Merge pull request #171 from ved-rivos/1026

Rename software error exception to software check exception

cfi_backward.adoc

@@ -39,7 +39,7 @@ epilogue), the function loads the link register from the regular stack and
 the shadow copy of the link register from the shadow stack. Then, the link register
 value from the regular stack and the shadow link register value from the shadow
 stack are compared.  A mismatch of the two values is indicative of a subversion
-of the return address control variable and causes a software error exception.
+of the return address control variable and causes a software check exception.
 
 The Zicfiss instructions are encoded using a subset of "May be op" instructions
 defined by the Zimop and Zcmop extensions cite:[ZIMOP]. This subset of
@@ -508,20 +508,20 @@ if (xSSE == 1)
                                # cause an SW integrity fault exception
                                # if they are not bitwise equal.
                                # Only x1 and x5 may be used as src
-       Raise software error exception
+       Raise software check exception
     else
        ssp = ssp + (XLEN/8)    # increment ssp by XLEN/8.
     endif
 endif
 ----
 
 If the value loaded from the address in `ssp` does not match the value in `rs1`,
-a software error exception (cause=18) is raised with `__x__tval` set to "shadow
-stack fault (code=3)". The software error exception caused by `SSPOPCHK`/
+a software check exception (cause=18) is raised with `__x__tval` set to "shadow
+stack fault (code=3)". The software check exception caused by `SSPOPCHK`/
 `C.SSPOPCHK` is lower in priority than a load access-fault exception.
 
 The `ssp` is incremented by `SSPOPCHK` and `C.SSPOPCHK` only if the load from
-the shadow stack completes successfully and no software error exception is
+the shadow stack completes successfully and no software check exception is
 raised.
 
 [NOTE]

cfi_forward.adoc

@@ -17,7 +17,7 @@ using indirect call and jumps, and this is referred to as forward-edge
 protection. When the Zicfilp is active, the hart tracks an expected landing pad
 (`ELP`) state that is updated by an _indirect_call_ or _indirect_jump_ to
 require a landing pad instruction at the target of the branch. If the
-instruction at the target is not a landing pad, then a software error exception
+instruction at the target is not a landing pad, then a software check exception
 is raised.
 
 A landing pad may be optionally associated with a 20-bit label. With labeling
@@ -155,7 +155,7 @@ not need to establish an expected landing pad label value in `x7`.
 When `ELP` is set to `LP_EXPECTED`, if the next instruction in the instruction
 stream is not 4-byte aligned, or is not `LPAD`, or if the landing pad label
 encoded in `LPAD` is not zero and does not match the expected landing pad label
-in bits 31:12 of the `x7` register, then a software error exception (cause=18) with
+in bits 31:12 of the `x7` register, then a software check exception (cause=18) with
 `*tval` set to "landing pad fault (code=2)" is raised else the `ELP` is updated to
 `NO_LP_EXPECTED`.
 
@@ -500,9 +500,9 @@ following conditions are true:
 * The `ELP` is `LP_EXPECTED` and the `LPL` is not zero and the `LPL` does not
   match the expected landing pad label in bits 31:12 of the `x7` register.
 
-If the instruction causes an software error exception, the `ELP` does not
-change. The behavior of the trap caused by this software error exception is
-specified in section <<FORWARD_TRAPS>>. If a software error exception is not
+If the instruction causes an software check exception, the `ELP` does not
+change. The behavior of the trap caused by this software check exception is
+specified in section <<FORWARD_TRAPS>>. If a software check exception is not
 caused then the `ELP` is updated to `NO_LP_EXPECTED`.
 
 [wavedrom, ,svg]
@@ -522,10 +522,10 @@ The operation of the `LPAD` instruction is as follows:
 if (xLPE != 0)
     // If PC not 4-byte aligned then software integrity fault
     if pc[1:0] != 0
-        Cause software error exception
+        Cause software check exception
     // If landing pad label not matched -> software integrity fault
     else if (inst.LPL != x7[31:12] && inst.LPL != 0 && ELP == LP_EXPECTED)
-        Cause software error exception
+        Cause software check exception
     else
         ELP = NO_LP_EXPECTED
 else
@@ -545,11 +545,11 @@ of indirect call/jump was decoded, due to:
   error exception with `*tval` set to "landing pad fault (code=2)"
   (See Table 3.7 of Privileged Specification cite:[PRIV]).
 
-The software error exception caused by Zicfilp has higher priority than an
+The software check exception caused by Zicfilp has higher priority than an
 illegal instruction exception but lower priority than instruction access fault.
 
-The software error exception due to the instruction not being an `LPAD`
-instruction when `ELP` is `LP_EXPECTED` or an software error exception caused by
+The software check exception due to the instruction not being an `LPAD`
+instruction when `ELP` is `LP_EXPECTED` or an software check exception caused by
 the `LPAD` instruction itself (See <<LP_INST>>) leads to a trap being delivered
 to the same or to a higher privilege mode.