[PATCH v2 2/3] iommu/io-pgtable-arm: Add support for AARCH64 split pagetables

Jordan Crouse
2019-07-08T18:10:43Z

Add a new sub-format ARM_64_LPAE_SPLIT_S1 to create and set up split
pagetables (TTBR0 and TTBR1). The initialization function sets up the
correct va_size and sign extension bits and programs the TCR registers.
Split pagetable formats use their own own map/unmap wrappers to ensure
that the correct pagetable is selected based on the incoming iova but
most of the heavy lifting is common to the other formats.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
---

drivers/iommu/io-pgtable-arm.c | 261 +++++++++++++++++++++++++++++++++++++----
drivers/iommu/io-pgtable.c | 1 +
include/linux/io-pgtable.h | 2 +
3 files changed, 240 insertions(+), 24 deletions(-)

diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 161a7d56..aec35e5 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -118,7 +118,12 @@
#define ARM_LPAE_TCR_TG0_64K (1 << 14)
#define ARM_LPAE_TCR_TG0_16K (2 << 14)

+#define ARM_LPAE_TCR_TG1_4K (0 << 30)
+#define ARM_LPAE_TCR_TG1_64K (1 << 30)
+#define ARM_LPAE_TCR_TG1_16K (2 << 30)
+
#define ARM_LPAE_TCR_SH0_SHIFT 12
+#define ARM_LPAE_TCR_SH1_SHIFT 28
#define ARM_LPAE_TCR_SH0_MASK 0x3
#define ARM_LPAE_TCR_SH_NS 0
#define ARM_LPAE_TCR_SH_OS 2
@@ -126,6 +131,8 @@

#define ARM_LPAE_TCR_ORGN0_SHIFT 10
#define ARM_LPAE_TCR_IRGN0_SHIFT 8
+#define ARM_LPAE_TCR_ORGN1_SHIFT 26
+#define ARM_LPAE_TCR_IRGN1_SHIFT 24
#define ARM_LPAE_TCR_RGN_MASK 0x3
#define ARM_LPAE_TCR_RGN_NC 0
#define ARM_LPAE_TCR_RGN_WBWA 1
@@ -136,6 +143,7 @@
#define ARM_LPAE_TCR_SL0_MASK 0x3

#define ARM_LPAE_TCR_T0SZ_SHIFT 0
+#define ARM_LPAE_TCR_T1SZ_SHIFT 16
#define ARM_LPAE_TCR_SZ_MASK 0xf

#define ARM_LPAE_TCR_PS_SHIFT 16
@@ -152,6 +160,14 @@
#define ARM_LPAE_TCR_PS_48_BIT 0x5ULL
#define ARM_LPAE_TCR_PS_52_BIT 0x6ULL

+#define ARM_LPAE_TCR_SEP_SHIFT 47
+#define ARM_LPAE_TCR_SEP_31 (0x0ULL << ARM_LPAE_TCR_SEP_SHIFT)
+#define ARM_LPAE_TCR_SEP_35 (0x1ULL << ARM_LPAE_TCR_SEP_SHIFT)
+#define ARM_LPAE_TCR_SEP_39 (0x2ULL << ARM_LPAE_TCR_SEP_SHIFT)
+#define ARM_LPAE_TCR_SEP_41 (0x3ULL << ARM_LPAE_TCR_SEP_SHIFT)
+#define ARM_LPAE_TCR_SEP_43 (0x4ULL << ARM_LPAE_TCR_SEP_SHIFT)
+#define ARM_LPAE_TCR_SEP_UPSTREAM (0x7ULL << ARM_LPAE_TCR_SEP_SHIFT)
+
#define ARM_LPAE_MAIR_ATTR_SHIFT(n) ((n) << 3)
#define ARM_LPAE_MAIR_ATTR_MASK 0xff
#define ARM_LPAE_MAIR_ATTR_DEVICE 0x04
@@ -179,11 +195,12 @@ struct arm_lpae_io_pgtable {
struct io_pgtable iop;

int levels;
+ u32 sep;
size_t pgd_size;
unsigned long pg_shift;
unsigned long bits_per_level;

- void *pgd;
+ void *pgd[2];
};

typedef u64 arm_lpae_iopte;
@@ -426,7 +443,8 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
arm_lpae_iopte pte;

if (data->iop.fmt == ARM_64_LPAE_S1 ||
- data->iop.fmt == ARM_32_LPAE_S1) {
+ data->iop.fmt == ARM_32_LPAE_S1 ||
+ data->iop.fmt == ARM_64_LPAE_SPLIT_S1) {
pte = ARM_LPAE_PTE_nG;
if (!(prot & IOMMU_WRITE) && (prot & IOMMU_READ))
pte |= ARM_LPAE_PTE_AP_RDONLY;
@@ -470,11 +488,10 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
return pte;
}

-static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
- phys_addr_t paddr, size_t size, int iommu_prot)
+static int _arm_lpae_map(struct arm_lpae_io_pgtable *data, unsigned long iova,
+ phys_addr_t paddr, size_t size, int iommu_prot,
+ arm_lpae_iopte *ptep)
{
- struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
- arm_lpae_iopte *ptep = data->pgd;
int ret, lvl = ARM_LPAE_START_LVL(data);
arm_lpae_iopte prot;

@@ -497,12 +514,39 @@ static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
return ret;
}

+static int arm_lpae_split_map(struct io_pgtable_ops *ops, unsigned long iova,
+ phys_addr_t paddr, size_t size, int iommu_prot)
+{
+ struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+ unsigned long mask = 1UL << data->sep;
+ arm_lpae_iopte *ptep;
+
+ if (iova & mask) {
+ ptep = data->pgd[1];
+ iova &= (mask - 1);
+ } else
+ ptep = data->pgd[0];
+
+ return _arm_lpae_map(data, iova, paddr, size, iommu_prot, ptep);
+}
+
+static int arm_lpae_map(struct io_pgtable_ops *ops, unsigned long iova,
+ phys_addr_t paddr, size_t size, int iommu_prot)
+{
+ struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+
+ return _arm_lpae_map(data, iova, paddr, size, iommu_prot, data->pgd[0]);
+}
+
static void __arm_lpae_free_pgtable(struct arm_lpae_io_pgtable *data, int lvl,
arm_lpae_iopte *ptep)
{
arm_lpae_iopte *start, *end;
unsigned long table_size;

+ if (!ptep)
+ return;
+
if (lvl == ARM_LPAE_START_LVL(data))
table_size = data->pgd_size;
else
@@ -532,7 +576,8 @@ static void arm_lpae_free_pgtable(struct io_pgtable *iop)
{
struct arm_lpae_io_pgtable *data = io_pgtable_to_data(iop);

- __arm_lpae_free_pgtable(data, ARM_LPAE_START_LVL(data), data->pgd);
+ __arm_lpae_free_pgtable(data, ARM_LPAE_START_LVL(data), data->pgd[0]);
+ __arm_lpae_free_pgtable(data, ARM_LPAE_START_LVL(data), data->pgd[1]);
kfree(data);
}

@@ -643,11 +688,28 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
return __arm_lpae_unmap(data, iova, size, lvl + 1, ptep);
}

+static size_t arm_lpae_split_unmap(struct io_pgtable_ops *ops,
+ unsigned long iova, size_t size)
+{
+ struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+ unsigned long mask = 1UL << data->sep;
+ arm_lpae_iopte *ptep;
+ int lvl = ARM_LPAE_START_LVL(data);
+
+ if (iova & mask) {
+ ptep = data->pgd[1];
+ iova &= (mask - 1);
+ } else
+ ptep = data->pgd[0];
+
+ return __arm_lpae_unmap(data, iova, size, lvl, ptep);
+}
+
static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
size_t size)
{
struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
- arm_lpae_iopte *ptep = data->pgd;
+ arm_lpae_iopte *ptep = data->pgd[0];
int lvl = ARM_LPAE_START_LVL(data);

if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
@@ -656,11 +718,11 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops, unsigned long iova,
return __arm_lpae_unmap(data, iova, size, lvl, ptep);
}

-static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
- unsigned long iova)
+static phys_addr_t _arm_lpae_iova_to_phys(struct arm_lpae_io_pgtable *data,
+ unsigned long iova,
+ arm_lpae_iopte *ptep)
{
- struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
- arm_lpae_iopte pte, *ptep = data->pgd;
+ arm_lpae_iopte pte;
int lvl = ARM_LPAE_START_LVL(data);

do {
@@ -692,6 +754,31 @@ static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
return iopte_to_paddr(pte, data) | iova;
}

+
+static phys_addr_t arm_lpae_split_iova_to_phys(struct io_pgtable_ops *ops,
+ unsigned long iova)
+{
+ struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+ unsigned long mask = 1UL << data->sep;
+ arm_lpae_iopte *ptep;
+
+ if (iova & mask) {
+ ptep = data->pgd[1];
+ iova &= (mask - 1);
+ } else
+ ptep = data->pgd[0];
+
+ return _arm_lpae_iova_to_phys(data, iova, ptep);
+}
+
+static phys_addr_t arm_lpae_iova_to_phys(struct io_pgtable_ops *ops,
+ unsigned long iova)
+{
+ struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
+
+ return _arm_lpae_iova_to_phys(data, iova, data->pgd[0]);
+}
+
static void arm_lpae_restrict_pgsizes(struct io_pgtable_cfg *cfg)
{
unsigned long granule, page_sizes;
@@ -771,6 +858,9 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
pgd_bits = va_bits - (data->bits_per_level * (data->levels - 1));
data->pgd_size = 1UL << (pgd_bits + ilog2(sizeof(arm_lpae_iopte)));

+ data->pgd[0] = NULL;
+ data->pgd[1] = NULL;
+
data->iop.ops = (struct io_pgtable_ops) {
.map = arm_lpae_map,
.unmap = arm_lpae_unmap,
@@ -780,8 +870,8 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
return data;
}

-static struct io_pgtable *
-arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
+static struct arm_lpae_io_pgtable *
+_arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg)
{
u64 reg;
struct arm_lpae_io_pgtable *data;
@@ -845,8 +935,6 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)

reg |= (64ULL - cfg->ias) << ARM_LPAE_TCR_T0SZ_SHIFT;

- /* Disable speculative walks through TTBR1 */
- reg |= ARM_LPAE_TCR_EPD1;
cfg->arm_lpae_s1_cfg.tcr = reg;

/* MAIRs */
@@ -863,24 +951,143 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
cfg->arm_lpae_s1_cfg.mair[1] = 0;

/* Looking good; allocate a pgd */
- data->pgd = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
- if (!data->pgd)
+ data->pgd[0] = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
+ if (!data->pgd[0])
goto out_free_data;

/* Ensure the empty pgd is visible before any actual TTBR write */
wmb();

/* TTBRs */
- cfg->arm_lpae_s1_cfg.ttbr[0] = virt_to_phys(data->pgd);
+ cfg->arm_lpae_s1_cfg.ttbr[0] = virt_to_phys(data->pgd[0]);
cfg->arm_lpae_s1_cfg.ttbr[1] = 0;
+ return data;
+
+out_free_data:
+ kfree(data);
+ return NULL;
+}
+
+
+/* Allocate split pagetables */
+static struct io_pgtable *
+arm_64_lpae_alloc_pgtable_split_s1(struct io_pgtable_cfg *cfg, void *cookie)
+{
+ u64 reg;
+ struct arm_lpae_io_pgtable *data;
+ u32 sep;
+
+ /* Figure out what the sign extension bit should be */
+ switch (cfg->ias) {
+ case 32:
+ case 36:
+ case 40:
+ case 42:
+ case 44:
+ sep = cfg->ias - 1;
+ /* Adjust the address size to account for the extension bit */
+ cfg->ias--;
+ break;
+ case 48:
+ /* IAS of 48 is a special case, it has a dedicated bit */
+ sep = 48;
+ break;
+ default:
+ return NULL;
+ }
+
+ data = _arm_64_lpae_alloc_pgtable_s1(cfg);
+ if (!data)
+ return NULL;
+
+ /* Add the TTBR1 settings */
+ reg = cfg->arm_lpae_s1_cfg.tcr;
+
+ /* TCR */
+ reg |= (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH1_SHIFT) |
+ (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN1_SHIFT) |
+ (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN1_SHIFT);
+
+ switch (ARM_LPAE_GRANULE(data)) {
+ case SZ_4K:
+ reg |= ARM_LPAE_TCR_TG1_4K;
+ break;
+ case SZ_16K:
+ reg |= ARM_LPAE_TCR_TG1_16K;
+ break;
+ case SZ_64K:
+ reg |= ARM_LPAE_TCR_TG1_64K;
+ break;
+ }
+
+ reg |= (64ULL - cfg->ias) << ARM_LPAE_TCR_T1SZ_SHIFT;
+
+ switch (sep) {
+ case 31:
+ reg |= ARM_LPAE_TCR_SEP_31;
+ break;
+ case 35:
+ reg |= ARM_LPAE_TCR_SEP_35;
+ break;
+ case 39:
+ reg |= ARM_LPAE_TCR_SEP_39;
+ break;
+ case 41:
+ reg |= ARM_LPAE_TCR_SEP_41;
+ break;
+ case 43:
+ reg |= ARM_LPAE_TCR_SEP_43;
+ break;
+ case 48:
+ reg |= ARM_LPAE_TCR_SEP_UPSTREAM;
+ break;
+ }
+
+ cfg->arm_lpae_s1_cfg.tcr = reg;
+
+ /* Allocate the TTBR1 pagetable */
+ data->pgd[1] = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
+ if (!data->pgd[1])
+ goto out_free_data;
+
+ /* Override the data ops with split table specific ops */
+ data->iop.ops = (struct io_pgtable_ops) {
+ .map = arm_lpae_split_map,
+ .unmap = arm_lpae_split_unmap,
+ .iova_to_phys = arm_lpae_split_iova_to_phys,
+ };
+
+ /*
+ * remember the sign extension bit, we'll need it later to figure out
+ * which pagetable to use
+ */
+ data->sep = sep;
+
+ /* Ensure the empty pgd is visible before any actual TTBR write */
+ wmb();
+
+ cfg->arm_lpae_s1_cfg.ttbr[1] = virt_to_phys(data->pgd[1]);
return &data->iop;

out_free_data:
+ __arm_lpae_free_pages(data->pgd[0], data->pgd_size, cfg);
kfree(data);
return NULL;
}

static struct io_pgtable *
+arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
+{
+ struct arm_lpae_io_pgtable *data;
+
+ data = _arm_64_lpae_alloc_pgtable_s1(cfg);
+ if (!data)
+ return NULL;
+
+ return &data->iop;
+}
+
+static struct io_pgtable *
arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
{
u64 reg, sl;
@@ -960,15 +1167,15 @@ arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
cfg->arm_lpae_s2_cfg.vtcr = reg;

/* Allocate pgd pages */
- data->pgd = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
- if (!data->pgd)
+ data->pgd[0] = __arm_lpae_alloc_pages(data->pgd_size, GFP_KERNEL, cfg);
+ if (!data->pgd[0])
goto out_free_data;

/* Ensure the empty pgd is visible before any actual TTBR write */
wmb();

/* VTTBR */
- cfg->arm_lpae_s2_cfg.vttbr = virt_to_phys(data->pgd);
+ cfg->arm_lpae_s2_cfg.vttbr = virt_to_phys(data->pgd[0]);
return &data->iop;

out_free_data:
@@ -1041,6 +1248,11 @@ struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns = {
.free = arm_lpae_free_pgtable,
};

+struct io_pgtable_init_fns io_pgtable_arm_64_lpae_split_s1_init_fns = {
+ .alloc = arm_64_lpae_alloc_pgtable_split_s1,
+ .free = arm_lpae_free_pgtable,
+};
+
struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s2_init_fns = {
.alloc = arm_64_lpae_alloc_pgtable_s2,
.free = arm_lpae_free_pgtable,
@@ -1095,9 +1307,9 @@ static void __init arm_lpae_dump_ops(struct io_pgtable_ops *ops)

pr_err("cfg: pgsize_bitmap 0x%lx, ias %u-bit\n",
cfg->pgsize_bitmap, cfg->ias);
- pr_err("data: %d levels, 0x%zx pgd_size, %lu pg_shift, %lu bits_per_level, pgd @ %p\n",
+ pr_err("data: %d levels, 0x%zx pgd_size, %lu pg_shift, %lu bits_per_level, pgd @ %p %p\n",
data->levels, data->pgd_size, data->pg_shift,
- data->bits_per_level, data->pgd);
+ data->bits_per_level, data->pgd[0], data->pgd[1]);
}

#define __FAIL(ops, i) ({ \
@@ -1112,6 +1324,7 @@ static int __init arm_lpae_run_tests(struct io_pgtable_cfg *cfg)
static const enum io_pgtable_fmt fmts[] = {
ARM_64_LPAE_S1,
ARM_64_LPAE_S2,
+ ARM_64_LPAE_SPLIT_S1,
};

int i, j;
diff --git a/drivers/iommu/io-pgtable.c b/drivers/iommu/io-pgtable.c
index ced53e5..ed1985f 100644
--- a/drivers/iommu/io-pgtable.c
+++ b/drivers/iommu/io-pgtable.c
@@ -20,6 +20,7 @@ io_pgtable_init_table[IO_PGTABLE_NUM_FMTS] = {
[ARM_64_LPAE_S1] = &io_pgtable_arm_64_lpae_s1_init_fns,
[ARM_64_LPAE_S2] = &io_pgtable_arm_64_lpae_s2_init_fns,
[ARM_MALI_LPAE] = &io_pgtable_arm_mali_lpae_init_fns,
+ [ARM_64_LPAE_SPLIT_S1] = &io_pgtable_arm_64_lpae_split_s1_init_fns,
#endif
#ifdef CONFIG_IOMMU_IO_PGTABLE_ARMV7S
[ARM_V7S] = &io_pgtable_arm_v7s_init_fns,
diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index b5a450a..2ed0e6a 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -10,6 +10,7 @@ enum io_pgtable_fmt {
ARM_32_LPAE_S1,
ARM_32_LPAE_S2,
ARM_64_LPAE_S1,
+ ARM_64_LPAE_SPLIT_S1,
ARM_64_LPAE_S2,
ARM_V7S,
ARM_MALI_LPAE,
@@ -211,6 +212,7 @@ extern struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s1_init_fns;
extern struct io_pgtable_init_fns io_pgtable_arm_32_lpae_s2_init_fns;
extern struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s1_init_fns;
extern struct io_pgtable_init_fns io_pgtable_arm_64_lpae_s2_init_fns;
+extern struct io_pgtable_init_fns io_pgtable_arm_64_lpae_split_s1_init_fns;
extern struct io_pgtable_init_fns io_pgtable_arm_v7s_init_fns;
extern struct io_pgtable_init_fns io_pgtable_arm_mali_lpae_init_fns;

--
2.7.4