From 8767e9badca7cdf0adc2564d7524092d47ababf3 Mon Sep 17 00:00:00 2001 From: Milton Miller Date: Fri, 10 Oct 2008 01:56:23 +0000 Subject: [PATCH] powerpc/xics: EOI unmapped irqs after disabling them When reciving an irq vector that does not have a linux mapping, the kernel prints a message and calls RTAS to disable the irq source. Previously the kernel did not EOI the interrupt, causing the source to think it is still being processed by software. While this does add an additional layer of protection against interrupt storms had RTAS failed to disable the source, it also prevents the interrupt from working when a driver later enables it. (We could alternatively send an EOI on startup, but that strategy would likely fail on an emulated xics.) All interrupts should be disabled when the kernel starts, but this can be observed if a driver does not shutdown an interrupt in its reboot hook before starting a new kernel with kexec. Michael reports this can be reproduced trivially by banging the keyboard while kexec'ing on a P5 LPAR: even though the hvc_console driver request's the console irq later in boot, the console is non-functional because we're receiving no console interrupts. Reported-By: Michael Ellerman Signed-off-by: Milton Miller Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/platforms/pseries/xics.c | 53 +++++++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 12 deletions(-) diff --git a/arch/powerpc/platforms/pseries/xics.c b/arch/powerpc/platforms/pseries/xics.c index 6b1a005..1bccd4a 100644 --- a/arch/powerpc/platforms/pseries/xics.c +++ b/arch/powerpc/platforms/pseries/xics.c @@ -332,32 +332,61 @@ static void xics_eoi_lpar(unsigned int virq) lpar_xirr_info_set((0xff << 24) | irq); } -static inline unsigned int xics_remap_irq(unsigned int vec) +static inline unsigned int xics_xirr_vector(unsigned int xirr) { - unsigned int irq; + /* + * The top byte is the old cppr, to be restored on EOI. + * The remaining 24 bits are the vector. + */ + return xirr & 0x00ffffff; +} - vec &= 0x00ffffff; +static void xics_mask_unknown_vec(unsigned int vec) +{ + printk(KERN_ERR "Interrupt %u (real) is invalid, disabling it.\n", vec); + xics_mask_real_irq(vec); +} + +static unsigned int xics_get_irq_direct(void) +{ + unsigned int xirr = direct_xirr_info_get(); + unsigned int vec = xics_xirr_vector(xirr); + unsigned int irq; if (vec == XICS_IRQ_SPURIOUS) return NO_IRQ; + irq = irq_radix_revmap_lookup(xics_host, vec); if (likely(irq != NO_IRQ)) return irq; - printk(KERN_ERR "Interrupt %u (real) is invalid," - " disabling it.\n", vec); - xics_mask_real_irq(vec); - return NO_IRQ; -} + /* We don't have a linux mapping, so have rtas mask it. */ + xics_mask_unknown_vec(vec); -static unsigned int xics_get_irq_direct(void) -{ - return xics_remap_irq(direct_xirr_info_get()); + /* We might learn about it later, so EOI it */ + direct_xirr_info_set(xirr); + return NO_IRQ; } static unsigned int xics_get_irq_lpar(void) { - return xics_remap_irq(lpar_xirr_info_get()); + unsigned int xirr = lpar_xirr_info_get(); + unsigned int vec = xics_xirr_vector(xirr); + unsigned int irq; + + if (vec == XICS_IRQ_SPURIOUS) + return NO_IRQ; + + irq = irq_radix_revmap_lookup(xics_host, vec); + if (likely(irq != NO_IRQ)) + return irq; + + /* We don't have a linux mapping, so have RTAS mask it. */ + xics_mask_unknown_vec(vec); + + /* We might learn about it later, so EOI it */ + lpar_xirr_info_set(xirr); + return NO_IRQ; } #ifdef CONFIG_SMP -- 2.7.4