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Define macros to list ppc interrupt types in interttupt.h, replace the
reference of the trap hex values with these macros.
Referred the hex numbers in arch/powerpc/kernel/exceptions-64e.S,
arch/powerpc/kernel/exceptions-64s.S, arch/powerpc/kernel/head_*.S,
arch/powerpc/kernel/head_booke.h and arch/powerpc/include/asm/kvm_asm.h.
Signed-off-by: Xiongwei Song <sxwjean@gmail.com>
[mpe: Resolve conflicts in nmi_disables_ftrace(), fix 40x build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1618398033-13025-1-git-send-email-sxwjean@me.com
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All subarchitectures always save all GPRs to pt_regs interrupt frames
now. Remove FULL_REGS and associated bits.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210316104206.407354-11-npiggin@gmail.com
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Move all KUAP management in C.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/199365ddb58d579daf724815f2d0acb91cc49d19.1615552867.git.christophe.leroy@csgroup.eu
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ksp_limit is there to help detect stack overflows.
That is specific to ppc32 as it was removed from ppc64 in
commit cbc9565ee826 ("powerpc: Remove ksp_limit on ppc64").
There are other means for detecting stack overflows.
As ppc64 has proven to not need it, ppc32 should be able to do
without it too.
Lets remove it and simplify exception handling.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d789c3385b22e07bedc997613c0d26074cb513e7.1615552866.git.christophe.leroy@csgroup.eu
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Both rt_sigreturn() and handle_rt_signal_64() contain TM-related ifdefs
which break-up an if/else block. Provide stubs for the ifdef-guarded TM
functions and remove the need for an ifdef in rt_sigreturn().
Rework the remaining TM ifdef in handle_rt_signal64() similar to
commit f1cf4f93de2f ("powerpc/signal32: Remove ifdefery in middle of if/else").
Unlike in the commit for ppc32, the ifdef can't be removed entirely
since uc_transact in sigframe depends on CONFIG_PPC_TRANSACTIONAL_MEM.
Signed-off-by: Christopher M. Riedl <cmr@codefail.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210227011259.11992-6-cmr@codefail.de
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Pull io_uring thread rewrite from Jens Axboe:
"This converts the io-wq workers to be forked off the tasks in question
instead of being kernel threads that assume various bits of the
original task identity.
This kills > 400 lines of code from io_uring/io-wq, and it's the worst
part of the code. We've had several bugs in this area, and the worry
is always that we could be missing some pieces for file types doing
unusual things (recent /dev/tty example comes to mind, userfaultfd
reads installing file descriptors is another fun one... - both of
which need special handling, and I bet it's not the last weird oddity
we'll find).
With these identical workers, we can have full confidence that we're
never missing anything. That, in itself, is a huge win. Outside of
that, it's also more efficient since we're not wasting space and code
on tracking state, or switching between different states.
I'm sure we're going to find little things to patch up after this
series, but testing has been pretty thorough, from the usual
regression suite to production. Any issue that may crop up should be
manageable.
There's also a nice series of further reductions we can do on top of
this, but I wanted to get the meat of it out sooner rather than later.
The general worry here isn't that it's fundamentally broken. Most of
the little issues we've found over the last week have been related to
just changes in how thread startup/exit is done, since that's the main
difference between using kthreads and these kinds of threads. In fact,
if all goes according to plan, I want to get this into the 5.10 and
5.11 stable branches as well.
That said, the changes outside of io_uring/io-wq are:
- arch setup, simple one-liner to each arch copy_thread()
implementation.
- Removal of net and proc restrictions for io_uring, they are no
longer needed or useful"
* tag 'io_uring-worker.v3-2021-02-25' of git://git.kernel.dk/linux-block: (30 commits)
io-wq: remove now unused IO_WQ_BIT_ERROR
io_uring: fix SQPOLL thread handling over exec
io-wq: improve manager/worker handling over exec
io_uring: ensure SQPOLL startup is triggered before error shutdown
io-wq: make buffered file write hashed work map per-ctx
io-wq: fix race around io_worker grabbing
io-wq: fix races around manager/worker creation and task exit
io_uring: ensure io-wq context is always destroyed for tasks
arch: ensure parisc/powerpc handle PF_IO_WORKER in copy_thread()
io_uring: cleanup ->user usage
io-wq: remove nr_process accounting
io_uring: flag new native workers with IORING_FEAT_NATIVE_WORKERS
net: remove cmsg restriction from io_uring based send/recvmsg calls
Revert "proc: don't allow async path resolution of /proc/self components"
Revert "proc: don't allow async path resolution of /proc/thread-self components"
io_uring: move SQPOLL thread io-wq forked worker
io-wq: make io_wq_fork_thread() available to other users
io-wq: only remove worker from free_list, if it was there
io_uring: remove io_identity
io_uring: remove any grabbing of context
...
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In the arch addition of PF_IO_WORKER, I missed parisc and powerpc for
some reason. Fix that up, ensuring they handle PF_IO_WORKER like they do
PF_KTHREAD in copy_thread().
Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Fixes: 4727dc20e042 ("arch: setup PF_IO_WORKER threads like PF_KTHREAD")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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In commit bf13718bc57a ("powerpc: show registers when unwinding
interrupt frames") we changed our stack dumping logic to show the full
registers whenever we find an interrupt frame on the stack.
However we didn't notice that on 64-bit this doesn't show the final
frame, ie. the interrupt that brought us in from userspace, whereas on
32-bit it does.
That is due to confusion about the size of that last frame. The code
in show_stack() calls validate_sp(), passing it STACK_INT_FRAME_SIZE
to check the sp is at least that far below the top of the stack.
However on 64-bit that size is too large for the final frame, because
it includes the red zone, but we don't allocate a red zone for the
first frame.
So add a new define that encodes the correct size for 32-bit and
64-bit, and use it in show_stack().
This results in the full trace being shown on 64-bit, eg:
sysrq: Trigger a crash
Kernel panic - not syncing: sysrq triggered crash
CPU: 0 PID: 83 Comm: sh Not tainted 5.11.0-rc2-gcc-8.2.0-00188-g571abcb96b10-dirty #649
Call Trace:
[c00000000a1c3ac0] [c000000000897b70] dump_stack+0xc4/0x114 (unreliable)
[c00000000a1c3b00] [c00000000014334c] panic+0x178/0x41c
[c00000000a1c3ba0] [c00000000094e600] sysrq_handle_crash+0x40/0x50
[c00000000a1c3c00] [c00000000094ef98] __handle_sysrq+0xd8/0x210
[c00000000a1c3ca0] [c00000000094f820] write_sysrq_trigger+0x100/0x188
[c00000000a1c3ce0] [c0000000005559dc] proc_reg_write+0x10c/0x1b0
[c00000000a1c3d10] [c000000000479950] vfs_write+0xf0/0x360
[c00000000a1c3d60] [c000000000479d9c] ksys_write+0x7c/0x140
[c00000000a1c3db0] [c00000000002bf5c] system_call_exception+0x19c/0x2c0
[c00000000a1c3e10] [c00000000000d35c] system_call_common+0xec/0x278
--- interrupt: c00 at 0x7fff9fbab428
NIP: 00007fff9fbab428 LR: 000000001000b724 CTR: 0000000000000000
REGS: c00000000a1c3e80 TRAP: 0c00 Not tainted (5.11.0-rc2-gcc-8.2.0-00188-g571abcb96b10-dirty)
MSR: 900000000280f033 <SF,HV,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 22002884 XER: 00000000
IRQMASK: 0
GPR00: 0000000000000004 00007fffc3cb8960 00007fff9fc59900 0000000000000001
GPR04: 000000002a4b32d0 0000000000000002 0000000000000063 0000000000000063
GPR08: 000000002a4b32d0 0000000000000000 0000000000000000 0000000000000000
GPR12: 0000000000000000 00007fff9fcca9a0 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 0000000000000000 00000000100b8fd0
GPR20: 000000002a4b3485 00000000100b8f90 0000000000000000 0000000000000000
GPR24: 000000002a4b0440 00000000100e77b8 0000000000000020 000000002a4b32d0
GPR28: 0000000000000001 0000000000000002 000000002a4b32d0 0000000000000001
NIP [00007fff9fbab428] 0x7fff9fbab428
LR [000000001000b724] 0x1000b724
--- interrupt: c00
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210209141627.2898485-1-mpe@ellerman.id.au
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If we try to stack trace very early during boot, either due to a
WARN/BUG or manual dump_stack(), we will oops in
valid_emergency_stack() when we try to dereference the paca_ptrs
array.
The fix is simple, we just return false if paca_ptrs isn't allocated
yet. The stack pointer definitely isn't part of any emergency stack
because we haven't allocated any yet.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210202130207.1303975-1-mpe@ellerman.id.au
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Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-29-npiggin@gmail.com
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Similar to the previous patch this makes interrupt handler function
types more regular so they can be wrapped with the next patch.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210130130852.2952424-9-npiggin@gmail.com
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__set_dabr() are simple functions that can be inline directly
inside set_dabr() and using IS_ENABLED() instead of #ifdef
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c10b263668e137236c71d76648b03cf2cd1ee66f.1607076733.git.christophe.leroy@csgroup.eu
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Now that kernel correctly store/restore userspace AMR/IAMR values, avoid
manipulating AMR and IAMR from the kernel on behalf of userspace.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-15-aneesh.kumar@linux.ibm.com
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On fork, we inherit from the parent and on exec, we should switch to default_amr values.
Also, avoid changing the AMR register value within the kernel. The kernel now runs with
different AMR values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-13-aneesh.kumar@linux.ibm.com
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Child thread.kuap value is inherited from the parent in copy_thread_tls. We still
need to make sure when the child returns from a fork in the kernel we start with the kernel
default AMR value.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: Sandipan Das <sandipan@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-12-aneesh.kumar@linux.ibm.com
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In later patches during exec, we would like to access default regs.amr to
control access to the user mapping. Having thread.regs set early makes the
code changes simpler.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201127044424.40686-10-aneesh.kumar@linux.ibm.com
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It's often useful to know the register state for interrupts in
the stack frame. In the below example (with this patch applied),
the important information is the state of the page fault.
A blatant case like this probably rather should have the page
fault regs passed down to the warning, but quite often there are
less obvious cases where an interrupt shows up that might give
some more clues.
The downside is longer and more complex bug output.
Bug: Write fault blocked by AMR!
WARNING: CPU: 0 PID: 72 at arch/powerpc/include/asm/book3s/64/kup-radix.h:164 __do_page_fault+0x880/0xa90
Modules linked in:
CPU: 0 PID: 72 Comm: systemd-gpt-aut Not tainted
NIP: c00000000006e2f0 LR: c00000000006e2ec CTR: 0000000000000000
REGS: c00000000a4f3420 TRAP: 0700
MSR: 8000000000021033 <SF,ME,IR,DR,RI,LE> CR: 28002840 XER: 20040000
CFAR: c000000000128be0 IRQMASK: 3
GPR00: c00000000006e2ec c00000000a4f36c0 c0000000014f0700 0000000000000020
GPR04: 0000000000000001 c000000001290f50 0000000000000001 c000000001290f80
GPR08: c000000001612b08 0000000000000000 0000000000000000 00000000ffffe0f7
GPR12: 0000000048002840 c0000000016e0000 c00c000000021c80 c000000000fd6f60
GPR16: 0000000000000000 c00000000a104698 0000000000000003 c0000000087f0000
GPR20: 0000000000000100 c0000000070330b8 0000000000000000 0000000000000004
GPR24: 0000000002000000 0000000000000300 0000000002000000 c00000000a5b0c00
GPR28: 0000000000000000 000000000a000000 00007fffb2a90038 c00000000a4f3820
NIP [c00000000006e2f0] __do_page_fault+0x880/0xa90
LR [c00000000006e2ec] __do_page_fault+0x87c/0xa90
Call Trace:
[c00000000a4f36c0] [c00000000006e2ec] __do_page_fault+0x87c/0xa90 (unreliable)
[c00000000a4f3780] [c000000000e1c034] do_page_fault+0x34/0x90
[c00000000a4f37b0] [c000000000008908] data_access_common_virt+0x158/0x1b0
--- interrupt: 300 at __copy_tofrom_user_base+0x9c/0x5a4
NIP: c00000000009b028 LR: c000000000802978 CTR: 0000000000000800
REGS: c00000000a4f3820 TRAP: 0300
MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 24004840 XER: 00000000
CFAR: c00000000009aff4 DAR: 00007fffb2a90038 DSISR: 0a000000 IRQMASK: 0
GPR00: 0000000000000000 c00000000a4f3ac0 c0000000014f0700 00007fffb2a90028
GPR04: c000000008720010 0000000000010000 0000000000000000 0000000000000000
GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000001
GPR12: 0000000000004000 c0000000016e0000 c00c000000021c80 c000000000fd6f60
GPR16: 0000000000000000 c00000000a104698 0000000000000003 c0000000087f0000
GPR20: 0000000000000100 c0000000070330b8 0000000000000000 0000000000000004
GPR24: c00000000a4f3c80 c000000008720000 0000000000010000 0000000000000000
GPR28: 0000000000010000 0000000008720000 0000000000010000 c000000001515b98
NIP [c00000000009b028] __copy_tofrom_user_base+0x9c/0x5a4
LR [c000000000802978] copyout+0x68/0xc0
--- interrupt: 300
[c00000000a4f3af0] [c0000000008074b8] copy_page_to_iter+0x188/0x540
[c00000000a4f3b50] [c00000000035c678] generic_file_buffered_read+0x358/0xd80
[c00000000a4f3c40] [c0000000004c1e90] blkdev_read_iter+0x50/0x80
[c00000000a4f3c60] [c00000000045733c] new_sync_read+0x12c/0x1c0
[c00000000a4f3d00] [c00000000045a1f0] vfs_read+0x1d0/0x240
[c00000000a4f3d50] [c00000000045a7f4] ksys_read+0x84/0x140
[c00000000a4f3da0] [c000000000033a60] system_call_exception+0x100/0x280
[c00000000a4f3e10] [c00000000000c508] system_call_common+0xf8/0x2f8
Instruction dump:
eae10078 3be0000b 4bfff890 60420000 792917e1 4182ff18 3c82ffab 3884a5e0
3c62ffab 3863a6e8 480ba891 60000000 <0fe00000> 3be0000b 4bfff860 e93c0938
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201107023305.2384874-1-npiggin@gmail.com
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There is no point in copying floating point regs when there
is no FPU and MATH_EMULATION is not selected.
Create a new CONFIG_PPC_FPU_REGS bool that is selected by
CONFIG_MATH_EMULATION and CONFIG_PPC_FPU, and use it to
opt out everything related to fp_state in thread_struct.
The asm const used only by fpu.S are opted out with CONFIG_PPC_FPU
as fpu.S build is conditionnal to CONFIG_PPC_FPU.
The following app spends approx 8.1 seconds system time on an 8xx
without the patch, and 7.0 seconds with the patch (13.5% reduction).
On an 832x, it spends approx 2.6 seconds system time without
the patch and 2.1 seconds with the patch (19% reduction).
void sigusr1(int sig) { }
int main(int argc, char **argv)
{
int i = 100000;
signal(SIGUSR1, sigusr1);
for (;i--;)
raise(SIGUSR1);
exit(0);
}
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7569070083e6cd5b279bb5023da601aba3c06f3c.1597770847.git.christophe.leroy@csgroup.eu
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Clang, and GCC with -Wmaybe-uninitialized, can't see that val is
unused in get_fpexec_mode():
arch/powerpc/kernel/process.c:1940:7: error: variable 'val' is used
uninitialized whenever 'if' condition is true
if (cpu_has_feature(CPU_FTR_SPE)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~
We know that CPU_FTR_SPE will only be true iff CONFIG_SPE is also
true, but the compiler doesn't.
Avoid it by initialising val to zero.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 532ed1900d37 ("powerpc/process: Remove useless #ifdef CONFIG_SPE")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200917024509.3253837-1-mpe@ellerman.id.au
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Add a stub for __giveup_fpu() when CONFIG_PPC_FPU is
not selected, as done for CONFIG_SPE and CONFIG_ALTIVEC.
This allows to remove some #ifdef CONFIG_PPC_FPU.
Also change one to IS_ENABLED().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/69c8b7954ceeccc6b849e52e1fa41b3a0f10f6c1.1597643221.git.christophe.leroy@csgroup.eu
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cpu_has_feature(CPU_FTR_SPE) returns false when CONFIG_SPE is
not set.
There is no need to enclose the test in an #ifdef CONFIG_SPE.
Remove it.
CPU_FTR_SPE only exists on 32 bits. Define it as 0 on 64 bits.
We have a couple of places like:
#ifdef CONFIG_SPE
if (cpu_has_feature(CPU_FTR_SPE)) {
do_something_that_requires_CONFIG_SPE
} else {
return -EINVAL;
}
#else
return -EINVAL;
#endif
Replace them by a cleaner version:
if (cpu_has_feature(CPU_FTR_SPE)) {
#ifdef CONFIG_SPE
do_something_that_requires_CONFIG_SPE
#endif
} else {
return -EINVAL;
}
When CONFIG_SPE is not set, this resolves to an unconditional
return of -EINVAL
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/698df8387555765b70ea42e4a7fa48141c309c1f.1597643221.git.christophe.leroy@csgroup.eu
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cpu_has_feature(CPU_FTR_ALTIVEC) returns false when CONFIG_ALTIVEC is
not set.
There is no need to enclose the test in an #ifdef CONFIG_ALTIVEC.
Remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/03ba6b52344ca7c336df2bc6e3d31d736c804ae2.1597643221.git.christophe.leroy@csgroup.eu
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cpu_has_feature(CPU_FTR_VSX) returns false when CONFIG_VSX is
not set.
There is no need to enclose the test in an #ifdef CONFIG_VSX.
Remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0eb61cf0dc66d781d47deb2228498cd61d03a754.1597643221.git.christophe.leroy@csgroup.eu
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That #endif is more than 100 lines after the matching #ifdef,
and there are several #ifdef/#else/#endif inbetween.
Tag it as /* CONFIG_PPC_BOOK3S_64 */ to help locate the
matching #ifdef.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/3612a8f8aaca16de3fc414a7e66293319d6e213c.1597643147.git.christophe.leroy@csgroup.eu
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The #ifdef CONFIG_KALLSYMS encloses some printk which can
compile in all cases.
Replace by IS_ENABLED().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/2d89732a9062b2cf2651728804e4b8f6c9b9358e.1597643164.git.christophe.leroy@csgroup.eu
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by IS_ENABLED()
The #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE) encloses some
printk which can be compiled in all cases.
Replace by IS_ENABLED().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a1b6ef3d657c8f249193442f56868fc358ea5b6c.1597643160.git.christophe.leroy@csgroup.eu
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This #ifdef CONFIG_PPC_BOOK3S_64 calls preload_new_slb_context()
when radix is not enabled.
radix_enabled() is always defined, and the prototype for
preload_new_slb_context() is always present, so the #ifdef
is unneeded.
Replace it by IS_ENABLED().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d31506ca9bac9def68cf7424eded63fdc4fb6660.1597643167.git.christophe.leroy@csgroup.eu
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isync() is always defined, no need for an #ifdef.
Replace it by IS_ENABLED(CONFIG_PPC_47x).
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/ac8da0e3baa91dda805e1e492fd65aecd90c1fb5.1597643156.git.christophe.leroy@csgroup.eu
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On powerpc, ptrace watchpoint works in one-shot mode. i.e. kernel
disables event every time it fires and user has to re-enable it.
Also, in case of ptrace watchpoint, kernel notifies ptrace user
before executing instruction.
With CONFIG_HAVE_HW_BREAKPOINT=N, kernel is missing to disable
ptrace event and thus it's causing infinite loop of exceptions.
This is especially harmful when user watches on a data which is
also read/written by kernel, eg syscall parameters. In such case,
infinite exceptions happens in kernel mode which causes soft-lockup.
Fixes: 9422de3e953d ("powerpc: Hardware breakpoints rewrite to handle non DABR breakpoint registers")
Reported-by: Pedro Miraglia Franco de Carvalho <pedromfc@linux.ibm.com>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200902042945.129369-6-ravi.bangoria@linux.ibm.com
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Bring in our fixes branch for this cycle which avoids some small
conflicts with upcoming commits.
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The ISA v3.1 the copy-paste facility has a new memory move functionality
which allows the copy buffer to be pasted to domestic memory (RAM) as
opposed to foreign memory (accelerator).
This means the POWER9 trick of avoiding the cp_abort on context switch if
the process had not mapped foreign memory does not work on POWER10. Do the
cp_abort unconditionally there.
KVM must also cp_abort on guest exit to prevent copy buffer state leaking
between contexts.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200825075535.224536-1-npiggin@gmail.com
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ftrace_graph_ret_addr() is always defined and returns 'ip' when
CONFIG_FUNCTION GRAPH_TRACER is not set.
So the #ifdef is not needed, remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/9d11143d4e27ba8274369a926968756917584868.1597643153.git.christophe.leroy@csgroup.eu
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The recent commit 01eb01877f33 ("powerpc/64s: Fix restore_math
unnecessarily changing MSR") changed some of the handling of floating
point/vector restore.
In particular it caused current->thread.fpexc_mode to be copied into
the current MSR (via msr_check_and_set()), rather than just into
regs->msr (which is moved into MSR on return to userspace).
This can lead to a crash in the kernel if we take a floating point
exception when restoring FPSCR:
Oops: Exception in kernel mode, sig: 8 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
Modules linked in:
CPU: 3 PID: 101213 Comm: ld64.so.2 Not tainted 5.9.0-rc1-00098-g18445bf405cb-dirty #9
NIP: c00000000000fbb4 LR: c00000000001a7ac CTR: c000000000183570
REGS: c0000016b7cfb3b0 TRAP: 0700 Not tainted (5.9.0-rc1-00098-g18445bf405cb-dirty)
MSR: 900000000290b933 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 44002444 XER: 00000000
CFAR: c00000000001a7a8 IRQMASK: 1
GPR00: c00000000001ae40 c0000016b7cfb640 c0000000011b7f00 c000001542a0f740
GPR04: c000001542a0f720 c000001542a0eb00 0000000000000900 c000001542a0eb00
GPR08: 000000000000000a 0000000000002000 9000000000009033 0000000000000000
GPR12: 0000000000004000 c0000017ffffd900 0000000000000001 c000000000df5a58
GPR16: c000000000e19c18 c0000000010e1123 0000000000000001 c000000000e1a638
GPR20: 0000000000000000 c0000000044b1d00 0000000000000000 c000001542a0f2a0
GPR24: 00000016c7fe0000 c000001542a0f720 c000000001c93da0 c000000000fe5f28
GPR28: c000001542a0f720 0000000000800000 c0000016b7cfbe90 0000000002802900
NIP load_fp_state+0x4/0x214
LR restore_math+0x17c/0x1f0
Call Trace:
0xc0000016b7cfb680 (unreliable)
__switch_to+0x330/0x460
__schedule+0x318/0x920
schedule+0x74/0x140
schedule_timeout+0x318/0x3f0
wait_for_completion+0xc8/0x210
call_usermodehelper_exec+0x234/0x280
do_coredump+0xedc/0x13c0
get_signal+0x1d4/0xbe0
do_notify_resume+0x1a0/0x490
interrupt_exit_user_prepare+0x1c4/0x230
interrupt_return+0x14/0x1c0
Instruction dump:
ebe10168 e88101a0 7c8ff120 382101e0 e8010010 7c0803a6 4e800020 790605c4
782905c4 7c0008a8 7c0008a8 c8030200 <fffe058e> 48000088 c8030000 c8230010
Fix it by only loading the fpexc_mode value into regs->msr.
Also add a comment to explain that although VSX is subject to the
value of fpexc_mode, we don't have to handle that separately because
we only allow VSX to be enabled if FP is also enabled.
Fixes: 01eb01877f33 ("powerpc/64s: Fix restore_math unnecessarily changing MSR")
Reported-by: Milton Miller <miltonm@us.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20200825093424.3967813-1-mpe@ellerman.id.au
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Add support for (optionally) using queued spinlocks & rwlocks.
- Support for a new faster system call ABI using the scv instruction on
Power9 or later.
- Drop support for the PROT_SAO mmap/mprotect flag as it will be
unsupported on Power10 and future processors, leaving us with no way
to implement the functionality it requests. This risks breaking
userspace, though we believe it is unused in practice.
- A bug fix for, and then the removal of, our custom stack expansion
checking. We now allow stack expansion up to the rlimit, like other
architectures.
- Remove the remnants of our (previously disabled) topology update
code, which tried to react to NUMA layout changes on virtualised
systems, but was prone to crashes and other problems.
- Add PMU support for Power10 CPUs.
- A change to our signal trampoline so that we don't unbalance the link
stack (branch return predictor) in the signal delivery path.
- Lots of other cleanups, refactorings, smaller features and so on as
usual.
Thanks to: Abhishek Goel, Alastair D'Silva, Alexander A. Klimov, Alexey
Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju
T Sudhakar, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Balamuruhan
S, Bharata B Rao, Bill Wendling, Bin Meng, Cédric Le Goater, Chris
Packham, Christophe Leroy, Christoph Hellwig, Daniel Axtens, Dan
Williams, David Lamparter, Desnes A. Nunes do Rosario, Erhard F., Finn
Thain, Frederic Barrat, Ganesh Goudar, Gautham R. Shenoy, Geoff Levand,
Greg Kurz, Gustavo A. R. Silva, Hari Bathini, Harish, Imre Kaloz, Joel
Stanley, Joe Perches, John Crispin, Jordan Niethe, Kajol Jain, Kamalesh
Babulal, Kees Cook, Laurent Dufour, Leonardo Bras, Li RongQing, Madhavan
Srinivasan, Mahesh Salgaonkar, Mark Cave-Ayland, Michal Suchanek, Milton
Miller, Mimi Zohar, Murilo Opsfelder Araujo, Nathan Chancellor, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Piggin, Oliver O'Halloran,
Palmer Dabbelt, Pedro Miraglia Franco de Carvalho, Philippe Bergheaud,
Pingfan Liu, Pratik Rajesh Sampat, Qian Cai, Qinglang Miao, Randy
Dunlap, Ravi Bangoria, Sachin Sant, Sam Bobroff, Sandipan Das, Santosh
Sivaraj, Satheesh Rajendran, Shirisha Ganta, Sourabh Jain, Srikar
Dronamraju, Stan Johnson, Stephen Rothwell, Thadeu Lima de Souza
Cascardo, Thiago Jung Bauermann, Tom Lane, Vaibhav Jain, Vladis Dronov,
Wei Yongjun, Wen Xiong, YueHaibing.
* tag 'powerpc-5.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (337 commits)
selftests/powerpc: Fix pkey syscall redefinitions
powerpc: Fix circular dependency between percpu.h and mmu.h
powerpc/powernv/sriov: Fix use of uninitialised variable
selftests/powerpc: Skip vmx/vsx/tar/etc tests on older CPUs
powerpc/40x: Fix assembler warning about r0
powerpc/papr_scm: Add support for fetching nvdimm 'fuel-gauge' metric
powerpc/papr_scm: Fetch nvdimm performance stats from PHYP
cpuidle: pseries: Fixup exit latency for CEDE(0)
cpuidle: pseries: Add function to parse extended CEDE records
cpuidle: pseries: Set the latency-hint before entering CEDE
selftests/powerpc: Fix online CPU selection
powerpc/perf: Consolidate perf_callchain_user_[64|32]()
powerpc/pseries/hotplug-cpu: Remove double free in error path
powerpc/pseries/mobility: Add pr_debug() for device tree changes
powerpc/pseries/mobility: Set pr_fmt()
powerpc/cacheinfo: Warn if cache object chain becomes unordered
powerpc/cacheinfo: Improve diagnostics about malformed cache lists
powerpc/cacheinfo: Use name@unit instead of full DT path in debug messages
powerpc/cacheinfo: Set pr_fmt()
powerpc: fix function annotations to avoid section mismatch warnings with gcc-10
...
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From Nick's cover letter:
Linux powerpc new system call instruction and ABI
System Call Vectored (scv) ABI
==============================
The scv instruction is introduced with POWER9 / ISA3, it comes with an
rfscv counter-part. The benefit of these instructions is
performance (trading slower SRR0/1 with faster LR/CTR registers, and
entering the kernel with MSR[EE] and MSR[RI] left enabled, which can
reduce MSR updates. The scv instruction has 128 levels (not enough to
cover the Linux system call space).
Assignment and advertisement
----------------------------
The proposal is to assign scv levels conservatively, and advertise
them with HWCAP feature bits as we add support for more.
Linux has not enabled FSCR[SCV] yet, so executing the scv instruction
will cause the kernel to log a "SCV facility unavilable" message, and
deliver a SIGILL with ILL_ILLOPC to the process. Linux has defined a
HWCAP2 bit PPC_FEATURE2_SCV for SCV support, but does not set it.
This change allocates the zero level ('scv 0'), advertised with
PPC_FEATURE2_SCV, which will be used to provide normal Linux system
calls (equivalent to 'sc').
Attempting to execute scv with other levels will cause a SIGILL to be
delivered the same as before, but will not log a "SCV facility
unavailable" message (because the processor facility is enabled).
Calling convention
------------------
The proposal is for scv 0 to provide the standard Linux system call
ABI with the following differences from sc convention[1]:
- LR is to be volatile across scv calls. This is necessary because the
scv instruction clobbers LR. From previous discussion, this should
be possible to deal with in GCC clobbers and CFI.
- cr1 and cr5-cr7 are volatile. This matches the C ABI and would allow
the kernel system call exit to avoid restoring the volatile cr
registers (although we probably still would anyway to avoid
information leaks).
- Error handling: The consensus among kernel, glibc, and musl is to
move to using negative return values in r3 rather than CR0[SO]=1 to
indicate error, which matches most other architectures, and is
closer to a function call.
Notes
-----
- r0,r4-r8 are documented as volatile in the ABI, but the kernel patch
as submitted currently preserves them. This is to leave room for
deciding which way to go with these. Some small benefit was found by
preserving them[1] but I'm not convinced it's worth deviating from
the C function call ABI just for this. Release code should follow
the ABI.
Previous discussions:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-April/208691.html
https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-April/209268.html
[1] https://github.com/torvalds/linux/blob/master/Documentation/powerpc/syscall64-abi.rst
[2] https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-April/209263.html
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Add support for the scv instruction on POWER9 and later CPUs.
For now this implements the zeroth scv vector 'scv 0', as identical to
'sc' system calls, with the exception that LR is not preserved, nor
are volatile CR registers, and error is not indicated with CR0[SO],
but by returning a negative errno.
rfscv is implemented to return from scv type system calls. It can not
be used to return from sc system calls because those are defined to
preserve LR.
getpid syscall throughput on POWER9 is improved by 26% (428 to 318
cycles), largely due to reducing mtmsr and mtspr.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix ppc64e build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200611081203.995112-3-npiggin@gmail.com
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Before returning to user, if there are missing FP/VEC/VSX bits from the
user MSR then those registers had been saved and must be restored again
before use. restore_math will decide whether to restore immediately, or
skip the restore and let fp/vec/vsx unavailable faults demand load the
registers.
Each time restore_math restores one of the FP/VSX or VEC register sets
is loaded, an 8-bit counter is incremented (load_fp and load_vec). When
these wrap to zero, restore_math no longer restores that register set
until after they are next demand faulted.
It's quite usual for those counters to have different values, so if one
wraps to zero and restore_math no longer restores its registers or user
MSR bit but the other is not zero yet does not need to be restored
(because the kernel is not frequently using the FPU), then restore_math
will be called and it will also not return in the early exit check.
This causes msr_check_and_set to test and set the MSR at every kernel
exit despite having no work to do.
This can cause workloads (e.g., a NULL syscall microbenchmark) to run
fast for a time while both counters are non-zero, then slow down when
one of the counters reaches zero, then speed up again after the second
counter reaches zero. The cost is significant, about 10% slowdown on a
NULL syscall benchmark, and the jittery behaviour is very undesirable.
Fix this by having restore_math test all conditions first, and only
update MSR if we will be loading registers.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200623234139.2262227-2-npiggin@gmail.com
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The TM test in restore_math added by commit dc16b553c949e ("powerpc:
Always restore FPU/VEC/VSX if hardware transactional memory in use") is
no longer necessary after commit a8318c13e79ba ("powerpc/tm: Fix
restoring FP/VMX facility incorrectly on interrupts"), which removed
the cases where restore_math has to restore if TM is active.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200623234139.2262227-1-npiggin@gmail.com
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Now that HAVE_COPY_THREAD_TLS has been removed, rename copy_thread_tls()
back simply copy_thread(). It's a simpler name, and doesn't imply that only
tls is copied here. This finishes an outstanding chunk of internal process
creation work since we've added clone3().
Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>A
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>A
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Michael Ellerman:
- One fix for the interrupt rework we did last release which broke
KVM-PR
- Three commits fixing some fallout from the READ_ONCE() changes
interacting badly with our 8xx 16K pages support, which uses a pte_t
that is a structure of 4 actual PTEs
- A cleanup of the 8xx pte_update() to use the newly added pmd_off()
- A fix for a crash when handling an oops if CONFIG_DEBUG_VIRTUAL is
enabled
- A minor fix for the SPU syscall generation
Thanks to Aneesh Kumar K.V, Christian Zigotzky, Christophe Leroy, Mike
Rapoport, Nicholas Piggin.
* tag 'powerpc-5.8-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/8xx: Provide ptep_get() with 16k pages
mm: Allow arches to provide ptep_get()
mm/gup: Use huge_ptep_get() in gup_hugepte()
powerpc/syscalls: Use the number when building SPU syscall table
powerpc/8xx: use pmd_off() to access a PMD entry in pte_update()
powerpc/64s: Fix KVM interrupt using wrong save area
powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL
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Better describe what this helper does, and match the naming of
copy_from_kernel_nofault.
Also switch the argument order around, so that it acts and looks
like get_user().
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Better describe what these functions do.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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With CONFIG_DEBUG_VIRTUAL=y, we can hit a BUG() if we take a hard
lockup watchdog interrupt when in OPAL mode.
This happens in show_instructions() if the kernel takes the watchdog
NMI IPI, or any other interrupt, with MSR_IR == 0. show_instructions()
updates the variable pc in the loop and the second iteration will
result in BUG().
We hit the BUG_ON due the below check in __va()
#define __va(x)
({
VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET);
(void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET);
})
Fix it by moving the check out of the loop. Also update nip so that
the nip == pc check still matches.
Fixes: 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va and __pa addresses")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Use IS_ENABLED(), massage change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200524093822.423487-1-aneesh.kumar@linux.ibm.com
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Patch series "mm: consolidate definitions of page table accessors", v2.
The low level page table accessors (pXY_index(), pXY_offset()) are
duplicated across all architectures and sometimes more than once. For
instance, we have 31 definition of pgd_offset() for 25 supported
architectures.
Most of these definitions are actually identical and typically it boils
down to, e.g.
static inline unsigned long pmd_index(unsigned long address)
{
return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1);
}
static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)
{
return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address);
}
These definitions can be shared among 90% of the arches provided
XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined.
For architectures that really need a custom version there is always
possibility to override the generic version with the usual ifdefs magic.
These patches introduce include/linux/pgtable.h that replaces
include/asm-generic/pgtable.h and add the definitions of the page table
accessors to the new header.
This patch (of 12):
The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the
functions involving page table manipulations, e.g. pte_alloc() and
pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h>
in the files that include <linux/mm.h>.
The include statements in such cases are remove with a simple loop:
for f in $(git grep -l "include <linux/mm.h>") ; do
sed -i -e '/include <asm\/pgtable.h>/ d' $f
done
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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Now the last users of show_stack() got converted to use an explicit log
level, show_stack_loglvl() can drop it's redundant suffix and become once
again well known show_stack().
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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|
Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).
Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages. And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.
Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers. Also, it will consolidate
printings with headers.
Introduce show_stack_loglvl(), that eventually will substitute
show_stack().
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Link: http://lkml.kernel.org/r/20200418201944.482088-27-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently we assume that we have only one watchpoint supported by hw.
Get rid of that assumption and use dynamic loop instead. This should
make supporting more watchpoints very easy.
With more than one watchpoint, exception handler needs to know which
DAWR caused the exception, and hw currently does not provide it. So
we need sw logic for the same. To figure out which DAWR caused the
exception, check all different combinations of user specified range,
DAWR address range, actual access range and DAWRX constrains. For ex,
if user specified range and actual access range overlaps but DAWRX is
configured for readonly watchpoint and the instruction is store, this
DAWR must not have caused exception.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Michael Neuling <mikey@neuling.org>
[mpe: Unsplit multi-line printk() strings, fix some sparse warnings]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200514111741.97993-14-ravi.bangoria@linux.ibm.com
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Currently we calculate hw aligned start and end addresses manually.
Replace them with builtin ALIGN_DOWN() and ALIGN() macros.
So far end_addr was inclusive but this patch makes it exclusive (by
avoiding -1) for better readability.
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-13-ravi.bangoria@linux.ibm.com
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ptrace_bps is already an array of size HBP_NUM_MAX. But we use
hardcoded index 0 while fetching/updating it. Convert such code
to loop over array.
ptrace interface to use multiple watchpoint remains same. eg:
two PPC_PTRACE_SETHWDEBUG calls will create two watchpoint if
underneath hw supports it.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-11-ravi.bangoria@linux.ibm.com
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So far powerpc hw supported only one watchpoint. But Power10 is
introducing 2nd DAWR. Convert thread_struct->hw_brk into an array.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-10-ravi.bangoria@linux.ibm.com
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