powerpc: Work around gcc's -fno-omit-frame-pointer bug
This bug is causing random crashes
(http://bugzilla.kernel.org/show_bug.cgi?id=11414).
-fno-omit-frame-pointer is only needed on powerpc when -pg is also
supplied, and there is a gcc bug that causes incorrect code generation
on 32-bit powerpc when -fno-omit-frame-pointer is used---it uses stack
locations below the stack pointer, which is not allowed by the ABI
because those locations can and sometimes do get corrupted by an
interrupt.
This ensures that CONFIG_FRAME_POINTER is only selected by ftrace.
When CONFIG_FTRACE is enabled we also pass -mno-sched-epilog to work
around the gcc codegen bug.
Patch based on work by:
Andreas Schwab <schwab@suse.de>
Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8b5a7d3..0b50481 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -394,7 +394,7 @@
bool
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
select STACKTRACE
- select FRAME_POINTER if !X86 && !MIPS
+ select FRAME_POINTER if !X86 && !MIPS && !PPC
select KALLSYMS
select KALLSYMS_ALL
@@ -676,13 +676,13 @@
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
depends on !X86_64
select STACKTRACE
- select FRAME_POINTER
+ select FRAME_POINTER if !PPC
help
Provide stacktrace filter for fault-injection capabilities
config LATENCYTOP
bool "Latency measuring infrastructure"
- select FRAME_POINTER if !MIPS
+ select FRAME_POINTER if !MIPS && !PPC
select KALLSYMS
select KALLSYMS_ALL
select STACKTRACE