x86: offer frame pointers in all build modes

CONFIG_FRAME_POINTERS=y results in much better debug info for the
kernel (clear and precise backtraces), with the only drawback being
a ~1% increase in kernel size.

So offer it unconditionally and enable it by default.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 862adb9..73f7fe8 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -27,6 +27,7 @@ config X86
        select HAVE_IOREMAP_PROT
        select HAVE_KPROBES
        select ARCH_WANT_OPTIONAL_GPIOLIB
+       select ARCH_WANT_FRAME_POINTERS
        select HAVE_KRETPROBES
        select HAVE_FTRACE_MCOUNT_RECORD
        select HAVE_DYNAMIC_FTRACE

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2e75478..2d0f144 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -566,14 +566,14 @@ config DEBUG_NOTIFIERS
 config FRAME_POINTER
        bool "Compile the kernel with frame pointers"
        depends on DEBUG_KERNEL && \
-               (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
-                AVR32 || SUPERH || BLACKFIN || MN10300)
-       default y if DEBUG_INFO && UML
-       help
-         If you say Y here the resulting kernel image will be slightly larger
-         and slower, but it might give very useful debugging information on
-         some architectures or if you use external debuggers.
-         If you don't debug the kernel, you can say N.
+               (CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
+                AVR32 || SUPERH || BLACKFIN || MN10300) || \
+               ARCH_WANT_FRAME_POINTERS
+       default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
+       help
+         If you say Y here the resulting kernel image will be slightly
+         larger and slower, but it gives very useful debugging information
+         in case of kernel bugs. (precise oopses/stacktraces/warnings)
 
 config BOOT_PRINTK_DELAY
        bool "Delay each boot printk message by N milliseconds"