A couple of Kconfig changes which make it much easier to switch to the new CONFIG_ORC_UNWINDER: 1) Remove x86 dependencies on CONFIG_FRAME_POINTER for lockdep, latencytop, and fault injection. x86 has a 'guess' unwinder which just scans the stack for kernel text addresses. It's not 100% accurate but in many cases it's good enough. This allows those users who don't want the text overhead of the frame pointer or ORC unwinders to still use these features. More importantly, this also makes it much more straightforward to disable frame pointers. 2) Make CONFIG_ORC_UNWINDER depend on !CONFIG_FRAME_POINTER. While it would be possible to have both enabled, it doesn't really make sense to do so. So enforce a sane configuration to prevent the user from making a dumb mistake. With these changes, when you disable CONFIG_FRAME_POINTER, "make oldconfig" will ask if you want to enable CONFIG_ORC_UNWINDER. Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> --- arch/x86/Kconfig.debug | 7 +++---- lib/Kconfig.debug | 6 +++--- 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index dc10ec6..268a318 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -357,7 +357,7 @@ config PUNIT_ATOM_DEBUG config ORC_UNWINDER bool "ORC unwinder" - depends on X86_64 + depends on X86_64 && !FRAME_POINTER select STACK_VALIDATION ---help--- This option enables the ORC (Oops Rewind Capability) unwinder for @@ -365,9 +365,8 @@ config ORC_UNWINDER a simplified version of the DWARF Call Frame Information standard. This unwinder is more accurate across interrupt entry frames than the - frame pointer unwinder. It can also enable a 5-10% performance - improvement across the entire kernel if CONFIG_FRAME_POINTER is - disabled. + frame pointer unwinder. It also enables a 5-10% performance + improvement across the entire kernel compared to frame pointers. Enabling this option will increase the kernel's runtime memory usage by roughly 2-4MB, depending on your kernel config. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index a7abffa..325c1c5 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1113,7 +1113,7 @@ config LOCKDEP bool depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT select STACKTRACE - select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE + select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE && !X86 select KALLSYMS select KALLSYMS_ALL @@ -1504,7 +1504,7 @@ config FAULT_INJECTION_STACKTRACE_FILTER depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT depends on !X86_64 select STACKTRACE - select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE + select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE && !X86 help Provide stacktrace filter for fault-injection capabilities @@ -1513,7 +1513,7 @@ config LATENCYTOP depends on DEBUG_KERNEL depends on STACKTRACE_SUPPORT depends on PROC_FS - select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC + select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86 select KALLSYMS select KALLSYMS_ALL select STACKTRACE -- 2.7.5 -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
