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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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8cf868affd
Some tracepoints have a registration function that gets enabled when the tracepoint is enabled. There may be cases that the registraction function must fail (for example, can't allocate enough memory). In this case, the tracepoint should also fail to register, otherwise the user would not know why the tracepoint is not working. Cc: David Howells <dhowells@redhat.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Anton Blanchard <anton@samba.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
88 lines
1.6 KiB
C
88 lines
1.6 KiB
C
#include <linux/percpu.h>
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#include <linux/jump_label.h>
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#include <asm/trace.h>
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#include <asm/asm-prototypes.h>
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#ifdef HAVE_JUMP_LABEL
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struct static_key opal_tracepoint_key = STATIC_KEY_INIT;
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int opal_tracepoint_regfunc(void)
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{
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static_key_slow_inc(&opal_tracepoint_key);
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return 0;
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}
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void opal_tracepoint_unregfunc(void)
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{
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static_key_slow_dec(&opal_tracepoint_key);
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}
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#else
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/*
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* We optimise OPAL calls by placing opal_tracepoint_refcount
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* directly in the TOC so we can check if the opal tracepoints are
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* enabled via a single load.
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*/
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/* NB: reg/unreg are called while guarded with the tracepoints_mutex */
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extern long opal_tracepoint_refcount;
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int opal_tracepoint_regfunc(void)
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{
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opal_tracepoint_refcount++;
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return 0;
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}
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void opal_tracepoint_unregfunc(void)
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{
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opal_tracepoint_refcount--;
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}
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#endif
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/*
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* Since the tracing code might execute OPAL calls we need to guard against
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* recursion.
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*/
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static DEFINE_PER_CPU(unsigned int, opal_trace_depth);
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void __trace_opal_entry(unsigned long opcode, unsigned long *args)
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{
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unsigned long flags;
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unsigned int *depth;
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local_irq_save(flags);
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depth = this_cpu_ptr(&opal_trace_depth);
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if (*depth)
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goto out;
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(*depth)++;
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preempt_disable();
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trace_opal_entry(opcode, args);
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(*depth)--;
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out:
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local_irq_restore(flags);
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}
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void __trace_opal_exit(long opcode, unsigned long retval)
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{
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unsigned long flags;
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unsigned int *depth;
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local_irq_save(flags);
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depth = this_cpu_ptr(&opal_trace_depth);
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if (*depth)
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goto out;
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(*depth)++;
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trace_opal_exit(opcode, retval);
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preempt_enable();
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(*depth)--;
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out:
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local_irq_restore(flags);
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}
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