diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2023-09-16 22:20:00 +0300 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2023-09-18 18:03:45 +0300 |
| commit | 6b93bb41f6eaa1cc5c5f30ec3b687b380f116cd0 (patch) | |
| tree | 50a6cc0fc648eac631c23acf94a73045ec316881 /kernel/printk/Makefile | |
| parent | 01a46efcd8f4af44691d7273edf0c5c07dc9b619 (diff) | |
| download | linux-6b93bb41f6eaa1cc5c5f30ec3b687b380f116cd0.tar.xz | |
printk: Add non-BKL (nbcon) console basic infrastructure
The current console/printk subsystem is protected by a Big Kernel Lock,
(aka console_lock) which has ill defined semantics and is more or less
stateless. This puts severe limitations on the console subsystem and
makes forced takeover and output in emergency and panic situations a
fragile endeavour that is based on try and pray.
The goal of non-BKL (nbcon) consoles is to break out of the console lock
jail and to provide a new infrastructure that avoids the pitfalls and
also allows console drivers to be gradually converted over.
The proposed infrastructure aims for the following properties:
- Per console locking instead of global locking
- Per console state that allows to make informed decisions
- Stateful handover and takeover
As a first step, state is added to struct console. The per console state
is an atomic_t using a 32bit bit field.
Reserve state bits, which will be populated later in the series. Wire
it up into the console register/unregister functionality.
It was decided to use a bitfield because using a plain u32 with
mask/shift operations resulted in uncomprehensible code.
Co-developed-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Thomas Gleixner (Intel) <tglx@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230916192007.608398-2-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk/Makefile')
| -rw-r--r-- | kernel/printk/Makefile | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile index f5b388e810b9..39a2b61c7232 100644 --- a/kernel/printk/Makefile +++ b/kernel/printk/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-only obj-y = printk.o -obj-$(CONFIG_PRINTK) += printk_safe.o +obj-$(CONFIG_PRINTK) += printk_safe.o nbcon.o obj-$(CONFIG_A11Y_BRAILLE_CONSOLE) += braille.o obj-$(CONFIG_PRINTK_INDEX) += index.o |