diff options
| author | Nicholas Piggin <npiggin@gmail.com> | 2019-07-11 12:24:03 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-01-16 14:59:37 +1000 |
| commit | ed0bc98f8cbe4f8254759d333a47aedc816ff8c5 (patch) | |
| tree | 7e5768afb6d7e895930d578954d3c4061998cb9a /arch/powerpc/kernel/idle_power4.S | |
| parent | 30e813cf46ccaeea6508607632e49b4a1d743d2a (diff) | |
powerpc/64s: Reimplement power4_idle code in C
This implements the tricky tracing and soft irq handling bits in C,
leaving the low level bit to asm.
A functional difference is that this redirects the interrupt exit to
a return stub to execute blr, rather than the lr address itself. This
is probably barely measurable on real hardware, but it keeps the link
stack balanced.
Tested with QEMU.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Move power4_fixup_nap back into exceptions-64s.S]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190711022404.18132-1-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/kernel/idle_power4.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_power4.S | 83 |
1 files changed, 0 insertions, 83 deletions
diff --git a/arch/powerpc/kernel/idle_power4.S b/arch/powerpc/kernel/idle_power4.S deleted file mode 100644 index 33c625329078..000000000000 --- a/arch/powerpc/kernel/idle_power4.S +++ /dev/null @@ -1,83 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ -/* - * This file contains the power_save function for 970-family CPUs. - */ - -#include <linux/threads.h> -#include <asm/processor.h> -#include <asm/page.h> -#include <asm/cputable.h> -#include <asm/thread_info.h> -#include <asm/ppc_asm.h> -#include <asm/asm-offsets.h> -#include <asm/irqflags.h> -#include <asm/hw_irq.h> -#include <asm/feature-fixups.h> - -#undef DEBUG - - .text - -_GLOBAL(power4_idle) -BEGIN_FTR_SECTION - blr -END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP) - /* Now check if user or arch enabled NAP mode */ - LOAD_REG_ADDRBASE(r3,powersave_nap) - lwz r4,ADDROFF(powersave_nap)(r3) - cmpwi 0,r4,0 - beqlr - - /* This sequence is similar to prep_irq_for_idle() */ - - /* Hard disable interrupts */ - mfmsr r7 - rldicl r0,r7,48,1 - rotldi r0,r0,16 - mtmsrd r0,1 - - /* Check if something happened while soft-disabled */ - lbz r0,PACAIRQHAPPENED(r13) - cmpwi cr0,r0,0 - bne- 2f - - /* - * Soft-enable interrupts. This will make power4_fixup_nap return - * to our caller with interrupts enabled (soft and hard). The caller - * can cope with either interrupts disabled or enabled upon return. - */ -#ifdef CONFIG_TRACE_IRQFLAGS - /* Tell the tracer interrupts are on, because idle responds to them. */ - mflr r0 - std r0,16(r1) - stdu r1,-128(r1) - bl trace_hardirqs_on - addi r1,r1,128 - ld r0,16(r1) - mtlr r0 - mfmsr r7 -#endif /* CONFIG_TRACE_IRQFLAGS */ - - li r0,IRQS_ENABLED - stb r0,PACAIRQSOFTMASK(r13) /* we'll hard-enable shortly */ -BEGIN_FTR_SECTION - DSSALL - sync -END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) - ld r9, PACA_THREAD_INFO(r13) - ld r8,TI_LOCAL_FLAGS(r9) /* set napping bit */ - ori r8,r8,_TLF_NAPPING /* so when we take an exception */ - std r8,TI_LOCAL_FLAGS(r9) /* it will return to our caller */ - ori r7,r7,MSR_EE - oris r7,r7,MSR_POW@h -1: sync - isync - mtmsrd r7 - isync - b 1b - -2: /* Return if an interrupt had happened while soft disabled */ - /* Set the HARD_DIS flag because interrupts are now hard disabled */ - ori r0,r0,PACA_IRQ_HARD_DIS - stb r0,PACAIRQHAPPENED(r13) - blr |