summaryrefslogtreecommitdiffstats
path: root/arch/s390/kernel/Makefile
diff options
context:
space:
mode:
authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-03-14 13:44:25 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-04-17 14:07:28 +0200
commit1bca09f7144450989e409c82ff0db83dddf489ac (patch)
treeb09d99a3ae8d557b0ba50759814ee422e82788ab /arch/s390/kernel/Makefile
parent2b55732ad23fcc9eaec05acc21fd579ef8a9f38b (diff)
downloadlinux-1bca09f7144450989e409c82ff0db83dddf489ac.tar.bz2
s390/dumpstack: fix call chain walking
dumpstack() did not always print a sane callchain when being called. The reason is that show_trace() accessed register 15 directly to get the current stack pointer and passed that pointer to __show_trace() which expects a valid stack frame pointer as argument. However due to tail call optimization the stack frame may not exist anymore when __show_trace() gets called and therefore an invalid stack frame pointer gets passed. To prevent that disable tail call optimization for call chain walking functions. So move all the show_* functions to a dumpstack.c file like other architectures have it already and add a -fno-optimize-sibling-calls compile flag to both dumpstack.c and stacktrace.c to prevent tail call optimization. Fixes callchains that looked e.g. like this: [ 12.868258] Call Trace: [ 12.868262] ([<0000000000008000>] 0x8000) Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/Makefile')
-rw-r--r--arch/s390/kernel/Makefile17
1 files changed, 13 insertions, 4 deletions
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 2ac311ef5c9b..1386fcaf4ef6 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -14,16 +14,25 @@ endif
CFLAGS_smp.o := -Wno-nonnull
#
+# Disable tailcall optimizations for stack / callchain walking functions
+# since this might generate broken code when accessing register 15 and
+# passing its content to other functions.
+#
+CFLAGS_stacktrace.o += -fno-optimize-sibling-calls
+CFLAGS_dumpstack.o += -fno-optimize-sibling-calls
+
+#
# Pass UTS_MACHINE for user_regset definition
#
CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"'
CFLAGS_sysinfo.o += -Iinclude/math-emu -Iarch/s390/math-emu -w
-obj-y := bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o \
- processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o \
- debug.o irq.o ipl.o dis.o diag.o mem_detect.o sclp.o vdso.o \
- sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o
+obj-y := bitmap.o traps.o time.o process.o base.o early.o setup.o vtime.o
+obj-y += processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
+obj-y += debug.o irq.o ipl.o dis.o diag.o mem_detect.o sclp.o vdso.o
+obj-y += sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o
+obj-y += dumpstack.o
obj-y += $(if $(CONFIG_64BIT),entry64.o,entry.o)
obj-y += $(if $(CONFIG_64BIT),reipl64.o,reipl.o)