On Thu, Sep 14, 2023 at 08:43:46PM +0206, John Ogness wrote: > From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > > When a serial port is used for kernel console output, then all > modifications to the UART registers which are done from other contexts, > e.g. getty, termios, are interference points for the kernel console. > > So far this has been ignored and the printk output is based on the > principle of hope. The rework of the console infrastructure which aims to > support threaded and atomic consoles, requires to mark sections which > modify the UART registers as unsafe. This allows the atomic write function > to make informed decisions and eventually to restore operational state. It > also allows to prevent the regular UART code from modifying UART registers > while printk output is in progress. > > All modifications of UART registers are guarded by the UART port lock, > which provides an obvious synchronization point with the console > infrastructure. > > To avoid adding this functionality to all UART drivers, wrap the > spin_[un]lock*() invocations for uart_port::lock into helper functions > which just contain the spin_[un]lock*() invocations for now. In a > subsequent step these helpers will gain the console synchronization > mechanisms. > > Converted with coccinelle. No functional change. > > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> This lacks a Signed-off line by John. Otherwise looks fine to me. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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