diff options
| author | Daniel Mentz <[email protected]> | 2024-10-01 18:53:57 -0700 |
|---|---|---|
| committer | Will Deacon <[email protected]> | 2024-10-08 18:37:48 +0100 |
| commit | f63237f54cf18448728201a65e6c82018e807cd9 (patch) | |
| tree | f58b345b48d037b3d37515f3725e6548f7b0fa8c /tools/testing/selftests/bpf/prog_tests/autoload.c | |
| parent | 0dfe314cdd0d378f96bb9c6bdc05c8120f48606d (diff) | |
iommu/arm-smmu-v3: Fix last_sid_idx calculation for sid_bits==32
The function arm_smmu_init_strtab_2lvl uses the expression
((1 << smmu->sid_bits) - 1)
to calculate the largest StreamID value. However, this fails for the
maximum allowed value of SMMU_IDR1.SIDSIZE which is 32. The C standard
states:
"If the value of the right operand is negative or is greater than or
equal to the width of the promoted left operand, the behavior is
undefined."
With smmu->sid_bits being 32, the prerequisites for undefined behavior
are met. We observed that the value of (1 << 32) is 1 and not 0 as we
initially expected.
Similar bit shift operations in arm_smmu_init_strtab_linear seem to not
be affected, because it appears to be unlikely for an SMMU to have
SMMU_IDR1.SIDSIZE set to 32 but then not support 2-level Stream tables
This issue was found by Ryan Huang <[email protected]> on our team.
Fixes: ce410410f1a7 ("iommu/arm-smmu-v3: Add arm_smmu_strtab_l1/2_idx()")
Signed-off-by: Daniel Mentz <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>
Diffstat (limited to 'tools/testing/selftests/bpf/prog_tests/autoload.c')
0 files changed, 0 insertions, 0 deletions