[PATCH v2 26/27] dyndbg: 4 new trace-events: pr_debug, dev_dbg, drm_{, dev}debug

ddebug_trace() currently issues a single printk:console event. Replace that, adding include/trace/events/dyndbg.h, which defines 2 new events:

- dyndbg:prdbg - from trace_prdbg() - if !dev - dyndbg:devdbg - from trace_devdbg() - if !!dev

This links the legacy pr_debug API to tracefs, via dyndbg, allowing pr_debug()s etc to add just a little more user-context to the trace-logs, and then at users option, less syslog.

The 2 new trace_*() calls accept their caller's args respectively, keeping the available info w/o alteration; we can't improve on transparency. The args:

1- struct _ddebug *descriptor, giving tracefs all of dyndbg's info. 2- struct device *dev, used by trace_devdbg(), if !!dev

The trace_*() calls need the descriptor arg, the callchain prototypes above them are extended to provide it.

The existing category param in this callchain is partially redundant; when descriptor is available, it has the class_id.

dev_dbg(desc, dev...), if dev is true, issues a trace_devdbg(), otherwise trace_prdbg(). This way we dont consume buffer space storing nulls. Otherwise the events are equivalent.

Also add include/trace/events/drm.h, to create 2 events for use in drm_dbg() and drm_devdbg(), and call them. This recapitulates the changes described above, connecting 3-10K drm.debug callsites to tracefs.

Signed-off-by: Jim Cromie jim.cromie@gmail.com --- drivers/gpu/drm/drm_print.c | 9 +++++ include/trace/events/drm.h | 68 ++++++++++++++++++++++++++++++++ include/trace/events/dyndbg.h | 74 +++++++++++++++++++++++++++++++++++ lib/dynamic_debug.c | 73 +++++++++++++++++----------------- 4 files changed, 188 insertions(+), 36 deletions(-) create mode 100644 include/trace/events/drm.h create mode 100644 include/trace/events/dyndbg.h

diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c index 63125a507577..9afb676bda4d 100644 --- a/drivers/gpu/drm/drm_print.c +++ b/drivers/gpu/drm/drm_print.c @@ -34,6 +34,9 @@ #include <drm/drm_drv.h> #include <drm/drm_print.h>

+#define CREATE_TRACE_POINTS +#include <trace/events/drm.h> + /* * __drm_debug: Enable debug output. * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details. @@ -283,10 +286,14 @@ void __drm_dev_dbg(struct _ddebug *desc, const struct device *dev, if (desc->flags & _DPRINTK_FLAGS_PRINTK) dev_printk(KERN_DEBUG, dev, "[" DRM_NAME ":%ps] %pV", __builtin_return_address(0), &vaf); + if (desc->flags & _DPRINTK_FLAGS_TRACE) + trace_drm_devdbg(dev, category, &vaf); } else { if (desc->flags & _DPRINTK_FLAGS_PRINTK) printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", __builtin_return_address(0), &vaf); + if (desc->flags & _DPRINTK_FLAGS_TRACE) + trace_drm_debug(category, &vaf); } va_end(args); } @@ -307,6 +314,8 @@ void ___drm_dbg(struct _ddebug *desc, enum drm_debug_category category, const ch printk(KERN_DEBUG "[" DRM_NAME ":%ps] %pV", __builtin_return_address(0), &vaf);

+ trace_drm_debug(category, &vaf); + va_end(args); } EXPORT_SYMBOL(___drm_dbg); diff --git a/include/trace/events/drm.h b/include/trace/events/drm.h new file mode 100644 index 000000000000..6de80dd68620 --- /dev/null +++ b/include/trace/events/drm.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM drm + +#if !defined(_TRACE_DRM_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_DRM_H + +#include <linux/tracepoint.h> + +/* drm_debug() was called, pass its args */ +TRACE_EVENT(drm_debug, + TP_PROTO(int drm_debug_category, struct va_format *vaf), + + TP_ARGS(drm_debug_category, vaf), + + TP_STRUCT__entry( + __field(int, drm_debug_category) + __dynamic_array(char, msg, 256) + ), + + TP_fast_assign( + int len; + + __entry->drm_debug_category = drm_debug_category; + vsnprintf(__get_str(msg), 256, vaf->fmt, *vaf->va); + + len = strlen(__get_str(msg)); + if (len > 0 && (__get_str(msg)[len - 1] == '\n')) + len -= 1; + __get_str(msg)[len] = 0; + ), + + TP_printk("%s", __get_str(msg)) +); + +/* drm_devdbg() was called, pass its args, preserving order */ +TRACE_EVENT(drm_devdbg, + TP_PROTO(const struct device *dev, int drm_debug_category, struct va_format *vaf), + + TP_ARGS(dev, drm_debug_category, vaf), + + TP_STRUCT__entry( + __field(const struct device*, dev) + __field(int, drm_debug_category) + __dynamic_array(char, msg, 256) + ), + + TP_fast_assign( + int len; + + __entry->drm_debug_category = drm_debug_category; + __entry->dev = dev; + vsnprintf(__get_str(msg), 256, vaf->fmt, *vaf->va); + + len = strlen(__get_str(msg)); + if (len > 0 && (__get_str(msg)[len - 1] == '\n')) + len -= 1; + __get_str(msg)[len] = 0; + ), + + TP_printk("cat:%d, %s %s", __entry->drm_debug_category, + dev_name(__entry->dev), __get_str(msg)) +); + +#endif /* _TRACE_DRM_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/include/trace/events/dyndbg.h b/include/trace/events/dyndbg.h new file mode 100644 index 000000000000..e19fcb56566c --- /dev/null +++ b/include/trace/events/dyndbg.h @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM dyndbg + +#if !defined(_TRACE_DYNDBG_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_DYNDBG_H + +#include <linux/tracepoint.h> + +/* capture pr_debug() callsite descriptor and message */ +TRACE_EVENT(prdbg, + TP_PROTO(const struct _ddebug *desc, const char *text, size_t len), + + TP_ARGS(desc, text, len), + + TP_STRUCT__entry( + __field(const struct _ddebug *, desc) + __dynamic_array(char, msg, len + 1) + ), + + TP_fast_assign( + __entry->desc = desc; + /* + * Each trace entry is printed in a new line. + * If the msg finishes with '\n', cut it off + * to avoid blank lines in the trace. + */ + if (len > 0 && (text[len - 1] == '\n')) + len -= 1; + + memcpy(__get_str(msg), text, len); + __get_str(msg)[len] = 0; + ), + + TP_printk("%s.%s %s", __entry->desc->modname, + __entry->desc->function, __get_str(msg)) +); + +/* capture dev_dbg() callsite descriptor, device, and message */ +TRACE_EVENT(devdbg, + TP_PROTO(const struct _ddebug *desc, const struct device *dev, + const char *text, size_t len), + + TP_ARGS(desc, dev, text, len), + + TP_STRUCT__entry( + __field(const struct _ddebug *, desc) + __field(const struct device *, dev) + __dynamic_array(char, msg, len + 1) + ), + + TP_fast_assign( + __entry->desc = desc; + __entry->dev = (struct device *) dev; + /* + * Each trace entry is printed in a new line. + * If the msg finishes with '\n', cut it off + * to avoid blank lines in the trace. + */ + if (len > 0 && (text[len - 1] == '\n')) + len -= 1; + + memcpy(__get_str(msg), text, len); + __get_str(msg)[len] = 0; + ), + + TP_printk("%s.%s %s", __entry->desc->modname, + __entry->desc->function, __get_str(msg)) +); + +#endif /* _TRACE_DYNDBG_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index 81cfe6e21d15..a97ca94a266a 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -36,7 +36,9 @@ #include <linux/sched.h> #include <linux/device.h> #include <linux/netdevice.h> -#include <trace/events/printk.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/dyndbg.h>

#include <rdma/ib_verbs.h>

@@ -790,7 +792,9 @@ struct ddebug_trace_bufs { static DEFINE_PER_CPU(struct ddebug_trace_bufs, ddebug_trace_bufs); static DEFINE_PER_CPU(int, ddebug_trace_reserve);

-static void ddebug_trace(const char *fmt, va_list args) +__printf(3, 0) +static void ddebug_trace(struct _ddebug *desc, const struct device *dev, + const char *fmt, va_list args) { struct ddebug_trace_buf *buf; int bufidx; @@ -809,7 +813,11 @@ static void ddebug_trace(const char *fmt, va_list args) buf = this_cpu_ptr(ddebug_trace_bufs.bufs) + bufidx;

len = vscnprintf(buf->buf, sizeof(buf->buf), fmt, args); - trace_console(buf->buf, len); + + if (!dev) + trace_prdbg(desc, buf->buf, len); + else + trace_devdbg(desc, dev, buf->buf, len);

out: /* As above. */ @@ -819,9 +827,9 @@ static void ddebug_trace(const char *fmt, va_list args) }

__printf(2, 3) -static void ddebug_printk(unsigned int flags, const char *fmt, ...) +static void ddebug_printk(struct _ddebug *desc, const char *fmt, ...) { - if (flags & _DPRINTK_FLAGS_TRACE) { + if (desc->flags & _DPRINTK_FLAGS_TRACE) { va_list args;

va_start(args, fmt); @@ -829,11 +837,11 @@ static void ddebug_printk(unsigned int flags, const char *fmt, ...) * All callers include the KERN_DEBUG prefix to keep the * vprintk case simple; strip it out for tracing. */ - ddebug_trace(fmt + strlen(KERN_DEBUG), args); + ddebug_trace(desc, NULL, fmt + strlen(KERN_DEBUG), args); va_end(args); }

- if (flags & _DPRINTK_FLAGS_PRINTK) { + if (desc->flags & _DPRINTK_FLAGS_PRINTK) { va_list args;

va_start(args, fmt); @@ -843,19 +851,19 @@ static void ddebug_printk(unsigned int flags, const char *fmt, ...) }

__printf(3, 4) -static void ddebug_dev_printk(unsigned int flags, const struct device *dev, +static void ddebug_dev_printk(struct _ddebug *desc, const struct device *dev, const char *fmt, ...) {

- if (flags & _DPRINTK_FLAGS_TRACE) { + if (desc->flags & _DPRINTK_FLAGS_TRACE) { va_list args;

va_start(args, fmt); - ddebug_trace(fmt, args); + ddebug_trace(desc, dev, fmt, args); va_end(args); }

- if (flags & _DPRINTK_FLAGS_PRINTK) { + if (desc->flags & _DPRINTK_FLAGS_PRINTK) { va_list args;

va_start(args, fmt); @@ -878,7 +886,7 @@ void __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...) vaf.fmt = fmt; vaf.va = &args;

- ddebug_printk(descriptor->flags, KERN_DEBUG "%s%pV", + ddebug_printk(descriptor, KERN_DEBUG "%s%pV", dynamic_emit_prefix(descriptor, buf), &vaf);

va_end(args); @@ -889,7 +897,6 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor, const struct device *dev, const char *fmt, ...) { struct va_format vaf; - unsigned int flags; va_list args;

BUG_ON(!descriptor); @@ -899,15 +906,14 @@ void __dynamic_dev_dbg(struct _ddebug *descriptor,

vaf.fmt = fmt; vaf.va = &args; - flags = descriptor->flags;

if (!dev) { - ddebug_printk(flags, KERN_DEBUG "(NULL device *): %pV", - &vaf); + ddebug_printk(descriptor, KERN_DEBUG "(NULL device *): %pV", + &vaf); } else { char buf[PREFIX_SIZE] = "";

- ddebug_dev_printk(flags, dev, "%s%s %s: %pV", + ddebug_dev_printk(descriptor, dev, "%s%s %s: %pV", dynamic_emit_prefix(descriptor, buf), dev_driver_string(dev), dev_name(dev), &vaf); @@ -923,7 +929,6 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor, const struct net_device *dev, const char *fmt, ...) { struct va_format vaf; - unsigned int flags; va_list args;

BUG_ON(!descriptor); @@ -933,24 +938,22 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor,

vaf.fmt = fmt; vaf.va = &args; - flags = descriptor->flags;

if (dev && dev->dev.parent) { char buf[PREFIX_SIZE] = "";

- ddebug_dev_printk(flags, dev->dev.parent, - "%s%s %s %s%s: %pV", - dynamic_emit_prefix(descriptor, buf), - dev_driver_string(dev->dev.parent), - dev_name(dev->dev.parent), - netdev_name(dev), netdev_reg_state(dev), - &vaf); + ddebug_dev_printk(descriptor, dev->dev.parent, + "%s%s %s %s%s: %pV", + dynamic_emit_prefix(descriptor, buf), + dev_driver_string(dev->dev.parent), + dev_name(dev->dev.parent), + netdev_name(dev), netdev_reg_state(dev), + &vaf); } else if (dev) { - ddebug_printk(flags, KERN_DEBUG "%s%s: %pV", - netdev_name(dev), netdev_reg_state(dev), &vaf); + ddebug_dev_printk(descriptor, &dev->dev, KERN_DEBUG "%s%s: %pV", + netdev_name(dev), netdev_reg_state(dev), &vaf); } else { - ddebug_printk(flags, KERN_DEBUG "(NULL net_device): %pV", - &vaf); + ddebug_printk(descriptor, KERN_DEBUG "(NULL net_device): %pV", &vaf); }

va_end(args); @@ -966,18 +969,16 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, { struct va_format vaf; va_list args; - unsigned int flags;

va_start(args, fmt);

vaf.fmt = fmt; vaf.va = &args; - flags = descriptor->flags;

if (ibdev && ibdev->dev.parent) { char buf[PREFIX_SIZE] = "";

- ddebug_dev_printk(flags, ibdev->dev.parent, + ddebug_dev_printk(descriptor, ibdev->dev.parent, "%s%s %s %s: %pV", dynamic_emit_prefix(descriptor, buf), dev_driver_string(ibdev->dev.parent), @@ -985,10 +986,10 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, dev_name(&ibdev->dev), &vaf); } else if (ibdev) { - ddebug_printk(flags, KERN_DEBUG "%s: %pV", - dev_name(&ibdev->dev), &vaf); + ddebug_dev_printk(descriptor, &ibdev->dev, KERN_DEBUG "%s: %pV", + dev_name(&ibdev->dev), &vaf); } else { - ddebug_printk(flags, KERN_DEBUG "(NULL ip_device): %pV", &vaf); + ddebug_printk(descriptor, KERN_DEBUG "(NULL ip_device): %pV", &vaf); }

va_end(args);