From: John Garry <john.garry@huawei.com>
Date: Wed, 11 Aug 2021 23:49:26 +0800
Subject: iommu/arm-smmu-v3: Stop pre-zeroing batch commands
Git-commit: fac956710ab0812f9e395e9f7a27da551412830f
Patch-mainline: v5.15-rc1
References: bsc#1192202
Pre-zeroing the batched commands structure is inefficient, as individual
commands are zeroed later in arm_smmu_cmdq_build_cmd(). The size is quite
large and commonly most commands won't even be used:
struct arm_smmu_cmdq_batch cmds = {};
345c: 52800001 mov w1, #0x0 // #0
3460: d2808102 mov x2, #0x408 // #1032
3464: 910143a0 add x0, x29, #0x50
3468: 94000000 bl 0 <memset>
Stop pre-zeroing the complete structure and only zero the num member.
Signed-off-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/1628696966-88386-1-git-send-email-john.garry@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -955,7 +955,7 @@ static void arm_smmu_sync_cd(struct arm_
size_t i;
unsigned long flags;
struct arm_smmu_master *master;
- struct arm_smmu_cmdq_batch cmds = {};
+ struct arm_smmu_cmdq_batch cmds;
struct arm_smmu_device *smmu = smmu_domain->smmu;
struct arm_smmu_cmdq_ent cmd = {
.opcode = CMDQ_OP_CFGI_CD,
@@ -965,6 +965,8 @@ static void arm_smmu_sync_cd(struct arm_
},
};
+ cmds.num = 0;
+
spin_lock_irqsave(&smmu_domain->devices_lock, flags);
list_for_each_entry(master, &smmu_domain->devices, domain_head) {
for (i = 0; i < master->num_streams; i++) {
@@ -1781,7 +1783,7 @@ int arm_smmu_atc_inv_domain(struct arm_s
unsigned long flags;
struct arm_smmu_cmdq_ent cmd;
struct arm_smmu_master *master;
- struct arm_smmu_cmdq_batch cmds = {};
+ struct arm_smmu_cmdq_batch cmds;
if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_ATS))
return 0;
@@ -1805,6 +1807,8 @@ int arm_smmu_atc_inv_domain(struct arm_s
arm_smmu_atc_inv_to_cmd(ssid, iova, size, &cmd);
+ cmds.num = 0;
+
spin_lock_irqsave(&smmu_domain->devices_lock, flags);
list_for_each_entry(master, &smmu_domain->devices, domain_head) {
if (!master->ats_enabled)
@@ -1852,7 +1856,7 @@ static void __arm_smmu_tlb_inv_range(str
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;
@@ -1870,6 +1874,8 @@ static void __arm_smmu_tlb_inv_range(str
num_pages = size >> tg;
}
+ cmds.num = 0;
+
while (iova < end) {
if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
/*