mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-23 09:56:16 +07:00
f6c9b16023
The diagnose tracer will indirectly call back into the lockdep code when lockdep does not expect it (arch_spinlock). This causes lockdep to disable itself and therefore we don't have a working lock dependency validator anymore. This patch effectively disables tracing of diag 0x9c and 0x44 if lockdep is enabled. If however lockdep is enabled spinlocks are mainly implemented using a trylock variant, which will not issue any diag 0x9c or 0x44. So this change has hardly any effect on tracing except when arch_spinlock and friends are explicitly used. Reported-and-Tested-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
33 lines
671 B
C
33 lines
671 B
C
/*
|
|
* Tracepoint definitions for s390
|
|
*
|
|
* Copyright IBM Corp. 2015
|
|
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
|
|
*/
|
|
|
|
#include <linux/percpu.h>
|
|
#define CREATE_TRACE_POINTS
|
|
#include <asm/trace/diag.h>
|
|
|
|
EXPORT_TRACEPOINT_SYMBOL(s390_diagnose);
|
|
|
|
static DEFINE_PER_CPU(unsigned int, diagnose_trace_depth);
|
|
|
|
void trace_s390_diagnose_norecursion(int diag_nr)
|
|
{
|
|
unsigned long flags;
|
|
unsigned int *depth;
|
|
|
|
/* Avoid lockdep recursion. */
|
|
if (IS_ENABLED(CONFIG_LOCKDEP))
|
|
return;
|
|
local_irq_save(flags);
|
|
depth = this_cpu_ptr(&diagnose_trace_depth);
|
|
if (*depth == 0) {
|
|
(*depth)++;
|
|
trace_s390_diagnose(diag_nr);
|
|
(*depth)--;
|
|
}
|
|
local_irq_restore(flags);
|
|
}
|