tracing: Remove TRACE_FLAG_IRQS_NOSUPPORT

It was possible to enable tracing with no IRQ tracing support. The
tracing infrastructure would then record TRACE_FLAG_IRQS_NOSUPPORT as
the only tracing flag and show an 'X' in the output.

The last user of this feature was PPC32 which managed to implement it
during PowerPC merge in 2009. Since then, it was unused and the PPC32
dependency was finally removed in commit 0ea5ee035133a ("tracing: Remove
PPC32 wart from config TRACING_SUPPORT").
Since the PowerPC merge the code behind !CONFIG_TRACE_IRQFLAGS_SUPPORT
with TRACING enabled can no longer be selected used and the 'X' is not
displayed or recorded.

Remove the CONFIG_TRACE_IRQFLAGS_SUPPORT from the tracing code. Remove
TRACE_FLAG_IRQS_NOSUPPORT.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/20241022110112.XJI8I9T2@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/Documentation/trace/ftrace.rst b/Documentation/trace/ftrace.rst
index 4073ca48af4ad2639c2289eb28c691a5c3538850..74d5bd801b1a8e99513cd7a978dcea716c6496a9 100644 (file)
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -1031,9 +1031,6 @@ explains which is which.
   CPU#: The CPU which the process was running on.
 
   irqs-off: 'd' interrupts are disabled. '.' otherwise.
-       .. caution:: If the architecture does not support a way to
-               read the irq flags variable, an 'X' will always
-               be printed here.
 
   need-resched:
        - 'N' both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED is set,

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index f8f2e52653df33ba7e1bc68e9ba3c5c102c7eddc..016b29a56c875f9e97bea918b0f229d95891a77d 100644 (file)
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -184,7 +184,6 @@ unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status);
 
 enum trace_flag_type {
        TRACE_FLAG_IRQS_OFF             = 0x01,
-       TRACE_FLAG_IRQS_NOSUPPORT       = 0x02,
        TRACE_FLAG_NEED_RESCHED         = 0x04,
        TRACE_FLAG_HARDIRQ              = 0x08,
        TRACE_FLAG_SOFTIRQ              = 0x10,
@@ -193,7 +192,6 @@ enum trace_flag_type {
        TRACE_FLAG_BH_OFF               = 0x80,
 };
 
-#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
 static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
 {
        unsigned int irq_status = irqs_disabled_flags(irqflags) ?
@@ -207,17 +205,6 @@ static inline unsigned int tracing_gen_ctx(void)
        local_save_flags(irqflags);
        return tracing_gen_ctx_flags(irqflags);
 }
-#else
-
-static inline unsigned int tracing_gen_ctx_flags(unsigned long irqflags)
-{
-       return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
-}
-static inline unsigned int tracing_gen_ctx(void)
-{
-       return tracing_gen_ctx_irq_test(TRACE_FLAG_IRQS_NOSUPPORT);
-}
-#endif
 
 static inline unsigned int tracing_gen_ctx_dec(void)
 {

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 868f2f912f2809e9ec63537e4da878958bef1b99..2ee6613dce6dcead6237bb6c290b985080bdad70 100644 (file)
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -460,7 +460,6 @@ int trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry)
                (entry->flags & TRACE_FLAG_IRQS_OFF && bh_off) ? 'D' :
                (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
                bh_off ? 'b' :
-               (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' :
                '.';
 
        switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |