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Commit 9cff86fd authored by Yisheng Xie's avatar Yisheng Xie Committed by Will Deacon
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iommu/arm-smmu-v3: Avoid ILLEGAL setting of STE.S1STALLD and CD.S 



According to Spec, it is ILLEGAL to set STE.S1STALLD if STALL_MODEL
is not 0b00, which means we should not disable stall mode if stall
or terminate mode is not configuable.

Meanwhile, it is also ILLEGAL when STALL_MODEL==0b10 && CD.S==0 which
means if stall mode is force we should always set CD.S.

As Jean-Philippe's suggestion, this patch introduce a feature bit
ARM_SMMU_FEAT_STALL_FORCE, which means smmu only supports stall force.
Therefore, we can avoid the ILLEGAL setting of STE.S1STALLD.by checking
ARM_SMMU_FEAT_STALL_FORCE.

This patch keeps the ARM_SMMU_FEAT_STALLS as the meaning of stall supported
(force or configuable) to easy to expand the future function, i.e. we can
only use ARM_SMMU_FEAT_STALLS to check whether we should register fault
handle or enable master can_stall, etc to supporte platform SVM.

The feature bit, STE.S1STALLD and CD.S setting will be like:

STALL_MODEL  FEATURE                                         S1STALLD CD.S
0b00         ARM_SMMU_FEAT_STALLS                                 0b1 0b0
0b01         !ARM_SMMU_FEAT_STALLS && !ARM_SMMU_FEAT_STALL_FORCE  0b0 0b0
0b10         ARM_SMMU_FEAT_STALLS && ARM_SMMU_FEAT_STALL_FORCE    0b0 0b1

after apply this patch.

Signed-off-by: default avatarYisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 74f55d34

drivers/iommu/arm-smmu-v3.c

+12 −3
Original line number Diff line number Diff line
@@ -316,6 +316,7 @@ 
#define ARM64_TCR_TBI0_MASK		0x1UL



#define CTXDESC_CD_0_AA64		(1UL << 41)

#define CTXDESC_CD_0_S			(1UL << 44)

#define CTXDESC_CD_0_R			(1UL << 45)

#define CTXDESC_CD_0_A			(1UL << 46)

#define CTXDESC_CD_0_ASET_SHIFT		47
@@ -595,6 +596,7 @@ struct arm_smmu_device { 
#define ARM_SMMU_FEAT_TRANS_S2		(1 << 10)

#define ARM_SMMU_FEAT_STALLS		(1 << 11)

#define ARM_SMMU_FEAT_HYP		(1 << 12)

#define ARM_SMMU_FEAT_STALL_FORCE	(1 << 13)

	u32				features;



#define ARM_SMMU_OPT_SKIP_PREFETCH	(1 << 0)
@@ -987,6 +989,11 @@ static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu, 
	      CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET_PRIVATE |

	      CTXDESC_CD_0_AA64 | (u64)cfg->cd.asid << CTXDESC_CD_0_ASID_SHIFT |

	      CTXDESC_CD_0_V;



	/* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */

	if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE)

		val |= CTXDESC_CD_0_S;



	cfg->cdptr[0] = cpu_to_le64(val);



	val = cfg->cd.ttbr & CTXDESC_CD_1_TTB0_MASK << CTXDESC_CD_1_TTB0_SHIFT;
@@ -1107,7 +1114,8 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid, 
#endif

			 STRTAB_STE_1_STRW_NSEL1 << STRTAB_STE_1_STRW_SHIFT);



		if (smmu->features & ARM_SMMU_FEAT_STALLS)

		if (smmu->features & ARM_SMMU_FEAT_STALLS &&

		   !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))

			dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);



		val |= (ste->s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK
@@ -2531,9 +2539,10 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu) 
			 coherent ? "true" : "false");



	switch (reg & IDR0_STALL_MODEL_MASK << IDR0_STALL_MODEL_SHIFT) {

	case IDR0_STALL_MODEL_STALL:

		/* Fallthrough */

	case IDR0_STALL_MODEL_FORCE:

		smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;

		/* Fallthrough */

	case IDR0_STALL_MODEL_STALL:

		smmu->features |= ARM_SMMU_FEAT_STALLS;

	}