8b79d4e994
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 <kernel@esmil.dk>
Fixes: 88ead68e76 ("tty: Add SBI debug console support to HVC SBI driver")
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Reviewed-by: Paul Walmsley <paul.walmsley@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240214153429.16484-2-palmer@rivosinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
137 lines
4.2 KiB
Plaintext
137 lines
4.2 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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config HVC_DRIVER
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bool
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help
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Generic "hypervisor virtual console" infrastructure for various
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hypervisors (pSeries, iSeries, Xen).
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It will automatically be selected if one of the back-end console drivers
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is selected.
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config HVC_IRQ
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bool
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config HVC_CONSOLE
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bool "pSeries Hypervisor Virtual Console support"
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depends on PPC_PSERIES
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select HVC_DRIVER
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select HVC_IRQ
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help
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pSeries machines when partitioned support a hypervisor virtual
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console. This driver allows each pSeries partition to have a console
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which is accessed via the HMC.
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config HVC_OLD_HVSI
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bool "Old driver for pSeries serial port (/dev/hvsi*)"
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depends on HVC_CONSOLE
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config HVC_OPAL
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bool "OPAL Console support"
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depends on PPC_POWERNV
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select HVC_DRIVER
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select HVC_IRQ
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default y
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help
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PowerNV machines running under OPAL need that driver to get a console
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config HVC_RTAS
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bool "IBM RTAS Console support"
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depends on PPC_RTAS
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select HVC_DRIVER
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help
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IBM Console device driver which makes use of RTAS
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config HVC_IUCV
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bool "z/VM IUCV Hypervisor console support (VM only)"
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depends on S390 && NET
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select HVC_DRIVER
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select IUCV
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default y
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help
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This driver provides a Hypervisor console (HVC) back-end to access
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a Linux (console) terminal via a z/VM IUCV communication path.
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config HVC_XEN
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bool "Xen Hypervisor Console support"
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depends on XEN
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select HVC_DRIVER
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select HVC_IRQ
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default y
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help
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Xen virtual console device driver
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config HVC_XEN_FRONTEND
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bool "Xen Hypervisor Multiple Consoles support"
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depends on HVC_XEN
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select XEN_XENBUS_FRONTEND
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default y
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help
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Xen driver for secondary virtual consoles
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config HVC_UDBG
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bool "udbg based fake hypervisor console"
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depends on PPC
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select HVC_DRIVER
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help
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This is meant to be used during HW bring up or debugging when
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no other console mechanism exist but udbg, to get you a quick
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console for userspace. Do NOT enable in production kernels.
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config HVC_DCC
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bool "ARM JTAG DCC console"
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depends on ARM || ARM64
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select HVC_DRIVER
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select SERIAL_CORE_CONSOLE
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help
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This console uses the JTAG DCC on ARM to create a console under the HVC
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driver. This console is used through a JTAG only on ARM. If you don't have
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a JTAG then you probably don't want this option.
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config HVC_DCC_SERIALIZE_SMP
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bool "Use DCC only on CPU core 0"
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depends on SMP && HVC_DCC
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help
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This is a DEBUG option to serialize all console input and output to CPU 0.
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Some external debuggers, do not handle reads/writes from/to DCC on more
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than one CPU core. Each core has its own DCC device registers, so when a
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CPU core reads or writes from/to DCC, it only accesses its own DCC device.
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Since kernel code can run on any CPU core, every time the kernel wants to
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write to the console, it might write to a different DCC.
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In SMP mode, external debuggers create multiple windows, and each window
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shows the DCC output only from that core's DCC. The result is that
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console output is either lost or scattered across windows.
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Enable this option only if you are sure that you do not need features like
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CPU hotplug to work. For example, during early chipset bringups without
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debug serial console support. If unsure, say N.
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config HVC_RISCV_SBI
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bool "RISC-V SBI console support"
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depends on RISCV_SBI && NONPORTABLE
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select HVC_DRIVER
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help
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This enables support for console output via RISC-V SBI calls, which
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is normally used only during boot to output printk. This driver
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conflicts with real console drivers and should not be enabled on
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systems that directly access the console.
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If you don't know what do to here, say N.
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config HVCS
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tristate "IBM Hypervisor Virtual Console Server support"
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depends on PPC_PSERIES && HVC_CONSOLE
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help
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Partitionable IBM Power5 ppc64 machines allow hosting of
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firmware virtual consoles from one Linux partition by
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another Linux partition. This driver allows console data
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from Linux partitions to be accessed through TTY device
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interfaces in the device tree of a Linux partition running
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this driver.
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To compile this driver as a module, choose M here: the
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module will be called hvcs. Additionally, this module
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will depend on arch specific APIs exported from hvcserver.ko
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which will also be compiled when this driver is built as a
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module.
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