linux.git/arch/powerpc/platforms/pseries/ras.c, branch vsnprintf

powerpc/rtas: arch-wide function token lookup conversions

2023-02-13T11:35:03+00:00

With the tokens for all implemented RTAS functions now available via
rtas_function_token(), which is optimal and safe for arbitrary
contexts, there is no need to use rtas_token() or cache its result.

Most conversions are trivial, but a few are worth describing in more
detail:

* Error injection token comparisons for lockdown purposes are
  consolidated into a simple predicate: token_is_restricted_errinjct().

* A couple of special cases in block_rtas_call() do not use
  rtas_token() but perform string comparisons against names in the
  function table. These are converted to compare against token values
  instead, which is logically equivalent but less expensive.

* The lookup for the ibm,os-term token can be deferred until needed,
  instead of caching it at boot to avoid device tree traversal during
  panic.

* Since rtas_function_token() accesses a read-only data structure
  without taking any locks, xmon's lookup of set-indicator can be
  performed as needed instead of cached at startup.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-20-26929c8cce78@linux.ibm.com

powerpc/mce: Avoid using irq_work_queue() in realmode

2022-03-07T13:05:00+00:00

In realmode mce handler we use irq_work_queue() to defer
the processing of mce events, irq_work_queue() can only
be called when translation is enabled because it touches
memory outside RMA, hence we enable translation before
calling irq_work_queue and disable on return, though it
is not safe to do in realmode.

To avoid this, program the decrementer and call the event
processing functions from timer handler.

Signed-off-by: Ganesh Goudar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220120121931.517974-1-ganeshgr@linux.ibm.com

powerpc/pseries: Parse control memory access error

2022-03-07T13:04:59+00:00

Add support to parse and log control memory access
error for pseries. These changes are made according to
PAPR v2.11 10.3.2.2.12.

Signed-off-by: Ganesh Goudar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220107141428.67862-1-ganeshgr@linux.ibm.com

powerpc/64s: Move hash MMU support code under CONFIG_PPC_64S_HASH_MMU

2021-12-09T11:41:13+00:00

Compiling out hash support code when CONFIG_PPC_64S_HASH_MMU=n saves
128kB kernel image size (90kB text) on powernv_defconfig minus KVM,
350kB on pseries_defconfig minus KVM, 40kB on a tiny config.

Signed-off-by: Nicholas Piggin 
[mpe: Fixup defined(ARCH_HAS_MEMREMAP_COMPAT_ALIGN), which needs CONFIG.
      Fix radix_enabled() use in setup_initial_memory_limit(). Add some
      stubs to reduce number of ifdefs.]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20211201144153.2456614-18-npiggin@gmail.com

powerpc: Refactor verification of MSR_RI

2021-08-26T11:21:07+00:00

40x and BOOKE don't have MSR_RI therefore all tests involving
MSR_RI may be problematic on those plateforms.

Create helpers to check or set MSR_RI in regs, and use them
in common code.

Signed-off-by: Christophe Leroy 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/c2fb93708196734f4176dda334aaa3055f213b89.1629707037.git.christophe.leroy@csgroup.eu

powerpc/64s: avoid reloading (H)SRR registers if they are still valid

2021-06-24T14:06:55+00:00

When an interrupt is taken, the SRR registers are set to return to where
it left off. Unless they are modified in the meantime, or the return
address or MSR are modified, there is no need to reload these registers
when returning from interrupt.

Introduce per-CPU flags that track the validity of SRR and HSRR
registers. These are cleared when returning from interrupt, when
using the registers for something else (e.g., OPAL calls), when
adjusting the return address or MSR of a context, and when context
switching (which changes the return address and MSR).

This improves the performance of interrupt returns.

Signed-off-by: Nicholas Piggin 
[mpe: Fold in fixup patch from Nick]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com

powerpc/pseries/ras: Delete a redundant condition branch

2021-05-23T10:51:34+00:00

The statement of the last "if (xxx)" branch is the same as the "else"
branch. Delete it to simplify code.

No functional change.

Signed-off-by: Zhen Lei 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210510131924.3907-1-thunder.leizhen@huawei.com

powerpc/pseries/mce: Fix a typo in error type assignment

2021-04-20T04:22:23+00:00

The error type is ICACHE not DCACHE, for case MCE_ERROR_TYPE_ICACHE.

Signed-off-by: Ganesh Goudar 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210416125750.49550-1-ganeshgr@linux.ibm.com

powerpc/pseries/mce: restore msr before returning from handler

2021-02-08T13:10:50+00:00

The pseries real-mode machine check handler can enable the MMU, and
return from the handler with the MMU still enabled.

This works, but real-mode handler wrapper exit handlers want to rely
on the MMU being in real-mode. So change the pseries handler to
restore the MSR after it has finished virtual mode tasks.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/1612702361.lm7fqo56re.astroid@bobo.none

powerpc: introduce die_mce

2021-02-08T13:02:11+00:00

As explained by commit daf00ae71dad ("powerpc/traps: restore
recoverability of machine_check interrupts"), die() can't be called from
within nmi_enter to nicely kill a process context that was interrupted.
nmi_exit must be called first.

This adds a function die_mce which takes care of this for machine check
handlers.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-24-npiggin@gmail.com