x86, bts: improve help text for BTS config
Improve the help text of the X86_PTRACE_BTS config.
Make X86_DS invisible and depend on X86_PTRACE_BTS.
Reported-by: Roland Dreier <rdreier@cisco.com>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 0b7c4a3..b815664 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -513,19 +513,19 @@
If unsure, say N.
config X86_DS
- bool "Debug Store support"
- default y
- help
- Add support for Debug Store.
- This allows the kernel to provide a memory buffer to the hardware
- to store various profiling and tracing events.
+ def_bool X86_PTRACE_BTS
+ depends on X86_DEBUGCTLMSR
config X86_PTRACE_BTS
- bool "ptrace interface to Branch Trace Store"
+ bool "Branch Trace Store"
default y
- depends on (X86_DS && X86_DEBUGCTLMSR)
+ depends on X86_DEBUGCTLMSR
help
- Add a ptrace interface to allow collecting an execution trace
- of the traced task.
- This collects control flow changes in a (cyclic) buffer and allows
- debuggers to fill in the gaps and show an execution trace of the debuggee.
+ This adds a ptrace interface to the hardware's branch trace store.
+
+ Debuggers may use it to collect an execution trace of the debugged
+ application in order to answer the question 'how did I get here?'.
+ Debuggers may trace user mode as well as kernel mode.
+
+ Say Y unless there is no application development on this machine
+ and you want to save a small amount of code size.