search for: local_irq_restore

Hi, I have some confusion on local_irq_save() and local_irq_restore(). From the definitions, you can see that local_irq_save() calls local_irq_disable(). But why there is no local_irq_enable() in local_irq_restore? #define local_irq_save(x) ({ local_save_flags(x); local_irq_disable(); }) #define local_irq_restore(x) ({ BUILD_BUG_ON(sizeof(x) != sizeof...

...; static grant_ref_t gnttab_list[NR_GRANT_ENTRIES]; +static __DECLARE_SEMAPHORE_GENERIC(gnttab_sem, NR_GRANT_ENTRIES); static void put_free_entry(grant_ref_t ref) { + unsigned long flags; + local_irq_save(flags); gnttab_list[ref] = gnttab_list[0]; gnttab_list[0] = ref; - + local_irq_restore(flags); + up(&gnttab_sem); } static grant_ref_t get_free_entry(void) { - unsigned int ref = gnttab_list[0]; + unsigned int ref; + unsigned long flags; + down(&gnttab_sem); + local_irq_save(flags); + ref = gnttab_list[0]; gnttab_list[0] = gnttab_list[ref]; +...

On Tue, Aug 11, 2020 at 11:20:54AM +0200, peterz at infradead.org wrote: > On Tue, Aug 11, 2020 at 10:38:50AM +0200, J?rgen Gro? wrote: > > In case you don't want to do it I can send the patch for the Xen > > variants. > > I might've opened a whole new can of worms here. I'm not sure we > can/want to fix the entire fallout this release :/ > > Let me

On Tue, Aug 11, 2020 at 11:20:54AM +0200, peterz at infradead.org wrote: > On Tue, Aug 11, 2020 at 10:38:50AM +0200, J?rgen Gro? wrote: > > In case you don't want to do it I can send the patch for the Xen > > variants. > > I might've opened a whole new can of worms here. I'm not sure we > can/want to fix the entire fallout this release :/ > > Let me

...b/kernel/workqueue.c > index d951daa..042d221 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -2982,7 +2982,7 @@ bool cancel_delayed_work(struct delayed_work *dwork) > > set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work)); > local_irq_restore(flags); > - return true; > + return ret; > } > EXPORT_SYMBOL(cancel_delayed_work); > > -- > 1.7.7.3 >

...s go away. >>>> >>>> Thanks for testing! >>>> >>>> I take it you are doing the tests in a KVM guest? >>> >>> Yes, correct. >>> >>>> If so I have a gut feeling that the use of local_irq_save() and >>>> local_irq_restore() in kvm_wait() might be fishy. I might be completely >>>> wrong here, though. >>> >>> Happy to help debug more, although I might need patches or pointers >>> what to play with. >>> >>>> BTW, I think Xen's variant of pv spinlocks is fi...

...) + { + v->arch.pending_msix_unmask.ctrl_address = address; goto out; + } virt = msixtbl_addr_to_virt(entry, address); if ( !virt ) @@ -528,3 +531,15 @@ void msixtbl_pt_cleanup(struct domain *d) spin_unlock(&d->arch.hvm_domain.msixtbl_list_lock); local_irq_restore(flags); } + +bool_t msix_post_handler(struct vcpu *v) +{ + unsigned long ctrl_address = v->arch.pending_msix_unmask.ctrl_address; + + if ( ctrl_address == 0 ) + return 1; + + v->arch.pending_msix_unmask.ctrl_address = 0; + return msixtbl_write(v, ctrl_address, 4, 0) == X86...

...t; + DEFINE_WAIT(wait); > + struct percpu_ida_cpu *tags; > + unsigned long flags; > + int tag; > + > + local_irq_save(flags); > + tags = this_cpu_ptr(pool->tag_cpu); > + > + /* Fastpath */ > + tag = alloc_local_tag(pool, tags); > + if (likely(tag >= 0)) { > + local_irq_restore(flags); > + return tag; > + } > + > + while (1) { > + spin_lock(&pool->lock); > + > + /* > + * prepare_to_wait() must come before steal_tags(), in case > + * percpu_ida_free() on another cpu flips a bit in > + * cpus_have_tags > + * > + * glob...

...t; + DEFINE_WAIT(wait); > + struct percpu_ida_cpu *tags; > + unsigned long flags; > + int tag; > + > + local_irq_save(flags); > + tags = this_cpu_ptr(pool->tag_cpu); > + > + /* Fastpath */ > + tag = alloc_local_tag(pool, tags); > + if (likely(tag >= 0)) { > + local_irq_restore(flags); > + return tag; > + } > + > + while (1) { > + spin_lock(&pool->lock); > + > + /* > + * prepare_to_wait() must come before steal_tags(), in case > + * percpu_ida_free() on another cpu flips a bit in > + * cpus_have_tags > + * > + * glob...

...ck); + } while (unlikely(lock->slock != 0)); + HMT_medium(); + } +} + +static inline +void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) +{ + unsigned long flags_dis; + + while (1) { + if (likely(__arch_spin_trylock(lock) == 0)) + break; + local_save_flags(flags_dis); + local_irq_restore(flags); + do { + HMT_low(); + if (is_shared_processor()) + splpar_spin_yield(lock); + } while (unlikely(lock->slock != 0)); + HMT_medium(); + local_irq_restore(flags_dis); + } +} +#define arch_spin_lock_flags arch_spin_lock_flags + +static inline void arch_spin_unlock(arch_spinlock_t...

...gt; > + tag = tags->freelist[--tags->nr_free]; > > > + if (tags->nr_free) > > > + set_bit(smp_processor_id(), > > > + pool->cpus_have_tags); > > > + } > > > + > > > + spin_unlock(&pool->lock); > > > + local_irq_restore(flags); > > > + > > > + if (tag >= 0 || !(gfp & __GFP_WAIT)) > > > + break; > > > + > > > + schedule(); > > > + > > > + local_irq_save(flags); > > > + tags = this_cpu_ptr(pool->tag_cpu); > > > + } >...

...gt; > + tag = tags->freelist[--tags->nr_free]; > > > + if (tags->nr_free) > > > + set_bit(smp_processor_id(), > > > + pool->cpus_have_tags); > > > + } > > > + > > > + spin_unlock(&pool->lock); > > > + local_irq_restore(flags); > > > + > > > + if (tag >= 0 || !(gfp & __GFP_WAIT)) > > > + break; > > > + > > > + schedule(); > > > + > > > + local_irq_save(flags); > > > + tags = this_cpu_ptr(pool->tag_cpu); > > > + } >...

...ched_clock_running, > + * sched_clock_tick() continues where sched_clock() left off. > + * > + * Even if TSC is buggered, we're still UP at this point so it > + * can't really be out of sync. > + */ > + local_irq_save(flags); > + __sched_clock_gtod_offset(); > + local_irq_restore(flags); > + > sched_clock_running = 1; > + > + /* Now that sched_clock_running is set adjust scd */ > + local_irq_save(flags); > + sched_clock_tick(); > + local_irq_restore(flags); > } > /* > * We run this as late_initcall() such that it runs after all built-in d...

...s[i]); > + for (j = 0; j < counts[i]; ++j, ++page_count) > + input_page->gpa_page_list[page_count] = base_pfn + j; > + } > + status = hv_do_rep_hypercall(HVCALL_DEPOSIT_MEMORY, > + page_count, 0, input_page, > + NULL) & HV_HYPERCALL_RESULT_MASK; > + local_irq_restore(flags); > + > + if (status != HV_STATUS_SUCCESS) { Nit: same like in one ov the previous patches, status can be 'u16'. > + pr_err("Failed to deposit pages: %d\n", status); > + ret = status; > + goto err_free_allocations; > + } > + > + ret = 0; > + g...

...16 +459,7 @@ struct alt_instr { #define set_wmb(var, value) do { var = value; wmb(); } while (0) -/* interrupt control.. */ -#define local_save_flags(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */); } while (0) -#define local_irq_restore(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc"); } while (0) -#define local_irq_disable() __asm__ __volatile__("cli": : :"memory") -#define local_irq_enable() __asm__...

...16 +459,7 @@ struct alt_instr { #define set_wmb(var, value) do { var = value; wmb(); } while (0) -/* interrupt control.. */ -#define local_save_flags(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */); } while (0) -#define local_irq_restore(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc"); } while (0) -#define local_irq_disable() __asm__ __volatile__("cli": : :"memory") -#define local_irq_enable() __asm__...

...led(); /* Pass - expectedly blind. */ Indeed, we didn't trace the above disable, so software state is still on. > + local_irq_save(flags2); So here we save IRQ state, and unconditionally disable IRQs and trace them disabled. > + lockdep_assert_irqs_disabled(); /* Pass. */ > + local_irq_restore(flags2); But here, we restore IRQ state to 'disabled' and explicitly trace it disabled *again* (which is a bit daft, but whatever). > + } > + raw_local_irq_restore(flags1); This then restores the IRQ state to enable, but no tracing. > + } > + lockdep_assert_irqs_enabled();...

...fffff86271ef4: ff 14 25 30 a6 0b 88 callq *0xffffffff880ba630 > ffffffff86271efb: c3 retq > ffffffff86271efc: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271f01: 0f 0b ud2 > ffffffff86271a90 <arch_local_irq_restore>: > ffffffff86271a90: 53 push %rbx > ffffffff86271a91: 48 89 fb mov %rdi,%rbx > ffffffff86271a94: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271a99: 48 83 3d 97 8b e4 01 cmpq $0x0,0x1e48b97(%ri...

...fffff86271ef4: ff 14 25 30 a6 0b 88 callq *0xffffffff880ba630 > ffffffff86271efb: c3 retq > ffffffff86271efc: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271f01: 0f 0b ud2 > ffffffff86271a90 <arch_local_irq_restore>: > ffffffff86271a90: 53 push %rbx > ffffffff86271a91: 48 89 fb mov %rdi,%rbx > ffffffff86271a94: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > ffffffff86271a99: 48 83 3d 97 8b e4 01 cmpq $0x0,0x1e48b97(%ri...

...t percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp) +{ + DEFINE_WAIT(wait); + struct percpu_ida_cpu *tags; + unsigned long flags; + int tag; + + local_irq_save(flags); + tags = this_cpu_ptr(pool->tag_cpu); + + /* Fastpath */ + tag = alloc_local_tag(pool, tags); + if (likely(tag >= 0)) { + local_irq_restore(flags); + return tag; + } + + while (1) { + spin_lock(&pool->lock); + + /* + * prepare_to_wait() must come before steal_tags(), in case + * percpu_ida_free() on another cpu flips a bit in + * cpus_have_tags + * + * global lock held and irqs disabled, don't need percpu lock +...