From 6398268d2bc454735f11e08705e858f9fdf5c750 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Tue, 5 Jun 2012 13:23:44 +0200 Subject: x86/apic: Factor out default cpu_mask_to_apicid() operations Signed-off-by: Alexander Gordeev Cc: Suresh Siddha Cc: Yinghai Lu Link: http://lkml.kernel.org/r/20120605112340.GA11454@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/apic.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'arch/x86/kernel/apic/apic.c') diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 39a222e094af..96a2608252f1 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2123,6 +2123,34 @@ void default_init_apic_ldr(void) apic_write(APIC_LDR, val); } +unsigned int default_cpu_mask_to_apicid(const struct cpumask *cpumask) +{ + int cpu; + + /* + * We're using fixed IRQ delivery, can only return one phys APIC ID. + * May as well be the first. + */ + cpu = cpumask_first(cpumask); + if (likely((unsigned)cpu < nr_cpu_ids)) + return per_cpu(x86_cpu_to_apicid, cpu); + + return BAD_APICID; +} + +unsigned int +default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, + const struct cpumask *andmask) +{ + int cpu; + + for_each_cpu_and(cpu, cpumask, andmask) { + if (cpumask_test_cpu(cpu, cpu_online_mask)) + break; + } + return per_cpu(x86_cpu_to_apicid, cpu); +} + /* * Power management */ -- cgit v1.2.3 From ff164324123c0fe181d8de7dadcc7b3fbe25f2cf Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Thu, 7 Jun 2012 15:15:59 +0200 Subject: x86/apic: Make cpu_mask_to_apicid() operations return error code Current cpu_mask_to_apicid() and cpu_mask_to_apicid_and() implementations have few shortcomings: 1. A value returned by cpu_mask_to_apicid() is written to hardware registers unconditionally. Should BAD_APICID get ever returned it will be written to a hardware too. But the value of BAD_APICID is not universal across all hardware in all modes and might cause unexpected results, i.e. interrupts might get routed to CPUs that are not configured to receive it. 2. Because the value of BAD_APICID is not universal it is counter- intuitive to return it for a hardware where it does not make sense (i.e. x2apic). 3. cpu_mask_to_apicid_and() operation is thought as an complement to cpu_mask_to_apicid() that only applies a AND mask on top of a cpumask being passed. Yet, as consequence of 18374d8 commit the two operations are inconsistent in that of: cpu_mask_to_apicid() should not get a offline CPU with the cpumask cpu_mask_to_apicid_and() should not fail and return BAD_APICID These limitations are impossible to realize just from looking at the operations prototypes. Most of these shortcomings are resolved by returning a error code instead of BAD_APICID. As the result, faults are reported back early rather than possibilities to cause a unexpected behaviour exist (in case of [1]). The only exception is setup_timer_IRQ0_pin() routine. Although obviously controversial to this fix, its existing behaviour is preserved to not break the fragile check_timer() and would better addressed in a separate fix. Signed-off-by: Alexander Gordeev Acked-by: Suresh Siddha Cc: Yinghai Lu Link: http://lkml.kernel.org/r/20120607131559.GF4759@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/apic.c | 33 ++++++++++++++++++--------------- 1 file changed, 18 insertions(+), 15 deletions(-) (limited to 'arch/x86/kernel/apic/apic.c') diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 96a2608252f1..b8d92606f84f 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2123,24 +2123,26 @@ void default_init_apic_ldr(void) apic_write(APIC_LDR, val); } -unsigned int default_cpu_mask_to_apicid(const struct cpumask *cpumask) +static inline int __default_cpu_to_apicid(int cpu, unsigned int *apicid) { - int cpu; - - /* - * We're using fixed IRQ delivery, can only return one phys APIC ID. - * May as well be the first. - */ - cpu = cpumask_first(cpumask); - if (likely((unsigned)cpu < nr_cpu_ids)) - return per_cpu(x86_cpu_to_apicid, cpu); + if (likely((unsigned int)cpu < nr_cpu_ids)) { + *apicid = per_cpu(x86_cpu_to_apicid, cpu); + return 0; + } else { + return -EINVAL; + } +} - return BAD_APICID; +int default_cpu_mask_to_apicid(const struct cpumask *cpumask, + unsigned int *apicid) +{ + int cpu = cpumask_first(cpumask); + return __default_cpu_to_apicid(cpu, apicid); } -unsigned int -default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, - const struct cpumask *andmask) +int default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, + const struct cpumask *andmask, + unsigned int *apicid) { int cpu; @@ -2148,7 +2150,8 @@ default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, if (cpumask_test_cpu(cpu, cpu_online_mask)) break; } - return per_cpu(x86_cpu_to_apicid, cpu); + + return __default_cpu_to_apicid(cpu, apicid); } /* -- cgit v1.2.3 From 4988a40c3981212fa8c64da68722affc1cb6697a Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Thu, 7 Jun 2012 15:16:25 +0200 Subject: x86/apic: Make cpu_mask_to_apicid() operations check cpu_online_mask Currently cpu_mask_to_apicid() should not get a offline CPU with the cpumask. Otherwise some apic drivers might try to access non-existent per-cpu variables (i.e. x2apic). In that regard cpu_mask_to_apicid() and cpu_mask_to_apicid_and() operations are inconsistent. This fix makes the two operations do not rely on calling functions and always return the apicid for only online CPUs. As result, the meaning and implementations of cpu_mask_to_apicid() and cpu_mask_to_apicid_and() operations become straight. Signed-off-by: Alexander Gordeev Acked-by: Suresh Siddha Cc: Yinghai Lu Link: http://lkml.kernel.org/r/20120607131624.GG4759@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/apic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/apic/apic.c') diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index b8d92606f84f..7e9bbe73bc5a 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2136,7 +2136,7 @@ static inline int __default_cpu_to_apicid(int cpu, unsigned int *apicid) int default_cpu_mask_to_apicid(const struct cpumask *cpumask, unsigned int *apicid) { - int cpu = cpumask_first(cpumask); + int cpu = cpumask_first_and(cpumask, cpu_online_mask); return __default_cpu_to_apicid(cpu, apicid); } -- cgit v1.2.3 From a5a391561bc25898ba1a702a0c4b028aa5b11ce9 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Thu, 14 Jun 2012 09:49:35 +0200 Subject: x86/apic: Eliminate cpu_mask_to_apicid() operation Since there are only two locations where cpu_mask_to_apicid() is called from, remove the operation and use only cpu_mask_to_apicid_and() instead. Signed-off-by: Alexander Gordeev Suggested-and-acked-by: Suresh Siddha Acked-by: Yinghai Lu Link: http://lkml.kernel.org/r/20120614074935.GE3383@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/apic.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-) (limited to 'arch/x86/kernel/apic/apic.c') diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 7e9bbe73bc5a..048a4f806d46 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2123,23 +2123,6 @@ void default_init_apic_ldr(void) apic_write(APIC_LDR, val); } -static inline int __default_cpu_to_apicid(int cpu, unsigned int *apicid) -{ - if (likely((unsigned int)cpu < nr_cpu_ids)) { - *apicid = per_cpu(x86_cpu_to_apicid, cpu); - return 0; - } else { - return -EINVAL; - } -} - -int default_cpu_mask_to_apicid(const struct cpumask *cpumask, - unsigned int *apicid) -{ - int cpu = cpumask_first_and(cpumask, cpu_online_mask); - return __default_cpu_to_apicid(cpu, apicid); -} - int default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, const struct cpumask *andmask, unsigned int *apicid) @@ -2151,7 +2134,12 @@ int default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, break; } - return __default_cpu_to_apicid(cpu, apicid); + if (likely((unsigned int)cpu < nr_cpu_ids)) { + *apicid = per_cpu(x86_cpu_to_apicid, cpu); + return 0; + } else { + return -EINVAL; + } } /* -- cgit v1.2.3 From ea3807ea52a53f2cdfd60c89d8491fc9a8208d1c Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Thu, 14 Jun 2012 09:49:55 +0200 Subject: x86/apic: Fix ugly casting and branching in cpu_mask_to_apicid_and() Signed-off-by: Alexander Gordeev Cc: Suresh Siddha Cc: Yinghai Lu Link: http://lkml.kernel.org/r/20120614074954.GF3383@dhcp-26-207.brq.redhat.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/apic/apic.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'arch/x86/kernel/apic/apic.c') diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 048a4f806d46..c421512ca5eb 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2127,19 +2127,19 @@ int default_cpu_mask_to_apicid_and(const struct cpumask *cpumask, const struct cpumask *andmask, unsigned int *apicid) { - int cpu; + unsigned int cpu; for_each_cpu_and(cpu, cpumask, andmask) { if (cpumask_test_cpu(cpu, cpu_online_mask)) break; } - if (likely((unsigned int)cpu < nr_cpu_ids)) { + if (likely(cpu < nr_cpu_ids)) { *apicid = per_cpu(x86_cpu_to_apicid, cpu); return 0; - } else { - return -EINVAL; } + + return -EINVAL; } /* -- cgit v1.2.3 From 1551df646dd42122e17401013dba7a509d0f1b0d Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 15 Jul 2012 15:56:46 +0300 Subject: apic: add apic_set_eoi_write for PV use KVM PV EOI optimization overrides eoi_write apic op with its own version. Add an API for this to avoid meddling with core x86 apic driver data structures directly. For KVM use, we don't need any guarantees about when the switch to the new op will take place, so it could in theory use this API after SMP init, but it currently doesn't, and restricting callers to early init makes it clear that it's safe as it won't race with actual APIC driver use. Signed-off-by: Michael S. Tsirkin Acked-by: Ingo Molnar Signed-off-by: Avi Kivity --- arch/x86/kernel/apic/apic.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'arch/x86/kernel/apic/apic.c') diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 39a222e094af..c7520b6184ef 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2123,6 +2123,23 @@ void default_init_apic_ldr(void) apic_write(APIC_LDR, val); } +/* + * Override the generic EOI implementation with an optimized version. + * Only called during early boot when only one CPU is active and with + * interrupts disabled, so we know this does not race with actual APIC driver + * use. + */ +void __init apic_set_eoi_write(void (*eoi_write)(u32 reg, u32 v)) +{ + struct apic **drv; + + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) { + /* Should happen once for each apic */ + WARN_ON((*drv)->eoi_write == eoi_write); + (*drv)->eoi_write = eoi_write; + } +} + /* * Power management */ -- cgit v1.2.3