From 7563dc64585324f443f5ac107eb6d89ee813a2d2 Mon Sep 17 00:00:00 2001 From: Tony Breeds <tony@bakeyournoodle.com> Date: Tue, 2 Sep 2008 16:50:38 +1000 Subject: [PATCH] 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> --- arch/powerpc/Makefile | 5 +++++ arch/powerpc/kernel/Makefile | 7 ++++--- arch/powerpc/platforms/powermac/Makefile | 2 +- lib/Kconfig.debug | 6 +++--- 4 files changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 9155c9312c1..c6be19e9cea 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -116,6 +116,11 @@ ifeq ($(CONFIG_6xx),y) KBUILD_CFLAGS += -mcpu=powerpc endif +# Work around a gcc code-gen bug with -fno-omit-frame-pointer. +ifeq ($(CONFIG_FTRACE),y) +KBUILD_CFLAGS += -mno-sched-epilog +endif + cpu-as-$(CONFIG_4xx) += -Wa,-m405 cpu-as-$(CONFIG_6xx) += -Wa,-maltivec cpu-as-$(CONFIG_POWER4) += -Wa,-maltivec diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 64f5948ebc9..946daea780f 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -14,12 +14,13 @@ endif ifdef CONFIG_FTRACE # Do not trace early boot code -CFLAGS_REMOVE_cputable.o = -pg -CFLAGS_REMOVE_prom_init.o = -pg +CFLAGS_REMOVE_cputable.o = -pg -mno-sched-epilog +CFLAGS_REMOVE_prom_init.o = -pg -mno-sched-epilog +CFLAGS_REMOVE_btext.o = -pg -mno-sched-epilog ifdef CONFIG_DYNAMIC_FTRACE # dynamic ftrace setup. -CFLAGS_REMOVE_ftrace.o = -pg +CFLAGS_REMOVE_ftrace.o = -pg -mno-sched-epilog endif endif diff --git a/arch/powerpc/platforms/powermac/Makefile b/arch/powerpc/platforms/powermac/Makefile index 58ecdd72630..be60d64be7a 100644 --- a/arch/powerpc/platforms/powermac/Makefile +++ b/arch/powerpc/platforms/powermac/Makefile @@ -2,7 +2,7 @@ CFLAGS_bootx_init.o += -fPIC ifdef CONFIG_FTRACE # Do not trace early boot code -CFLAGS_REMOVE_bootx_init.o = -pg +CFLAGS_REMOVE_bootx_init.o = -pg -mno-sched-epilog endif obj-y += pic.o setup.o time.o feature.o pci.o \ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8b5a7d304a5..0b504814e37 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -394,7 +394,7 @@ config LOCKDEP 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 @@ config FAULT_INJECTION_STACKTRACE_FILTER 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 -- 2.41.3