[PATCH v2 04/11] powerpc/64: handle MSR EE and RI in interrupt entry wrapper
Nicholas Piggin
npiggin at gmail.com
Fri May 21 21:44:15 AEST 2021
Similarly to the system call change in the previous patch, the mtmsrd to
enable RI can be combined with the mtmsrd to enable EE for interrupts
which enable the latter, which tends to be the important synchronous
interrupts (i.e., page faults).
Do this by enabling EE and RI together at the beginning of the entry
wrapper if PACA_IRQ_HARD_DIS is clear, and just enabling RI if it is set
(which means something wanted EE=0).
Asynchronous interrupts set PACA_IRQ_HARD_DIS, but synchronous ones
leave it unchanged, so by default they always get EE=1 unless they
interrupt a caller that has hard disabled. When the sync interrupt
later calls interrupt_cond_local_irq_enable(), that will not require
another mtmsrd because we already enabled here.
This tends to save one mtmsrd L=1 for synchronous interrupts on 64s.
64e is conceptually unchanged, but it also sets MSR[EE]=1 now in the
interrupt wrapper for synchronous interrupts with the same code.
From: Nicholas Piggin <npiggin at gmail.com>
---
arch/powerpc/include/asm/interrupt.h | 22 ++++++++++++++++++--
arch/powerpc/kernel/exceptions-64s.S | 30 ----------------------------
2 files changed, 20 insertions(+), 32 deletions(-)
diff --git a/arch/powerpc/include/asm/interrupt.h b/arch/powerpc/include/asm/interrupt.h
index 6e9d18838d56..b9c510187b58 100644
--- a/arch/powerpc/include/asm/interrupt.h
+++ b/arch/powerpc/include/asm/interrupt.h
@@ -126,9 +126,21 @@ static inline void interrupt_enter_prepare(struct pt_regs *regs, struct interrup
#endif
#ifdef CONFIG_PPC64
- if (irq_soft_mask_set_return(IRQS_ALL_DISABLED) == IRQS_ENABLED)
+ bool trace_enable = false;
+
+ if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS)) {
+ if (irq_soft_mask_set_return(IRQS_DISABLED) == IRQS_ENABLED)
+ trace_enable = true;
+ } else {
+ irq_soft_mask_set(IRQS_DISABLED);
+ }
+ /* If the interrupt was taken with HARD_DIS set, don't enable MSR[EE] */
+ if (local_paca->irq_happened & PACA_IRQ_HARD_DIS)
+ __hard_RI_enable();
+ else
+ __hard_irq_enable();
+ if (trace_enable)
trace_hardirqs_off();
- local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
if (user_mode(regs)) {
CT_WARN_ON(ct_state() != CONTEXT_USER);
@@ -175,6 +187,10 @@ static inline void interrupt_async_enter_prepare(struct pt_regs *regs, struct in
__ppc64_runlatch_on();
#endif
+#ifdef CONFIG_PPC64
+ /* Ensure interrupt_enter_prepare does not enable MSR[EE] */
+ local_paca->irq_happened |= PACA_IRQ_HARD_DIS;
+#endif
interrupt_enter_prepare(regs, state);
irq_enter();
}
@@ -239,6 +255,8 @@ static inline void interrupt_nmi_enter_prepare(struct pt_regs *regs, struct inte
regs->softe = IRQS_ALL_DISABLED;
}
+ __hard_RI_enable();
+
/* Don't do any per-CPU operations until interrupt state is fixed */
if (nmi_disables_ftrace(regs)) {
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 5c18a2a3058d..a2ae14d0600e 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -129,7 +129,6 @@ name:
#define IISIDE .L_IISIDE_\name\() /* Uses SRR0/1 not DAR/DSISR */
#define IDAR .L_IDAR_\name\() /* Uses DAR (or SRR0) */
#define IDSISR .L_IDSISR_\name\() /* Uses DSISR (or SRR1) */
-#define ISET_RI .L_ISET_RI_\name\() /* Run common code w/ MSR[RI]=1 */
#define IBRANCH_TO_COMMON .L_IBRANCH_TO_COMMON_\name\() /* ENTRY branch to common */
#define IREALMODE_COMMON .L_IREALMODE_COMMON_\name\() /* Common runs in realmode */
#define IMASK .L_IMASK_\name\() /* IRQ soft-mask bit */
@@ -174,9 +173,6 @@ do_define_int n
.ifndef IDSISR
IDSISR=0
.endif
- .ifndef ISET_RI
- ISET_RI=1
- .endif
.ifndef IBRANCH_TO_COMMON
IBRANCH_TO_COMMON=1
.endif
@@ -581,11 +577,6 @@ DEFINE_FIXED_SYMBOL(\name\()_common_real)
stb r10,PACASRR_VALID(r13)
.endif
- .if ISET_RI
- li r10,MSR_RI
- mtmsrd r10,1 /* Set MSR_RI */
- .endif
-
.if ISTACK
.if IKUAP
kuap_save_amr_and_lock r9, r10, cr1, cr0
@@ -906,11 +897,6 @@ INT_DEFINE_BEGIN(system_reset)
IVEC=0x100
IAREA=PACA_EXNMI
IVIRT=0 /* no virt entry point */
- /*
- * MSR_RI is not enabled, because PACA_EXNMI and nmi stack is
- * being used, so a nested NMI exception would corrupt it.
- */
- ISET_RI=0
ISTACK=0
IKVM_REAL=1
INT_DEFINE_END(system_reset)
@@ -991,8 +977,6 @@ EXC_COMMON_BEGIN(system_reset_common)
lhz r10,PACA_IN_NMI(r13)
addi r10,r10,1
sth r10,PACA_IN_NMI(r13)
- li r10,MSR_RI
- mtmsrd r10,1
mr r10,r1
ld r1,PACA_NMI_EMERG_SP(r13)
@@ -1068,12 +1052,6 @@ INT_DEFINE_BEGIN(machine_check_early)
IAREA=PACA_EXMC
IVIRT=0 /* no virt entry point */
IREALMODE_COMMON=1
- /*
- * MSR_RI is not enabled, because PACA_EXMC is being used, so a
- * nested machine check corrupts it. machine_check_common enables
- * MSR_RI.
- */
- ISET_RI=0
ISTACK=0
IDAR=1
IDSISR=1
@@ -1084,7 +1062,6 @@ INT_DEFINE_BEGIN(machine_check)
IVEC=0x200
IAREA=PACA_EXMC
IVIRT=0 /* no virt entry point */
- ISET_RI=0
IDAR=1
IDSISR=1
IKVM_SKIP=1
@@ -1155,9 +1132,6 @@ EXC_COMMON_BEGIN(machine_check_early_common)
BEGIN_FTR_SECTION
bl enable_machine_check
END_FTR_SECTION_IFSET(CPU_FTR_HVMODE)
- li r10,MSR_RI
- mtmsrd r10,1
-
addi r3,r1,STACK_FRAME_OVERHEAD
bl machine_check_early
std r3,RESULT(r1) /* Save result */
@@ -1245,10 +1219,6 @@ EXC_COMMON_BEGIN(machine_check_common)
* save area: PACA_EXMC instead of PACA_EXGEN.
*/
GEN_COMMON machine_check
-
- /* Enable MSR_RI when finished with PACA_EXMC */
- li r10,MSR_RI
- mtmsrd r10,1
addi r3,r1,STACK_FRAME_OVERHEAD
bl machine_check_exception
b interrupt_return_srr
--
2.23.0
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