Module Name: src Committed By: martin Date: Thu Nov 30 14:03:41 UTC 2017
Modified Files: src/sys/arch/amd64/amd64 [netbsd-8]: machdep.c Log Message: Pull up following revision(s) (requested by maxv in ticket #401): sys/arch/amd64/amd64/machdep.c: revision 1.267 Mmh, don't forget to clear the TLS gdt slots on Xen. Otherwise, when doing a lwp32->lwp64 context switch, the new lwp can use the slots to reconstruct the address of the previous lwp's TLS space (and defeat ASLR?). To generate a diff of this commit: cvs rdiff -u -r1.255.6.1 -r1.255.6.2 src/sys/arch/amd64/amd64/machdep.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.
Modified files: Index: src/sys/arch/amd64/amd64/machdep.c diff -u src/sys/arch/amd64/amd64/machdep.c:1.255.6.1 src/sys/arch/amd64/amd64/machdep.c:1.255.6.2 --- src/sys/arch/amd64/amd64/machdep.c:1.255.6.1 Mon Sep 4 20:41:28 2017 +++ src/sys/arch/amd64/amd64/machdep.c Thu Nov 30 14:03:41 2017 @@ -1,4 +1,4 @@ -/* $NetBSD: machdep.c,v 1.255.6.1 2017/09/04 20:41:28 snj Exp $ */ +/* $NetBSD: machdep.c,v 1.255.6.2 2017/11/30 14:03:41 martin Exp $ */ /*- * Copyright (c) 1996, 1997, 1998, 2000, 2006, 2007, 2008, 2011 @@ -111,7 +111,7 @@ */ #include <sys/cdefs.h> -__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.255.6.1 2017/09/04 20:41:28 snj Exp $"); +__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.255.6.2 2017/11/30 14:03:41 martin Exp $"); /* #define XENDEBUG_LOW */ @@ -427,6 +427,7 @@ x86_64_tls_switch(struct lwp *l) struct cpu_info *ci = curcpu(); struct pcb *pcb = lwp_getpcb(l); struct trapframe *tf = l->l_md.md_regs; + uint64_t zero = 0; /* * Raise the IPL to IPL_HIGH. @@ -449,6 +450,8 @@ x86_64_tls_switch(struct lwp *l) setfs(tf->tf_fs); HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, tf->tf_gs); } else { + update_descriptor(&curcpu()->ci_gdt[GUFS_SEL], &zero); + update_descriptor(&curcpu()->ci_gdt[GUGS_SEL], &zero); setfs(0); HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, 0); HYPERVISOR_set_segment_base(SEGBASE_FS, pcb->pcb_fs);