On Wed, 2012-01-18 at 16:35 +0200, Laurentiu Tudor wrote:
> This patch adds a menuconfig option that allows controlling
> the lazy interrupt disabling feature implemented by this
> commit:
>
> commit d04c56f73c30a5e593202ecfcf25ed43d42363a2
> Author: Paul Mackerras
> Date: Wed Oct 4 16:47:49 2006 +1000
>
> [POWERPC] Lazy interrupt disabling for 64-bit machines
>
> The code in 'powerpc/include/asm/hw_irq.h' was rearranged and
> cleaned-up a bit in order to reduce the number of needed #ifdef's.
It's still nasty. Do you have numbers showing that it's worth disabling
on BookE ?
Cheers,
Ben.
> Signed-off-by: Laurentiu Tudor <laurentiu.tu...@freescale.com>
> ---
> Patch is against
> git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc.git next
>
> arch/powerpc/Kconfig | 16 ++++++
> arch/powerpc/include/asm/hw_irq.h | 86
> ++++++++++++++--------------------
> arch/powerpc/include/asm/irqflags.h | 22 +++++++++
> arch/powerpc/include/asm/paca.h | 4 ++
> arch/powerpc/kernel/asm-offsets.c | 3 +
> arch/powerpc/kernel/entry_64.S | 4 ++
> arch/powerpc/kernel/exceptions-64e.S | 36 +++++++++++---
> arch/powerpc/kernel/head_64.S | 10 ++++
> arch/powerpc/kernel/idle_book3e.S | 7 +++
> arch/powerpc/kernel/irq.c | 5 ++
> arch/powerpc/kernel/setup_64.c | 2 +
> 11 files changed, 138 insertions(+), 57 deletions(-)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index ce5e045..2792278 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -609,6 +609,22 @@ config SECCOMP
>
> If unsure, say Y. Only embedded should say N here.
>
> +config PPC_LAZY_EE
> + bool
> + prompt "Lazy interrupt disabling" if PPC_BOOK3E_64
> + default y if PPC_BOOK3S_64
> + help
> + Local interrupt disabling functions don't disable
> + interrupts right away and instead just clear an
> + internal 'interrupts are enabled' flag. If an
> + interrupt is triggered during this time, the
> + interrupt handling code checks the flag, and if
> + interrupts are supposed to be off, disables them
> + for real and returns, skipping interrupt handling.
> + When interrupts are enabled back, the interrupt
> + fires again and this time gets handled.
> +
> + If unsure, say N.
> endmenu
>
> config ISA_DMA_API
> diff --git a/arch/powerpc/include/asm/hw_irq.h
> b/arch/powerpc/include/asm/hw_irq.h
> index bb712c9..6f32593 100644
> --- a/arch/powerpc/include/asm/hw_irq.h
> +++ b/arch/powerpc/include/asm/hw_irq.h
> @@ -13,7 +13,20 @@
>
> extern void timer_interrupt(struct pt_regs *);
>
> +#ifdef CONFIG_BOOKE
> +#define __hard_irq_enable() asm volatile("wrteei 1" : : : "memory");
> +#define __hard_irq_disable() asm volatile("wrteei 0" : : : "memory");
> +#else
> #ifdef CONFIG_PPC64
> +#define __hard_irq_enable() __mtmsrd(mfmsr() | MSR_EE, 1)
> +#define __hard_irq_disable() __mtmsrd(mfmsr() & ~MSR_EE, 1)
> +#else
> +#define __hard_irq_enable() mtmsr(mfmsr() | MSR_EE)
> +#define __hard_irq_disable() mtmsr(mfmsr() & ~MSR_EE)
> +#endif
> +#endif /* CONFIG_BOOKE */
> +
> +#if defined(CONFIG_PPC64) && defined(CONFIG_PPC_LAZY_EE)
> #include <asm/paca.h>
>
> static inline unsigned long arch_local_save_flags(void)
> @@ -49,9 +62,11 @@ static inline void arch_local_irq_enable(void)
> arch_local_irq_restore(1);
> }
>
> -static inline unsigned long arch_local_irq_save(void)
> +static inline void hard_irq_disable(void)
> {
> - return arch_local_irq_disable();
> + __hard_irq_disable();
> + get_paca()->soft_enabled = 0;
> + get_paca()->hard_enabled = 0;
> }
>
> static inline bool arch_irqs_disabled_flags(unsigned long flags)
> @@ -59,29 +74,7 @@ static inline bool arch_irqs_disabled_flags(unsigned long
> flags)
> return flags == 0;
> }
>
> -static inline bool arch_irqs_disabled(void)
> -{
> - return arch_irqs_disabled_flags(arch_local_save_flags());
> -}
> -
> -#ifdef CONFIG_PPC_BOOK3E
> -#define __hard_irq_enable() asm volatile("wrteei 1" : : : "memory");
> -#define __hard_irq_disable() asm volatile("wrteei 0" : : : "memory");
> -#else
> -#define __hard_irq_enable() __mtmsrd(mfmsr() | MSR_EE, 1)
> -#define __hard_irq_disable() __mtmsrd(mfmsr() & ~MSR_EE, 1)
> -#endif
> -
> -#define hard_irq_disable() \
> - do { \
> - __hard_irq_disable(); \
> - get_paca()->soft_enabled = 0; \
> - get_paca()->hard_enabled = 0; \
> - } while(0)
> -
> -#else /* CONFIG_PPC64 */
> -
> -#define SET_MSR_EE(x) mtmsr(x)
> +#else /* CONFIG_PPC64 && CONFIG_PPC_LAZY_EE */
>
> static inline unsigned long arch_local_save_flags(void)
> {
> @@ -97,34 +90,24 @@ static inline void arch_local_irq_restore(unsigned long
> flags)
> #endif
> }
>
> -static inline unsigned long arch_local_irq_save(void)
> +static inline void arch_local_irq_enable(void)
> {
> - unsigned long flags = arch_local_save_flags();
> -#ifdef CONFIG_BOOKE
> - asm volatile("wrteei 0" : : : "memory");
> -#else
> - SET_MSR_EE(flags & ~MSR_EE);
> -#endif
> - return flags;
> + __hard_irq_enable();
> }
>
> -static inline void arch_local_irq_disable(void)
> +static inline unsigned long arch_local_irq_disable(void)
> {
> -#ifdef CONFIG_BOOKE
> - asm volatile("wrteei 0" : : : "memory");
> -#else
> - arch_local_irq_save();
> -#endif
> + unsigned long flags;
> +
> + flags = arch_local_save_flags();
> + __hard_irq_disable();
> +
> + return flags;
> }
>
> -static inline void arch_local_irq_enable(void)
> +static inline void hard_irq_disable(void)
> {
> -#ifdef CONFIG_BOOKE
> - asm volatile("wrteei 1" : : : "memory");
> -#else
> - unsigned long msr = mfmsr();
> - SET_MSR_EE(msr | MSR_EE);
> -#endif
> + __hard_irq_disable();
> }
>
> static inline bool arch_irqs_disabled_flags(unsigned long flags)
> @@ -132,15 +115,18 @@ static inline bool arch_irqs_disabled_flags(unsigned
> long flags)
> return (flags & MSR_EE) == 0;
> }
>
> +#endif /* CONFIG_PPC64 && CONFIG_PPC_LAZY_EE */
> +
> +static inline unsigned long arch_local_irq_save(void)
> +{
> + return arch_local_irq_disable();
> +}
> +
> static inline bool arch_irqs_disabled(void)
> {
> return arch_irqs_disabled_flags(arch_local_save_flags());
> }
>
> -#define hard_irq_disable() arch_local_irq_disable()
> -
> -#endif /* CONFIG_PPC64 */
> -
> #define ARCH_IRQ_INIT_FLAGS IRQ_NOREQUEST
>
> /*
> diff --git a/arch/powerpc/include/asm/irqflags.h
> b/arch/powerpc/include/asm/irqflags.h
> index b0b06d8..9685b75c 100644
> --- a/arch/powerpc/include/asm/irqflags.h
> +++ b/arch/powerpc/include/asm/irqflags.h
> @@ -39,6 +39,8 @@
> #define TRACE_ENABLE_INTS TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_on)
> #define TRACE_DISABLE_INTS TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_off)
>
> +#ifdef CONFIG_PPC_LAZY_EE
> +
> #define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip) \
> cmpdi en,0; \
> bne 95f; \
> @@ -51,12 +53,32 @@
> TRACE_AND_RESTORE_IRQ_PARTIAL(en,96f); \
> stb en,PACASOFTIRQEN(r13); \
> 96:
> +
> +#else /* CONFIG_PPC_LAZY_EE */
> +
> +#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip) \
> + cmpdi en,0; \
> + bne 95f; \
> + TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_off) \
> + b skip; \
> +95: TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_on) \
> + li en,1;
> +#define TRACE_AND_RESTORE_IRQ(en) \
> + TRACE_AND_RESTORE_IRQ_PARTIAL(en,96f); \
> +96:
> +
> +#endif /* CONFIG_PPC_LAZY_EE */
> +
> #else
> #define TRACE_ENABLE_INTS
> #define TRACE_DISABLE_INTS
> #define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip)
> +#ifdef CONFIG_PPC_LAZY_EE
> #define TRACE_AND_RESTORE_IRQ(en) \
> stb en,PACASOFTIRQEN(r13)
> +#else
> +#define TRACE_AND_RESTORE_IRQ(en)
> +#endif
> #endif
> #endif
>
> diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h
> index 269c05a..b74c2b1 100644
> --- a/arch/powerpc/include/asm/paca.h
> +++ b/arch/powerpc/include/asm/paca.h
> @@ -131,8 +131,12 @@ struct paca_struct {
> u64 saved_r1; /* r1 save for RTAS calls or PM */
> u64 saved_msr; /* MSR saved here by enter_rtas */
> u16 trap_save; /* Used when bad stack is encountered */
> +
> +#ifdef CONFIG_PPC_LAZY_EE
> u8 soft_enabled; /* irq soft-enable flag */
> u8 hard_enabled; /* set if irqs are enabled in MSR */
> +#endif
> +
> u8 io_sync; /* writel() needs spin_unlock sync */
> u8 irq_work_pending; /* IRQ_WORK interrupt while
> soft-disable */
> u8 nap_state_lost; /* NV GPR values lost in power7_idle */
> diff --git a/arch/powerpc/kernel/asm-offsets.c
> b/arch/powerpc/kernel/asm-offsets.c
> index 04caee7..5b1fac9 100644
> --- a/arch/powerpc/kernel/asm-offsets.c
> +++ b/arch/powerpc/kernel/asm-offsets.c
> @@ -146,8 +146,11 @@ int main(void)
> DEFINE(PACATOC, offsetof(struct paca_struct, kernel_toc));
> DEFINE(PACAKBASE, offsetof(struct paca_struct, kernelbase));
> DEFINE(PACAKMSR, offsetof(struct paca_struct, kernel_msr));
> +#ifdef CONFIG_PPC_LAZY_EE
> DEFINE(PACASOFTIRQEN, offsetof(struct paca_struct, soft_enabled));
> DEFINE(PACAHARDIRQEN, offsetof(struct paca_struct, hard_enabled));
> +#endif
> +
> DEFINE(PACACONTEXTID, offsetof(struct paca_struct, context.id));
> #ifdef CONFIG_PPC_MM_SLICES
> DEFINE(PACALOWSLICESPSIZE, offsetof(struct paca_struct,
> diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
> index d834425..ce7620b 100644
> --- a/arch/powerpc/kernel/entry_64.S
> +++ b/arch/powerpc/kernel/entry_64.S
> @@ -124,8 +124,10 @@ END_FW_FTR_SECTION_IFSET(FW_FEATURE_SPLPAR)
> ld r12,_MSR(r1)
> #endif /* CONFIG_TRACE_IRQFLAGS */
> li r10,1
> +#ifdef CONFIG_PPC_LAZY_EE
> stb r10,PACASOFTIRQEN(r13)
> stb r10,PACAHARDIRQEN(r13)
> +#endif
> std r10,SOFTE(r1)
> #ifdef CONFIG_PPC_ISERIES
> BEGIN_FW_FTR_SECTION
> @@ -602,10 +604,12 @@ ALT_FW_FTR_SECTION_END_IFCLR(FW_FEATURE_ISERIES)
> 2:
> TRACE_AND_RESTORE_IRQ(r5);
>
> +#ifdef CONFIG_PPC_LAZY_EE
> /* extract EE bit and use it to restore paca->hard_enabled */
> ld r3,_MSR(r1)
> rldicl r4,r3,49,63 /* r0 = (r3 >> 15) & 1 */
> stb r4,PACAHARDIRQEN(r13)
> +#endif
>
> #ifdef CONFIG_PPC_BOOK3E
> b .exception_return_book3e
> diff --git a/arch/powerpc/kernel/exceptions-64e.S
> b/arch/powerpc/kernel/exceptions-64e.S
> index 429983c..d17abb3 100644
> --- a/arch/powerpc/kernel/exceptions-64e.S
> +++ b/arch/powerpc/kernel/exceptions-64e.S
> @@ -96,11 +96,6 @@
> #define PROLOG_ADDITION_NONE_DBG
> #define PROLOG_ADDITION_NONE_MC
>
> -#define PROLOG_ADDITION_MASKABLE_GEN \
> - lbz r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */ \
> - cmpwi cr0,r11,0; /* yes -> go out of line */ \
> - beq masked_interrupt_book3e;
> -
> #define PROLOG_ADDITION_2REGS_GEN \
> std r14,PACA_EXGEN+EX_R14(r13); \
> std r15,PACA_EXGEN+EX_R15(r13)
> @@ -120,11 +115,29 @@
> std r14,PACA_EXMC+EX_R14(r13); \
> std r15,PACA_EXMC+EX_R15(r13)
>
> +#ifdef CONFIG_PPC_LAZY_EE
> +#define PROLOG_ADDITION_MASKABLE_GEN \
> + lbz r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */ \
> + cmpwi cr0,r11,0; /* yes -> go out of line */ \
> + beq masked_interrupt_book3e;
> +
> #define PROLOG_ADDITION_DOORBELL_GEN \
> lbz r11,PACASOFTIRQEN(r13); /* are irqs soft-disabled ? */ \
> cmpwi cr0,r11,0; /* yes -> go out of line */ \
> beq masked_doorbell_book3e
> -
> +#else /* CONFIG_PPC_LAZY_EE */
> +#define PROLOG_ADDITION_MASKABLE_GEN
> +#define PROLOG_ADDITION_DOORBELL_GEN
> +#endif /* CONFIG_PPC_LAZY_EE */
> +
> +#ifdef CONFIG_PPC_LAZY_EE
> +#define GET_IRQ_SOFT_ENABLED \
> + lbz r11,PACASOFTIRQEN(r13)
> +#else
> +#define GET_IRQ_SOFT_ENABLED \
> + mfmsr r11; \
> + rlwimi r11,r11,0,16,16
> +#endif
>
> /* Core exception code for all exceptions except TLB misses.
> * XXX: Needs to make SPRN_SPRG_GEN depend on exception type
> @@ -148,7 +161,7 @@
> mfspr r8,SPRN_XER; /* save XER in stackframe */ \
> ld r9,excf+EX_R1(r13); /* load orig r1 back from PACA */ \
> lwz r10,excf+EX_CR(r13); /* load orig CR back from PACA */ \
> - lbz r11,PACASOFTIRQEN(r13); /* get current IRQ softe */ \
> + GET_IRQ_SOFT_ENABLED; /* get current IRQ softe */ \
> ld r12,exception_marker@toc(r2); \
> li r0,0; \
> std r3,GPR10(r1); /* save r10 to stackframe */ \
> @@ -169,11 +182,18 @@
>
> /* Variants for the "ints" argument */
> #define INTS_KEEP
> +
> +#ifdef CONFIG_PPC_LAZY_EE
> #define INTS_DISABLE_SOFT \
> stb r0,PACASOFTIRQEN(r13); /* mark interrupts soft-disabled */ \
> TRACE_DISABLE_INTS;
> #define INTS_DISABLE_HARD \
> stb r0,PACAHARDIRQEN(r13); /* and hard disabled */
> +#else
> +#define INTS_DISABLE_SOFT
> +#define INTS_DISABLE_HARD
> +#endif
> +
> #define INTS_DISABLE_ALL \
> INTS_DISABLE_SOFT \
> INTS_DISABLE_HARD
> @@ -553,6 +573,7 @@ kernel_dbg_exc:
> MASKABLE_EXCEPTION(0x320, ehpriv, .unknown_exception, ACK_NONE)
>
>
> +#ifdef CONFIG_PPC_LAZY_EE
> /*
> * An interrupt came in while soft-disabled; clear EE in SRR1,
> * clear paca->hard_enabled and return.
> @@ -577,6 +598,7 @@ masked_interrupt_book3e_common:
> mfspr r13,SPRN_SPRG_GEN_SCRATCH;
> rfi
> b .
> +#endif /* CONFIG_PPC_LAZY_EE */
>
> /*
> * This is called from 0x300 and 0x400 handlers after the prologs with
> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index 06c7251..017d669 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -559,12 +559,14 @@ _GLOBAL(pmac_secondary_start)
> add r13,r13,r4 /* for this processor. */
> SET_PACA(r13) /* Save vaddr of paca in an SPRG*/
>
> +#ifdef CONFIG_PPC_LAZY_EE
> /* Mark interrupts soft and hard disabled (they might be enabled
> * in the PACA when doing hotplug)
> */
> li r0,0
> stb r0,PACASOFTIRQEN(r13)
> stb r0,PACAHARDIRQEN(r13)
> +#endif
>
> /* Create a temp kernel stack for use before relocation is on. */
> ld r1,PACAEMERGSP(r13)
> @@ -621,14 +623,18 @@ __secondary_start:
> #ifdef CONFIG_PPC_ISERIES
> BEGIN_FW_FTR_SECTION
> ori r4,r4,MSR_EE
> +#ifdef CONFIG_PPC_LAZY_EE
> li r8,1
> stb r8,PACAHARDIRQEN(r13)
> +#endif
> END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
> #endif
> +#ifdef CONFIG_PPC_LAZY_EE
> BEGIN_FW_FTR_SECTION
> stb r7,PACAHARDIRQEN(r13)
> END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)
> stb r7,PACASOFTIRQEN(r13)
> +#endif
>
> mtspr SPRN_SRR0,r3
> mtspr SPRN_SRR1,r4
> @@ -775,8 +781,10 @@ _INIT_GLOBAL(start_here_common)
>
> /* Load up the kernel context */
> 5:
> +#ifdef CONFIG_PPC_LAZY_EE
> li r5,0
> stb r5,PACASOFTIRQEN(r13) /* Soft Disabled */
> +#endif
> #ifdef CONFIG_PPC_ISERIES
> BEGIN_FW_FTR_SECTION
> mfmsr r5
> @@ -785,7 +793,9 @@ BEGIN_FW_FTR_SECTION
> li r5,1
> END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
> #endif
> +#ifdef CONFIG_PPC_LAZY_EE
> stb r5,PACAHARDIRQEN(r13) /* Hard Disabled on others */
> +#endif
>
> bl .start_kernel
>
> diff --git a/arch/powerpc/kernel/idle_book3e.S
> b/arch/powerpc/kernel/idle_book3e.S
> index 16c002d..34b09e0 100644
> --- a/arch/powerpc/kernel/idle_book3e.S
> +++ b/arch/powerpc/kernel/idle_book3e.S
> @@ -28,6 +28,7 @@ _GLOBAL(book3e_idle)
> /* Hard disable interrupts */
> wrteei 0
>
> +#ifdef CONFIG_PPC_LAZY_EE
> /* Now check if an interrupt came in while we were soft disabled
> * since we may otherwise lose it (doorbells etc...). We know
> * that since PACAHARDIRQEN will have been cleared in that case.
> @@ -35,6 +36,7 @@ _GLOBAL(book3e_idle)
> lbz r3,PACAHARDIRQEN(r13)
> cmpwi cr0,r3,0
> beqlr
> +#endif
>
> /* Now we are going to mark ourselves as soft and hard enables in
> * order to be able to take interrupts while asleep. We inform lockdep
> @@ -44,9 +46,12 @@ _GLOBAL(book3e_idle)
> stdu r1,-128(r1)
> bl .trace_hardirqs_on
> #endif
> +
> +#ifdef CONFIG_PPC_LAZY_EE
> li r0,1
> stb r0,PACASOFTIRQEN(r13)
> stb r0,PACAHARDIRQEN(r13)
> +#endif
>
> /* Interrupts will make use return to LR, so get something we want
> * in there
> @@ -56,10 +61,12 @@ _GLOBAL(book3e_idle)
> /* Hard disable interrupts again */
> wrteei 0
>
> +#ifdef CONFIG_PPC_LAZY_EE
> /* Mark them off again in the PACA as well */
> li r0,0
> stb r0,PACASOFTIRQEN(r13)
> stb r0,PACAHARDIRQEN(r13)
> +#endif
>
> /* Tell lockdep about it */
> #ifdef CONFIG_TRACE_IRQFLAGS
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 701d4ac..e2d1784 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -99,6 +99,8 @@ EXPORT_SYMBOL(irq_desc);
>
> int distribute_irqs = 1;
>
> +#ifdef CONFIG_PPC_LAZY_EE
> +
> static inline notrace unsigned long get_hard_enabled(void)
> {
> unsigned long enabled;
> @@ -193,6 +195,9 @@ notrace void arch_local_irq_restore(unsigned long en)
> __hard_irq_enable();
> }
> EXPORT_SYMBOL(arch_local_irq_restore);
> +
> +#endif /* CONFIG_PPC_LAZY_EE */
> +
> #endif /* CONFIG_PPC64 */
>
> int arch_show_interrupts(struct seq_file *p, int prec)
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index 4cb8f1e..06f5b19 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -233,8 +233,10 @@ void __init early_setup(unsigned long dt_ptr)
> #ifdef CONFIG_SMP
> void early_setup_secondary(void)
> {
> +#ifdef CONFIG_PPC_LAZY_EE
> /* Mark interrupts enabled in PACA */
> get_paca()->soft_enabled = 0;
> +#endif
>
> /* Initialize the hash table or TLB handling */
> early_init_mmu_secondary();
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