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4d2bb3f500
On pseries machines, consoles are provided by the hypervisor using
a low level get_chars/put_chars type interface. However, this is
really just a transport to the service processor which implements
them either as "raw" console (networked consoles, HMC, ...) or as
"hvsi" serial ports.
The later is a simple packet protocol on top of the raw character
interface that is supposed to convey additional "serial port" style
semantics. In practice however, all it does is provide a way to
read the CD line and set/clear our DTR line, that's it.
We currently implement the "raw" protocol as an hvc console backend
(/dev/hvcN) and the "hvsi" protocol using a separate tty driver
(/dev/hvsi0).
However this is quite impractical. The arbitrary difference between
the two type of devices has been a major source of user (and distro)
confusion. Additionally, there's an additional mini -hvsi implementation
in the pseries platform code for our low level debug console and early
boot kernel messages, which means code duplication, though that low
level variant is impractical as it's incapable of doing the initial
protocol negociation to establish the link to the FSP.
This essentially replaces the dedicated hvsi driver and the platform
udbg code completely by extending the existing hvc_vio backend used
in "raw" mode so that:
- It now supports HVSI as well
- We add support for hvc backend providing tiocm{get,set}
- It also provides a udbg interface for early debug and boot console
This is overall less code, though this will only be obvious once we
remove the old "hvsi" driver, which is still available for now. When
the old driver is enabled, the new code still kicks in for the low
level udbg console, replacing the old mini implementation in the platform
code, it just doesn't provide the higher level "hvc" interface.
In addition to producing generally simler code, this has several benefits
over our current situation:
- The user/distro only has to deal with /dev/hvcN for the hypervisor
console, avoiding all sort of confusion that has plagued us in the past
- The tty, kernel and low level debug console all use the same code
base which supports the full protocol establishment process, thus the
console is now available much earlier than it used to be with the
old HVSI driver. The kernel console works much earlier and udbg is
available much earlier too. Hackers can enable a hard coded very-early
debug console as well that works with HVSI (previously that was only
supported for the "raw" mode).
I've tried to keep the same semantics as hvsi relative to how I react
to things like CD changes, with some subtle differences though:
- I clear DTR on close if HUPCL is set
- Current hvsi triggers a hangup if it detects a up->down transition
on CD (you can still open a console with CD down). My new implementation
triggers a hangup if the link to the FSP is severed, and severs it upon
detecting a up->down transition on CD.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
302 lines
9.1 KiB
Plaintext
302 lines
9.1 KiB
Plaintext
menu "Kernel hacking"
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source "lib/Kconfig.debug"
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config PPC_DISABLE_WERROR
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bool "Don't build arch/powerpc code with -Werror"
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default n
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help
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This option tells the compiler NOT to build the code under
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arch/powerpc with the -Werror flag (which means warnings
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are treated as errors).
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Only enable this if you are hitting a build failure in the
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arch/powerpc code caused by a warning, and you don't feel
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inclined to fix it.
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config PPC_WERROR
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bool
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depends on !PPC_DISABLE_WERROR
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default y
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config PRINT_STACK_DEPTH
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int "Stack depth to print" if DEBUG_KERNEL
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default 64
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help
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This option allows you to set the stack depth that the kernel
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prints in stack traces. This can be useful if your display is
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too small and stack traces cause important information to
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scroll off the screen.
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config DEBUG_STACKOVERFLOW
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bool "Check for stack overflows"
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depends on DEBUG_KERNEL
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help
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This option will cause messages to be printed if free stack space
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drops below a certain limit.
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config HCALL_STATS
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bool "Hypervisor call instrumentation"
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depends on PPC_PSERIES && DEBUG_FS && TRACEPOINTS
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help
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Adds code to keep track of the number of hypervisor calls made and
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the amount of time spent in hypervisor calls. Wall time spent in
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each call is always calculated, and if available CPU cycles spent
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are also calculated. A directory named hcall_inst is added at the
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root of the debugfs filesystem. Within the hcall_inst directory
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are files that contain CPU specific call statistics.
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This option will add a small amount of overhead to all hypervisor
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calls.
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config PPC_EMULATED_STATS
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bool "Emulated instructions tracking"
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depends on DEBUG_FS
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help
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Adds code to keep track of the number of instructions that are
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emulated by the in-kernel emulator. Counters for the various classes
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of emulated instructions are available under
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powerpc/emulated_instructions/ in the root of the debugfs file
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system. Optionally (controlled by
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powerpc/emulated_instructions/do_warn in debugfs), rate-limited
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warnings can be printed to the console when instructions are
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emulated.
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config CODE_PATCHING_SELFTEST
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bool "Run self-tests of the code-patching code."
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depends on DEBUG_KERNEL
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default n
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config FTR_FIXUP_SELFTEST
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bool "Run self-tests of the feature-fixup code."
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depends on DEBUG_KERNEL
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default n
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config MSI_BITMAP_SELFTEST
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bool "Run self-tests of the MSI bitmap code."
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depends on DEBUG_KERNEL
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default n
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config XMON
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bool "Include xmon kernel debugger"
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depends on DEBUG_KERNEL
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help
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Include in-kernel hooks for the xmon kernel monitor/debugger.
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Unless you are intending to debug the kernel, say N here.
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Make sure to enable also CONFIG_BOOTX_TEXT on Macs. Otherwise
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nothing will appear on the screen (xmon writes directly to the
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framebuffer memory).
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The cmdline option 'xmon' or 'xmon=early' will drop into xmon
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very early during boot. 'xmon=on' will just enable the xmon
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debugger hooks. 'xmon=off' will disable the debugger hooks
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if CONFIG_XMON_DEFAULT is set.
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xmon will print a backtrace on the very first invocation.
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'xmon=nobt' will disable this autobacktrace.
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config XMON_DEFAULT
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bool "Enable xmon by default"
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depends on XMON
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help
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xmon is normally disabled unless booted with 'xmon=on'.
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Use 'xmon=off' to disable xmon init during runtime.
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config XMON_DISASSEMBLY
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bool "Include disassembly support in xmon"
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depends on XMON
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default y
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help
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Include support for disassembling in xmon. You probably want
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to say Y here, unless you're building for a memory-constrained
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system.
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config DEBUGGER
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bool
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depends on KGDB || XMON
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default y
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config VIRQ_DEBUG
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bool "Expose hardware/virtual IRQ mapping via debugfs"
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depends on DEBUG_FS
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help
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This option will show the mapping relationship between hardware irq
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numbers and virtual irq numbers. The mapping is exposed via debugfs
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in the file powerpc/virq_mapping.
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If you don't know what this means you don't need it.
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config BDI_SWITCH
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bool "Include BDI-2000 user context switcher"
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depends on DEBUG_KERNEL && PPC32
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help
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Include in-kernel support for the Abatron BDI2000 debugger.
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Unless you are intending to debug the kernel with one of these
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machines, say N here.
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config BOOTX_TEXT
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bool "Support for early boot text console (BootX or OpenFirmware only)"
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depends on PPC_OF && PPC_BOOK3S
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help
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Say Y here to see progress messages from the boot firmware in text
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mode. Requires either BootX or Open Firmware.
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config PPC_EARLY_DEBUG
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bool "Early debugging (dangerous)"
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# PPC_EARLY_DEBUG on 440 leaves AS=1 mappings above the TLB high water
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# mark, which doesn't work with current 440 KVM.
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depends on !KVM
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help
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Say Y to enable some early debugging facilities that may be available
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for your processor/board combination. Those facilities are hacks
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intended to debug problems early during boot, this should not be
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enabled in a production kernel.
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Note that enabling this will also cause the kernel default log level
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to be pushed to max automatically very early during boot
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choice
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prompt "Early debugging console"
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depends on PPC_EARLY_DEBUG
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help
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Use the selected console for early debugging. Careful, if you
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enable debugging for the wrong type of machine your kernel
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_will not boot_.
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config PPC_EARLY_DEBUG_LPAR
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bool "LPAR HV Console"
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depends on PPC_PSERIES
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help
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Select this to enable early debugging for a machine with a HVC
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console on vterm 0.
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config PPC_EARLY_DEBUG_LPAR_HVSI
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bool "LPAR HVSI Console"
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depends on PPC_PSERIES
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help
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Select this to enable early debugging for a machine with a HVSI
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console on a specified vterm.
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config PPC_EARLY_DEBUG_G5
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bool "Apple G5"
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depends on PPC_PMAC64
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help
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Select this to enable early debugging for Apple G5 machines.
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config PPC_EARLY_DEBUG_RTAS_PANEL
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bool "RTAS Panel"
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depends on PPC_RTAS
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help
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Select this to enable early debugging via the RTAS panel.
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config PPC_EARLY_DEBUG_RTAS_CONSOLE
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bool "RTAS Console"
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depends on PPC_RTAS
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select UDBG_RTAS_CONSOLE
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help
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Select this to enable early debugging via the RTAS console.
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config PPC_EARLY_DEBUG_MAPLE
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bool "Maple real mode"
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depends on PPC_MAPLE
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help
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Select this to enable early debugging for Maple.
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config PPC_EARLY_DEBUG_ISERIES
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bool "iSeries HV Console"
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depends on PPC_ISERIES
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help
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Select this to enable early debugging for legacy iSeries. You need
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to hit "Ctrl-x Ctrl-x" to see the messages on the console.
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config PPC_EARLY_DEBUG_PAS_REALMODE
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bool "PA Semi real mode"
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depends on PPC_PASEMI
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help
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Select this to enable early debugging for PA Semi.
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Output will be on UART0.
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config PPC_EARLY_DEBUG_BEAT
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bool "Beat HV Console"
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depends on PPC_CELLEB
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select PPC_UDBG_BEAT
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help
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Select this to enable early debugging for Celleb with Beat.
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config PPC_EARLY_DEBUG_44x
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bool "Early serial debugging for IBM/AMCC 44x CPUs"
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depends on 44x
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help
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Select this to enable early debugging for IBM 44x chips via the
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inbuilt serial port. If you enable this, ensure you set
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PPC_EARLY_DEBUG_44x_PHYSLOW below to suit your target board.
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config PPC_EARLY_DEBUG_40x
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bool "Early serial debugging for IBM/AMCC 40x CPUs"
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depends on 40x
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help
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Select this to enable early debugging for IBM 40x chips via the
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inbuilt serial port. This works on chips with a 16550 compatible
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UART. Xilinx chips with uartlite cannot use this option.
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config PPC_EARLY_DEBUG_CPM
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bool "Early serial debugging for Freescale CPM-based serial ports"
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depends on SERIAL_CPM
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select PIN_TLB if PPC_8xx
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help
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Select this to enable early debugging for Freescale chips
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using a CPM-based serial port. This assumes that the bootwrapper
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has run, and set up the CPM in a particular way.
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config PPC_EARLY_DEBUG_USBGECKO
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bool "Early debugging through the USB Gecko adapter"
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depends on GAMECUBE_COMMON
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select USBGECKO_UDBG
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help
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Select this to enable early debugging for Nintendo GameCube/Wii
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consoles via an external USB Gecko adapter.
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config PPC_EARLY_DEBUG_WSP
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bool "Early debugging via WSP's internal UART"
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depends on PPC_WSP
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select PPC_UDBG_16550
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endchoice
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config PPC_EARLY_DEBUG_HVSI_VTERMNO
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hex "vterm number to use with early debug HVSI"
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depends on PPC_EARLY_DEBUG_LPAR_HVSI
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default "0x30000000"
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help
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You probably want 0x30000000 for your first serial port and
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0x30000001 for your second one
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config PPC_EARLY_DEBUG_44x_PHYSLOW
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hex "Low 32 bits of early debug UART physical address"
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depends on PPC_EARLY_DEBUG_44x
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default "0x40000200"
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help
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You probably want 0x40000200 for ebony boards and
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0x40000300 for taishan
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config PPC_EARLY_DEBUG_44x_PHYSHIGH
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hex "EPRN of early debug UART physical address"
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depends on PPC_EARLY_DEBUG_44x
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default "0x1"
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config PPC_EARLY_DEBUG_40x_PHYSADDR
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hex "Early debug UART physical address"
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depends on PPC_EARLY_DEBUG_40x
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default "0xef600300"
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config PPC_EARLY_DEBUG_CPM_ADDR
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hex "CPM UART early debug transmit descriptor address"
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depends on PPC_EARLY_DEBUG_CPM
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default "0xfa202008" if PPC_EP88XC
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default "0xf0001ff8" if CPM2
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default "0xff002008" if CPM1
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help
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This specifies the address of the transmit descriptor
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used for early debug output. Because it is needed before
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platform probing is done, all platforms selected must
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share the same address.
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endmenu
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