2024-02-14 16:00:22

by Palmer Dabbelt

[permalink] [raw]
Subject: [PATCH] tty: hvc: Don't enable the RISC-V SBI console by default

From: Palmer Dabbelt <[email protected]>

The new SBI console has the same problem as the old one: there's only
one shared backing hardware and no synchronization, so the two drivers
end up stepping on each other. This was the same issue the old SBI-0.1
console drivers had, but that was disabled by default when SBI-0.1 was.

So just mark the new driver as nonportable.

Reported-by: Emil Renner Berthing <[email protected]>
Fixes: 88ead68e764c ("tty: Add SBI debug console support to HVC SBI driver")
Signed-off-by: Palmer Dabbelt <[email protected]>
---
drivers/tty/hvc/Kconfig | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/hvc/Kconfig b/drivers/tty/hvc/Kconfig
index 6e05c5c7bca1..c2a4e88b328f 100644
--- a/drivers/tty/hvc/Kconfig
+++ b/drivers/tty/hvc/Kconfig
@@ -108,13 +108,15 @@ config HVC_DCC_SERIALIZE_SMP

config HVC_RISCV_SBI
bool "RISC-V SBI console support"
- depends on RISCV_SBI
+ depends on RISCV_SBI && NONPORTABLE
select HVC_DRIVER
help
This enables support for console output via RISC-V SBI calls, which
- is normally used only during boot to output printk.
+ is normally used only during boot to output printk. This driver
+ conflicts with real console drivers and should not be enabled on
+ systems that directly access the console.

- If you don't know what do to here, say Y.
+ If you don't know what do to here, say N.

config HVCS
tristate "IBM Hypervisor Virtual Console Server support"
--
2.43.0



Subject: Re: [PATCH] tty: hvc: Don't enable the RISC-V SBI console by default

Hello:

This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <[email protected]>:

On Wed, 14 Feb 2024 07:34:30 -0800 you wrote:
> From: Palmer Dabbelt <[email protected]>
>
> The new SBI console has the same problem as the old one: there's only
> one shared backing hardware and no synchronization, so the two drivers
> end up stepping on each other. This was the same issue the old SBI-0.1
> console drivers had, but that was disabled by default when SBI-0.1 was.
>
> [...]

Here is the summary with links:
- tty: hvc: Don't enable the RISC-V SBI console by default
https://git.kernel.org/riscv/c/481860974faa

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html