linux-kernel - [PATCH v4 10/16] arm64/mm: Split the arm64_mm_context

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Date:   Wed, 14 Apr 2021 12:23:06 +0100
From:   Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
To:     <linux-arm-kernel@...ts.infradead.org>,
        <kvmarm@...ts.cs.columbia.edu>, <linux-kernel@...r.kernel.org>
CC:     <maz@...nel.org>, <will@...nel.org>, <catalin.marinas@....com>,
        <james.morse@....com>, <julien.thierry.kdev@...il.com>,
        <suzuki.poulose@....com>, <jean-philippe@...aro.org>,
        <julien@....org>, <linuxarm@...wei.com>
Subject: [PATCH v4 10/16] arm64/mm: Split the arm64_mm_context_get/put

Keep only the mm specific part in arm64_mm_context_get/put
and move the rest to generic functions.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
---
 arch/arm64/mm/context.c | 53 +++++++++++++++++++++++++++--------------
 1 file changed, 35 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 40ef013c90c3..901472a57b5d 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -307,20 +307,21 @@ void check_and_switch_context(struct mm_struct *mm)
 		cpu_switch_mm(mm->pgd, mm);
 }
 
-unsigned long arm64_mm_context_get(struct mm_struct *mm)
+static unsigned long asid_context_pinned_get(struct asid_info *info,
+					     atomic64_t *pasid,
+					     refcount_t *pinned)
 {
 	unsigned long flags;
 	u64 asid;
-	struct asid_info *info = &asid_info;
 
 	if (!info->pinned_map)
 		return 0;
 
 	raw_spin_lock_irqsave(&info->lock, flags);
 
-	asid = atomic64_read(&mm->context.id);
+	asid = atomic64_read(pasid);
 
-	if (refcount_inc_not_zero(&mm->context.pinned))
+	if (refcount_inc_not_zero(pinned))
 		goto out_unlock;
 
 	if (info->nr_pinned_asids >= info->max_pinned_asids) {
@@ -333,45 +334,61 @@ unsigned long arm64_mm_context_get(struct mm_struct *mm)
 		 * We went through one or more rollover since that ASID was
 		 * used. Ensure that it is still valid, or generate a new one.
 		 */
-		asid = new_context(info, &mm->context.id, &mm->context.pinned);
-		atomic64_set(&mm->context.id, asid);
+		asid = new_context(info, pasid, pinned);
+		atomic64_set(pasid, asid);
 	}
 
 	info->nr_pinned_asids++;
 	__set_bit(asid2idx(info, asid), info->pinned_map);
-	refcount_set(&mm->context.pinned, 1);
+	refcount_set(pinned, 1);
 
 out_unlock:
 	raw_spin_unlock_irqrestore(&info->lock, flags);
-
 	asid &= ~ASID_MASK(info);
-
-	/* Set the equivalent of USER_ASID_BIT */
-	if (asid && arm64_kernel_unmapped_at_el0())
-		asid |= 1;
-
 	return asid;
 }
-EXPORT_SYMBOL_GPL(arm64_mm_context_get);
 
-void arm64_mm_context_put(struct mm_struct *mm)
+static void asid_context_pinned_put(struct asid_info *info, atomic64_t *pasid,
+				    refcount_t *pinned)
 {
 	unsigned long flags;
-	struct asid_info *info = &asid_info;
-	u64 asid = atomic64_read(&mm->context.id);
+	u64 asid = atomic64_read(pasid);
 
 	if (!info->pinned_map)
 		return;
 
 	raw_spin_lock_irqsave(&info->lock, flags);
 
-	if (refcount_dec_and_test(&mm->context.pinned)) {
+	if (refcount_dec_and_test(pinned)) {
 		__clear_bit(asid2idx(info, asid), info->pinned_map);
 		info->nr_pinned_asids--;
 	}
 
 	raw_spin_unlock_irqrestore(&info->lock, flags);
 }
+
+unsigned long arm64_mm_context_get(struct mm_struct *mm)
+{
+	u64 asid;
+	struct asid_info *info = &asid_info;
+
+	asid = asid_context_pinned_get(info, &mm->context.id,
+				       &mm->context.pinned);
+
+	/* Set the equivalent of USER_ASID_BIT */
+	if (asid && arm64_kernel_unmapped_at_el0())
+		asid |= 1;
+
+	return asid;
+}
+EXPORT_SYMBOL_GPL(arm64_mm_context_get);
+
+void arm64_mm_context_put(struct mm_struct *mm)
+{
+	struct asid_info *info = &asid_info;
+
+	asid_context_pinned_put(info, &mm->context.id, &mm->context.pinned);
+}
 EXPORT_SYMBOL_GPL(arm64_mm_context_put);
 
 /* Errata workaround post TTBRx_EL1 update. */
-- 
2.17.1