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| author | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-08-05 18:22:30 +0400 |
|---|---|---|
| committer | Jason Wessel <jason.wessel@windriver.com> | 2010-08-05 18:22:30 +0400 |
| commit | b45cfba4e9005d64d419718e7ff7f7cab44c1994 (patch) | |
| tree | 2d454a67c9a87ffc01579d958f9d95dd5e13170e /drivers/char/vt.c | |
| parent | 3fa43aba08c5b5a4b407e402606fbe463239b14a (diff) | |
| download | linux-b45cfba4e9005d64d419718e7ff7f7cab44c1994.tar.xz | |
vt,console,kdb: implement atomic console enter/leave functions
These functions allow the kernel debugger to save and restore the
state of the system console.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
CC: David Airlie <airlied@linux.ie>
CC: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers/char/vt.c')
| -rw-r--r-- | drivers/char/vt.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/char/vt.c b/drivers/char/vt.c index 7cdb6ee569cd..117ce99115dc 100644 --- a/drivers/char/vt.c +++ b/drivers/char/vt.c @@ -187,10 +187,15 @@ static DECLARE_WORK(console_work, console_callback); * fg_console is the current virtual console, * last_console is the last used one, * want_console is the console we want to switch to, + * saved_* variants are for save/restore around kernel debugger enter/leave */ int fg_console; int last_console; int want_console = -1; +int saved_fg_console; +int saved_last_console; +int saved_want_console; +int saved_vc_mode; /* * For each existing display, we have a pointer to console currently visible @@ -3414,6 +3419,62 @@ int con_is_bound(const struct consw *csw) EXPORT_SYMBOL(con_is_bound); /** + * con_debug_enter - prepare the console for the kernel debugger + * @sw: console driver + * + * Called when the console is taken over by the kernel debugger, this + * function needs to save the current console state, then put the console + * into a state suitable for the kernel debugger. + * + * RETURNS: + * Zero on success, nonzero if a failure occurred when trying to prepare + * the console for the debugger. + */ +int con_debug_enter(struct vc_data *vc) +{ + int ret = 0; + + saved_fg_console = fg_console; + saved_last_console = last_console; + saved_want_console = want_console; + saved_vc_mode = vc->vc_mode; + vc->vc_mode = KD_TEXT; + console_blanked = 0; + if (vc->vc_sw->con_debug_enter) + ret = vc->vc_sw->con_debug_enter(vc); + return ret; +} +EXPORT_SYMBOL_GPL(con_debug_enter); + +/** + * con_debug_leave - restore console state + * @sw: console driver + * + * Restore the console state to what it was before the kernel debugger + * was invoked. + * + * RETURNS: + * Zero on success, nonzero if a failure occurred when trying to restore + * the console. + */ +int con_debug_leave(void) +{ + struct vc_data *vc; + int ret = 0; + + fg_console = saved_fg_console; + last_console = saved_last_console; + want_console = saved_want_console; + vc_cons[fg_console].d->vc_mode = saved_vc_mode; + + vc = vc_cons[fg_console].d; + if (vc->vc_sw->con_debug_leave) + ret = vc->vc_sw->con_debug_leave(vc); + return ret; +} +EXPORT_SYMBOL_GPL(con_debug_leave); + +/** * register_con_driver - register console driver to console layer * @csw: console driver * @first: the first console to take over, minimum value is 0 |