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GCC v13.1 updated support for -fpatchable-function-entry on ppc64le to
emit nops after the local entry point, rather than before it. This
allows us to use this in the kernel for ftrace purposes. A new script is
added under arch/powerpc/tools/ to help detect if nops are emitted after
the function local entry point, or before the global entry point.
With -fpatchable-function-entry, we no longer have the profiling
instructions generated at function entry, so we only need to validate
the presence of two nops at the ftrace location in ftrace_init_nop(). We
patch the preceding instruction with 'mflr r0' to match the
-mprofile-kernel ABI for subsequent ftrace use.
This changes the profiling instructions used on ppc32. The default -pg
option emits an additional 'stw' instruction after 'mflr r0' and before
the branch to _mcount 'bl _mcount'. This is very similar to the original
-mprofile-kernel implementation on ppc64le, where an additional 'std'
instruction was used to save LR to its save location in the caller's
stackframe. Subsequently, this additional store was removed in later
compiler versions for performance reasons. The same reasons apply for
ppc32 so we only patch in a 'mflr r0'.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/68586d22981a2c3bb45f27a2b621173d10a7d092.1687166935.git.naveen@kernel.org
Implement ftrace_replace_code() to consolidate logic from the different
ftrace patching routines: ftrace_make_nop(), ftrace_make_call() and
ftrace_modify_call(). Note that ftrace_make_call() is still required
primarily to handle patching modules during their load time. The other
two routines should no longer be called.
This lays the groundwork to enable better control in patching ftrace
locations, including the ability to nop-out preceding profiling
instructions when ftrace is disabled.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/c28f852225646b0561bbf3c1d22d03f041ace8e0.1687166935.git.naveen@kernel.org
Now that we validate the ftrace location during initialization in
ftrace_init_nop(), we can simplify ftrace_modify_call() to patch-in the
updated branch instruction without worrying about the instructions
surrounding the ftrace location. Note that we continue to ensure we
have the expected branch instruction at the ftrace location before
patching it with the updated branch destination.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/06275720939f8ee4c2f61c9e9a3e89b1fa3c441d.1687166935.git.naveen@kernel.org
Now that we validate the ftrace location during initialization in
ftrace_init_nop(), we can simplify ftrace_make_call() to replace the nop
without worrying about the instructions surrounding the ftrace location.
Note that we continue to ensure that we have a nop at the ftrace
location before patching it.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2d28866d2f556488a663981abe5621511efb207b.1687166935.git.naveen@kernel.org
Now that we validate the ftrace location during initialization in
ftrace_init_nop(), we can simplify ftrace_make_nop() to patch-in the nop
without worrying about the instructions surrounding the ftrace location.
Note that we continue to ensure that we have a bl to
ftrace_[regs_]caller at the ftrace location before nop-ing it out.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/e12ccbf28c50c3a07fb614f4d392e55f7098a729.1687166935.git.naveen@kernel.org
Currently, we validate instructions around the ftrace location every
time we have to enable/disable ftrace. Introduce ftrace_init_nop() to
instead perform all the validation during ftrace initialization. This
allows us to simply patch the necessary instructions during
enabling/disabling ftrace.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/f373684081e8e98be09b7f44d2d93069768324dc.1687166935.git.naveen@kernel.org
Commit 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs")
added ftrace support for ppc64 kernel images with a text section larger
than 32MB. The patch did two things:
1. Add stubs at the end of .text to branch into ftrace_[regs_]caller for
functions that were out of branch range.
2. Re-purpose linker-generated long branches to _mcount to instead branch
to ftrace_[regs_]caller.
Before that, we only supported kernel .text up to ~32MB. With the above,
we now support up to ~96MB:
- The first 32MB of kernel text can branch directly into
ftrace_[regs_]caller since that symbol is usually at the beginning.
- The modified long_branch from (2) above is used by the next 32MB of
kernel text.
- The next 32MB of kernel text can use the stub at the end of text to
branch back to ftrace_[regs_]caller.
While re-purposing the long branch works in practice, it still restricts
ftrace to kernel text up to ~96MB. The stub at the end of kernel text
from (1) already enables us to extend ftrace support for kernel text
up to 64MB, which fulfils the original requirement. Further, once we
switch to -fpatchable-function-entry, there will not be a long branch
that we can use.
Stop re-purposing the linker-generated long branches for ftrace to
simplify the code. If there are good reasons to support ftrace on
kernels beyond 64MB, we can consider adding support by using
-fpatchable-function-entry.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/33fa3be97f8e1f2171254ef2e1b0d5c8836c11fd.1687166935.git.naveen@kernel.org
ftrace_low.S has just the _mcount stub and return_to_handler(). Merge
this back into ftrace_mprofile.S and ftrace_64_pg.S to keep all ftrace
code together, and to allow those to evolve independently.
ftrace_mprofile.S is also not an entirely accurate name since this also
holds ppc32 code. This will be all the more incorrect once support for
-fpatchable-function-entry is added. Rename files here to more
accurately describe the code:
- ftrace_mprofile.S is renamed to ftrace_entry.S
- ftrace_pg.c is renamed to ftrace_64_pg.c
- ftrace_64_pg.S is rename to ftrace_64_pg_entry.S
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b900c9a8bba9d6c3c295e0f99886acf3e5bf6f7b.1687166935.git.naveen@kernel.org
Commit 67361cf8071286 ("powerpc/ftrace: Handle large kernel configs")
added ftrace support for ppc64 kernel images with a text section larger
than 32MB. The approach itself isn't specific to ppc64, so extend the
same to also work on ppc32.
While at it, reduce the space reserved for the stub from 64 bytes to 32
bytes since the different stub variants are all less than 8
instructions.
To reduce use of #ifdef, a stub implementation is provided for
kernel_toc_address() and -SZ_2G is cast to 'long long' to prevent
errors on ppc32.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9fa3258cbb9105cf8a0a8135214d44ffbc75fe84.1687166935.git.naveen@kernel.org
Instead of keying off DYNAMIC_FTRACE_WITH_REGS, use FTRACE_REGS_ADDR to
identify the proper ftrace trampoline address to use.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/6045a280a57a7ea937a5bb13ccac747026dbfb07.1687166935.git.naveen@kernel.org
Since we now support DYNAMIC_FTRACE_WITH_ARGS across ppc32 and ppc64
ELFv2, we can simplify function_graph tracer support code in ftrace.c
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/4dc92c4b1ed444dc62b748ae7327acdb9e096864.1687166935.git.naveen@kernel.org
ELFv1 support is deprecated and on the way out. Pre -mprofile-kernel
ftrace support (-pg only) is very limited and is retained primarily for
clang builds. It won't be necessary once clang lands support for
-fpatchable-function-entry.
Copy the existing ftrace code supporting these into ftrace_pg.c.
ftrace.c can then be refactored and enhanced with a focus on ppc32 and
ppc64 ELFv2.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/1eb6cc6c3141ddb77a2a25f8a9e83d83ff312b02.1687166935.git.naveen@kernel.org
.ftrace.tramp section is not used for any purpose. This code was added
all the way back in the original commit introducing support for dynamic
ftrace on ppc64 modules. Remove it.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/9cf6d7f37ba82f7cb6dafecf660f44925c526d8d.1687166935.git.naveen@kernel.org
The minimum level of gcc supported for building the kernel is v5.1.
v5.x releases of gcc emitted a three instruction sequence for
-mprofile-kernel:
mflr r0
std r0, 16(r1)
bl _mcount
It is only with the v6.x releases that gcc started emitting the two
instruction sequence for -mprofile-kernel, omitting the second store
instruction.
With the older three instruction sequence, the actual ftrace location
can be the 5th instruction into a function. Update the allowed offset
for ftrace location from 12 to 16 to accommodate the same.
Cc: stable@vger.kernel.org
Fixes: 7af82ff90a2b06 ("powerpc/ftrace: Ignore weak functions")
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/7b265908a9461e38fc756ef9b569703860a80621.1687166935.git.naveen@kernel.org
CC arch/powerpc/perf/core-fsl-emb.o
arch/powerpc/perf/core-fsl-emb.c:675:6: error: no previous prototype for 'hw_perf_event_setup' [-Werror=missing-prototypes]
675 | void hw_perf_event_setup(int cpu)
| ^~~~~~~~~~~~~~~~~~~
Looks like fsl_emb was completely missed by commit 3f6da3905398 ("perf:
Rework and fix the arch CPU-hotplug hooks")
So, apply same changes as commit 3f6da3905398 ("perf: Rework and fix
the arch CPU-hotplug hooks") then commit 57ecde42cc74 ("powerpc/perf:
Convert book3s notifier to state machine callbacks")
While at it, also fix following error:
arch/powerpc/perf/core-fsl-emb.c: In function 'perf_event_interrupt':
arch/powerpc/perf/core-fsl-emb.c:648:13: error: variable 'found' set but not used [-Werror=unused-but-set-variable]
648 | int found = 0;
| ^~~~~
Fixes: 3f6da3905398 ("perf: Rework and fix the arch CPU-hotplug hooks")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/603e1facb32608f88f40b7d7b9094adc50e7b2dc.1692349125.git.christophe.leroy@csgroup.eu
When certain PHB HW failure causes pHyp to recover PHB, it marks the PE
state as temporarily unavailable until recovery is complete. This also
triggers an EEH handler in Linux which needs to notify drivers, and perform
recovery. But before notifying the driver about the PCI error it uses
get_adapter_status()->rpaphp_get_sensor_state()->rtas_call(get-sensor-state)
operation of the hotplug_slot to determine if the slot contains a device or
not. If the slot is empty, the recovery is skipped entirely.
eeh_event_handler()
->eeh_handle_normal_event()
->eeh_slot_presence_check()
->get_adapter_status()
->rpaphp_get_sensor_state()
->rtas_get_sensor()
->rtas_call(get-sensor-state)
However on certain PHB failures, the RTAS call rtas_call(get-sensor-state)
returns extended busy error (9902) until PHB is recovered by pHyp. Once PHB
is recovered, the rtas_call(get-sensor-state) returns success with correct
presence status. The RTAS call interface rtas_get_sensor() loops over the
RTAS call on extended delay return code (9902) until the return value is
either success (0) or error (-1). This causes the EEH handler to get stuck
for ~6 seconds before it could notify that the PCI error has been detected
and stop any active operations. Hence with running I/O traffic, during this
6 seconds, the network driver continues its operation and hits a timeout
(netdev watchdog).
------------
[52732.244731] DEBUG: ibm_read_slot_reset_state2()
[52732.244762] DEBUG: ret = 0, rets[0]=5, rets[1]=1, rets[2]=4000, rets[3]=>
[52732.244798] DEBUG: in eeh_slot_presence_check
[52732.244804] DEBUG: error state check
[52732.244807] DEBUG: Is slot hotpluggable
[52732.244810] DEBUG: hotpluggable ops ?
[52732.244953] DEBUG: Calling ops->get_adapter_status
[52732.244958] DEBUG: calling rpaphp_get_sensor_state
[52736.564262] ------------[ cut here ]------------
[52736.564299] NETDEV WATCHDOG: enP64p1s0f3 (tg3): transmit queue 0 timed o>
[52736.564324] WARNING: CPU: 1442 PID: 0 at net/sched/sch_generic.c:478 dev>
[...]
[52736.564505] NIP [c000000000c32368] dev_watchdog+0x438/0x440
[52736.564513] LR [c000000000c32364] dev_watchdog+0x434/0x440
------------
On timeouts, network driver starts dumping debug information to console
(e.g bnx2 driver calls bnx2x_panic_dump()), and go into recovery path while
pHyp is still recovering the PHB. As part of recovery, the driver tries to
reset the device and it keeps failing since every PCI read/write returns
ff's. And when EEH recovery kicks-in, the driver is unable to recover the
device. This impacts the ssh connection and leads to the system being
inaccessible. To get the NIC working again it needs a reboot or re-assign
the I/O adapter from HMC.
[ 9531.168587] EEH: Beginning: 'slot_reset'
[ 9531.168601] PCI 0013:01:00.0#10000: EEH: Invoking bnx2x->slot_reset()
[...]
[ 9614.110094] bnx2x: [bnx2x_func_stop:9129(enP19p1s0f0)]FUNC_STOP ramrod failed. Running a dry transaction
[ 9614.110300] bnx2x: [bnx2x_igu_int_disable:902(enP19p1s0f0)]BUG! Proper val not read from IGU!
[ 9629.178067] bnx2x: [bnx2x_fw_command:3055(enP19p1s0f0)]FW failed to respond!
[ 9629.178085] bnx2x 0013:01:00.0 enP19p1s0f0: bc 7.10.4
[ 9629.178091] bnx2x: [bnx2x_fw_dump_lvl:789(enP19p1s0f0)]Cannot dump MCP info while in PCI error
[ 9644.241813] bnx2x: [bnx2x_io_slot_reset:14245(enP19p1s0f0)]IO slot reset --> driver unload
[...]
[ 9644.241819] PCI 0013:01:00.0#10000: EEH: bnx2x driver reports: 'disconnect'
[ 9644.241823] PCI 0013:01:00.1#10000: EEH: Invoking bnx2x->slot_reset()
[ 9644.241827] bnx2x: [bnx2x_io_slot_reset:14229(enP19p1s0f1)]IO slot reset initializing...
[ 9644.241916] bnx2x 0013:01:00.1: enabling device (0140 -> 0142)
[ 9644.258604] bnx2x: [bnx2x_io_slot_reset:14245(enP19p1s0f1)]IO slot reset --> driver unload
[ 9644.258612] PCI 0013:01:00.1#10000: EEH: bnx2x driver reports: 'disconnect'
[ 9644.258615] EEH: Finished:'slot_reset' with aggregate recovery state:'disconnect'
[ 9644.258620] EEH: Unable to recover from failure from PHB#13-PE#10000.
[ 9644.261811] EEH: Beginning: 'error_detected(permanent failure)'
[...]
[ 9644.261823] EEH: Finished:'error_detected(permanent failure)'
Hence, it becomes important to inform driver about the PCI error detection
as early as possible, so that driver is aware of PCI error and waits for
EEH handler's next action for successful recovery.
Current implementation uses rtas_get_sensor() API which blocks the slot
check state until RTAS call returns success. To avoid this, fix the PCI
hotplug driver (rpaphp) to return an error (-EBUSY) if the slot presence
state can not be detected immediately while PE is in EEH recovery state.
Change rpaphp_get_sensor_state() to invoke rtas_call(get-sensor-state)
directly only if the respective PE is in EEH recovery state, and take
actions based on RTAS return status. This way EEH handler will not be
blocked on rpaphp_get_sensor_state() and can immediately notify driver
about the PCI error and stop any active operations.
In normal cases (non-EEH case) rpaphp_get_sensor_state() will continue to
invoke rtas_get_sensor() as it was earlier with no change in existing
behavior.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/169235815601.193557.13989873835811325343.stgit@jupiter
This patch enables config option GENERIC_IDLE_POLL_SETUP for arch
powerpc. This adds support for kernel param 'nohlt'.
Powerpc kernel also supports another kernel boot-time param called
'powersave' which can also be used to disable all cpu idle-states and
forces CPU to an idle-loop similar to what cpu_idle_poll() does. This
patch however makes powerpc kernel-parameters better aligned to the
generic boot-time parameters.
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230818050739.827851-1-vaibhav@linux.ibm.com
Invoke ibm,os-term call with rtas_call_unlocked(), without using the
RTAS spinlock, to avoid deadlock in the unlikely event of a machine
crash while making an RTAS call.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230609071404.425529-1-hbathini@linux.ibm.com
This reverts commit 9c87156cce5a63735d1218f0096a65c50a7a32aa.
I have not been able to reproduce the reported -Wframe-larger-than=
warning (or disassembly) with clang-11 or clang-18.
I don't know precisely when this was fixed in llvm, but it may be time
to revert this.
Closes: https://github.com/ClangBuiltLinux/linux/issues/252
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230817-ppc_xmon-v1-1-8cc2d51b9995@google.com
Parse the device tree in early init to find the memory block size to be
used by the kernel. Consolidate the memory block size device tree parsing
to one helper and use that on both powernv and pseries. We still want to
use machine-specific callback because on all machine types other than
powernv and pseries we continue to return MIN_MEMORY_BLOCK_SIZE.
pseries_memory_block_size used to look for the second memory
block (memory@x) to determine the memory_block_size value. This patch
changed that to look at all memory blocks and make sure we can map them all
correctly using the computed memory block size value.
Add workaround to force 256MB memory block size if device driver managed
memory such as GPU memory is present. This helps to add GPU memory
that is not aligned to 1G.
Co-developed-by: Reza Arbab <arbab@linux.ibm.com>
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>
Signed-off-by: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801044447.11275-1-aneesh.kumar@linux.ibm.com
Drop CONFIG_IP_NF_TARGET_CLUSTERIP as it was removed in commit 9db5d918e2c0
("netfilter: ip_tables: remove clusterip target").
Signed-off-by: Trevor Woerner <twoerner@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230817115017.35663-5-twoerner@gmail.com
In case fadump_reserve_mem() fails to reserve memory, the
reserve_dump_area_size variable will retain the reserve area size. This
will lead to /sys/kernel/fadump/mem_reserved node displaying an incorrect
memory reserved by fadump.
To fix this problem, reserve dump area size variable is set to 0 if fadump
failed to reserve memory.
Fixes: 8255da95e545 ("powerpc/fadump: release all the memory above boot memory size")
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Acked-by: Mahesh Salgaonkar <mahesh@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230704050715.203581-1-sourabhjain@linux.ibm.com
A W=1 build of ppc40x_defconfig throws the followings errors:
CC arch/powerpc/platforms/4xx/uic.o
arch/powerpc/platforms/4xx/uic.c:274:13: warning: no previous prototype for 'uic_init_tree' [-Wmissing-prototypes]
274 | void __init uic_init_tree(void)
| ^~~~~~~~~~~~~
arch/powerpc/platforms/4xx/uic.c:319:14: warning: no previous prototype for 'uic_get_irq' [-Wmissing-prototypes]
319 | unsigned int uic_get_irq(void)
| ^~~~~~~~~~~
CC arch/powerpc/platforms/4xx/machine_check.o
CC arch/powerpc/platforms/4xx/soc.o
arch/powerpc/platforms/4xx/soc.c:193:6: warning: no previous prototype for 'ppc4xx_reset_system' [-Wmissing-prototypes]
193 | void ppc4xx_reset_system(char *cmd)
| ^~~~~~~~~~~~~~~~~~~
Add missing includes to get the missing prototypes.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/c8253017e355638132737ff47936e290df8738d1.1692282432.git.christophe.leroy@csgroup.eu
A W=1 build of 44x/iss476-smp_defconfig gives:
arch/powerpc/mm/nohash/44x.c:220:13: error: no previous prototype for 'mmu_init_secondary' [-Werror=missing-prototypes]
220 | void __init mmu_init_secondary(int cpu)
| ^~~~~~~~~~~~~~~~~~
That function is called from head_4xx.S
Add a prototype in mmu_decl.h
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/e89d9927c926044e54fd056a849785f526c6414f.1692282340.git.christophe.leroy@csgroup.eu
4xx/iss476-smp_defconfig leads to:
CC arch/powerpc/mm/nohash/tlb.o
arch/powerpc/mm/nohash/tlb.c:322:13: error: no previous prototype for 'early_init_mmu_47x' [-Werror=missing-prototypes]
322 | void __init early_init_mmu_47x(void)
| ^~~~~~~~~~~~~~~~~~
early_init_mmu_47x() is used only at one place and only locally.
Fold it into its only caller and remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/0a667b7c2e05d3cf41ecd38f33cc334083a61c8d.1692282396.git.christophe.leroy@csgroup.eu
ppc4xx_defconfig with W=1 results in:
CC arch/powerpc/platforms/44x/warp.o
arch/powerpc/platforms/44x/warp.c:369:5: error: no previous prototype for 'pika_dtm_register_shutdown' [-Werror=missing-prototypes]
369 | int pika_dtm_register_shutdown(void (*func)(void *arg), void *arg)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
arch/powerpc/platforms/44x/warp.c:374:5: error: no previous prototype for 'pika_dtm_unregister_shutdown' [-Werror=missing-prototypes]
374 | int pika_dtm_unregister_shutdown(void (*func)(void *arg), void *arg)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
The functions were added by commit 4ebef31fa6e0 ("[POWERPC] PIKA Warp:
Update platform code to support Rev B boards")
Those functions are not used localy and allthough their symbols are
exported they are not declared in any header file so they can't be used.
Remove them, then remove the associated list as it will now remain empty
hence becomes useless.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/830923f0e0375a14609204246d302c7476a8f948.1692279855.git.christophe.leroy@csgroup.eu
Building ppc40x_defconfig throws the following error:
CC arch/powerpc/kernel/traps.o
arch/powerpc/kernel/traps.c:2232:29: warning: no previous prototype for 'WatchdogHandler' [-Wmissing-prototypes]
2232 | void __attribute__ ((weak)) WatchdogHandler(struct pt_regs *regs)
| ^~~~~~~~~~~~~~~
This function was imported by commit 14cf11af6cf6 ("powerpc: Merge
enough to start building in arch/powerpc.") as a weak function but
never defined and/or called outside traps.c
As it has only one caller fold it inside its caller and remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/38fe1078eb403eef74dc8f29387636fd7ecdf43c.1692276041.git.christophe.leroy@csgroup.eu
__set_pte_at() handles 3 main cases with #ifdefs plus the 'percpu'
subcase which leads to code duplication.
Rewrite the function using IS_ENABLED() to minimise the total number
of cases and remove duplicated code.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2322dd08217bccab25456fe8b189edf0e6a8b6dd.1692121353.git.christophe.leroy@csgroup.eu
A W=1 build of mpc885_ads_defconfig throws the following error:
CC arch/powerpc/platforms/8xx/m8xx_setup.o
arch/powerpc/platforms/8xx/m8xx_setup.c:41:1: error: no previous prototype for 'init_internal_rtc' [-Werror=missing-prototypes]
41 | init_internal_rtc(void)
| ^~~~~~~~~~~~~~~~~
init_internal_rtc() was introduced by commit df34403dcaac ("[POWERPC]
8xx: Add mpc885ads support and common mpc8xx files") as a weak
function but has never been defined and/or used outside m8xx_setup.c
As it is called only once there, just fold it into its caller and
remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/0aa1141e18a84d926e199093204b37ec993f0c87.1692275185.git.christophe.leroy@csgroup.eu
Replace printk(KERN_WARN with pr_warn(
Remove a couple of blank lines
Re-align multi-line code.
Replace asm/io.h by linux/io.h
mpc83xx.h doesn't need linux/device.h or asm/pci-bridge.h
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/2cb498f637e082a4af8032311fad3cae84d6aa5d.1692199324.git.christophe.leroy@csgroup.eu
objtool reports the following warning:
arch/powerpc/kernel/ptrace/ptrace-view.o: warning: objtool:
gpr32_set_common+0x23c (.text+0x860): redundant UACCESS disable
gpr32_set_common() conditionally opens and closes UACCESS based on
whether kbuf pointer is NULL or not. This is wackelig.
Split gpr32_set_common() in two fonctions, one for user one for
kernel.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Fix oops in gpr32_set_common_user() due to NULL kbuf]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b8d6ae4483fcfd17524e79d803c969694a85cc02.1687428075.git.christophe.leroy@csgroup.eu
The documented ptrace request names are currently wrong/incomplete.
Fix this to improve correctness and searchability.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230725005841.28854-2-bgray@linux.ibm.com
PowerPC was the only user of these hooks, and has been refactored to no
longer require them. There is no need to keep them around, so remove
them to reduce complexity.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-8-bgray@linux.ibm.com
Now that ptrace and perf are no longer exclusive, update the
test to exercise interesting interactions.
An assembly file is used for the children to allow precise instruction
choice and addresses, while avoiding any compiler quirks.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-7-bgray@linux.ibm.com
ptrace and perf watchpoints were considered incompatible in
commit 29da4f91c0c1 ("powerpc/watchpoint: Don't allow concurrent perf
and ptrace events"), but the logic in that commit doesn't really apply.
Ptrace doesn't automatically single step; the ptracer must request this
explicitly. And the ptracer can do so regardless of whether a
ptrace/perf watchpoint triggered or not: it could single step every
instruction if it wanted to. Whatever stopped the ptracee before
executing the instruction that would trigger the perf watchpoint is no
longer relevant by this point.
To get correct behaviour when perf and ptrace are watching the same
data we must ignore the perf watchpoint. After all, ptrace has
before-execute semantics, and perf is after-execute, so perf doesn't
actually care about the watchpoint trigger at this point in time.
Pausing before execution does not mean we will actually end up executing
the instruction.
Importantly though, we don't remove the perf watchpoint yet. This is
key.
The ptracer is free to do whatever it likes right now. E.g., it can
continue the process, single step. or even set the child PC somewhere
completely different.
If it does try to execute the instruction though, without reinserting
the watchpoint (in which case we go back to the start of this example),
the perf watchpoint would immediately trigger. This time there is no
ptrace watchpoint, so we can safely perform a single step and increment
the perf counter. Upon receiving the single step exception, the existing
code already handles propagating or consuming it based on whether
another subsystem (e.g. ptrace) requested a single step. Again, this is
needed with or without perf/ptrace exclusion, because ptrace could be
single stepping this instruction regardless of if a watchpoint is
involved.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-6-bgray@linux.ibm.com
We only remove watchpoints when they have the perf_single_step flag set,
so we can reinsert them during the first iteration.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-5-bgray@linux.ibm.com
There is a bug in the current watchpoint tracking logic, where the
teardown in arch_unregister_hw_breakpoint() uses bp->ctx->task, which it
does not have a reference of and parallel threads may be in the process
of destroying. This was partially addressed in commit fb822e6076d9
("powerpc/hw_breakpoint: Fix oops when destroying hw_breakpoint event"),
but the underlying issue of accessing a struct member in an unknown
state still remained. Syzkaller managed to trigger a null pointer
derefernce due to the race between the task destructor and checking the
pointer and dereferencing it in the loop.
While this null pointer dereference could be fixed by using READ_ONCE
to access the task up front, that just changes the error to manipulating
possbily freed memory.
Instead, the breakpoint logic needs to be reworked to remove any
dependency on a context or task struct during breakpoint removal.
The reason we have this currently is to clear thread.last_hit_ubp. This
member is used to differentiate the perf DAWR single-step sequence from
other causes of single-step, such as userspace just calling
ptrace(PTRACE_SINGLESTEP, ...). We need to differentiate them because,
when the single step interrupt is received, we need to know whether to
re-insert the DAWR breakpoint (perf) or not (ptrace / other).
arch_unregister_hw_breakpoint() needs to clear this information to
prevent dangling pointers to possibly freed memory. These pointers are
dereferenced in single_step_dabr_instruction() without a way to check
their validity.
This patch moves the tracking of this information to the breakpoint
itself. This means we no longer have to do anything special to clean up.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-4-bgray@linux.ibm.com
info is cheap to retrieve, and is likely optimised by the compiler
anyway. On the other hand, propagating it across the functions makes it
possible to be inconsistent and adds needless complexity.
Remove it, and invoke counter_arch_bp() when we need to work with it.
As we don't persist it, we just use the local bp array to track whether
we are ignoring a breakpoint.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230801011744.153973-3-bgray@linux.ibm.com
