linux.git/arch/powerpc/kernel/traps.c, branch v5.12

powerpc/traps: unrecoverable_exception() is not an interrupt handler

2021-03-12T00:02:12+00:00

unrecoverable_exception() is called from interrupt handlers or
after an interrupt handler has failed.

Make it a standard function to avoid doubling the actions
performed on interrupt entry (e.g.: user time accounting).

Fixes: 3a96570ffceb ("powerpc: convert interrupt handlers to use wrappers")
Signed-off-by: Christophe Leroy 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/ae96c59fa2cb7f24a8929c58cfa2c909cb8ff1f1.1615291471.git.christophe.leroy@csgroup.eu

powerpc: remove interrupt handler functions from the noinstr section

2021-02-11T12:28:34+00:00

The allyesconfig ppc64 kernel fails to link with relocations unable to
fit after commit 3a96570ffceb ("powerpc: convert interrupt handlers to
use wrappers"), which is due to the interrupt handler functions being
put into the .noinstr.text section, which the linker script places on
the opposite side of the main .text section from the interrupt entry
asm code which calls the handlers.

This results in a lot of linker stubs that overwhelm the 252-byte sized
space we allow for them, or in the case of BE a .opd relocation link
error for some reason.

It's not required to put interrupt handlers in the .noinstr section,
previously they used NOKPROBE_SYMBOL, so take them out and replace
with a NOKPROBE_SYMBOL in the wrapper macro. Remove the explicit
NOKPROBE_SYMBOL macros in the interrupt handler functions. This makes
a number of interrupt handlers nokprobe that were not prior to the
interrupt wrappers commit, but since that commit they were made
nokprobe due to being in .noinstr.text, so this fix does not change
that.

The fixes tag is different to the commit that first exposes the problem
because it is where the wrapper macros were introduced.

Fixes: 8d41fc618ab8 ("powerpc: interrupt handler wrapper functions")
Reported-by: Stephen Rothwell 
Signed-off-by: Nicholas Piggin 
[mpe: Slightly fix up comment wording]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210211063636.236420-1-npiggin@gmail.com

powerpc: move NMI entry/exit code into wrapper

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

This moves the common NMI entry and exit code into the interrupt handler
wrappers.

This changes the behaviour of soft-NMI (watchdog) and HMI interrupts, and
also MCE interrupts on 64e, by adding missing parts of the NMI entry to
them.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-40-npiggin@gmail.com

powerpc: handle irq_enter/irq_exit in interrupt handler wrappers

2021-02-08T13:10:49+00:00

Move irq_enter/irq_exit into asynchronous interrupt handler wrappers.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-35-npiggin@gmail.com

powerpc/64: context tracking move to interrupt wrappers

2021-02-08T13:10:46+00:00

This moves exception_enter/exit calls to wrapper functions for
synchronous interrupts. More interrupt handlers are covered by
this than previously.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-33-npiggin@gmail.com

powerpc: add interrupt_cond_local_irq_enable helper

2021-02-08T13:02:12+00:00

Simple helper for synchronous interrupt handlers (i.e., process-context)
to enable interrupts if it was taken in an interrupts-enabled context.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-30-npiggin@gmail.com

powerpc: convert interrupt handlers to use wrappers

2021-02-08T13:02:12+00:00

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-29-npiggin@gmail.com

powerpc/traps: factor common code from program check and emulation assist

2021-02-08T13:02:12+00:00

Move the program check handling into a function called by both, rather
than have the emulation assist handler call the program check handler.

This allows each of these handlers to be implemented with "interrupt
wrappers" in a later change.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/1612702475.d6qyt6qtfy.astroid@bobo.none

powerpc: improve handling of unrecoverable system reset

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

If an unrecoverable system reset hits in process context, the system
does not have to panic. Similar to machine check, call nmi_exit()
before die().

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-26-npiggin@gmail.com

powerpc/mce: ensure machine check handler always tests RI

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

A machine check that is handled must still check MSR[RI] for
recoverability of the interrupted context. Without this patch
it's possible for a handled machine check to return to a
context where it has clobbered live registers.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-25-npiggin@gmail.com