[PATCH AUTOSEL 5.7 227/388] iommu/arm-smmu-v3: Don't reserve implementation defined register space

Sasha Levin
2020-06-18T02:39:37Z

From: Jean-Philippe Brucker <jean-philippe@linaro.org>

[ Upstream commit 52f3fab0067d6fa9e99c1b7f63265dd48ca76046 ]

Some SMMUv3 implementation embed the Perf Monitor Group Registers (PMCG)
inside the first 64kB region of the SMMU. Since PMCG are managed by a
separate driver, this layout causes resource reservation conflicts
during boot.

To avoid this conflict, don't reserve the MMIO regions that are
implementation defined. Although devm_ioremap_resource() still works on
full pages under the hood, this way we benefit from resource conflict
checks.

Fixes: 7d839b4b9e00 ("perf/smmuv3: Add arm64 smmuv3 pmu driver")
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20200513110255.597203-1-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/arm-smmu-v3.c | 35 +++++++++++++++++++++++++++++++----
1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 82508730feb7..af21d24a09e8 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -171,6 +171,8 @@
#define ARM_SMMU_PRIQ_IRQ_CFG1 0xd8
#define ARM_SMMU_PRIQ_IRQ_CFG2 0xdc

+#define ARM_SMMU_REG_SZ 0xe00
+
/* Common MSI config fields */
#define MSI_CFG0_ADDR_MASK GENMASK_ULL(51, 2)
#define MSI_CFG2_SH GENMASK(5, 4)
@@ -628,6 +630,7 @@ struct arm_smmu_strtab_cfg {
struct arm_smmu_device {
struct device *dev;
void __iomem *base;
+ void __iomem *page1;

#define ARM_SMMU_FEAT_2_LVL_STRTAB (1 << 0)
#define ARM_SMMU_FEAT_2_LVL_CDTAB (1 << 1)
@@ -733,9 +736,8 @@ static struct arm_smmu_option_prop arm_smmu_options[] = {
static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset,
struct arm_smmu_device *smmu)
{
- if ((offset > SZ_64K) &&
- (smmu->options & ARM_SMMU_OPT_PAGE0_REGS_ONLY))
- offset -= SZ_64K;
+ if (offset > SZ_64K)
+ return smmu->page1 + offset - SZ_64K;

return smmu->base + offset;
}
@@ -4021,6 +4023,18 @@ err_reset_pci_ops: __maybe_unused;
return err;
}

+static void __iomem *arm_smmu_ioremap(struct device *dev, resource_size_t start,
+ resource_size_t size)
+{
+ struct resource res = {
+ .flags = IORESOURCE_MEM,
+ .start = start,
+ .end = start + size - 1,
+ };
+
+ return devm_ioremap_resource(dev, &res);
+}
+
static int arm_smmu_device_probe(struct platform_device *pdev)
{
int irq, ret;
@@ -4056,10 +4070,23 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
}
ioaddr = res->start;

- smmu->base = devm_ioremap_resource(dev, res);
+ /*
+ * Don't map the IMPLEMENTATION DEFINED regions, since they may contain
+ * the PMCG registers which are reserved by the PMU driver.
+ */
+ smmu->base = arm_smmu_ioremap(dev, ioaddr, ARM_SMMU_REG_SZ);
if (IS_ERR(smmu->base))
return PTR_ERR(smmu->base);

+ if (arm_smmu_resource_size(smmu) > SZ_64K) {
+ smmu->page1 = arm_smmu_ioremap(dev, ioaddr + SZ_64K,
+ ARM_SMMU_REG_SZ);
+ if (IS_ERR(smmu->page1))
+ return PTR_ERR(smmu->page1);
+ } else {
+ smmu->page1 = smmu->base;
+ }
+
/* Interrupt lines */

irq = platform_get_irq_byname_optional(pdev, "combined");
--
2.25.1