Author: kib Date: Sun Sep 2 20:07:36 2018 New Revision: 338434 URL: https://svnweb.freebsd.org/changeset/base/338434
Log: Swap order of dererencing PCPU curpmap and checking for usermode in trap_pfault() KPTI violation check. EFI RT may set curpmap to NULL for the duration of the call for some machines (PCID but no INVPCID). Since apparently EFI RT code must be ready for exceptions from the calls, avoid dereferencing curpmap until we know that this call does not come from usermode. Reviewed by: kevans Sponsored by: The FreeBSD Foundation MFC after: 1 week Approved by: re (rgrimes) Differential revision: https://reviews.freebsd.org/D16972 Modified: head/sys/amd64/amd64/trap.c Modified: head/sys/amd64/amd64/trap.c ============================================================================== --- head/sys/amd64/amd64/trap.c Sun Sep 2 19:48:41 2018 (r338433) +++ head/sys/amd64/amd64/trap.c Sun Sep 2 20:07:36 2018 (r338434) @@ -806,7 +806,7 @@ trap_pfault(struct trapframe *frame, int usermode) * If nx protection of the usermode portion of kernel page * tables caused trap, panic. */ - if (PCPU_GET(curpmap)->pm_ucr3 != PMAP_NO_CR3 && usermode && + if (usermode && PCPU_GET(curpmap)->pm_ucr3 != PMAP_NO_CR3 && pg_nx != 0 && (frame->tf_err & (PGEX_P | PGEX_W | PGEX_U | PGEX_I)) == (PGEX_P | PGEX_U | PGEX_I) && (curpcb->pcb_saved_ucr3 & ~CR3_PCID_MASK)== _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
