| Message ID | 20230301175540.19891-1-ilkka@os.amperecomputing.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | perf/arm-cmn: Move overlapping wp_combine field | expand |
On 2023-03-01 17:55, Ilkka Koskinen wrote: > As eventid field was expanded to support new mesh versions, it started to > overlap with wp_combine field. Move wp_combine to fix the issue. Watchpoint events still only strictly need 2 bits of eventid, though. Could you clarify whether userspace is getting confused by this, or whether it's just arm_cmn_event_init() falling over itself (FWIW I can see how I broke things there...) Thanks, Robin. > Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support") > Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com> > --- > drivers/perf/arm-cmn.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c > index c9689861be3f..9f2edc28d16e 100644 > --- a/drivers/perf/arm-cmn.c > +++ b/drivers/perf/arm-cmn.c > @@ -166,7 +166,7 @@ > #define CMN_EVENT_BYNODEID(event) FIELD_GET(CMN_CONFIG_BYNODEID, (event)->attr.config) > #define CMN_EVENT_NODEID(event) FIELD_GET(CMN_CONFIG_NODEID, (event)->attr.config) > > -#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(27, 24) > +#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(30, 27) > #define CMN_CONFIG_WP_DEV_SEL GENMASK_ULL(50, 48) > #define CMN_CONFIG_WP_CHN_SEL GENMASK_ULL(55, 51) > /* Note that we don't yet support the tertiary match group on newer IPs */
Hi Robin, On Wed, 1 Mar 2023, Robin Murphy wrote: > On 2023-03-01 17:55, Ilkka Koskinen wrote: >> As eventid field was expanded to support new mesh versions, it started to >> overlap with wp_combine field. Move wp_combine to fix the issue. > > Watchpoint events still only strictly need 2 bits of eventid, though. Could > you clarify whether userspace is getting confused by this, or whether it's > just arm_cmn_event_init() falling over itself (FWIW I can see how I broke > things there...) Basically, perf seems to set eventid at first and then wp_combine field into the config argument. The problem is when arm_cmn_event_init() is doing: eventid = CMN_EVENT_EVENTID(event); .... if (eventid != CMN_WP_UP && eventid != CMN_WP_DOWN) return -EINVAL; If wp_combine has any of the overlapping bits set, eventid doesn't match with either up or down event. Cheers, Ilkka > > Thanks, > Robin. > >> Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support") >> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com> >> --- >> drivers/perf/arm-cmn.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c >> index c9689861be3f..9f2edc28d16e 100644 >> --- a/drivers/perf/arm-cmn.c >> +++ b/drivers/perf/arm-cmn.c >> @@ -166,7 +166,7 @@ >> #define CMN_EVENT_BYNODEID(event) FIELD_GET(CMN_CONFIG_BYNODEID, >> (event)->attr.config) >> #define CMN_EVENT_NODEID(event) FIELD_GET(CMN_CONFIG_NODEID, >> (event)->attr.config) >> -#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(27, 24) >> +#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(30, 27) >> #define CMN_CONFIG_WP_DEV_SEL GENMASK_ULL(50, 48) >> #define CMN_CONFIG_WP_CHN_SEL GENMASK_ULL(55, 51) >> /* Note that we don't yet support the tertiary match group on newer IPs >> */ >
Hi Robin, On Wed, 1 Mar 2023, Ilkka Koskinen wrote: > > Hi Robin, > > On Wed, 1 Mar 2023, Robin Murphy wrote: >> On 2023-03-01 17:55, Ilkka Koskinen wrote: >>> As eventid field was expanded to support new mesh versions, it started to >>> overlap with wp_combine field. Move wp_combine to fix the issue. >> >> Watchpoint events still only strictly need 2 bits of eventid, though. Could >> you clarify whether userspace is getting confused by this, or whether it's >> just arm_cmn_event_init() falling over itself (FWIW I can see how I broke >> things there...) > > Basically, perf seems to set eventid at first and then wp_combine field into > the config argument. The problem is when arm_cmn_event_init() is doing: > > eventid = CMN_EVENT_EVENTID(event); > .... > if (eventid != CMN_WP_UP && eventid != CMN_WP_DOWN) > return -EINVAL; > > If wp_combine has any of the overlapping bits set, eventid doesn't match with > either up or down event. I probably should have also copy pasted what the format files say: $ cat format/eventid format/wp_combine config:16-26 config:24-27 So, here you can see that those two fields overlap. If wp_combine has any of the bits 24-26 set, arm_cmn_event_init() returns -EINVAL as shown in the code above. Would you need some more clarification from me? Br, Ilkka > > Cheers, Ilkka > >> >> Thanks, >> Robin. >> >>> Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support") >>> Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com> >>> --- >>> drivers/perf/arm-cmn.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c >>> index c9689861be3f..9f2edc28d16e 100644 >>> --- a/drivers/perf/arm-cmn.c >>> +++ b/drivers/perf/arm-cmn.c >>> @@ -166,7 +166,7 @@ >>> #define CMN_EVENT_BYNODEID(event) FIELD_GET(CMN_CONFIG_BYNODEID, >>> (event)->attr.config) >>> #define CMN_EVENT_NODEID(event) FIELD_GET(CMN_CONFIG_NODEID, >>> (event)->attr.config) >>> -#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(27, 24) >>> +#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(30, 27) >>> #define CMN_CONFIG_WP_DEV_SEL GENMASK_ULL(50, 48) >>> #define CMN_CONFIG_WP_CHN_SEL GENMASK_ULL(55, 51) >>> /* Note that we don't yet support the tertiary match group on newer IPs >>> */ >> >
On Wed, 1 Mar 2023 09:55:40 -0800, Ilkka Koskinen wrote: > As eventid field was expanded to support new mesh versions, it started to > overlap with wp_combine field. Move wp_combine to fix the issue. > > Applied to will (for-next/perf), thanks! [1/1] perf/arm-cmn: Move overlapping wp_combine field https://git.kernel.org/will/c/f87e9114b5e5 Cheers,
diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c index c9689861be3f..9f2edc28d16e 100644 --- a/drivers/perf/arm-cmn.c +++ b/drivers/perf/arm-cmn.c @@ -166,7 +166,7 @@ #define CMN_EVENT_BYNODEID(event) FIELD_GET(CMN_CONFIG_BYNODEID, (event)->attr.config) #define CMN_EVENT_NODEID(event) FIELD_GET(CMN_CONFIG_NODEID, (event)->attr.config) -#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(27, 24) +#define CMN_CONFIG_WP_COMBINE GENMASK_ULL(30, 27) #define CMN_CONFIG_WP_DEV_SEL GENMASK_ULL(50, 48) #define CMN_CONFIG_WP_CHN_SEL GENMASK_ULL(55, 51) /* Note that we don't yet support the tertiary match group on newer IPs */
As eventid field was expanded to support new mesh versions, it started to overlap with wp_combine field. Move wp_combine to fix the issue. Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support") Signed-off-by: Ilkka Koskinen <ilkka@os.amperecomputing.com> --- drivers/perf/arm-cmn.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)