From a4d75360f7a6d979edd66af577847b0f4dbf4377 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Mon, 10 Jun 2024 21:31:11 -0300 Subject: [PATCH] iommu/arm-smmu-v3: Shrink the strtab l1_desc array The top of the 2 level stream table is (at most) 128k entries big, and two high order allocations are required. One of __le64 which is programmed into the HW (1M), and one of struct arm_smmu_strtab_l1_desc which holds the CPU pointer (3M). There is no reason to store the l2ptr_dma as nothing reads it. devm stores a copy of it and the DMA memory will be freed via devm mechanisms. span is a constant of 8+1. Remove both. This removes 16 bytes from each arm_smmu_l1_ctx_desc and saves up to 2M of memory per iommu instance. Tested-by: Nicolin Chen Reviewed-by: Mostafa Saleh Signed-off-by: Jason Gunthorpe Reviewed-by: Nicolin Chen Link: https://lore.kernel.org/r/2-v2-318ed5f6983b+198f-smmuv3_tidy_jgg@nvidia.com Signed-off-by: Will Deacon --- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 13 ++++++------- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 --- 2 files changed, 6 insertions(+), 10 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 bb2d9b0c0f634..fbb7eb152d82f 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c @@ -1448,13 +1448,12 @@ static void arm_smmu_free_cd_tables(struct arm_smmu_master *master) } /* Stream table manipulation functions */ -static void -arm_smmu_write_strtab_l1_desc(__le64 *dst, struct arm_smmu_strtab_l1_desc *desc) +static void arm_smmu_write_strtab_l1_desc(__le64 *dst, dma_addr_t l2ptr_dma) { u64 val = 0; - val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, desc->span); - val |= desc->l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK; + val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, STRTAB_SPLIT + 1); + val |= l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK; /* The HW has 64 bit atomicity with stores to the L2 STE table */ WRITE_ONCE(*dst, cpu_to_le64(val)); @@ -1663,6 +1662,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid) { size_t size; void *strtab; + dma_addr_t l2ptr_dma; struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg; struct arm_smmu_strtab_l1_desc *desc = &cfg->l1_desc[sid >> STRTAB_SPLIT]; @@ -1672,8 +1672,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid) size = 1 << (STRTAB_SPLIT + ilog2(STRTAB_STE_DWORDS) + 3); strtab = &cfg->strtab[(sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS]; - desc->span = STRTAB_SPLIT + 1; - desc->l2ptr = dmam_alloc_coherent(smmu->dev, size, &desc->l2ptr_dma, + desc->l2ptr = dmam_alloc_coherent(smmu->dev, size, &l2ptr_dma, GFP_KERNEL); if (!desc->l2ptr) { dev_err(smmu->dev, @@ -1683,7 +1682,7 @@ static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid) } arm_smmu_init_initial_stes(desc->l2ptr, 1 << STRTAB_SPLIT); - arm_smmu_write_strtab_l1_desc(strtab, desc); + arm_smmu_write_strtab_l1_desc(strtab, l2ptr_dma); return 0; } diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h index 91ec2d49ecbf2..a05e02d6afd1d 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -579,10 +579,7 @@ struct arm_smmu_priq { /* High-level stream table and context descriptor structures */ struct arm_smmu_strtab_l1_desc { - u8 span; - struct arm_smmu_ste *l2ptr; - dma_addr_t l2ptr_dma; }; struct arm_smmu_ctx_desc {