Hi,
Can we use the regular trap panic for SMEP and SMAP? pageflttrap()
returns 0 to print a nice reason in kerntrap(). Especially if ddb
is disabled, additional information is printed.
attempt to access user address 0xe27539f1000 in supervisor mode
fatal page fault in supervisor mode
trap type 6 code 3 rip ffffffff819c2665 cs 8 rflags 10202 cr2 e27539f1000 cpl 0
rsp ffff80001ffbfe28
gsbase 0xffff80001fb63ff0 kgsbase 0x0
panic: trap type 6, code=3, pc=ffffffff819c2665
While there, prevent a double space in output.
If the kernel calls a NULL function, ddb tries to disassmble at 0
after SMEP. Don't do that to prevent a fault in ddb.
ok?
bluhm
Index: arch/amd64/amd64/trap.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/arch/amd64/amd64/trap.c,v
retrieving revision 1.77
diff -u -p -r1.77 trap.c
--- arch/amd64/amd64/trap.c 6 Sep 2019 12:22:01 -0000 1.77
+++ arch/amd64/amd64/trap.c 19 Dec 2019 23:46:40 -0000
@@ -163,14 +163,18 @@ pageflttrap(struct trapframe *frame, int
extern struct vm_map *kernel_map;
/* This will only trigger if SMEP is enabled */
- if (cr2 <= VM_MAXUSER_ADDRESS && frame->tf_err & PGEX_I)
- panic("attempt to execute user address %p "
- "in supervisor mode", (void *)cr2);
+ if (cr2 <= VM_MAXUSER_ADDRESS && frame->tf_err & PGEX_I) {
+ printf("attempt to execute user address %p "
+ "in supervisor mode\n", (void *)cr2);
+ return 0;
+ }
/* This will only trigger if SMAP is enabled */
if (pcb->pcb_onfault == NULL && cr2 <= VM_MAXUSER_ADDRESS &&
- frame->tf_err & PGEX_P)
- panic("attempt to access user address %p "
- "in supervisor mode", (void *)cr2);
+ frame->tf_err & PGEX_P) {
+ printf("attempt to access user address %p "
+ "in supervisor mode\n", (void *)cr2);
+ return 0;
+ }
/*
* It is only a kernel address space fault iff:
@@ -395,7 +399,7 @@ trap_print(struct trapframe *frame, int
printf(" in %s mode\n", KERNELMODE(frame->tf_cs, frame->tf_rflags) ?
"supervisor" : "user");
printf("trap type %d code %llx rip %llx cs %llx rflags %llx cr2 "
- " %llx cpl %x rsp %llx\n",
+ "%llx cpl %x rsp %llx\n",
type, frame->tf_err, frame->tf_rip, frame->tf_cs,
frame->tf_rflags, rcr2(), curcpu()->ci_ilevel, frame->tf_rsp);
printf("gsbase %p kgsbase %p\n",
Index: ddb/db_examine.c
===================================================================
RCS file: /data/mirror/openbsd/cvs/src/sys/ddb/db_examine.c,v
retrieving revision 1.26
diff -u -p -r1.26 db_examine.c
--- ddb/db_examine.c 7 Nov 2019 13:16:25 -0000 1.26
+++ ddb/db_examine.c 20 Dec 2019 00:38:11 -0000
@@ -288,8 +288,10 @@ void
db_print_loc_and_inst(vaddr_t loc)
{
db_printsym(loc, DB_STGY_PROC, db_printf);
- db_printf(":\t");
- (void) db_disasm(loc, 0);
+ if (loc) {
+ db_printf(":\t");
+ db_disasm(loc, 0);
+ }
}
/* local copy is needed here so that we can trace strlcpy() in libkern */
