linux.git/arch/powerpc/kernel/exceptions-64e.S, branch v5.12

powerpc/64: entry cpu time accounting in C

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

There is no need for this to be in asm, use the new interrupt entry wrapper.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-39-npiggin@gmail.com

powerpc: bad_page_fault get registers from regs

2021-02-08T13:02:09+00:00

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 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-12-npiggin@gmail.com

powerpc: DebugException remove args

2021-02-08T13:02:09+00:00

Like other interrupt handler conversions, switch to getting registers
from the pt_regs argument.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-10-npiggin@gmail.com

powerpc: remove arguments from fault handler functions

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

Make mm fault handlers all just take the pt_regs * argument and load
DAR/DSISR from that. Make those that return a value return long.

This is done to make the function signatures match other handlers, which
will help with a future patch to add wrappers. Explicit arguments could
be added for performance but that would require more wrapper macro
variants.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210130130852.2952424-7-npiggin@gmail.com

powerpc/fault: Perform exception fixup in do_page_fault()

2020-12-09T12:48:14+00:00

Exception fixup doesn't require the heady full regs saving,
do it from do_page_fault() directly.

For that, split bad_page_fault() in two parts.

As bad_page_fault() can also be called from other places than
handle_page_fault(), it will still perform exception fixup and
fallback on __bad_page_fault().

handle_page_fault() directly calls __bad_page_fault() as the
exception fixup will now be done by do_page_fault()

Signed-off-by: Christophe Leroy 
Reviewed-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/bd07d6fef9237614cd6d318d8f19faeeadaa816b.1607491748.git.christophe.leroy@csgroup.eu

powerpc/64e: remove 64s specific interrupt soft-mask code

2020-10-06T12:22:23+00:00

Since the assembly soft-masking code was moved to 64e specific, there
are some 64s specific interrupt types still there. Remove them.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200915114650.3980244-4-npiggin@gmail.com

powerpc/64e: remove PACA_IRQ_EE_EDGE

2020-10-06T12:22:23+00:00

This is not used anywhere.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200915114650.3980244-3-npiggin@gmail.com

powerpc/64s: Implement interrupt exit logic in C

2020-04-01T02:42:14+00:00

Implement the bulk of interrupt return logic in C. The asm return code
must handle a few cases: restoring full GPRs, and emulating stack
store.

The stack store emulation is significantly simplfied, rather than
creating a new return frame and switching to that before performing
the store, it uses the PACA to keep a scratch register around to
perform the store.

The asm return code is moved into 64e for now. The new logic has made
allowance for 64e, but I don't have a full environment that works well
to test it, and even booting in emulated qemu is not great for stress
testing. 64e shouldn't be too far off working with this, given a bit
more testing and auditing of the logic.

This is slightly faster on a POWER9 (page fault speed increases about
1.1%), probably due to reduced mtmsrd.

mpe: Includes fixes from Nick for _TIF_EMULATE_STACK_STORE
handling (including the fast_interrupt_return path), to remove
trace_hardirqs_on(), and fixes the interrupt-return part of the
MSR_VSX restore bug caught by tm-unavailable selftest.

mpe: Incorporate fix from Nick:

The return-to-kernel path has to replay any soft-pending interrupts if
it is returning to a context that had interrupts soft-enabled. It has
to do this carefully and avoid plain enabling interrupts if this is an
irq context, which can cause multiple nesting of interrupts on the
stack, and other unexpected issues.

The code which avoided this case got the soft-mask state wrong, and
marked interrupts as enabled before going around again to retry. This
seems to be mostly harmless except when PREEMPT=y, this calls
preempt_schedule_irq with irqs apparently enabled and runs into a BUG
in kernel/sched/core.c

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michal Suchanek 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200225173541.1549955-29-npiggin@gmail.com

powerpc/64: Implement soft interrupt replay in C

2020-04-01T02:42:13+00:00

When local_irq_enable() finds a pending soft-masked interrupt, it
"replays" it by setting up registers like the initial interrupt entry,
then calls into the low level handler to set up an interrupt stack
frame and process the interrupt.

This is not necessary, and uses more stack than needed. The high level
interrupt handler can be called directly from C, with just pt_regs set
up on stack. This should be faster and use less stack.

Signed-off-by: Nicholas Piggin 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20200225173541.1549955-28-npiggin@gmail.com

powerpc: unify definition of M_IF_NEEDED

2019-11-13T08:27:24+00:00

M_IF_NEEDED is defined too many times. Move it to a common place and
rename it to MAS2_M_IF_NEEDED which is much readable.

Signed-off-by: Jason Yan 
Reviewed-by: Christophe Leroy 
Reviewed-by: Diana Craciun 
Tested-by: Diana Craciun 
Signed-off-by: Scott Wood 
Signed-off-by: Michael Ellerman