diff options
Diffstat (limited to 'arch/arm/mm/context.c')
| -rw-r--r-- | arch/arm/mm/context.c | 64 |
1 files changed, 47 insertions, 17 deletions
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c index 2ac37372ef52..b55b1015724b 100644 --- a/arch/arm/mm/context.c +++ b/arch/arm/mm/context.c @@ -20,6 +20,7 @@ #include <asm/smp_plat.h> #include <asm/thread_notify.h> #include <asm/tlbflush.h> +#include <asm/proc-fns.h> /* * On ARMv6, we have the following structure in the Context ID: @@ -39,33 +40,51 @@ * non 64-bit operations. */ #define ASID_FIRST_VERSION (1ULL << ASID_BITS) -#define NUM_USER_ASIDS (ASID_FIRST_VERSION - 1) - -#define ASID_TO_IDX(asid) ((asid & ~ASID_MASK) - 1) -#define IDX_TO_ASID(idx) ((idx + 1) & ~ASID_MASK) +#define NUM_USER_ASIDS ASID_FIRST_VERSION static DEFINE_RAW_SPINLOCK(cpu_asid_lock); static atomic64_t asid_generation = ATOMIC64_INIT(ASID_FIRST_VERSION); static DECLARE_BITMAP(asid_map, NUM_USER_ASIDS); -DEFINE_PER_CPU(atomic64_t, active_asids); +static DEFINE_PER_CPU(atomic64_t, active_asids); static DEFINE_PER_CPU(u64, reserved_asids); static cpumask_t tlb_flush_pending; +#ifdef CONFIG_ARM_ERRATA_798181 +void a15_erratum_get_cpumask(int this_cpu, struct mm_struct *mm, + cpumask_t *mask) +{ + int cpu; + unsigned long flags; + u64 context_id, asid; + + raw_spin_lock_irqsave(&cpu_asid_lock, flags); + context_id = mm->context.id.counter; + for_each_online_cpu(cpu) { + if (cpu == this_cpu) + continue; + /* + * We only need to send an IPI if the other CPUs are + * running the same ASID as the one being invalidated. + */ + asid = per_cpu(active_asids, cpu).counter; + if (asid == 0) + asid = per_cpu(reserved_asids, cpu); + if (context_id == asid) + cpumask_set_cpu(cpu, mask); + } + raw_spin_unlock_irqrestore(&cpu_asid_lock, flags); +} +#endif + #ifdef CONFIG_ARM_LPAE static void cpu_set_reserved_ttbr0(void) { - unsigned long ttbl = __pa(swapper_pg_dir); - unsigned long ttbh = 0; - /* * Set TTBR0 to swapper_pg_dir which contains only global entries. The * ASID is set to 0. */ - asm volatile( - " mcrr p15, 0, %0, %1, c2 @ set TTBR0\n" - : - : "r" (ttbl), "r" (ttbh)); + cpu_set_ttbr(0, __pa(swapper_pg_dir)); isb(); } #else @@ -128,7 +147,16 @@ static void flush_context(unsigned int cpu) asid = 0; } else { asid = atomic64_xchg(&per_cpu(active_asids, i), 0); - __set_bit(ASID_TO_IDX(asid), asid_map); + /* + * If this CPU has already been through a + * rollover, but hasn't run another task in + * the meantime, we must preserve its reserved + * ASID, as this is the only trace we have of + * the process it is still running. + */ + if (asid == 0) + asid = per_cpu(reserved_asids, i); + __set_bit(asid & ~ASID_MASK, asid_map); } per_cpu(reserved_asids, i) = asid; } @@ -167,17 +195,19 @@ static u64 new_context(struct mm_struct *mm, unsigned int cpu) /* * Allocate a free ASID. If we can't find one, take a * note of the currently active ASIDs and mark the TLBs - * as requiring flushes. + * as requiring flushes. We always count from ASID #1, + * as we reserve ASID #0 to switch via TTBR0 and indicate + * rollover events. */ - asid = find_first_zero_bit(asid_map, NUM_USER_ASIDS); + asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, 1); if (asid == NUM_USER_ASIDS) { generation = atomic64_add_return(ASID_FIRST_VERSION, &asid_generation); flush_context(cpu); - asid = find_first_zero_bit(asid_map, NUM_USER_ASIDS); + asid = find_next_zero_bit(asid_map, NUM_USER_ASIDS, 1); } __set_bit(asid, asid_map); - asid = generation | IDX_TO_ASID(asid); + asid |= generation; cpumask_clear(mm_cpumask(mm)); } |