linux-kernel - [PATCH v5 3/5] iommu/io-pgtable-arm: add support for non-strict mode

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Date:   Wed, 15 Aug 2018 09:28:28 +0800
From:   Zhen Lei <thunder.leizhen@...wei.com>
To:     Robin Murphy <robin.murphy@....com>,
        Will Deacon <will.deacon@....com>,
        Joerg Roedel <joro@...tes.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        iommu <iommu@...ts.linux-foundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Zhen Lei <thunder.leizhen@...wei.com>,
        LinuxArm <linuxarm@...wei.com>,
        Hanjun Guo <guohanjun@...wei.com>,
        Libin <huawei.libin@...wei.com>,
        "John Garry" <john.garry@...wei.com>
Subject: [PATCH v5 3/5] iommu/io-pgtable-arm: add support for non-strict mode

To support the non-strict mode, now we only tlbi and sync for the strict
mode. But for the non-leaf case, always follow strict mode.

Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
---
 drivers/iommu/io-pgtable-arm.c | 20 ++++++++++++++------
 drivers/iommu/io-pgtable.h     |  3 +++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 010a254..20d3e98 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -538,6 +538,7 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 	phys_addr_t blk_paddr;
 	size_t tablesz = ARM_LPAE_GRANULE(data);
 	size_t split_sz = ARM_LPAE_BLOCK_SIZE(lvl, data);
+	size_t unmapped = size;
 	int i, unmap_idx = -1;

 	if (WARN_ON(lvl == ARM_LPAE_MAX_LEVELS))
@@ -575,11 +576,16 @@ static size_t arm_lpae_split_blk_unmap(struct arm_lpae_io_pgtable *data,
 		tablep = iopte_deref(pte, data);
 	}

-	if (unmap_idx < 0)
-		return __arm_lpae_unmap(data, iova, size, lvl, tablep);
+	if (unmap_idx < 0) {
+		unmapped = __arm_lpae_unmap(data, iova, size, lvl, tablep);
+		if (!(data->iop.cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT))
+			return unmapped;
+	}

 	io_pgtable_tlb_add_flush(&data->iop, iova, size, size, true);
-	return size;
+	io_pgtable_tlb_sync(&data->iop);
+
+	return unmapped;
 }

 static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
@@ -609,7 +615,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
 			io_pgtable_tlb_sync(iop);
 			ptep = iopte_deref(pte, data);
 			__arm_lpae_free_pgtable(data, lvl + 1, ptep);
-		} else {
+		} else if (!(iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT)) {
 			io_pgtable_tlb_add_flush(iop, iova, size, size, true);
 		}

@@ -771,7 +777,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
 	u64 reg;
 	struct arm_lpae_io_pgtable *data;

-	if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA))
+	if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA |
+			IO_PGTABLE_QUIRK_NON_STRICT))
 		return NULL;

 	data = arm_lpae_alloc_pgtable(cfg);
@@ -863,7 +870,8 @@ static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
 	struct arm_lpae_io_pgtable *data;

 	/* The NS quirk doesn't apply at stage 2 */
-	if (cfg->quirks & ~IO_PGTABLE_QUIRK_NO_DMA)
+	if (cfg->quirks & ~(IO_PGTABLE_QUIRK_NO_DMA |
+		IO_PGTABLE_QUIRK_NON_STRICT))
 		return NULL;

 	data = arm_lpae_alloc_pgtable(cfg);
diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
index 2df7909..beb14a3 100644
--- a/drivers/iommu/io-pgtable.h
+++ b/drivers/iommu/io-pgtable.h
@@ -71,12 +71,15 @@ struct io_pgtable_cfg {
 	 *	be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
 	 *	software-emulated IOMMU), such that pagetable updates need not
 	 *	be treated as explicit DMA data.
+	 * IO_PGTABLE_QUIRK_NON_STRICT: Put off TLBs invalidation and release
+	 *	memory first.
 	 */
 	#define IO_PGTABLE_QUIRK_ARM_NS		BIT(0)
 	#define IO_PGTABLE_QUIRK_NO_PERMS	BIT(1)
 	#define IO_PGTABLE_QUIRK_TLBI_ON_MAP	BIT(2)
 	#define IO_PGTABLE_QUIRK_ARM_MTK_4GB	BIT(3)
 	#define IO_PGTABLE_QUIRK_NO_DMA		BIT(4)
+	#define IO_PGTABLE_QUIRK_NON_STRICT	BIT(5)
 	unsigned long			quirks;
 	unsigned long			pgsize_bitmap;
 	unsigned int			ias;
--
1.8.3