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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/kernel/perf_event.c
parents390/mm: remove unnecessary indirection with pgste_update_all (diff)
downloadlinux-758d39ebd3d5666edb3b1c339f7f138c349ff8bf.tar.xz
linux-758d39ebd3d5666edb3b1c339f7f138c349ff8bf.zip
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/kernel/perf_event.c')
-rw-r--r--arch/s390/kernel/perf_event.c56
1 files changed, 6 insertions, 50 deletions
diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index 0943b11a2f6e..a1b708643a2c 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -222,64 +222,20 @@ static int __init service_level_perf_register(void)
}
arch_initcall(service_level_perf_register);
-/* See also arch/s390/kernel/traps.c */
-static unsigned long __store_trace(struct perf_callchain_entry *entry,
- unsigned long sp,
- unsigned long low, unsigned long high)
+static int __perf_callchain_kernel(void *data, unsigned long address)
{
- struct stack_frame *sf;
- struct pt_regs *regs;
-
- while (1) {
- if (sp < low || sp > high - sizeof(*sf))
- return sp;
- sf = (struct stack_frame *) sp;
- perf_callchain_store(entry, sf->gprs[8]);
- /* Follow the backchain. */
- while (1) {
- low = sp;
- sp = sf->back_chain;
- if (!sp)
- break;
- if (sp <= low || sp > high - sizeof(*sf))
- return sp;
- sf = (struct stack_frame *) sp;
- perf_callchain_store(entry, sf->gprs[8]);
- }
- /* 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;
- perf_callchain_store(entry, sf->gprs[8]);
- low = sp;
- sp = regs->gprs[15];
- }
+ struct perf_callchain_entry *entry = data;
+
+ perf_callchain_store(entry, address);
+ return 0;
}
void perf_callchain_kernel(struct perf_callchain_entry *entry,
struct pt_regs *regs)
{
- 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 || !head_sf->back_chain)
- return;
-
- head = head_sf->back_chain;
- head = __store_trace(entry, head,
- S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
- S390_lowcore.async_stack + frame_size);
-
- __store_trace(entry, head, S390_lowcore.thread_info,
- S390_lowcore.thread_info + THREAD_SIZE);
+ dump_trace(__perf_callchain_kernel, entry, NULL, regs->gprs[15]);
}
/* Perf defintions for PMU event attributes in sysfs */