On 8/8/24 06:11, Deepak Gupta wrote:
+ /*
+ * If forward cfi enabled for new priv, restore elp status
+ * and clear spelp in mstatus
+ */
+ if (cpu_get_fcfien(env)) {
+ env->elp = get_field(env->mstatus, MSTATUS_SPELP);
+ env->mstatus = set_field(env->mstatus, MSTATUS_SPELP, 0);
+ }
The spec is perhaps poorly written here. I read
... if xPP holds the value y, then ELP is set to the value of xPELP if yLPE is
1;
otherwise, it is set to NO_LP_EXPECTED; xPELP is set to NO_LP_EXPECTED.
as xPELP always being cleared, regardless of yLPE.
Yes that's what code above is also doing. restore elp status from SPELP field
and clear
it at SPELP.
No, my point is that the text doesn't seem to be
if (enabled) {
restore elp
clear pelp
}
but
if (enabled) {
restore elp
}
clear pelp
I.e. the clear is unconditional.
r~
