linux-toradex.git/arch/powerpc/kernel/entry_64.S, branch v4.14

powerpc/asm: Convert .llong directives to .8byte

2017-08-31T04:26:47+00:00

.llong is an undocumented PPC specific directive. The generic
equivalent is .quad, but even better (because it's self describing) is
.8byte.

Convert all .llong directives to .8byte.

Signed-off-by: Tobin C. Harding 
Signed-off-by: Michael Ellerman

powerpc/64: Remove redundant instruction in interrupt replay

2017-08-23T13:17:16+00:00

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman

powerpc/64s: Merge HV and non-HV paths for doorbell IRQ replay

2017-08-23T13:13:27+00:00

This results in smaller code, and fewer branches. This relies on the
fact that both the 0xe80 and 0xa00 handlers call the same upper level
code, namely doorbell_exception().

Signed-off-by: Nicholas Piggin 
[mpe: Mention we rely on the implementation of the 0xe80/0xa00 handlers]
Signed-off-by: Michael Ellerman

Revert "powerpc/64: Avoid restore_math call if possible in syscall exit"

2017-08-07T11:36:56+00:00

This reverts commit bc4f65e4cf9d6cc43e0e9ba0b8648cf9201cd55f.

As reported by Andreas, this commit is causing unrecoverable SLB misses in the
system call exit path:

  Unrecoverable exception 4100 at c00000000000a1ec
  Oops: Unrecoverable exception, sig: 6 [#1]
  SMP NR_CPUS=2 PowerMac
  ...
  CPU: 0 PID: 18626 Comm: rm Not tainted 4.13.0-rc3 #1
  task: c00000018335e080 task.stack: c000000139e50000
  NIP: c00000000000a1ec LR: c00000000000a118 CTR: 0000000000000000
  REGS: c000000139e53bb0 TRAP: 4100   Not tainted  (4.13.0-rc3)
  MSR: 9000000000001030  CR: 24000044  XER: 20000000 SOFTE: 1
  GPR00: 0000000000000000 c000000139e53e30 c000000000abb500 fffffffffffffffe
  GPR04: c0000001eb866298 0000000000000000 0000000000000000 c00000018335e080
  GPR08: 900000000000d032 0000000000000000 0000000000000002 fffffffffffff001
  GPR12: c000000139e50000 c00000000ffff000 00003fffa8c0dca0 00003fffa8c0dc88
  GPR16: 0000000010000000 0000000000000001 00003fffa8c0eaa0 0000000000000000
  GPR20: 00003fffa8c27528 00003fffa8c27b00 0000000000000000 0000000000000000
  GPR24: 00003fffa8c0d918 00003ffff1b3efa0 00003fffa8c26d68 0000000000000000
  GPR28: 00003fffa8c249e8 00003fffa8c263d0 00003fffa8c27550 00003ffff1b3ef10
  NIP [c00000000000a1ec] system_call_exit+0xc0/0x21c
  LR [c00000000000a118] system_call+0x58/0x6c
  Call Trace:
  [c000000139e53e30] [c00000000000a118] system_call+0x58/0x6c (unreliable)
  Instruction dump:
  64a51000 7c6300d0 f8a101a0 4bffff9c 3c000000 60000006 780007c6 64000000
  60000000 7c004039 4082001c e8ed0170 <88070b78> 88c70b79 7c003214 2c200000

This is caused by us trying to load THREAD_LOAD_FP with MSR_RI=0, and taking an
SLB miss on the thread struct.

Reported-by: Andreas Schwab 
Diagnosed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman

powerpc/64s: Blacklist rtas entry/exit from kprobes

2017-07-03T13:12:02+00:00

We can't take traps with relocation off, so blacklist enter_rtas() and
rtas_return_loc(). However, instead of blacklisting all of enter_rtas(),
introduce a new symbol __enter_rtas from where on we can't take a trap
and blacklist that.

Signed-off-by: Naveen N. Rao 
Signed-off-by: Michael Ellerman

powerpc/64s: Blacklist functions invoked on a trap

2017-07-03T13:12:01+00:00

Blacklist all functions involved while handling a trap. We:
- convert some of the symbols into private symbols, and
- blacklist most functions involved while handling a trap.

Reviewed-by: Masami Hiramatsu 
Signed-off-by: Naveen N. Rao 
Signed-off-by: Michael Ellerman

powerpc/64s: Un-blacklist system_call() from kprobes

2017-07-03T13:12:01+00:00

It is actually safe to probe system_call() in entry_64.S, but only till
we unset MSR_RI. To allow this, add a new symbol system_call_exit()
after the mtmsrd and blacklist that.

Suggested-by: Michael Ellerman 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Naveen N. Rao 
Signed-off-by: Michael Ellerman

powerpc/64s: Move system_call() symbol to just after setting MSR_EE

2017-07-03T13:12:00+00:00

It is common to get a PMU interrupt right after the mtmsr instruction that
enables interrupts. Due to this, the stack trace profile gets needlessly split
across system_call_common() and system_call().

Previously, system_call() symbol was at the current place to hide a few
earlier symbols which have since been made private or removed entirely.

So, let's move system_call() slightly higher up, right after the mtmsr
instruction that enables interrupts. Convert existing references to
system_call to a local syscall symbol.

Suggested-by: Nicholas Piggin 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Naveen N. Rao 
Signed-off-by: Michael Ellerman

powerpc/64s: Blacklist system_call() and system_call_common() from kprobes

2017-07-03T13:11:25+00:00

Convert some of the symbols into private symbols and blacklist
system_call_common() and system_call() from kprobes. We can't take a
trap at parts of these functions as either MSR_RI is unset or the
kernel stack pointer is not yet setup.

Reviewed-by: Masami Hiramatsu 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Naveen N. Rao 
[mpe: Don't convert system_call_common to _GLOBAL()]
Signed-off-by: Michael Ellerman

powerpc/64s: Avoid cpabort in context switch when possible

2017-06-15T06:34:39+00:00

The ISA v3.0B copy-paste facility only requires cpabort when switching
to a process that has foreign real addresses mapped (direct access to
accelerators), to clear a potential copy buffer filled by a previous
thread. There is no accelerator driver implemented yet, so cpabort can
be removed. It can be be re-added when a driver is implemented.

POWER9 DD1 requires the copy buffer to always be cleared on context
switch, but if accelerators are not in use, then an unpaired copy from
a dummy region is sufficient to clear data out of the copy buffer.

This increases context switch performance by about 5% on POWER9.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman