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| author | Mordechay Goodstein <mordechay.goodstein@intel.com> | 2024-07-02 19:21:18 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2024-07-03 12:24:22 +0200 |
| commit | 6555acdefc758a4dae7038c3f2301f311e287218 (patch) | |
| tree | 5da8eba64e5f122ce9ca3c5fc0682f564765e2a3 /arch/um/include | |
| parent | 267ed02c2121b75e0eaaa338240453b576039e4a (diff) | |
| download | linux-stable-6555acdefc758a4dae7038c3f2301f311e287218.tar.gz linux-stable-6555acdefc758a4dae7038c3f2301f311e287218.tar.bz2 linux-stable-6555acdefc758a4dae7038c3f2301f311e287218.zip | |
um: time-travel: support time-travel protocol broadcast messages
Add a message type to the time-travel protocol to broadcast
a small (64-bit) value to all participants in a simulation.
The main use case is to have an identical message come to
all participants in a simulation, e.g. to separate out logs
for different tests running in a single simulation.
Down in the guts of time_travel_handle_message() we can't
use printk() and not even printk_deferred(), so just store
the message and print it at the start of the userspace()
function.
Unfortunately this means that other prints in the kernel
can actually bypass the message, but in most cases where
this is used, for example to separate test logs, userspace
will be involved. Also, even if we could use
printk_deferred(), we'd still need to flush it out in the
userspace() function since otherwise userspace messages
might cross it.
As a result, this is a reasonable compromise, there's no
need to have any core changes and it solves the main use
case we have for it.
Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Link: https://patch.msgid.link/20240702192118.c4093bc5b15e.I2ca8d006b67feeb866ac2017af7b741c9e06445a@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'arch/um/include')
| -rw-r--r-- | arch/um/include/shared/timetravel.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/um/include/shared/timetravel.h b/arch/um/include/shared/timetravel.h index e5c3d69f1b69..c8db2f213dba 100644 --- a/arch/um/include/shared/timetravel.h +++ b/arch/um/include/shared/timetravel.h @@ -15,8 +15,17 @@ enum time_travel_mode { #if defined(UML_CONFIG_UML_TIME_TRAVEL_SUPPORT) || \ defined(CONFIG_UML_TIME_TRAVEL_SUPPORT) extern enum time_travel_mode time_travel_mode; +extern int time_travel_should_print_bc_msg; #else #define time_travel_mode TT_MODE_OFF +#define time_travel_should_print_bc_msg 0 #endif /* (UML_)CONFIG_UML_TIME_TRAVEL_SUPPORT */ +void _time_travel_print_bc_msg(void); +static inline void time_travel_print_bc_msg(void) +{ + if (time_travel_should_print_bc_msg) + _time_travel_print_bc_msg(); +} + #endif /* _UM_TIME_TRAVEL_H_ */ |