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| author | Peter Maydell <peter.maydell@linaro.org> | 2022-05-09 16:54:57 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2022-05-19 16:19:02 +0100 |
| commit | 75662f36e3d11b986456210670719a7837111cd7 (patch) | |
| tree | c14c771deb155975118d95194173e70a197489ec /docs/system | |
| parent | e04bf5a793ee5e7afdda8a1d1af08888fd67a989 (diff) | |
target/arm: Implement FEAT_IDST
The Armv8.4 feature FEAT_IDST specifies that exceptions generated by
read accesses to the feature ID space should report a syndrome code
of 0x18 (EC_SYSTEMREGISTERTRAP) rather than 0x00 (EC_UNCATEGORIZED).
The feature ID space is defined to be:
op0 == 3, op1 == {0,1,3}, CRn == 0, CRm == {0-7}, op2 == {0-7}
In our implementation we might return the EC_UNCATEGORIZED syndrome
value for a system register access in four cases:
* no reginfo struct in the hashtable
* cp_access_ok() fails (ie ri->access doesn't permit the access)
* ri->accessfn returns CP_ACCESS_TRAP_UNCATEGORIZED at runtime
* ri->type includes ARM_CP_RAISES_EXC, and the readfn raises
an UNDEF exception at runtime
We have very few regdefs that set ARM_CP_RAISES_EXC, and none of
them are in the feature ID space. (In the unlikely event that any
are added in future they would need to take care of setting the
correct syndrome themselves.) This patch deals with the other
three cases, and enables FEAT_IDST for AArch64 -cpu max.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220509155457.3560724-1-peter.maydell@linaro.org
Diffstat (limited to 'docs/system')
| -rw-r--r-- | docs/system/arm/emulation.rst | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst index 8f25502ced..3e95bba0d2 100644 --- a/docs/system/arm/emulation.rst +++ b/docs/system/arm/emulation.rst @@ -31,6 +31,7 @@ the following architecture extensions: - FEAT_FlagM2 (Enhancements to flag manipulation instructions) - FEAT_HPDS (Hierarchical permission disables) - FEAT_I8MM (AArch64 Int8 matrix multiplication instructions) +- FEAT_IDST (ID space trap handling) - FEAT_IESB (Implicit error synchronization event) - FEAT_JSCVT (JavaScript conversion instructions) - FEAT_LOR (Limited ordering regions) |