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authorSteven Rostedt <rostedt@goodmis.org>2008-10-24 09:42:59 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-31 00:03:26 +0100
commit9244489a7b69fe0746dc7cb3957f02e05bd1ceb0 (patch)
treef0fb4a422667f67e7e3ac587bbbc6b03fa83756a
parentf3384b28a05624783b53836ccfed95ecde66a7ad (diff)
ftrace: handle archs that do not support irqs_disabled_flags
Impact: build fix on non-lockdep architectures Some architectures do not support a way to read the irq flags that is set from "local_irq_save(flags)" to determine if interrupts were disabled or enabled. Ftrace uses this information to display to the user if the trace occurred with interrupts enabled or disabled. Besides the fact that those archs that do not support this will fail to compile, unless they fix it, we do not want to have the trace simply say interrupts were not disabled or they were enabled, without knowing the real answer. This patch adds a 'X' in the output to let the user know that the architecture they are running on does not support a way for the tracer to determine if interrupts were enabled or disabled. It also lets those same archs compile with tracing enabled. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--Documentation/ftrace.txt3
-rw-r--r--kernel/trace/trace.c7
-rw-r--r--kernel/trace/trace.h20
3 files changed, 20 insertions, 10 deletions
diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt
index d330fe3103da..ea5a827395dd 100644
--- a/Documentation/ftrace.txt
+++ b/Documentation/ftrace.txt
@@ -291,6 +291,9 @@ explains which is which.
CPU#: The CPU which the process was running on.
irqs-off: 'd' interrupts are disabled. '.' otherwise.
+ Note: If the architecture does not support a way to
+ read the irq flags variable, an 'X' will always
+ be printed here.
need-resched: 'N' task need_resched is set, '.' otherwise.
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a610ca771558..8a499e2adaec 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -656,7 +656,11 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
entry->preempt_count = pc & 0xff;
entry->pid = (tsk) ? tsk->pid : 0;
entry->flags =
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
+#else
+ TRACE_FLAG_IRQS_NOSUPPORT |
+#endif
((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
@@ -1244,7 +1248,8 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
trace_seq_printf(s, "%3d", cpu);
trace_seq_printf(s, "%c%c",
- (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
+ (entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
+ (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6889ca48f1f1..8465ad052707 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -120,18 +120,20 @@ struct trace_boot {
/*
* trace_flag_type is an enumeration that holds different
* states when a trace occurs. These are:
- * IRQS_OFF - interrupts were disabled
- * NEED_RESCED - reschedule is requested
- * HARDIRQ - inside an interrupt handler
- * SOFTIRQ - inside a softirq handler
- * CONT - multiple entries hold the trace item
+ * IRQS_OFF - interrupts were disabled
+ * IRQS_NOSUPPORT - arch does not support irqs_disabled_flags
+ * NEED_RESCED - reschedule is requested
+ * HARDIRQ - inside an interrupt handler
+ * SOFTIRQ - inside a softirq handler
+ * CONT - multiple entries hold the trace item
*/
enum trace_flag_type {
TRACE_FLAG_IRQS_OFF = 0x01,
- TRACE_FLAG_NEED_RESCHED = 0x02,
- TRACE_FLAG_HARDIRQ = 0x04,
- TRACE_FLAG_SOFTIRQ = 0x08,
- TRACE_FLAG_CONT = 0x10,
+ TRACE_FLAG_IRQS_NOSUPPORT = 0x02,
+ TRACE_FLAG_NEED_RESCHED = 0x04,
+ TRACE_FLAG_HARDIRQ = 0x08,
+ TRACE_FLAG_SOFTIRQ = 0x10,
+ TRACE_FLAG_CONT = 0x20,
};
#define TRACE_BUF_SIZE 1024