Now that there are three different instances of doing the addition trick to the preempt_count() and NMI_MASK, HARDIRQ_MASK and SOFTIRQ_OFFSET macros, it deserves a helper function defined in the preempt.h header.
Add the interrupt_context_level() helper and replace the three instances that do that logic with it.
Link: https://lore.kernel.org/all/20211015142541.4badd8a9@gandalf.local.home/
Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Stable-dep-of: 87c3a5893e86 ("sched/core: Optimize in_task() and in_interrupt() a bit") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/preempt.h | 21 +++++++++++++++++++++ include/linux/trace_recursion.h | 7 +------ kernel/events/internal.h | 7 +------ kernel/trace/ring_buffer.c | 7 +------ 4 files changed, 24 insertions(+), 18 deletions(-)
diff --git a/include/linux/preempt.h b/include/linux/preempt.h index 4d244e295e855..b32e3dabe28bd 100644 --- a/include/linux/preempt.h +++ b/include/linux/preempt.h @@ -77,6 +77,27 @@ /* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */ #include <asm/preempt.h>
+/** + * interrupt_context_level - return interrupt context level + * + * Returns the current interrupt context level. + * 0 - normal context + * 1 - softirq context + * 2 - hardirq context + * 3 - NMI context + */ +static __always_inline unsigned char interrupt_context_level(void) +{ + unsigned long pc = preempt_count(); + unsigned char level = 0; + + level += !!(pc & (NMI_MASK)); + level += !!(pc & (NMI_MASK | HARDIRQ_MASK)); + level += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); + + return level; +} + #define nmi_count() (preempt_count() & NMI_MASK) #define hardirq_count() (preempt_count() & HARDIRQ_MASK) #ifdef CONFIG_PREEMPT_RT diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h index 00acd7dca7a7d..816d7a0d2aad6 100644 --- a/include/linux/trace_recursion.h +++ b/include/linux/trace_recursion.h @@ -116,12 +116,7 @@ enum {
static __always_inline int trace_get_context_bit(void) { - unsigned long pc = preempt_count(); - unsigned char bit = 0; - - bit += !!(pc & (NMI_MASK)); - bit += !!(pc & (NMI_MASK | HARDIRQ_MASK)); - bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); + unsigned char bit = interrupt_context_level();
return TRACE_CTX_NORMAL - bit; } diff --git a/kernel/events/internal.h b/kernel/events/internal.h index aa23ffdaf819f..5150d5f84c033 100644 --- a/kernel/events/internal.h +++ b/kernel/events/internal.h @@ -210,12 +210,7 @@ DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user)
static inline int get_recursion_context(int *recursion) { - unsigned int pc = preempt_count(); - unsigned char rctx = 0; - - rctx += !!(pc & (NMI_MASK)); - rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK)); - rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); + unsigned char rctx = interrupt_context_level();
if (recursion[rctx]) return -1; diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c3c9960c9f27b..a930a9d7d834d 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3249,12 +3249,7 @@ static __always_inline int trace_recursive_lock(struct ring_buffer_per_cpu *cpu_buffer) { unsigned int val = cpu_buffer->current_context; - unsigned long pc = preempt_count(); - int bit = 0; - - bit += !!(pc & (NMI_MASK)); - bit += !!(pc & (NMI_MASK | HARDIRQ_MASK)); - bit += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); + int bit = interrupt_context_level();
bit = RB_CTX_NORMAL - bit;