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iommu/arm-smmu-qcom: Avoid disabling secured context banks

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Some Qualcomm SoCs' TZ/hypervisor configuration is disallowing the
disablement of some context banks, being them used for tzapps and/or
remote processors; any attempt to disable such CBs will result in
triggering a fault and the system will freeze and/or reset.

For this reason, get a list of context banks that should never get
disabled during smmu initialization through a DT array property
`qcom,reset-nodisable-cbs`.
It was chosen to not hardcode the CBs as this is dependant on the
SoC's firmware, which may vary on different boards.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
This commit is contained in:
AngeloGioacchino Del Regno 2021-08-06 13:19:14 +02:00 • committed by Jami Kettunen
parent 67c90625b8
commit 0af29df528
1 changed files with 32 additions and 0 deletions
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32
drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
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@ -5,6 +5,7 @@
#include <linux/acpi.h>
#include <linux/adreno-smmu-priv.h>
#include <linux/bitmap.h>
#include <linux/of_device.h>
#include <linux/qcom_scm.h>
@ -12,6 +13,7 @@
struct qcom_smmu {
struct arm_smmu_device smmu;
DECLARE_BITMAP(reset_cb_nodisable_mask, ARM_SMMU_MAX_CBS);
bool bypass_quirk;
u8 bypass_cbndx;
u32 stall_enabled;
@ -369,11 +371,20 @@ static int qcom_smmu500_reset(struct arm_smmu_device *smmu)
return 0;
}
static bool qcom_smmu500_reset_cb_nodisable(struct arm_smmu_device *smmu,
int cbndx)
{
struct qcom_smmu *qsmmu = to_qcom_smmu(smmu);
return test_bit(cbndx, qsmmu->reset_cb_nodisable_mask);
}
static const struct arm_smmu_impl qcom_smmu_impl = {
.init_context = qcom_smmu_init_context,
.cfg_probe = qcom_smmu_cfg_probe,
.def_domain_type = qcom_smmu_def_domain_type,
.reset = qcom_smmu500_reset,
.reset_cb_nodisable = qcom_smmu500_reset_cb_nodisable,
.write_s2cr = qcom_smmu_write_s2cr,
};
@ -381,6 +392,7 @@ static const struct arm_smmu_impl qcom_adreno_smmu_impl = {
.init_context = qcom_adreno_smmu_init_context,
.def_domain_type = qcom_smmu_def_domain_type,
.reset = qcom_smmu500_reset,
.reset_cb_nodisable = qcom_smmu500_reset_cb_nodisable,
.alloc_context_bank = qcom_adreno_smmu_alloc_context_bank,
.write_sctlr = qcom_adreno_smmu_write_sctlr,
};
@ -390,6 +402,8 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
{
const struct device_node *np = smmu->dev->of_node;
struct qcom_smmu *qsmmu;
u8 reset_nodisable_cbs[ARM_SMMU_MAX_CBS];
int i, sz;
/* Check to make sure qcom_scm has finished probing */
if (!qcom_scm_is_available())
@ -401,6 +415,7 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
qsmmu->smmu.impl = impl;
qsmmu->bypass_cbndx = 0xff;
bitmap_zero(qsmmu->reset_cb_nodisable_mask, ARM_SMMU_MAX_CBS);
if (np != NULL) {
/*
@ -409,6 +424,23 @@ static struct arm_smmu_device *qcom_smmu_create(struct arm_smmu_device *smmu,
* - We are booting on ACPI
*/
of_property_read_u8(np, "qcom,bypass-cbndx", &qsmmu->bypass_cbndx);
/*
* Some context banks may not be disabled because they are
* secured: read from DT a list of secured contexts that cannot
* be disabled without crashing the system.
* This list is optional, as not all firmware configurations do
* require us skipping disablement of context banks.
*/
sz = of_property_read_variable_u8_array(np, "qcom,reset-nodisable-cbs",
reset_nodisable_cbs,
1, ARM_SMMU_MAX_CBS);
if (sz > 0) {
for (i = 0; i < sz; i++) {
__set_bit(reset_nodisable_cbs[i],
qsmmu->reset_cb_nodisable_mask);
}
}
}
return &qsmmu->smmu;