From d1c6d2e547148c5aa0c0a4ff6aac82f7c6da1d8b Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 11 Sep 2008 17:18:56 +0100 Subject: MN10300: Change the fault handler to check in_atomic() not in_interrupt() Change the MN10300 fault handler to make it check in_atomic() rather than in_interrupt() as commit 6edaf68a87d17570790fd55f0c451a29ec1d6703 did for other architectures: Author: Peter Zijlstra Date: Wed Dec 6 20:32:18 2006 -0800 [PATCH] mm: arch do_page_fault() vs in_atomic() In light of the recent pagefault and filemap_copy_from_user work I've gone through all the arch pagefault handlers to make sure the inc_preempt_count() 'feature' works as expected. Several sections of code (including the new filemap_copy_from_user) rely on the fact that faults do not take locks under increased preempt count. Signed-off-by: David Howells Acked-by: Peter Zijlstra Signed-off-by: Linus Torvalds --- arch/mn10300/mm/fault.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/mn10300') diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c index 78f092ca031..33cf25025da 100644 --- a/arch/mn10300/mm/fault.c +++ b/arch/mn10300/mm/fault.c @@ -174,7 +174,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code, * If we're in an interrupt or have no user * context, we must not take the fault.. */ - if (in_interrupt() || !mm) + if (in_atomic() || !mm) goto no_context; down_read(&mm->mmap_sem); -- cgit v1.2.3 From 08ec3c2d45bac41c782acb4e3331ac5881b2c68a Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 24 Sep 2008 17:48:31 +0100 Subject: MN10300: Make sched_clock() report time since boot Make sched_clock() report time since boot rather than time since last timer interrupt. Make sched_clock() expand and scale the 32-bit TSC value running at IOCLK speed (~33MHz) to a 64-bit nanosecond counter, using cnt32_to_63() acquired from the ARM arch and without using slow DIVU instructions every call. Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/mn10300/kernel/time.c | 52 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 41 insertions(+), 11 deletions(-) (limited to 'arch/mn10300') diff --git a/arch/mn10300/kernel/time.c b/arch/mn10300/kernel/time.c index babb7c2ac37..e4606586f94 100644 --- a/arch/mn10300/kernel/time.c +++ b/arch/mn10300/kernel/time.c @@ -1,6 +1,6 @@ /* MN10300 Low level time management * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2007-2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from arch/i386/kernel/time.c * @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -40,27 +41,54 @@ static struct irqaction timer_irq = { .name = "timer", }; +static unsigned long sched_clock_multiplier; + /* * scheduler clock - returns current time in nanosec units. */ unsigned long long sched_clock(void) { union { - unsigned long long l; - u32 w[2]; - } quot; + unsigned long long ll; + unsigned l[2]; + } tsc64, result; + unsigned long tsc, tmp; + unsigned product[3]; /* 96-bit intermediate value */ + + /* read the TSC value + */ + tsc = 0 - get_cycles(); /* get_cycles() counts down */ - quot.w[0] = mn10300_last_tsc - get_cycles(); - quot.w[1] = 1000000000; + /* expand to 64-bits. + * - sched_clock() must be called once a minute or better or the + * following will go horribly wrong - see cnt32_to_63() + */ + tsc64.ll = cnt32_to_63(tsc) & 0x7fffffffffffffffULL; - asm("mulu %2,%3,%0,%1" - : "=r"(quot.w[1]), "=r"(quot.w[0]) - : "0"(quot.w[1]), "1"(quot.w[0]) + /* scale the 64-bit TSC value to a nanosecond value via a 96-bit + * intermediate + */ + asm("mulu %2,%0,%3,%0 \n" /* LSW * mult -> 0:%3:%0 */ + "mulu %2,%1,%2,%1 \n" /* MSW * mult -> %2:%1:0 */ + "add %3,%1 \n" + "addc 0,%2 \n" /* result in %2:%1:%0 */ + : "=r"(product[0]), "=r"(product[1]), "=r"(product[2]), "=r"(tmp) + : "0"(tsc64.l[0]), "1"(tsc64.l[1]), "2"(sched_clock_multiplier) : "cc"); - do_div(quot.l, MN10300_TSCCLK); + result.l[0] = product[1] << 16 | product[0] >> 16; + result.l[1] = product[2] << 16 | product[1] >> 16; - return quot.l; + return result.ll; +} + +/* + * initialise the scheduler clock + */ +static void __init mn10300_sched_clock_init(void) +{ + sched_clock_multiplier = + __muldiv64u(NSEC_PER_SEC, 1 << 16, MN10300_TSCCLK); } /* @@ -128,4 +156,6 @@ void __init time_init(void) /* start the watchdog timer */ watchdog_go(); #endif + + mn10300_sched_clock_init(); } -- cgit v1.2.3 From d6478fad430e37148b56f642c87301ba72476675 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 1 Oct 2008 13:47:06 +0100 Subject: MN10300: Fix IRQ handling Fix the IRQ handling on the MN10300 arch. This patch makes a number of significant changes: (1) It separates the irq_chip definition for edge-triggered interrupts from the one for level-triggered interrupts. This is necessary because the MN10300 PIC latches the IRQ channel's interrupt request bit (GxICR_REQUEST), even after the device has ceased to assert its interrupt line and the interrupt channel has been disabled in the PIC. So for level-triggered interrupts we need to clear this bit when we re-enable - which is achieved by setting GxICR_DETECT but not GxICR_REQUEST when writing to the register. Not doing this results in spurious interrupts occurring because calling mask_ack() at the start of handle_level_irq() is insufficient - it fails to clear the REQUEST latch because the device that caused the interrupt is still asserting its interrupt line at this point. (2) IRQ disablement [irq_chip::disable_irq()] shouldn't clear the interrupt request flag for edge-triggered interrupts lest it lose an interrupt. (3) IRQ unmasking [irq_chip::unmask_irq()] also shouldn't clear the interrupt request flag for edge-triggered interrupts lest it lose an interrupt. (4) The end() operation is now left to the default (no-operation) as __do_IRQ() is compiled out. This may affect misrouted_irq(), but according to Thomas Gleixner it's the correct thing to do. (5) handle_level_irq() is used for edge-triggered interrupts rather than handle_edge_irq() as the MN10300 PIC latches interrupt events even on masked IRQ channels, thus rendering IRQ_PENDING unnecessary. It is sufficient to call mask_ack() at the start and unmask() at the end. (6) For level-triggered interrupts, ack() is now NULL as it's not used, and there is no effective ACK function on the PIC. mask_ack() is now the same as mask() as the latch continues to latch, even when the channel is masked. Further, the patch discards the disable() op implementation as its now the same as the mask() op implementation, which is used instead. It also discards the enable() op implementations as they're now the same as the unmask() op implementations, which are used instead. Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- arch/mn10300/kernel/irq.c | 71 ++++++++++++++++++++++------------- arch/mn10300/unit-asb2303/unit-init.c | 2 +- arch/mn10300/unit-asb2305/unit-init.c | 2 +- 3 files changed, 47 insertions(+), 28 deletions(-) (limited to 'arch/mn10300') diff --git a/arch/mn10300/kernel/irq.c b/arch/mn10300/kernel/irq.c index 761c434a248..56c64ccc9c2 100644 --- a/arch/mn10300/kernel/irq.c +++ b/arch/mn10300/kernel/irq.c @@ -20,22 +20,8 @@ EXPORT_SYMBOL(__mn10300_irq_enabled_epsw); atomic_t irq_err_count; /* - * MN10300 INTC controller operations + * MN10300 interrupt controller operations */ -static void mn10300_cpupic_disable(unsigned int irq) -{ - u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT; - tmp = GxICR(irq); -} - -static void mn10300_cpupic_enable(unsigned int irq) -{ - u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE; - tmp = GxICR(irq); -} - static void mn10300_cpupic_ack(unsigned int irq) { u16 tmp; @@ -60,26 +46,54 @@ static void mn10300_cpupic_mask_ack(unsigned int irq) static void mn10300_cpupic_unmask(unsigned int irq) { u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT; + GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE; tmp = GxICR(irq); } -static void mn10300_cpupic_end(unsigned int irq) +static void mn10300_cpupic_unmask_clear(unsigned int irq) { + /* the MN10300 PIC latches its interrupt request bit, even after the + * device has ceased to assert its interrupt line and the interrupt + * channel has been disabled in the PIC, so for level-triggered + * interrupts we need to clear the request bit when we re-enable */ u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE; + GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT; tmp = GxICR(irq); } -static struct irq_chip mn10300_cpu_pic = { - .name = "cpu", - .disable = mn10300_cpupic_disable, - .enable = mn10300_cpupic_enable, +/* + * MN10300 PIC level-triggered IRQ handling. + * + * The PIC has no 'ACK' function per se. It is possible to clear individual + * channel latches, but each latch relatches whether or not the channel is + * masked, so we need to clear the latch when we unmask the channel. + * + * Also for this reason, we don't supply an ack() op (it's unused anyway if + * mask_ack() is provided), and mask_ack() just masks. + */ +static struct irq_chip mn10300_cpu_pic_level = { + .name = "cpu_l", + .disable = mn10300_cpupic_mask, + .enable = mn10300_cpupic_unmask_clear, + .ack = NULL, + .mask = mn10300_cpupic_mask, + .mask_ack = mn10300_cpupic_mask, + .unmask = mn10300_cpupic_unmask_clear, +}; + +/* + * MN10300 PIC edge-triggered IRQ handling. + * + * We use the latch clearing function of the PIC as the 'ACK' function. + */ +static struct irq_chip mn10300_cpu_pic_edge = { + .name = "cpu_e", + .disable = mn10300_cpupic_mask, + .enable = mn10300_cpupic_unmask, .ack = mn10300_cpupic_ack, .mask = mn10300_cpupic_mask, .mask_ack = mn10300_cpupic_mask_ack, .unmask = mn10300_cpupic_unmask, - .end = mn10300_cpupic_end, }; /* @@ -114,7 +128,8 @@ void set_intr_level(int irq, u16 level) */ void set_intr_postackable(int irq) { - set_irq_handler(irq, handle_level_irq); + set_irq_chip_and_handler(irq, &mn10300_cpu_pic_level, + handle_level_irq); } /* @@ -126,8 +141,12 @@ void __init init_IRQ(void) for (irq = 0; irq < NR_IRQS; irq++) if (irq_desc[irq].chip == &no_irq_type) - set_irq_chip_and_handler(irq, &mn10300_cpu_pic, - handle_edge_irq); + /* due to the PIC latching interrupt requests, even + * when the IRQ is disabled, IRQ_PENDING is superfluous + * and we can use handle_level_irq() for edge-triggered + * interrupts */ + set_irq_chip_and_handler(irq, &mn10300_cpu_pic_edge, + handle_level_irq); unit_init_IRQ(); } diff --git a/arch/mn10300/unit-asb2303/unit-init.c b/arch/mn10300/unit-asb2303/unit-init.c index 14b2c817cff..70e8cb4ea26 100644 --- a/arch/mn10300/unit-asb2303/unit-init.c +++ b/arch/mn10300/unit-asb2303/unit-init.c @@ -51,7 +51,7 @@ void __init unit_init_IRQ(void) switch (GET_XIRQ_TRIGGER(extnum)) { case XIRQ_TRIGGER_HILEVEL: case XIRQ_TRIGGER_LOWLEVEL: - set_irq_handler(XIRQ2IRQ(extnum), handle_level_irq); + set_intr_postackable(XIRQ2IRQ(extnum)); break; default: break; diff --git a/arch/mn10300/unit-asb2305/unit-init.c b/arch/mn10300/unit-asb2305/unit-init.c index 6a352414a35..72812a9439a 100644 --- a/arch/mn10300/unit-asb2305/unit-init.c +++ b/arch/mn10300/unit-asb2305/unit-init.c @@ -52,7 +52,7 @@ void __init unit_init_IRQ(void) switch (GET_XIRQ_TRIGGER(extnum)) { case XIRQ_TRIGGER_HILEVEL: case XIRQ_TRIGGER_LOWLEVEL: - set_irq_handler(XIRQ2IRQ(extnum), handle_level_irq); + set_intr_postackable(XIRQ2IRQ(extnum)); break; default: break; -- cgit v1.2.3