spec: scalar: es wording and oeprating mode fixes

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	modified:   riscv-crypto-scalar-entropy-source.adoc

doc/scalar/riscv-crypto-scalar-entropy-source.adoc

@@ -16,9 +16,9 @@ See <<crypto_scalar_appx_es>> for a non-normative description of a
 certification and self-certification procedures, design rationale, and more detailed suggestions on how the entropy source output can be used.
 
 [[crypto_scalar_seed_csr]]
-=== the seed CSR
+=== The seed CSR
 
-The `seed` CSR is located at address `0x015`. 
+`seed` is a user mode CSR located at address `0x015`. 
 The 32-bit contents of `seed` are as follows:
 
 [%autowidth.stretch,cols="^,^,<",options="header",]
@@ -38,8 +38,10 @@ The 32-bit contents of `seed` are as follows:
 The `seed` CSR must be accessed with a read-write instruction. A read-only
 instruction such as `CSRRS/CSRRC` with `rs1=x0` or `CSRRSI/CSRRCI` with
 `uimm=0` will raise an illegal instruction exception.
-The write value (in `rs1` or `uimm`) should be ignored by implementations.
-Its purpose is to merely signal polling and flushing.
+The write value (in `rs1` or `uimm`) must be ignored by implementations.
+Its purpose is to signal polling and flushing, and avoid introducing
+side effects (i.e. wipe-on-read, described below) due to a CSR read into the
+architecture.
 
 The instruction `csrrw rd, seed, x0` can be used for fetching seed status
 and entropy values. It is available on both RV32 and RV64 base architectures
@@ -262,22 +264,22 @@ other non-`M` modes will raise an Illegal Instruction Exception.
 CSR read-write instruction. Attempted read without a write raises an
 Illegal Instruction Exception regardless of mode access control bits).
 
-| `S/HS`
+| `S/HS/VS`
 | `0`
 | `*`
 | Any `seed` CSR access raises an Illegal Instruction Exception.
 
-| `S/HS`
+| `S/HS/VS`
 | `1`
 | `*`
 | The `seed` CSR is accessible as normal. No exception is raised for read-write.
 
-| `U/HU`
+| `U/VU`
 | `*`
 | `0`
 | Any `seed` CSR access raises an Illegal Instruction Exception.
 
-| `U/HU`
+| `U/VU`
 | `*`
 | `1`
 | The `seed` CSR is accessible as normal. No exception is raised for read-write.