[PATCH] iommu/arm-smmu-v3: Allocate cmdq_batch on the heap

[Cheng-Yang Chou]

The arm_smmu_cmdq_batch structure is large and was being allocated on
the stack in four call sites, causing stack frame sizes to exceed the
1024-byte limit:

- arm_smmu_atc_inv_domain: 1120 bytes
- arm_smmu_atc_inv_master: 1088 bytes
- arm_smmu_sync_cd: 1088 bytes
- __arm_smmu_tlb_inv_range: 1072 bytes

Move these allocations to the heap using kmalloc_obj() and kfree() to
eliminate the -Wframe-larger-than=1024 warnings and prevent potential
stack overflows.

Signed-off-by: Cheng-Yang Chou <yphbchou0911 at gmail.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 66 +++++++++++++++------
 1 file changed, 48 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 4d00d796f078..734546dc6a78 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1281,7 +1281,7 @@ static void arm_smmu_sync_cd(struct arm_smmu_master *master,
 			     int ssid, bool leaf)
 {
 	size_t i;
-	struct arm_smmu_cmdq_batch cmds;
+	struct arm_smmu_cmdq_batch *cmds;
 	struct arm_smmu_device *smmu = master->smmu;
 	struct arm_smmu_cmdq_ent cmd = {
 		.opcode	= CMDQ_OP_CFGI_CD,
@@ -1291,13 +1291,23 @@ static void arm_smmu_sync_cd(struct arm_smmu_master *master,
 		},
 	};
 
-	arm_smmu_cmdq_batch_init(smmu, &cmds, &cmd);
+	cmds = kmalloc_obj(*cmds);
+	if (!cmds) {
+		struct arm_smmu_cmdq_ent cmd_all = { .opcode = CMDQ_OP_CFGI_ALL };
+
+		WARN_ONCE(1, "arm-smmu-v3: failed to allocate cmdq_batch, falling back to full CD invalidation\n");
+		arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd_all);
+		return;
+	}
+
+	arm_smmu_cmdq_batch_init(smmu, cmds, &cmd);
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.cfgi.sid = master->streams[i].id;
-		arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
+		arm_smmu_cmdq_batch_add(smmu, cmds, &cmd);
 	}
 
-	arm_smmu_cmdq_batch_submit(smmu, &cmds);
+	arm_smmu_cmdq_batch_submit(smmu, cmds);
+	kfree(cmds);
 }
 
 static void arm_smmu_write_cd_l1_desc(struct arm_smmu_cdtab_l1 *dst,
@@ -2225,31 +2235,37 @@ arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
 static int arm_smmu_atc_inv_master(struct arm_smmu_master *master,
 				   ioasid_t ssid)
 {
-	int i;
+	int i, ret;
 	struct arm_smmu_cmdq_ent cmd;
-	struct arm_smmu_cmdq_batch cmds;
+	struct arm_smmu_cmdq_batch *cmds;
 
 	arm_smmu_atc_inv_to_cmd(ssid, 0, 0, &cmd);
 
-	arm_smmu_cmdq_batch_init(master->smmu, &cmds, &cmd);
+	cmds = kmalloc_obj(*cmds);
+	if (!cmds)
+		return -ENOMEM;
+
+	arm_smmu_cmdq_batch_init(master->smmu, cmds, &cmd);
 	for (i = 0; i < master->num_streams; i++) {
 		cmd.atc.sid = master->streams[i].id;
-		arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);
+		arm_smmu_cmdq_batch_add(master->smmu, cmds, &cmd);
 	}
 
-	return arm_smmu_cmdq_batch_submit(master->smmu, &cmds);
+	ret = arm_smmu_cmdq_batch_submit(master->smmu, cmds);
+	kfree(cmds);
+	return ret;
 }
 
 int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
 			    unsigned long iova, size_t size)
 {
 	struct arm_smmu_master_domain *master_domain;
-	int i;
+	int i, ret;
 	unsigned long flags;
 	struct arm_smmu_cmdq_ent cmd = {
 		.opcode = CMDQ_OP_ATC_INV,
 	};
-	struct arm_smmu_cmdq_batch cmds;
+	struct arm_smmu_cmdq_batch *cmds;
 
 	if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_ATS))
 		return 0;
@@ -2271,7 +2287,11 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
 	if (!atomic_read(&smmu_domain->nr_ats_masters))
 		return 0;
 
-	arm_smmu_cmdq_batch_init(smmu_domain->smmu, &cmds, &cmd);
+	cmds = kmalloc_obj(*cmds);
+	if (!cmds)
+		return -ENOMEM;
+
+	arm_smmu_cmdq_batch_init(smmu_domain->smmu, cmds, &cmd);
 
 	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
 	list_for_each_entry(master_domain, &smmu_domain->devices,
@@ -2294,12 +2314,14 @@ int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
 
 		for (i = 0; i < master->num_streams; i++) {
 			cmd.atc.sid = master->streams[i].id;
-			arm_smmu_cmdq_batch_add(smmu_domain->smmu, &cmds, &cmd);
+			arm_smmu_cmdq_batch_add(smmu_domain->smmu, cmds, &cmd);
 		}
 	}
 	spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
 
-	return arm_smmu_cmdq_batch_submit(smmu_domain->smmu, &cmds);
+	ret = arm_smmu_cmdq_batch_submit(smmu_domain->smmu, cmds);
+	kfree(cmds);
+	return ret;
 }
 
 /* IO_PGTABLE API */
@@ -2334,7 +2356,7 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	unsigned long end = iova + size, num_pages = 0, tg = 0;
 	size_t inv_range = granule;
-	struct arm_smmu_cmdq_batch cmds;
+	struct arm_smmu_cmdq_batch *cmds;
 
 	if (!size)
 		return;
@@ -2362,7 +2384,14 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
 			num_pages++;
 	}
 
-	arm_smmu_cmdq_batch_init(smmu, &cmds, cmd);
+	cmds = kmalloc_obj(*cmds);
+	if (!cmds) {
+		WARN_ONCE(1, "arm-smmu-v3: failed to allocate cmdq_batch, falling back to full TLB invalidation\n");
+		arm_smmu_tlb_inv_context(smmu_domain);
+		return;
+	}
+
+	arm_smmu_cmdq_batch_init(smmu, cmds, cmd);
 
 	while (iova < end) {
 		if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
@@ -2391,10 +2420,11 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
 		}
 
 		cmd->tlbi.addr = iova;
-		arm_smmu_cmdq_batch_add(smmu, &cmds, cmd);
+		arm_smmu_cmdq_batch_add(smmu, cmds, cmd);
 		iova += inv_range;
 	}
-	arm_smmu_cmdq_batch_submit(smmu, &cmds);
+	arm_smmu_cmdq_batch_submit(smmu, cmds);
+	kfree(cmds);
 }
 
 static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
-- 
2.48.1