With host and guest both using radix translation, it is feasible
for the host to take interrupts that come from the guest with
relocation on, and that is in fact what the POWER9 hardware will
do when LPCR[AIL] = 3. All such interrupts use HSRR0/1 not SRR0/1
except for system call with LEV=1 (hcall).
Therefore this adds the KVM tests to the _HV variants of the
relocation-on interrupt handlers, and adds the KVM test to the
relocation-on system call entry point.
We also instantiate the relocation-on versions of the hypervisor
data storage and instruction interrupt handlers, since these can
occur with relocation on in radix guests.
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
64-bit Book3S exception handlers must find the dynamic kernel base
to add to the target address when branching beyond __end_interrupts,
in order to support kernel running at non-0 physical address.
Support this in KVM by branching with CTR, similarly to regular
interrupt handlers. The guest CTR saved in HSTATE_SCRATCH1 and
restored after the branch.
Without this, the host kernel hangs and crashes randomly when it is
running at a non-0 address and a KVM guest is started.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently all the low-power idle states are expected to wake up
at reset vector 0x100. Which is why the macro IDLE_STATE_ENTER_SEQ
that puts the CPU to an idle state and never returns.
On ISA v3.0, when the ESL and EC bits in the PSSCR are zero, the CPU
is expected to wake up at the next instruction of the idle
instruction.
This patch adds a new macro named IDLE_STATE_ENTER_SEQ_NORET for the
no-return variant and reuses the name IDLE_STATE_ENTER_SEQ
for a variant that allows resuming operation at the instruction next
to the idle-instruction.
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
A subsequent patch to make KVM handlers relocation-safe makes them
unusable from within alt section "else" cases (due to the way fixed
addresses are taken from within fixed section head code).
Stop open-coding the KVM handlers, and add them both as normal. A more
optimal fix may be to allow some level of alternate feature patching in
the exception macros themselves, but for now this will do.
The TRAMP_KVM handlers must be moved to the "virt" fixed section area
(name is arbitrary) in order to be closer to .text and avoid the dreaded
"relocation truncated to fit" error.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull powerpc updates from Michael Ellerman:
"Highlights include:
- Support for the kexec_file_load() syscall, which is a prereq for
secure and trusted boot.
- Prevent kernel execution of userspace on P9 Radix (similar to
SMEP/PXN).
- Sort the exception tables at build time, to save time at boot, and
store them as relative offsets to save space in the kernel image &
memory.
- Allow building the kernel with thin archives, which should allow us
to build an allyesconfig once some other fixes land.
- Build fixes to allow us to correctly rebuild when changing the
kernel endian from big to little or vice versa.
- Plumbing so that we can avoid doing a full mm TLB flush on P9
Radix.
- Initial stack protector support (-fstack-protector).
- Support for dumping the radix (aka. Linux) and hash page tables via
debugfs.
- Fix an oops in cxl coredump generation when cxl_get_fd() is used.
- Freescale updates from Scott: "Highlights include 8xx hugepage
support, qbman fixes/cleanup, device tree updates, and some misc
cleanup."
- Many and varied fixes and minor enhancements as always.
Thanks to:
Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Anshuman
Khandual, Anton Blanchard, Balbir Singh, Bartlomiej Zolnierkiewicz,
Christophe Jaillet, Christophe Leroy, Denis Kirjanov, Elimar
Riesebieter, Frederic Barrat, Gautham R. Shenoy, Geliang Tang, Geoff
Levand, Jack Miller, Johan Hovold, Lars-Peter Clausen, Libin,
Madhavan Srinivasan, Michael Neuling, Nathan Fontenot, Naveen N.
Rao, Nicholas Piggin, Pan Xinhui, Peter Senna Tschudin, Rashmica
Gupta, Rui Teng, Russell Currey, Scott Wood, Simon Guo, Suraj
Jitindar Singh, Thiago Jung Bauermann, Tobias Klauser, Vaibhav Jain"
[ And thanks to Michael, who took time off from a new baby to get this
pull request done. - Linus ]
* tag 'powerpc-4.10-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (174 commits)
powerpc/fsl/dts: add FMan node for t1042d4rdb
powerpc/fsl/dts: add sg_2500_aqr105_phy4 alias on t1024rdb
powerpc/fsl/dts: add QMan and BMan nodes on t1024
powerpc/fsl/dts: add QMan and BMan nodes on t1023
soc/fsl/qman: test: use DEFINE_SPINLOCK()
powerpc/fsl-lbc: use DEFINE_SPINLOCK()
powerpc/8xx: Implement support of hugepages
powerpc: get hugetlbpage handling more generic
powerpc: port 64 bits pgtable_cache to 32 bits
powerpc/boot: Request no dynamic linker for boot wrapper
soc/fsl/bman: Use resource_size instead of computation
soc/fsl/qe: use builtin_platform_driver
powerpc/fsl_pmc: use builtin_platform_driver
powerpc/83xx/suspend: use builtin_platform_driver
powerpc/ftrace: Fix the comments for ftrace_modify_code
powerpc/perf: macros for power9 format encoding
powerpc/perf: power9 raw event format encoding
powerpc/perf: update attribute_group data structure
powerpc/perf: factor out the event format field
powerpc/mm/iommu, vfio/spapr: Put pages on VFIO container shutdown
...
Exception handlers are aligned to 128 bytes (L1 cache) on 64s, which is
overkill. It can reduce the icache footprint of any individual exception
path. However taken as a whole, the expansion in icache footprint seems
likely to be counter-productive and cause more total misses.
Create IFETCH_ALIGN_SHIFT/BYTES, which should give optimal ifetch
alignment with much more reasonable alignment. This saves 1792 bytes
from head_64.o text with an allmodconfig build.
Other subarchitectures should define appropriate IFETCH_ALIGN_SHIFT
values if this becomes more widely used.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Wakeups from winkle set the low bit of the HSPRG0 register, to
distinguish it from other sleep states. This is also the PACA pointer.
The system reset exception handler fails to mask this bit away before
using this value before using it as the PACA pointer.
Fix this by adding a new type of exception prolog macro where we already
have the PACA set in r13, and have the system reset vector mask it out.
The winkle wakeup handler will store the masked value back into HSPRG0.
Fixes: fb479e44a9 ("powerpc/64s: relocation, register save fixes for system reset interrupt")
Cc: stable@vger.kernel.org # v3.0+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch does a couple of things. First of all, powernv immediately
explodes when running a relocated kernel, because the system reset
exception for handling sleeps does not do correct relocated branches.
Secondly, the sleep handling code trashes the condition and cfar
registers, which we would like to preserve for debugging purposes (for
non-sleep case exception).
This patch changes the exception to use the standard format that saves
registers before any tests or branches are made. It adds the test for
idle-wakeup as an "extra" to break out of the normal exception path.
Then it branches to a relocated idle handler that calls the various
idle handling functions.
After this patch, POWER8 CPU simulator now boots powernv kernel that is
running at non-zero.
Fixes: 948cf67c47 ("powerpc: Add NAP mode support on Power7 in HV mode")
Cc: stable@vger.kernel.org # v3.0+
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
power4_fixup_nap is called from the "common" handlers, not the virt/real
handlers, therefore it should itself be a common handler. Placing it
down in the trampoline space caused it to go out of reach of its
callers, requiring a trampoline inserted at the start of the text
section, which breaks the fixed section address calculations.
Fixes: da2bc4644c ("powerpc/64s: Add new exception vector macros")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This was not done before the big patches because I only noticed
them afterwards. It has become much easier to see which handlers
are branched to from which exception vectors now, and to see
exactly what vector space is being used for what.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Simple substitution. This is possible now that both parts of the OOL
initial handler get linked into their correct location.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This is not an exception handler as such, it's called from
local_irq_enable(), not exception entry.
Also clean up some now redundant comments at the end of the
consolidation series.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Use assembler sections of fixed size and location to arrange the 64-bit
Book3S exception vector code (64-bit Book3E also uses it in head_64.S
for 0x0..0x100).
This allows better flexibility in arranging exception code and hiding
unimportant details behind macros.
Gas sections can be a bit painful to use this way, mainly because the
assembler does not know where they will be finally linked. Taking
absolute addresses requires a bit of trickery for example, but it can
be hidden behind macros for the most part.
Generated code is mostly the same except locations, offsets, alignments.
The "+ 0x2" is only required for the trap number / kvm exit number,
which gets loaded as a constant into a register.
Previously, code also used + 0x2 for label names, but we changed to
using "H" to distinguish HV case for that. Remove the last vestiges
of that.
__after_prom_start is taking absolute address of a label in another
fixed section. Newer toolchains seemed to compile this okay, but older
ones do not. FIXED_SYMBOL_ABS_ADDR is more foolproof, it just takes an
additional line to define.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Move exception handler alignment directives into the head-64.h macros,
beause they will no longer work in-place after the next patch. This
slightly changes functions that have alignments applied and therefore
code generation, which is why it was not done initially (see earlier
patch).
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Create arch/powerpc/include/asm/head-64.h with macros that specify
an exception vector (name, type, location), which will be used to
label and lay out exceptions into the object file.
Naming is moved out of exception-64s.h, which is used to specify the
implementation of exception handlers.
objdump of generated code in exception vectors is unchanged except for
names. Alignment directives scattered around are annoying, but done
this way so that disassembly can verify identical instruction
generation before and after patch. These get cleaned up in future
patch.
We change the way KVMTEST works, explicitly passing EXC_HV or EXC_STD
rather than overloading the trap number. This removes the need to have
SOFTEN values for the overloaded trap numbers, eg. 0x502.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
