Messages in this thread | | | From | jim.cromie@gmail ... | Date | Sat, 4 Nov 2023 15:48:55 -0600 | Subject | Re: [PATCH v1 11/12] dyndbg: write debug logs to trace instance |
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On Fri, Nov 3, 2023 at 7:10 AM Łukasz Bartosik <lb@semihalf.com> wrote: > > When trace is enabled (T flag is set) and trace_dst field is set > to value greater than 0 (0 is reserved for trace events) then > debug logs will be written to trace instance pointed by trace_dst > value, for example when trace_dst value is 2 then debug logs will > be written to <debugfs>/tracing/instances/dyndbg_inst_2 instance. > Given trace instance will not be initialized until debug logs are > requested to be written to it and afer init will persist until > reboot. >
restating 00 comments -
you can get rid of integer destination ids by adding a new command: open/close
$> echo \ open kms-instance \;\ class DRM_UT_KMS -T:kms-instance # preset-dests-disable-sites \;\ > /proc/dynamic_debug/control
echo "class DRM_UT_KMS +T # enable sites, with the preselected data" > /proc/dynamic_debug/control
open - assign name to id, reserve it, hide it from user +T:valid-name # fail command if name wasnt opened
and +T w/o dest means use existing setting, not just 0 (unless thats the existing setting)
> Signed-off-by: Łukasz Bartosik <lb@semihalf.com> > --- > lib/Kconfig.debug | 1 + > lib/dynamic_debug.c | 79 ++++++++++++++++++++++++++++++++++++++++++--- > 2 files changed, 76 insertions(+), 4 deletions(-) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index fa307f93fa2e..9617e92c046d 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -181,6 +181,7 @@ config DYNAMIC_DEBUG_CORE > bool "Enable core function of dynamic debug support" > depends on PRINTK > depends on (DEBUG_FS || PROC_FS) > + depends on TRACING > help > Enable core functional support of dynamic debug. It is useful > when you want to tie dynamic debug to your kernel modules with > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c > index c5cd28e74a02..541d9d522b3b 100644 > --- a/lib/dynamic_debug.c > +++ b/lib/dynamic_debug.c > @@ -36,6 +36,7 @@ > #include <linux/sched.h> > #include <linux/device.h> > #include <linux/netdevice.h> > +#include <linux/trace.h> > > #define CREATE_TRACE_POINTS > #include <trace/events/dyndbg.h> > @@ -81,6 +82,18 @@ module_param(verbose, int, 0644); > MODULE_PARM_DESC(verbose, " dynamic_debug/control processing " > "( 0 = off (default), 1 = module add/rm, 2 = >control summary, 3 = parsing, 4 = per-site changes)"); > > +/* > + * When trace is enabled (T flag is set) and trace_dst field is set > + * to value greater than 0 (0 is reserved for trace events) then > + * debug logs will be written to trace instance pointed by trace_dst > + * value, for example when trace_dst value is 2 then debug logs will > + * be written to <debugfs>/tracing/instances/dyndbg_inst_2 instance. > + * Given trace instance will not be initialized until debug logs are > + * requested to be written to it and afer init will persist until > + * reboot. > + */ > +static struct trace_array *trace_arr[TRACE_DST_MAX]; > + > static inline struct dd_ctrl *get_ctrl(struct _ddebug *desc) > { > return &desc->ctrl; > @@ -255,6 +268,45 @@ static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table cons > return NULL; > } > > +static int handle_trace_dst(struct dd_ctrl *ctrl) > +{ > +#define TRACE_INST_NAME_LEN 16 > + char instance_name[TRACE_INST_NAME_LEN]; > + struct trace_array *arr; > + int ret = -EINVAL; > + > + /* check if trace (T flag) is enabled */ > + if (!(ctrl->flags & _DPRINTK_FLAGS_TRACE)) > + return 0; > + > + /* check if trace destination are trace events */ > + if (!ctrl->trace_dst) > + return 0; > + > + /* check if trace instance is already set up */ > + if (trace_arr[ctrl->trace_dst]) > + return 0; > + > + snprintf(instance_name, TRACE_INST_NAME_LEN, > + "dyndbg_inst_%u", ctrl->trace_dst); > + arr = trace_array_get_by_name(instance_name); > + if (!arr) > + goto err; > + > + ret = trace_array_init_printk(arr); > + if (ret) > + goto err_init; > + > + trace_arr[ctrl->trace_dst] = arr; > + return 0; > + > +err_init: > + trace_array_put(arr); > + trace_array_destroy(arr); > +err: > + return ret; > +} > + > #define __outvar /* filled by callee */ > /* > * Search the tables for _ddebug's which match the given `query' and > @@ -338,6 +390,9 @@ static int ddebug_change(const struct ddebug_query *query, > nctrl.trace_dst = modifiers->trace_dst; > if (!memcmp(&nctrl, get_ctrl(dp), sizeof(nctrl))) > continue; > + > + if (handle_trace_dst(&nctrl)) > + continue; > #ifdef CONFIG_JUMP_LABEL > if (get_flags(dp) & _DPRINTK_FLAGS_ENABLED) { > if (!(nctrl.flags & _DPRINTK_FLAGS_ENABLED)) > @@ -977,8 +1032,8 @@ static DEFINE_PER_CPU(struct ddebug_trace_bufs, ddebug_trace_bufs); > static DEFINE_PER_CPU(int, ddebug_trace_reserve); > > __printf(3, 0) > -static void ddebug_trace(struct _ddebug *desc, const struct device *dev, > - const char *fmt, va_list args) > +static void ddebug_trace_event(struct _ddebug *desc, const struct device *dev, > + const char *fmt, va_list args) > { > struct ddebug_trace_buf *buf; > int bufidx; > @@ -1010,6 +1065,15 @@ static void ddebug_trace(struct _ddebug *desc, const struct device *dev, > preempt_enable_notrace(); > } > > +__printf(2, 0) > +static void ddebug_trace_instance(struct _ddebug *desc, const char *fmt, > + va_list *args) > +{ > + struct va_format vaf = { .fmt = fmt, .va = args}; > + > + trace_array_printk(trace_arr[get_trace_dst(desc)], _THIS_IP_, "%pV", &vaf); > +} > + > __printf(2, 3) > static void ddebug_printk(struct _ddebug *desc, const char *fmt, ...) > { > @@ -1022,7 +1086,11 @@ static void ddebug_printk(struct _ddebug *desc, const char *fmt, ...) > * All callers include the KERN_DEBUG prefix to keep the > * vprintk case simple; strip it out for tracing. > */ > - ddebug_trace(desc, NULL, fmt + strlen(KERN_DEBUG), args); > + if (get_trace_dst(desc)) > + ddebug_trace_instance(desc, fmt, &args); > + else > + ddebug_trace_event(desc, NULL, > + fmt + strlen(KERN_DEBUG), args); > va_end(args); > } > > @@ -1044,7 +1112,10 @@ static void ddebug_dev_printk(struct _ddebug *desc, const struct device *dev, > va_list args; > > va_start(args, fmt); > - ddebug_trace(desc, dev, fmt, args); > + if (get_trace_dst(desc)) > + ddebug_trace_instance(desc, fmt, &args); > + else > + ddebug_trace_event(desc, dev, fmt, args); > va_end(args); > } > > -- > 2.42.0.869.gea05f2083d-goog >
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