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From: Julien Grall <julien.grall@arm.com>
To: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu
Cc: marc.zyngier@arm.com, catalin.marinas@arm.com,
	will.deacon@arm.com, Julien Grall <julien.grall@arm.com>
Subject: [PATCH RFC 02/14] arm64/mm: Move active_asids and reserved_asids to asid_info
Date: Thu, 21 Mar 2019 16:36:11 +0000
Message-ID: <20190321163623.20219-3-julien.grall@arm.com> (raw)
In-Reply-To: <20190321163623.20219-1-julien.grall@arm.com>

The variables active_asids and reserved_asids hold information for a
given ASID allocator. So move them to the structure asid_info.

At the same time, introduce wrappers to access the active and reserved
ASIDs to make the code clearer.

Signed-off-by: Julien Grall <julien.grall@arm.com>
---
 arch/arm64/mm/context.c | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/mm/context.c b/arch/arm64/mm/context.c
index 34db54f1a39a..cfe4c5f7abf3 100644
--- a/arch/arm64/mm/context.c
+++ b/arch/arm64/mm/context.c
@@ -34,10 +34,16 @@ struct asid_info
 {
 	atomic64_t	generation;
 	unsigned long	*map;
+	atomic64_t __percpu	*active;
+	u64 __percpu		*reserved;
 } asid_info;
 
+#define active_asid(info, cpu)	*per_cpu_ptr((info)->active, cpu)
+#define reserved_asid(info, cpu) *per_cpu_ptr((info)->reserved, cpu)
+
 static DEFINE_PER_CPU(atomic64_t, active_asids);
 static DEFINE_PER_CPU(u64, reserved_asids);
+
 static cpumask_t tlb_flush_pending;
 
 #define ASID_MASK		(~GENMASK(asid_bits - 1, 0))
@@ -100,7 +106,7 @@ static void flush_context(struct asid_info *info)
 	bitmap_clear(info->map, 0, NUM_USER_ASIDS);
 
 	for_each_possible_cpu(i) {
-		asid = atomic64_xchg_relaxed(&per_cpu(active_asids, i), 0);
+		asid = atomic64_xchg_relaxed(&active_asid(info, i), 0);
 		/*
 		 * If this CPU has already been through a
 		 * rollover, but hasn't run another task in
@@ -109,9 +115,9 @@ static void flush_context(struct asid_info *info)
 		 * the process it is still running.
 		 */
 		if (asid == 0)
-			asid = per_cpu(reserved_asids, i);
+			asid = reserved_asid(info, i);
 		__set_bit(asid2idx(asid), info->map);
-		per_cpu(reserved_asids, i) = asid;
+		reserved_asid(info, i) = asid;
 	}
 
 	/*
@@ -121,7 +127,8 @@ static void flush_context(struct asid_info *info)
 	cpumask_setall(&tlb_flush_pending);
 }
 
-static bool check_update_reserved_asid(u64 asid, u64 newasid)
+static bool check_update_reserved_asid(struct asid_info *info, u64 asid,
+				       u64 newasid)
 {
 	int cpu;
 	bool hit = false;
@@ -136,9 +143,9 @@ static bool check_update_reserved_asid(u64 asid, u64 newasid)
 	 * generation.
 	 */
 	for_each_possible_cpu(cpu) {
-		if (per_cpu(reserved_asids, cpu) == asid) {
+		if (reserved_asid(info, cpu) == asid) {
 			hit = true;
-			per_cpu(reserved_asids, cpu) = newasid;
+			reserved_asid(info, cpu) = newasid;
 		}
 	}
 
@@ -158,7 +165,7 @@ static u64 new_context(struct asid_info *info, struct mm_struct *mm)
 		 * If our current ASID was active during a rollover, we
 		 * can continue to use it and this was just a false alarm.
 		 */
-		if (check_update_reserved_asid(asid, newasid))
+		if (check_update_reserved_asid(info, asid, newasid))
 			return newasid;
 
 		/*
@@ -207,8 +214,8 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
 
 	/*
 	 * The memory ordering here is subtle.
-	 * If our active_asids is non-zero and the ASID matches the current
-	 * generation, then we update the active_asids entry with a relaxed
+	 * If our active_asid is non-zero and the ASID matches the current
+	 * generation, then we update the active_asid entry with a relaxed
 	 * cmpxchg. Racing with a concurrent rollover means that either:
 	 *
 	 * - We get a zero back from the cmpxchg and end up waiting on the
@@ -219,10 +226,10 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
 	 *   relaxed xchg in flush_context will treat us as reserved
 	 *   because atomic RmWs are totally ordered for a given location.
 	 */
-	old_active_asid = atomic64_read(&per_cpu(active_asids, cpu));
+	old_active_asid = atomic64_read(&active_asid(info, cpu));
 	if (old_active_asid &&
 	    !((asid ^ atomic64_read(&info->generation)) >> asid_bits) &&
-	    atomic64_cmpxchg_relaxed(&per_cpu(active_asids, cpu),
+	    atomic64_cmpxchg_relaxed(&active_asid(info, cpu),
 				     old_active_asid, asid))
 		goto switch_mm_fastpath;
 
@@ -237,7 +244,7 @@ void check_and_switch_context(struct mm_struct *mm, unsigned int cpu)
 	if (cpumask_test_and_clear_cpu(cpu, &tlb_flush_pending))
 		local_flush_tlb_all();
 
-	atomic64_set(&per_cpu(active_asids, cpu), asid);
+	atomic64_set(&active_asid(info, cpu), asid);
 	raw_spin_unlock_irqrestore(&cpu_asid_lock, flags);
 
 switch_mm_fastpath:
@@ -278,6 +285,9 @@ static int asids_init(void)
 		panic("Failed to allocate bitmap for %lu ASIDs\n",
 		      NUM_USER_ASIDS);
 
+	info->active = &active_asids;
+	info->reserved = &reserved_asids;
+
 	pr_info("ASID allocator initialised with %lu entries\n", NUM_USER_ASIDS);
 	return 0;
 }
-- 
2.11.0

  parent reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-21 16:36 [PATCH RFC 00/14] kvm/arm: Align the VMID allocation with the arm64 ASID one Julien Grall
2019-03-21 16:36 ` [PATCH RFC 01/14] arm64/mm: Introduce asid_info structure and move asid_generation/asid_map to it Julien Grall
2019-03-21 17:03   ` Suzuki K Poulose
2019-03-21 17:27     ` Julien Grall
2019-03-21 16:36 ` Julien Grall [this message]
2019-03-21 16:36 ` [PATCH RFC 03/14] arm64/mm: Move bits to asid_info Julien Grall
2019-03-21 16:36 ` [PATCH RFC 04/14] arm64/mm: Move the variable lock and tlb_flush_pending " Julien Grall
2019-03-21 16:36 ` [PATCH RFC 05/14] arm64/mm: Remove dependency on MM in new_context Julien Grall
2019-03-21 16:36 ` [PATCH RFC 06/14] arm64/mm: Store the number of asid allocated per context Julien Grall
2019-03-21 16:36 ` [PATCH RFC 07/14] arm64/mm: Introduce NUM_ASIDS Julien Grall
2019-03-21 16:36 ` [PATCH RFC 08/14] arm64/mm: Split asid_inits in 2 parts Julien Grall
2019-03-21 16:36 ` [PATCH RFC 09/14] arm64/mm: Split the function check_and_switch_context in 3 parts Julien Grall
2019-03-21 16:36 ` [PATCH RFC 10/14] arm64/mm: Introduce a callback to flush the local context Julien Grall
2019-03-21 16:36 ` [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file Julien Grall
2019-06-05 16:56   ` Julien Grall
2019-06-05 20:41     ` Palmer Dabbelt
2019-06-11  1:56       ` Gary Guo
2019-06-19  8:07     ` Guo Ren
2019-06-19  8:54       ` Julien Grall
2019-06-19  9:12         ` Will Deacon
2019-06-19 12:18           ` Guo Ren
2019-06-19 12:39             ` Will Deacon
2019-06-20  9:33               ` Guo Ren
2019-06-24 10:40                 ` Will Deacon
2019-06-25  7:25                   ` Palmer Dabbelt
2019-09-07 23:52                   ` Guo Ren
2019-09-12 14:02                     ` Will Deacon
2019-09-12 14:59                       ` Guo Ren
2019-09-13  7:13                         ` Guo Ren
2019-09-14  8:49                           ` Guo Ren
2019-09-16 12:57                           ` Jean-Philippe Brucker
2019-09-19 13:07                             ` Guo Ren
2019-09-19 15:18                               ` Jean-Philippe Brucker
2019-09-20  0:07                                 ` Guo Ren
2019-09-20  7:18                                   ` Jean-Philippe Brucker
2019-09-14 14:01                       ` Palmer Dabbelt
2019-09-15  5:03                         ` Anup Patel
2019-09-16 18:18                           ` Will Deacon
2019-09-16 18:28                             ` Palmer Dabbelt
2019-09-17  3:42                             ` Anup Patel
2019-09-19 13:36                               ` Guo Ren
2019-06-19 11:51         ` Guo Ren
2019-06-19 12:52           ` Julien Grall
2019-06-21 14:16           ` Catalin Marinas
2019-06-23 16:35             ` Guo Ren
2019-06-24 10:22               ` Will Deacon
2019-06-27  9:41                 ` qi.fuli
2019-06-27 10:26                   ` Will Deacon
2019-06-24 15:38               ` Catalin Marinas
2019-06-30  4:29                 ` Guo Ren
2019-07-01  9:17                   ` Catalin Marinas
2019-07-16  3:31                     ` Guo Ren
2019-07-22 16:38                       ` Catalin Marinas
2019-03-21 16:36 ` [PATCH RFC 12/14] arm64/lib: asid: Allow user to update the context under the lock Julien Grall
2019-03-21 16:36 ` [PATCH RFC 13/14] arm/kvm: Introduce a new VMID allocator Julien Grall
2019-03-21 16:36 ` [PATCH RFC 14/14] kvm/arm: Align the VMID allocation with the arm64 ASID one Julien Grall

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