linux-kernel - [PATCH RFC 10/14] arm64/mm: Introduce a callback to flush the local context

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Message-Id: <20190321163623.20219-11-julien.grall@arm.com>
Date:   Thu, 21 Mar 2019 16:36:19 +0000
From:   Julien Grall <julien.grall@....com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        kvmarm@...ts.cs.columbia.edu
Cc:     christoffer.dall@....com, james.morse@....com,
        marc.zyngier@....com, julien.thierry@....com,
        suzuki.poulose@....com, catalin.marinas@....com,
        will.deacon@....com, Julien Grall <julien.grall@....com>
Subject: [PATCH RFC 10/14] arm64/mm: Introduce a callback to flush the local context

Flushing the local context will vary depending on the actual user of the ASID
allocator. Introduce a new callback to flush the local context and move
the call to flush local TLB in it.

Signed-off-by: Julien Grall <julien.grall@....com>
---
 arch/arm64/mm/context.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index cbf1c24cb3ee..678a57b77c91 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -39,6 +39,8 @@ struct asid_info
 	cpumask_t		flush_pending;
 	/* Number of ASID allocated by context (shift value) */
 	unsigned int		ctxt_shift;
+	/* Callback to locally flush the context. */
+	void			(*flush_cpu_ctxt_cb)(void);
 } asid_info;
 
 #define active_asid(info, cpu)	*per_cpu_ptr((info)->active, cpu)
@@ -266,7 +268,7 @@ static void asid_new_context(struct asid_info *info, atomic64_t *pasid,
 	}
 
 	if (cpumask_test_and_clear_cpu(cpu, &info->flush_pending))
-		local_flush_tlb_all();
+		info->flush_cpu_ctxt_cb();
 
 	atomic64_set(&active_asid(info, cpu), asid);
 	raw_spin_unlock_irqrestore(&info->lock, flags);
@@ -298,6 +300,11 @@ asmlinkage void post_ttbr_update_workaround(void)
 			CONFIG_CAVIUM_ERRATUM_27456));
 }
 
+static void asid_flush_cpu_ctxt(void)
+{
+	local_flush_tlb_all();
+}
+
 /*
  * Initialize the ASID allocator
  *
@@ -308,10 +315,12 @@ asmlinkage void post_ttbr_update_workaround(void)
  * 2.
  */
 static int asid_allocator_init(struct asid_info *info,
-			       u32 bits, unsigned int asid_per_ctxt)
+			       u32 bits, unsigned int asid_per_ctxt,
+			       void (*flush_cpu_ctxt_cb)(void))
 {
 	info->bits = bits;
 	info->ctxt_shift = ilog2(asid_per_ctxt);
+	info->flush_cpu_ctxt_cb = flush_cpu_ctxt_cb;
 	/*
 	 * Expect allocation after rollover to fail if we don't have at least
 	 * one more ASID than CPUs. ASID #0 is always reserved.
@@ -332,7 +341,8 @@ static int asids_init(void)
 {
 	u32 bits = get_cpu_asid_bits();
 
-	if (!asid_allocator_init(&asid_info, bits, ASID_PER_CONTEXT))
+	if (!asid_allocator_init(&asid_info, bits, ASID_PER_CONTEXT,
+				 asid_flush_cpu_ctxt))
 		panic("Unable to initialize ASID allocator for %lu ASIDs\n",
 		      1UL << bits);
 
-- 
2.11.0