The GUEST_STATE_BUFFER_TEST config option should default
to KUNIT_ALL_TESTS so that if all tests are enabled then
it is included, but currently the 'default KUNIT_ALL_TESTS'
statement is shadowed by 'def_tristate n',
meaning that this second default statement is currently dead code.
It looks to me like the commit
6ccbbc33f0 ("KVM: PPC: Add helper library for Guest State Buffers")
intended to set the default to KUNIT_ALL_TESTS, but mistakenly
missed the def_tristate.
This dead code was found by kconfirm, a static analysis tool for Kconfig.
Fixes: 6ccbbc33f0 ("KVM: PPC: Add helper library for Guest State Buffers")
Signed-off-by: Julian Braha <julianbraha@gmail.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Reviewed-by: Amit Machhiwal <amachhiw@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20260405161545.161006-1-julianbraha@gmail.com
The IBM Cell blade support was the last user of UDBG_RTAS_CONSOLE.
Although it's still possible to build it via
PPC_EARLY_DEBUG_UDBG_RTAS_CONSOLE, AFAIK it's not useful on any
other platfoms, because only Cell and JS20 era machines provided the
RTAS get/put-term-char functions.
If anyone is using it or needs it we can always resurrect it from git.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20241218105523.416573-19-mpe@ellerman.id.au
The non-standard "fast endian switch" syscall was added in 2008[1],
but was never widely used. It was disabled by default in 2017[2], and
there's no evidence it's ever been used since.
Remove it entirely.
A normal endian switch syscall was added in 2015[3].
[1]: 745a14cc26 ("[POWERPC] Add fast little-endian switch system call")
[2]: 529d235a0e ("powerpc: Add a proper syscall for switching endianness")
[3]: 727f13616c ("powerpc: Disable the fast-endian switch syscall by default")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240823070830.1269033-1-mpe@ellerman.id.au
Allmodconfig kernels produce a missing-prototypes warning:
arch/powerpc/platforms/ps3/gelic_udbg.c:239:6: error: no previous prototype for 'udbg_shutdown_ps3gelic' [-Werror=missing-prototypes]
Move the declaration from a local header to asm/ps3.h where it can be
seen from both the caller and the definition.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Geoff Levand <geoff@infradead.org>
Acked-by: Jakub Kicinski <kuba@kernel.org>
[mpe: Drop CONFIG_PS3GELIC_UDBG to fix build error]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231108125843.3806765-18-arnd@kernel.org
PowerPC has a 'btext' font used for the console which is almost identical
to the shared font_sun8x16, so use it rather than duplicating the data.
They were actually identical until about a decade ago when
commit bcfbeecea1 ("drivers: console: font_: Change a glyph from
"broken bar" to "vertical line"")
which changed the | in the shared font to be a solid
bar rather than a broken bar. That's the only difference.
This was originally spotted by the PMF source code analyser, which
noticed that sparc does the same thing with the same data, and they
also share a bunch of functions to manipulate the data. I've previously
posted a near identical patch for sparc.
Tested very lightly with a boot without FS in qemu.
Signed-off-by: "Dr. David Alan Gilbert" <linux@treblig.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230825142754.1487900-1-linux@treblig.org
The PAPR "Nestedv2" guest API introduces the concept of a Guest State
Buffer for communication about L2 guests between L1 and L0 hosts.
In the new API, the L0 manages the L2 on behalf of the L1. This means
that if the L1 needs to change L2 state (e.g. GPRs, SPRs, partition
table...), it must request the L0 perform the modification. If the
nested host needs to read L2 state likewise this request must
go through the L0.
The Guest State Buffer is a Type-Length-Value style data format defined
in the PAPR which assigns all relevant partition state a unique
identity. Unlike a typical TLV format the length is redundant as the
length of each identity is fixed but is included for checking
correctness.
A guest state buffer consists of an element count followed by a stream
of elements, where elements are composed of an ID number, data length,
then the data:
Header:
<---4 bytes--->
+----------------+-----
| Element Count | Elements...
+----------------+-----
Element:
<----2 bytes---> <-2 bytes-> <-Length bytes->
+----------------+-----------+----------------+
| Guest State ID | Length | Data |
+----------------+-----------+----------------+
Guest State IDs have other attributes defined in the PAPR such as
whether they are per thread or per guest, or read-only.
Introduce a library for using guest state buffers. This includes support
for actions such as creating buffers, adding elements to buffers,
reading the value of elements and parsing buffers. This will be used
later by the nestedv2 guest support.
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230914030600.16993-9-jniethe5@gmail.com
Currently powerpc early debugging contains lot of platform specific
options, but does not support standard UART / serial 16550 console.
Later legacy_serial.c code supports registering UART as early debug console
from device tree but it is not early during booting, but rather later after
machine description code finishes.
So for real early debugging via UART is current code unsuitable.
Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550
which enable Serial 16550 console on address defined by new option
CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option
CONFIG_PPC_EARLY_DEBUG_16550_STRIDE.
With this change it is possible to debug powerpc machine descriptor code.
For example this early debugging code can print on serial console also
"No suitable machine description found" error which is done before
legacy_serial.c code.
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220822231501.16827-1-pali@kernel.org
We now have memory organised in a way that allows
implementing KASAN.
Unlike book3s/64, book3e always has translation active so the only
thing needed to use KASAN is to setup an early zero shadow mapping
just after setting a stack pointer and before calling early_setup().
The memory layout is now as follows
+------------------------+ Kernel virtual map end (0xc000200000000000)
| |
| 16TB of KASAN map |
| |
+------------------------+ Kernel KASAN shadow map start
| |
| 16TB of IO map |
| |
+------------------------+ Kernel IO map start
| |
| 16TB of vmemmap |
| |
+------------------------+ Kernel vmemmap start
| |
| 16TB of vmap |
| |
+------------------------+ Kernel virt start (0xc000100000000000)
| |
| 64TB of linear mem |
| |
+------------------------+ Kernel linear (0xc.....)
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0bef8beda27baf71e3b9e8b13e620fba6e19499b.1656427701.git.christophe.leroy@csgroup.eu
Implement a limited form of KASAN for Book3S 64-bit machines running under
the Radix MMU, supporting only outline mode.
- Enable the compiler instrumentation to check addresses and maintain the
shadow region. (This is the guts of KASAN which we can easily reuse.)
- Require kasan-vmalloc support to handle modules and anything else in
vmalloc space.
- KASAN needs to be able to validate all pointer accesses, but we can't
instrument all kernel addresses - only linear map and vmalloc. On boot,
set up a single page of read-only shadow that marks all iomap and
vmemmap accesses as valid.
- Document KASAN in powerpc docs.
Background
----------
KASAN support on Book3S is a bit tricky to get right:
- It would be good to support inline instrumentation so as to be able to
catch stack issues that cannot be caught with outline mode.
- Inline instrumentation requires a fixed offset.
- Book3S runs code with translations off ("real mode") during boot,
including a lot of generic device-tree parsing code which is used to
determine MMU features.
[ppc64 mm note: The kernel installs a linear mapping at effective
address c000...-c008.... This is a one-to-one mapping with physical
memory from 0000... onward. Because of how memory accesses work on
powerpc 64-bit Book3S, a kernel pointer in the linear map accesses the
same memory both with translations on (accessing as an 'effective
address'), and with translations off (accessing as a 'real
address'). This works in both guests and the hypervisor. For more
details, see s5.7 of Book III of version 3 of the ISA, in particular
the Storage Control Overview, s5.7.3, and s5.7.5 - noting that this
KASAN implementation currently only supports Radix.]
- Some code - most notably a lot of KVM code - also runs with translations
off after boot.
- Therefore any offset has to point to memory that is valid with
translations on or off.
One approach is just to give up on inline instrumentation. This way
boot-time checks can be delayed until after the MMU is set is up, and we
can just not instrument any code that runs with translations off after
booting. Take this approach for now and require outline instrumentation.
Previous attempts allowed inline instrumentation. However, they came with
some unfortunate restrictions: only physically contiguous memory could be
used and it had to be specified at compile time. Maybe we can do better in
the future.
[paulus@ozlabs.org - Rebased onto 5.17. Note that a kernel with
CONFIG_KASAN=y will crash during boot on a machine using HPT
translation because not all the entry points to the generic
KASAN code are protected with a call to kasan_arch_is_ready().]
Originally-by: Balbir Singh <bsingharora@gmail.com> # ppc64 out-of-line radix version
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
[mpe: Update copyright year and comment formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YoTE69OQwiG7z+Gu@cleo
When an interrupt is taken, the SRR registers are set to return to where
it left off. Unless they are modified in the meantime, or the return
address or MSR are modified, there is no need to reload these registers
when returning from interrupt.
Introduce per-CPU flags that track the validity of SRR and HSRR
registers. These are cleared when returning from interrupt, when
using the registers for something else (e.g., OPAL calls), when
adjusting the return address or MSR of a context, and when context
switching (which changes the return address and MSR).
This improves the performance of interrupt returns.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fold in fixup patch from Nick]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com
When neither CONFIG_PCI nor CONFIG_IBMVIO is set/enabled, iommu.c has a
build error. The fault injection code is not useful in that kernel config,
so make the FAIL_IOMMU option depend on PCI || IBMVIO.
Prevents this build error (warning escalated to error):
../arch/powerpc/kernel/iommu.c:178:30: error: 'fail_iommu_bus_notifier' defined but not used [-Werror=unused-variable]
178 | static struct notifier_block fail_iommu_bus_notifier = {
Fixes: d6b9a81b2a ("powerpc: IOMMU fault injection")
Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210404192623.10697-1-rdunlap@infradead.org
Operations which write to memory and special purpose registers should be
restricted on systems with integrity guarantees (such as Secure Boot)
and, optionally, to avoid self-destructive behaviors.
Add a config option, XMON_DEFAULT_RO_MODE, to set default xmon behavior.
The kernel cmdline options xmon=ro and xmon=rw override this default.
The following xmon operations are affected:
memops:
disable memmove
disable memset
disable memzcan
memex:
no-op'd mwrite
super_regs:
no-op'd write_spr
bpt_cmds:
disable
proc_call:
disable
Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
Reviewed-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Implement code to walk all pages and warn if any are found to be both
writable and executable. Depends on STRICT_KERNEL_RWX enabled, and is
behind the DEBUG_WX config option.
This only runs on boot and has no runtime performance implications.
Very heavily influenced (and in some cases copied verbatim) from the
ARM64 code written by Laura Abbott (thanks!), since our ptdump
infrastructure is similar.
Signed-off-by: Russell Currey <ruscur@russell.cc>
[mpe: Fixup build error when disabled]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch prepares a shadow area for KASAN.
The shadow area will be at the top of the kernel virtual
memory space above the fixmap area and will occupy one
eighth of the total kernel virtual memory space.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
