[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH LINUX v4] xen: event channel arrays are xen_ulong_t and not unsigned long
On Tue, Feb 19, 2013 at 05:29:11PM +0000, Ian Campbell wrote: > On ARM we want these to be the same size on 32- and 64-bit. > > This is an ABI change on ARM. X86 does not change. Hehe. You didn't test this, did you :-) It hangs bootup on X86. > > Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx> > Cc: Jan Beulich <JBeulich@xxxxxxxx> > Cc: Keir (Xen.org) <keir@xxxxxxx> > Cc: Tim Deegan <tim@xxxxxxx> > Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: xen-devel@xxxxxxxxxxxxx > Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > --- > Changes since V3 > s/read_evtchn_pending_sel/xchg_xen_ulong/ in a comment. > Changes since V2 > Add comments about the correct bitops to use, and on the ordering/barrier > requirements on xchg_xen_ulong. > Changes since V1 > use find_first_set not __ffs > fix some more unsigned long -> xen_ulong_t > use more generic xchg_xen_ulong instead of ...read_evtchn... > --- > arch/arm/include/asm/xen/events.h | 22 +++++++ > arch/x86/include/asm/xen/events.h | 3 + > drivers/xen/events.c | 113 > +++++++++++++++++++++---------------- > include/xen/interface/xen.h | 8 +- > 4 files changed, 94 insertions(+), 52 deletions(-) > > diff --git a/arch/arm/include/asm/xen/events.h > b/arch/arm/include/asm/xen/events.h > index 94b4e90..5c27696 100644 > --- a/arch/arm/include/asm/xen/events.h > +++ b/arch/arm/include/asm/xen/events.h > @@ -15,4 +15,26 @@ static inline int xen_irqs_disabled(struct pt_regs *regs) > return raw_irqs_disabled_flags(regs->ARM_cpsr); > } > > +/* > + * We cannot use xchg because it does not support 8-byte > + * values. However it is safe to use {ldr,dtd}exd directly because all > + * platforms which Xen can run on support those instructions. > + */ > +static inline xen_ulong_t xchg_xen_ulong(xen_ulong_t *ptr, xen_ulong_t val) > +{ > + xen_ulong_t oldval; > + unsigned int tmp; > + > + wmb(); > + asm volatile("@ xchg_xen_ulong\n" > + "1: ldrexd %0, %H0, [%3]\n" > + " strexd %1, %2, %H2, [%3]\n" > + " teq %1, #0\n" > + " bne 1b" > + : "=&r" (oldval), "=&r" (tmp) > + : "r" (val), "r" (ptr) > + : "memory", "cc"); > + return oldval; > +} > + > #endif /* _ASM_ARM_XEN_EVENTS_H */ > diff --git a/arch/x86/include/asm/xen/events.h > b/arch/x86/include/asm/xen/events.h > index cc146d5..ca842f2 100644 > --- a/arch/x86/include/asm/xen/events.h > +++ b/arch/x86/include/asm/xen/events.h > @@ -16,4 +16,7 @@ static inline int xen_irqs_disabled(struct pt_regs *regs) > return raw_irqs_disabled_flags(regs->flags); > } > > +/* No need for a barrier -- XCHG is a barrier on x86. */ > +#define xchg_xen_ulong(ptr, val) xchg((ptr), (val)) > + > #endif /* _ASM_X86_XEN_EVENTS_H */ > diff --git a/drivers/xen/events.c b/drivers/xen/events.c > index 0be4df3..b8d84f5 100644 > --- a/drivers/xen/events.c > +++ b/drivers/xen/events.c > @@ -80,6 +80,12 @@ enum xen_irq_type { > }; > > /* > + * Make a bitmask (i.e. unsigned long *) of a xen_ulong_t > + * array. Primarily to avoid long lines (hence the terse name). > + */ > +#define BM(x) (unsigned long *)(x) > + > +/* > * Packed IRQ information: > * type - enum xen_irq_type > * event channel - irq->event channel mapping > @@ -120,7 +126,14 @@ static unsigned long *pirq_eoi_map; > #endif > static bool (*pirq_needs_eoi)(unsigned irq); > > -static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG], > +/* > + * Note sizeof(xen_ulong_t) can be more than sizeof(unsigned long). Be > + * careful to only use bitops which allow for this (e.g test_bit and > + * friends but not __ffs). > + */ > +#define BITS_PER_EVTCHN_WORD (sizeof(xen_ulong_t)*8) > + > +static DEFINE_PER_CPU(xen_ulong_t [NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD], > cpu_evtchn_mask); > > /* Xen will never allocate port zero for any purpose. */ > @@ -294,9 +307,9 @@ static bool pirq_needs_eoi_flag(unsigned irq) > return info->u.pirq.flags & PIRQ_NEEDS_EOI; > } > > -static inline unsigned long active_evtchns(unsigned int cpu, > - struct shared_info *sh, > - unsigned int idx) > +static inline xen_ulong_t active_evtchns(unsigned int cpu, > + struct shared_info *sh, > + unsigned int idx) > { > return sh->evtchn_pending[idx] & > per_cpu(cpu_evtchn_mask, cpu)[idx] & > @@ -312,8 +325,8 @@ static void bind_evtchn_to_cpu(unsigned int chn, unsigned > int cpu) > cpumask_copy(irq_to_desc(irq)->irq_data.affinity, cpumask_of(cpu)); > #endif > > - clear_bit(chn, per_cpu(cpu_evtchn_mask, cpu_from_irq(irq))); > - set_bit(chn, per_cpu(cpu_evtchn_mask, cpu)); > + clear_bit(chn, BM(per_cpu(cpu_evtchn_mask, cpu_from_irq(irq)))); > + set_bit(chn, BM(per_cpu(cpu_evtchn_mask, cpu))); > > info_for_irq(irq)->cpu = cpu; > } > @@ -339,19 +352,19 @@ static void init_evtchn_cpu_bindings(void) > static inline void clear_evtchn(int port) > { > struct shared_info *s = HYPERVISOR_shared_info; > - sync_clear_bit(port, &s->evtchn_pending[0]); > + sync_clear_bit(port, BM(&s->evtchn_pending[0])); > } > > static inline void set_evtchn(int port) > { > struct shared_info *s = HYPERVISOR_shared_info; > - sync_set_bit(port, &s->evtchn_pending[0]); > + sync_set_bit(port, BM(&s->evtchn_pending[0])); > } > > static inline int test_evtchn(int port) > { > struct shared_info *s = HYPERVISOR_shared_info; > - return sync_test_bit(port, &s->evtchn_pending[0]); > + return sync_test_bit(port, BM(&s->evtchn_pending[0])); > } > > > @@ -375,7 +388,7 @@ EXPORT_SYMBOL_GPL(notify_remote_via_irq); > static void mask_evtchn(int port) > { > struct shared_info *s = HYPERVISOR_shared_info; > - sync_set_bit(port, &s->evtchn_mask[0]); > + sync_set_bit(port, BM(&s->evtchn_mask[0])); > } > > static void unmask_evtchn(int port) > @@ -389,7 +402,7 @@ static void unmask_evtchn(int port) > if (unlikely((cpu != cpu_from_evtchn(port)))) > do_hypercall = 1; > else > - evtchn_pending = sync_test_bit(port, &s->evtchn_pending[0]); > + evtchn_pending = sync_test_bit(port, BM(&s->evtchn_pending[0])); > > if (unlikely(evtchn_pending && xen_hvm_domain())) > do_hypercall = 1; > @@ -403,7 +416,7 @@ static void unmask_evtchn(int port) > } else { > struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu); > > - sync_clear_bit(port, &s->evtchn_mask[0]); > + sync_clear_bit(port, BM(&s->evtchn_mask[0])); > > /* > * The following is basically the equivalent of > @@ -411,8 +424,8 @@ static void unmask_evtchn(int port) > * the interrupt edge' if the channel is masked. > */ > if (evtchn_pending && > - !sync_test_and_set_bit(port / BITS_PER_LONG, > - &vcpu_info->evtchn_pending_sel)) > + !sync_test_and_set_bit(port / BITS_PER_EVTCHN_WORD, > + BM(&vcpu_info->evtchn_pending_sel))) > vcpu_info->evtchn_upcall_pending = 1; > } > > @@ -1189,7 +1202,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id) > { > struct shared_info *sh = HYPERVISOR_shared_info; > int cpu = smp_processor_id(); > - unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu); > + xen_ulong_t *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu); > int i; > unsigned long flags; > static DEFINE_SPINLOCK(debug_lock); > @@ -1205,7 +1218,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id) > pending = (get_irq_regs() && i == cpu) > ? xen_irqs_disabled(get_irq_regs()) > : v->evtchn_upcall_mask; > - printk("%d: masked=%d pending=%d event_sel %0*lx\n ", i, > + printk("%d: masked=%d pending=%d event_sel %0*"PRI_xen_ulong"\n > ", i, > pending, v->evtchn_upcall_pending, > (int)(sizeof(v->evtchn_pending_sel)*2), > v->evtchn_pending_sel); > @@ -1214,49 +1227,52 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id) > > printk("\npending:\n "); > for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--) > - printk("%0*lx%s", (int)sizeof(sh->evtchn_pending[0])*2, > + printk("%0*"PRI_xen_ulong"%s", > + (int)sizeof(sh->evtchn_pending[0])*2, > sh->evtchn_pending[i], > i % 8 == 0 ? "\n " : " "); > printk("\nglobal mask:\n "); > for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) > - printk("%0*lx%s", > + printk("%0*"PRI_xen_ulong"%s", > (int)(sizeof(sh->evtchn_mask[0])*2), > sh->evtchn_mask[i], > i % 8 == 0 ? "\n " : " "); > > printk("\nglobally unmasked:\n "); > for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) > - printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2), > + printk("%0*"PRI_xen_ulong"%s", > + (int)(sizeof(sh->evtchn_mask[0])*2), > sh->evtchn_pending[i] & ~sh->evtchn_mask[i], > i % 8 == 0 ? "\n " : " "); > > printk("\nlocal cpu%d mask:\n ", cpu); > - for (i = (NR_EVENT_CHANNELS/BITS_PER_LONG)-1; i >= 0; i--) > - printk("%0*lx%s", (int)(sizeof(cpu_evtchn[0])*2), > + for (i = (NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--) > + printk("%0*"PRI_xen_ulong"%s", (int)(sizeof(cpu_evtchn[0])*2), > cpu_evtchn[i], > i % 8 == 0 ? "\n " : " "); > > printk("\nlocally unmasked:\n "); > for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) { > - unsigned long pending = sh->evtchn_pending[i] > + xen_ulong_t pending = sh->evtchn_pending[i] > & ~sh->evtchn_mask[i] > & cpu_evtchn[i]; > - printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2), > + printk("%0*"PRI_xen_ulong"%s", > + (int)(sizeof(sh->evtchn_mask[0])*2), > pending, i % 8 == 0 ? "\n " : " "); > } > > printk("\npending list:\n"); > for (i = 0; i < NR_EVENT_CHANNELS; i++) { > - if (sync_test_bit(i, sh->evtchn_pending)) { > - int word_idx = i / BITS_PER_LONG; > + if (sync_test_bit(i, BM(sh->evtchn_pending))) { > + int word_idx = i / BITS_PER_EVTCHN_WORD; > printk(" %d: event %d -> irq %d%s%s%s\n", > cpu_from_evtchn(i), i, > evtchn_to_irq[i], > - sync_test_bit(word_idx, &v->evtchn_pending_sel) > + sync_test_bit(word_idx, > BM(&v->evtchn_pending_sel)) > ? "" : " l2-clear", > - !sync_test_bit(i, sh->evtchn_mask) > + !sync_test_bit(i, BM(sh->evtchn_mask)) > ? "" : " globally-masked", > - sync_test_bit(i, cpu_evtchn) > + sync_test_bit(i, BM(cpu_evtchn)) > ? "" : " locally-masked"); > } > } > @@ -1273,7 +1289,7 @@ static DEFINE_PER_CPU(unsigned int, current_bit_idx); > /* > * Mask out the i least significant bits of w > */ > -#define MASK_LSBS(w, i) (w & ((~0UL) << i)) > +#define MASK_LSBS(w, i) (w & ((~((xen_ulong_t)0UL)) << i)) > > /* > * Search the CPUs pending events bitmasks. For each one found, map > @@ -1295,18 +1311,19 @@ static void __xen_evtchn_do_upcall(void) > unsigned count; > > do { > - unsigned long pending_words; > + xen_ulong_t pending_words; > > vcpu_info->evtchn_upcall_pending = 0; > > if (__this_cpu_inc_return(xed_nesting_count) - 1) > goto out; > > -#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */ > - /* Clear master flag /before/ clearing selector flag. */ > - wmb(); > -#endif > - pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0); > + /* > + * Master flag must be /before/ clearing selector > + * flag. xchg_xen_ulong must contain an appropriate > + * barrier. > + */ > + pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, > 0); > > start_word_idx = __this_cpu_read(current_word_idx); > start_bit_idx = __this_cpu_read(current_bit_idx); > @@ -1314,8 +1331,8 @@ static void __xen_evtchn_do_upcall(void) > word_idx = start_word_idx; > > for (i = 0; pending_words != 0; i++) { > - unsigned long pending_bits; > - unsigned long words; > + xen_ulong_t pending_bits; > + xen_ulong_t words; > > words = MASK_LSBS(pending_words, word_idx); > > @@ -1327,7 +1344,7 @@ static void __xen_evtchn_do_upcall(void) > bit_idx = 0; > continue; > } > - word_idx = __ffs(words); > + word_idx = find_first_bit(BM(&words), sizeof(words)); > > pending_bits = active_evtchns(cpu, s, word_idx); > bit_idx = 0; /* usually scan entire word from start */ > @@ -1342,7 +1359,7 @@ static void __xen_evtchn_do_upcall(void) > } > > do { > - unsigned long bits; > + xen_ulong_t bits; > int port, irq; > struct irq_desc *desc; > > @@ -1352,10 +1369,10 @@ static void __xen_evtchn_do_upcall(void) > if (bits == 0) > break; > > - bit_idx = __ffs(bits); > + bit_idx = find_first_bit(BM(&bits), > sizeof(bits)); > > /* Process port. */ > - port = (word_idx * BITS_PER_LONG) + bit_idx; > + port = (word_idx * BITS_PER_EVTCHN_WORD) + > bit_idx; > irq = evtchn_to_irq[port]; > > if (irq != -1) { > @@ -1364,12 +1381,12 @@ static void __xen_evtchn_do_upcall(void) > generic_handle_irq_desc(irq, > desc); > } > > - bit_idx = (bit_idx + 1) % BITS_PER_LONG; > + bit_idx = (bit_idx + 1) % BITS_PER_EVTCHN_WORD; > > /* Next caller starts at last processed + 1 */ > __this_cpu_write(current_word_idx, > bit_idx ? word_idx : > - (word_idx+1) % BITS_PER_LONG); > + (word_idx+1) % > BITS_PER_EVTCHN_WORD); > __this_cpu_write(current_bit_idx, bit_idx); > } while (bit_idx != 0); > > @@ -1377,7 +1394,7 @@ static void __xen_evtchn_do_upcall(void) > if ((word_idx != start_word_idx) || (i != 0)) > pending_words &= ~(1UL << word_idx); > > - word_idx = (word_idx + 1) % BITS_PER_LONG; > + word_idx = (word_idx + 1) % BITS_PER_EVTCHN_WORD; > } > > BUG_ON(!irqs_disabled()); > @@ -1487,8 +1504,8 @@ int resend_irq_on_evtchn(unsigned int irq) > if (!VALID_EVTCHN(evtchn)) > return 1; > > - masked = sync_test_and_set_bit(evtchn, s->evtchn_mask); > - sync_set_bit(evtchn, s->evtchn_pending); > + masked = sync_test_and_set_bit(evtchn, BM(s->evtchn_mask)); > + sync_set_bit(evtchn, BM(s->evtchn_pending)); > if (!masked) > unmask_evtchn(evtchn); > > @@ -1536,8 +1553,8 @@ static int retrigger_dynirq(struct irq_data *data) > if (VALID_EVTCHN(evtchn)) { > int masked; > > - masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask); > - sync_set_bit(evtchn, sh->evtchn_pending); > + masked = sync_test_and_set_bit(evtchn, BM(sh->evtchn_mask)); > + sync_set_bit(evtchn, BM(sh->evtchn_pending)); > if (!masked) > unmask_evtchn(evtchn); > ret = 1; > diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h > index 5d6c272..a9075df 100644 > --- a/include/xen/interface/xen.h > +++ b/include/xen/interface/xen.h > @@ -285,7 +285,7 @@ DEFINE_GUEST_HANDLE_STRUCT(multicall_entry); > * Event channel endpoints per domain: > * 1024 if a long is 32 bits; 4096 if a long is 64 bits. > */ > -#define NR_EVENT_CHANNELS (sizeof(unsigned long) * sizeof(unsigned long) * > 64) > +#define NR_EVENT_CHANNELS (sizeof(xen_ulong_t) * sizeof(xen_ulong_t) * 64) > > struct vcpu_time_info { > /* > @@ -341,7 +341,7 @@ struct vcpu_info { > */ > uint8_t evtchn_upcall_pending; > uint8_t evtchn_upcall_mask; > - unsigned long evtchn_pending_sel; > + xen_ulong_t evtchn_pending_sel; > struct arch_vcpu_info arch; > struct pvclock_vcpu_time_info time; > }; /* 64 bytes (x86) */ > @@ -384,8 +384,8 @@ struct shared_info { > * per-vcpu selector word to be set. Each bit in the selector covers a > * 'C long' in the PENDING bitfield array. > */ > - unsigned long evtchn_pending[sizeof(unsigned long) * 8]; > - unsigned long evtchn_mask[sizeof(unsigned long) * 8]; > + xen_ulong_t evtchn_pending[sizeof(xen_ulong_t) * 8]; > + xen_ulong_t evtchn_mask[sizeof(xen_ulong_t) * 8]; > > /* > * Wallclock time: updated only by control software. Guests should base > -- > 1.7.2.5 > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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