[PATCH 1/5] arm64: mm: Define asid_bitmap structure for pinned_asid

From: Yunfeng Ye
Date: Mon Oct 17 2022 - 04:33:10 EST


It is clearer to use the asid_bitmap structure for pinned_sid, and we
will use it for isolated asid later.

No functional change.

Signed-off-by: Yunfeng Ye <yeyunfeng@xxxxxxxxxx>
---
arch/arm64/mm/context.c | 38 +++++++++++++++++++++-----------------
1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index e1e0dca01839..8549b5f30352 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -17,6 +17,12 @@
#include <asm/smp.h>
#include <asm/tlbflush.h>

+struct asid_bitmap {
+ unsigned long *map;
+ unsigned long nr;
+ unsigned long max;
+};
+
static u32 asid_bits;
static DEFINE_RAW_SPINLOCK(cpu_asid_lock);

@@ -27,9 +33,7 @@ static DEFINE_PER_CPU(atomic64_t, active_asids);
static DEFINE_PER_CPU(u64, reserved_asids);
static cpumask_t tlb_flush_pending;

-static unsigned long max_pinned_asids;
-static unsigned long nr_pinned_asids;
-static unsigned long *pinned_asid_map;
+static struct asid_bitmap pinned_asid;

#define ASID_MASK (~GENMASK(asid_bits - 1, 0))
#define ASID_FIRST_VERSION (1UL << asid_bits)
@@ -90,8 +94,8 @@ static void set_kpti_asid_bits(unsigned long *map)

static void set_reserved_asid_bits(void)
{
- if (pinned_asid_map)
- bitmap_copy(asid_map, pinned_asid_map, NUM_USER_ASIDS);
+ if (pinned_asid.map)
+ bitmap_copy(asid_map, pinned_asid.map, NUM_USER_ASIDS);
else if (arm64_kernel_unmapped_at_el0())
set_kpti_asid_bits(asid_map);
else
@@ -275,7 +279,7 @@ unsigned long arm64_mm_context_get(struct mm_struct *mm)
unsigned long flags;
u64 asid;

- if (!pinned_asid_map)
+ if (!pinned_asid.map)
return 0;

raw_spin_lock_irqsave(&cpu_asid_lock, flags);
@@ -285,7 +289,7 @@ unsigned long arm64_mm_context_get(struct mm_struct *mm)
if (refcount_inc_not_zero(&mm->context.pinned))
goto out_unlock;

- if (nr_pinned_asids >= max_pinned_asids) {
+ if (pinned_asid.nr >= pinned_asid.max) {
asid = 0;
goto out_unlock;
}
@@ -299,8 +303,8 @@ unsigned long arm64_mm_context_get(struct mm_struct *mm)
atomic64_set(&mm->context.id, asid);
}

- nr_pinned_asids++;
- __set_bit(ctxid2asid(asid), pinned_asid_map);
+ pinned_asid.nr++;
+ __set_bit(ctxid2asid(asid), pinned_asid.map);
refcount_set(&mm->context.pinned, 1);

out_unlock:
@@ -321,14 +325,14 @@ void arm64_mm_context_put(struct mm_struct *mm)
unsigned long flags;
u64 asid = atomic64_read(&mm->context.id);

- if (!pinned_asid_map)
+ if (!pinned_asid.map)
return;

raw_spin_lock_irqsave(&cpu_asid_lock, flags);

if (refcount_dec_and_test(&mm->context.pinned)) {
- __clear_bit(ctxid2asid(asid), pinned_asid_map);
- nr_pinned_asids--;
+ __clear_bit(ctxid2asid(asid), pinned_asid.map);
+ pinned_asid.nr--;
}

raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
@@ -377,8 +381,8 @@ static int asids_update_limit(void)

if (arm64_kernel_unmapped_at_el0()) {
num_available_asids /= 2;
- if (pinned_asid_map)
- set_kpti_asid_bits(pinned_asid_map);
+ if (pinned_asid.map)
+ set_kpti_asid_bits(pinned_asid.map);
}
/*
* Expect allocation after rollover to fail if we don't have at least
@@ -393,7 +397,7 @@ static int asids_update_limit(void)
* even if all CPUs have a reserved ASID and the maximum number of ASIDs
* are pinned, there still is at least one empty slot in the ASID map.
*/
- max_pinned_asids = num_available_asids - num_possible_cpus() - 2;
+ pinned_asid.max = num_available_asids - num_possible_cpus() - 2;
return 0;
}
arch_initcall(asids_update_limit);
@@ -407,8 +411,8 @@ static int asids_init(void)
panic("Failed to allocate bitmap for %lu ASIDs\n",
NUM_USER_ASIDS);

- pinned_asid_map = bitmap_zalloc(NUM_USER_ASIDS, GFP_KERNEL);
- nr_pinned_asids = 0;
+ pinned_asid.map = bitmap_zalloc(NUM_USER_ASIDS, GFP_KERNEL);
+ pinned_asid.nr = 0;

/*
* We cannot call set_reserved_asid_bits() here because CPU
--
2.27.0