[RFC v2 04/14] arm64/mm: Move the variable lock and tlb_flush_pending to asid_info

From: Julien Grall
Date: Thu Jun 20 2019 - 09:12:31 EST


The variables lock and tlb_flush_pending holds information for a given
ASID allocator. So move them to the asid_info structure.

Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
---
arch/arm64/mm/context.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 7883347ece52..6457a9310fe4 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -27,8 +27,6 @@
#include <asm/smp.h>
#include <asm/tlbflush.h>

-static DEFINE_RAW_SPINLOCK(cpu_asid_lock);
-
static struct asid_info
{
atomic64_t generation;
@@ -36,6 +34,9 @@ static struct asid_info
atomic64_t __percpu *active;
u64 __percpu *reserved;
u32 bits;
+ raw_spinlock_t lock;
+ /* Which CPU requires context flush on next call */
+ cpumask_t flush_pending;
} asid_info;

#define active_asid(info, cpu) *per_cpu_ptr((info)->active, cpu)
@@ -44,8 +45,6 @@ static struct asid_info
static DEFINE_PER_CPU(atomic64_t, active_asids);
static DEFINE_PER_CPU(u64, reserved_asids);

-static cpumask_t tlb_flush_pending;
-
#define ASID_MASK(info) (~GENMASK((info)->bits - 1, 0))
#define ASID_FIRST_VERSION(info) (1UL << ((info)->bits))

@@ -124,7 +123,7 @@ static void flush_context(struct asid_info *info)
* Queue a TLB invalidation for each CPU to perform on next
* context-switch
*/
- cpumask_setall(&tlb_flush_pending);
+ cpumask_setall(&info->flush_pending);
}

static bool check_update_reserved_asid(struct asid_info *info, u64 asid,
@@ -233,7 +232,7 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
old_active_asid, asid))
goto switch_mm_fastpath;

- raw_spin_lock_irqsave(&cpu_asid_lock, flags);
+ raw_spin_lock_irqsave(&info->lock, flags);
/* Check that our ASID belongs to the current generation. */
asid = atomic64_read(&mm->context.id);
if ((asid ^ atomic64_read(&info->generation)) >> info->bits) {
@@ -241,11 +240,11 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
atomic64_set(&mm->context.id, asid);
}

- if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending))
+ if (cpumask_test_and_clear_cpu(cpu, &info->flush_pending))
local_flush_tlb_all();

atomic64_set(&active_asid(info, cpu), asid);
- raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
+ raw_spin_unlock_irqrestore(&info->lock, flags);

switch_mm_fastpath:

@@ -288,6 +287,8 @@ static int asids_init(void)
info->active = &active_asids;
info->reserved = &reserved_asids;

+ raw_spin_lock_init(&info->lock);
+
pr_info("ASID allocator initialised with %lu entries\n",
NUM_USER_ASIDS(info));
return 0;
--
2.11.0