linux-kernel - [PATCH v4 08/16] arm64/mm: Split asid

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Date:   Wed, 14 Apr 2021 12:23:04 +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 08/16] arm64/mm: Split asid_inits in 2 parts

From: Julien Grall <julien.grall@....com>

Move out the common initialization of the ASID allocator in a separate
function.

Signed-off-by: Julien Grall <julien.grall@....com>
Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
---
v3-->v4
  -dropped asid_per_ctxt and added pinned asid map init.
---
 arch/arm64/mm/context.c | 44 +++++++++++++++++++++++++++++++----------
 1 file changed, 34 insertions(+), 10 deletions(-)

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 8af54e06f5bc..041c3c5e0216 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -412,26 +412,50 @@ static int asids_update_limit(void)
 }
 arch_initcall(asids_update_limit);
 
-static int asids_init(void)
+/*
+ * Initialize the ASID allocator
+ *
+ * @info: Pointer to the asid allocator structure
+ * @bits: Number of ASIDs available
+ * @pinned: Support for Pinned ASIDs
+ */
+static int asid_allocator_init(struct asid_info *info, u32 bits, bool pinned)
 {
-	struct asid_info *info = &asid_info;
+	info->bits = bits;
 
-	info->bits = get_cpu_asid_bits();
+	/*
+	 * Expect allocation after rollover to fail if we don't have at least
+	 * one more ASID than CPUs. ASID #0 is always reserved.
+	 */
+	WARN_ON(NUM_CTXT_ASIDS(info) - 1 <= num_possible_cpus());
 	atomic64_set(&info->generation, ASID_FIRST_VERSION(info));
 	info->map = kcalloc(BITS_TO_LONGS(NUM_CTXT_ASIDS(info)),
 			    sizeof(*info->map), GFP_KERNEL);
 	if (!info->map)
-		panic("Failed to allocate bitmap for %lu ASIDs\n",
-		      NUM_CTXT_ASIDS(info));
+		return -ENOMEM;
 
 	info->map_idx = 1;
-	info->active = &active_asids;
-	info->reserved = &reserved_asids;
 	raw_spin_lock_init(&info->lock);
 
-	info->pinned_map = kcalloc(BITS_TO_LONGS(NUM_CTXT_ASIDS(info)),
-				   sizeof(*info->pinned_map), GFP_KERNEL);
-	info->nr_pinned_asids = 0;
+	if (pinned) {
+		info->pinned_map = kcalloc(BITS_TO_LONGS(NUM_CTXT_ASIDS(info)),
+					   sizeof(*info->pinned_map), GFP_KERNEL);
+		info->nr_pinned_asids = 0;
+	}
+
+	return 0;
+}
+
+static int asids_init(void)
+{
+	struct asid_info *info = &asid_info;
+
+	if (asid_allocator_init(info, get_cpu_asid_bits(), true))
+		panic("Unable to initialize ASID allocator for %lu ASIDs\n",
+		      NUM_CTXT_ASIDS(info));
+
+	info->active = &active_asids;
+	info->reserved = &reserved_asids;
 
 	/*
 	 * We cannot call set_reserved_asid_bits() here because CPU
-- 
2.17.1