Re: go/rust vs uvm_map_inentry()

[Theo de Raadt]

i386 has the same problem.

Index: arch/i386/i386/trap.c
===================================================================
RCS file: /cvs/src/sys/arch/i386/i386/trap.c,v
retrieving revision 1.143
diff -u -p -u -r1.143 trap.c
--- arch/i386/i386/trap.c       19 Aug 2020 10:10:58 -0000      1.143
+++ arch/i386/i386/trap.c       14 Sep 2020 11:23:01 -0000
@@ -119,7 +119,7 @@ trap(struct trapframe *frame)
        vm_prot_t ftype;
        union sigval sv;
        caddr_t onfault;
-       uint32_t cr2;
+       uint32_t cr2 = rcr2();
 
        uvmexp.traps++;
 
@@ -135,7 +135,7 @@ trap(struct trapframe *frame)
        if (trapdebug) {
                printf("trap %d code %x eip %x cs %x eflags %x cr2 %x cpl %x\n",
                    frame->tf_trapno, frame->tf_err, frame->tf_eip,
-                   frame->tf_cs, frame->tf_eflags, rcr2(), lapic_tpr);
+                   frame->tf_cs, frame->tf_eflags, rcr2, lapic_tpr);
                printf("curproc %p\n", curproc);
        }
 #endif
@@ -182,7 +182,7 @@ trap(struct trapframe *frame)
                printf(" in %s mode\n", (type & T_USER) ? "user" : 
"supervisor");
                printf("trap type %d code %x eip %x cs %x eflags %x cr2 %x cpl 
%x\n",
                    type, frame->tf_err, frame->tf_eip, frame->tf_cs,
-                   frame->tf_eflags, rcr2(), lapic_tpr);
+                   frame->tf_eflags, rcr2, lapic_tpr);
 
                panic("trap type %d, code=%x, pc=%x",
                    type, frame->tf_err, frame->tf_eip);
@@ -333,7 +333,6 @@ trap(struct trapframe *frame)
                        goto we_re_toast;
 
                pcb = &p->p_addr->u_pcb;
-               cr2 = rcr2();
                KERNEL_LOCK();
                /* This will only trigger if SMEP is enabled */
                if (cr2 <= VM_MAXUSER_ADDRESS && frame->tf_err & PGEX_I)
@@ -353,7 +352,6 @@ trap(struct trapframe *frame)
                int error;
                int signal, sicode;
 
-               cr2 = rcr2();
                KERNEL_LOCK();
        faultcommon:
                vm = p->p_vmspace;
@@ -434,11 +432,11 @@ trap(struct trapframe *frame)
 #endif
 
        case T_BPTFLT|T_USER:           /* bpt instruction fault */
-               sv.sival_int = rcr2();
+               sv.sival_int = rcr2;
                trapsignal(p, SIGTRAP, type &~ T_USER, TRAP_BRKPT, sv);
                break;
        case T_TRCTRAP|T_USER:          /* trace trap */
-               sv.sival_int = rcr2();
+               sv.sival_int = rcr2;
                trapsignal(p, SIGTRAP, type &~ T_USER, TRAP_TRACE, sv);
                break;