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authorHeiko Carstens <heiko.carstens@de.ibm.com>2016-02-09 12:58:54 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-02-23 08:56:20 +0100
commit758d39ebd3d5666edb3b1c339f7f138c349ff8bf (patch)
tree9315a925208d986101d59a10d3fd2754e99f3c0f /arch/s390/oprofile
parent3c2c126a675bd8a95d5ed186fe9cd788f438bff1 (diff)
s390/dumpstack: merge all four stack tracers
We have four different stack tracers of which three had bugs. So it's time to merge them to a single stack tracer which allows to specify a call back function which will be called for each step. This patch changes behavior a bit: - the "nosched" and "in_sched_functions" check within save_stack_trace_tsk did work only for the last stack frame within a context. Now it considers the check for each stack frame like it should. - both the oprofile variant and the perf_events variant did save a return address twice if a zero back chain was detected, which indicates an interrupt frame. The new dump_trace function will call the oprofile and perf_events backends with the psw address that is contained within the corresponding pt_regs structure instead. - the original show_trace and save_context_stack functions did already use the psw address of the pt_regs structure if a zero back chain was detected. However now we ignore the psw address if it is a user space address. After all we trace the kernel stack and not the user space stack. This way we also get rid of the garbage user space address in case of warnings and / or panic call traces. So this should make life easier since now there is only one stack tracer left which we can break. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/oprofile')
-rw-r--r--arch/s390/oprofile/Makefile2
-rw-r--r--arch/s390/oprofile/backtrace.c78
-rw-r--r--arch/s390/oprofile/init.c20
3 files changed, 19 insertions, 81 deletions
diff --git a/arch/s390/oprofile/Makefile b/arch/s390/oprofile/Makefile
index 1bd23017191e..496e4a7ee00e 100644
--- a/arch/s390/oprofile/Makefile
+++ b/arch/s390/oprofile/Makefile
@@ -6,5 +6,5 @@ DRIVER_OBJS = $(addprefix ../../../drivers/oprofile/, \
oprofilefs.o oprofile_stats.o \
timer_int.o )
-oprofile-y := $(DRIVER_OBJS) init.o backtrace.o
+oprofile-y := $(DRIVER_OBJS) init.o
oprofile-y += hwsampler.o
diff --git a/arch/s390/oprofile/backtrace.c b/arch/s390/oprofile/backtrace.c
deleted file mode 100644
index 1884e1759529..000000000000
--- a/arch/s390/oprofile/backtrace.c
+++ /dev/null
@@ -1,78 +0,0 @@
-/*
- * S390 Version
- * Copyright IBM Corp. 2005
- * Author(s): Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
- */
-
-#include <linux/oprofile.h>
-
-#include <asm/processor.h> /* for struct stack_frame */
-
-static unsigned long
-__show_trace(unsigned int *depth, unsigned long sp,
- unsigned long low, unsigned long high)
-{
- struct stack_frame *sf;
- struct pt_regs *regs;
-
- while (*depth) {
- if (sp < low || sp > high - sizeof(*sf))
- return sp;
- sf = (struct stack_frame *) sp;
- (*depth)--;
- oprofile_add_trace(sf->gprs[8]);
-
- /* Follow the backchain. */
- while (*depth) {
- low = sp;
- sp = sf->back_chain;
- if (!sp)
- break;
- if (sp <= low || sp > high - sizeof(*sf))
- return sp;
- sf = (struct stack_frame *) sp;
- (*depth)--;
- oprofile_add_trace(sf->gprs[8]);
-
- }
-
- if (*depth == 0)
- break;
-
- /* Zero backchain detected, check for interrupt frame. */
- sp = (unsigned long) (sf + 1);
- if (sp <= low || sp > high - sizeof(*regs))
- return sp;
- regs = (struct pt_regs *) sp;
- (*depth)--;
- oprofile_add_trace(sf->gprs[8]);
- low = sp;
- sp = regs->gprs[15];
- }
- return sp;
-}
-
-void s390_backtrace(struct pt_regs * const regs, unsigned int depth)
-{
- unsigned long head, frame_size;
- struct stack_frame* head_sf;
-
- if (user_mode(regs))
- return;
-
- frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
- head = regs->gprs[15];
- head_sf = (struct stack_frame*)head;
-
- if (!head_sf->back_chain)
- return;
-
- head = head_sf->back_chain;
-
- head = __show_trace(&depth, head,
- S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
- S390_lowcore.async_stack + frame_size);
-
- __show_trace(&depth, head, S390_lowcore.thread_info,
- S390_lowcore.thread_info + THREAD_SIZE);
-}
diff --git a/arch/s390/oprofile/init.c b/arch/s390/oprofile/init.c
index 9cfa2ffaa9d6..d85d1e6b1988 100644
--- a/arch/s390/oprofile/init.c
+++ b/arch/s390/oprofile/init.c
@@ -20,8 +20,6 @@
#include "../../../drivers/oprofile/oprof.h"
-extern void s390_backtrace(struct pt_regs * const regs, unsigned int depth);
-
#include "hwsampler.h"
#include "op_counter.h"
@@ -494,6 +492,24 @@ static void oprofile_hwsampler_exit(void)
hwsampler_shutdown();
}
+static int __s390_backtrace(void *data, unsigned long address)
+{
+ unsigned int *depth = data;
+
+ if (*depth == 0)
+ return 1;
+ (*depth)--;
+ oprofile_add_trace(address);
+ return 0;
+}
+
+static void s390_backtrace(struct pt_regs *regs, unsigned int depth)
+{
+ if (user_mode(regs))
+ return;
+ dump_trace(__s390_backtrace, &depth, NULL, regs->gprs[15]);
+}
+
int __init oprofile_arch_init(struct oprofile_operations *ops)
{
ops->backtrace = s390_backtrace;