d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Truncate a too-long interrupt handler name when there is only one handler.

Browse Source 
There are only 19 bytes available for the name of an interrupt plus the
name(s) of handlers/drivers using it. There is a mechanism from the days of
shared interrupts that replaces some of the handler names with '+' when they
don't all fit into 19 bytes.

In modern times there is typically only one device on an interrupt, but long
device names are the norm, especially with embedded systems. Also, in systems
with multiple interrupt controllers, the names of the interrupts themselves
can be long. For example, 'gic0,s54: imx6_anatop0' doesn't fit, and
replacing the device driver name with a '+' provides no useful info at all.

When there is only one handler but its name was too long to fit, this
change truncates enough leading chars of the handler name (replacing them
with a '-' char to indicate that some chars are missing) to use all 19
bytes, preserving the unit number typically on the end of the name. Using
the prior example, this results in: 'gic0,s54:-6_anatop0' which provides
plenty of info to figure out which device is involved.

PR:		211946
Reviewed by:	gonzo@ (prior version without the '-' char)
Differential Revision:	https://reviews.freebsd.org/D19675
This commit is contained in:
Ian Lepore 2019-03-24 17:53:26 +00:00
parent 425c24e5da
commit 67da50a047
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=345475
1 changed files with 14 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
sys/kern/kern_intr.c
View File

@ -197,7 +197,7 @@ intr_event_update(struct intr_event *ie)
/* Run through all the handlers updating values. */
CK_SLIST_FOREACH(ih, &ie->ie_handlers, ih_next) {
if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 1 <
if (strlen(ie->ie_fullname) + strlen(ih->ih_name) + 2 <
sizeof(ie->ie_fullname)) {
strcat(ie->ie_fullname, " ");
strcat(ie->ie_fullname, ih->ih_name);
@ -209,10 +209,20 @@ intr_event_update(struct intr_event *ie)
}
/*
* If the handler names were too long, add +'s to indicate missing
* names. If we run out of room and still have +'s to add, change
* the last character from a + to a *.
* If there is only one handler and its name is too long, just copy in
* as much of the end of the name (includes the unit number) as will
* fit. Otherwise, we have multiple handlers and not all of the names
* will fit. Add +'s to indicate missing names. If we run out of room
* and still have +'s to add, change the last character from a + to a *.
*/
if (missed == 1 && space == 1) {
ih = CK_SLIST_FIRST(&ie->ie_handlers);
missed = strlen(ie->ie_fullname) + strlen(ih->ih_name) + 2 -
sizeof(ie->ie_fullname);
strcat(ie->ie_fullname, (missed == 0) ? " " : "-");
strcat(ie->ie_fullname, &ih->ih_name[missed]);
missed = 0;
}
last = &ie->ie_fullname[sizeof(ie->ie_fullname) - 2];
while (missed-- > 0) {
if (strlen(ie->ie_fullname) + 1 == sizeof(ie->ie_fullname)) {