diff options
Diffstat (limited to 'usr/src/uts/intel/ia32/os/sundep.c')
| -rw-r--r-- | usr/src/uts/intel/ia32/os/sundep.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/usr/src/uts/intel/ia32/os/sundep.c b/usr/src/uts/intel/ia32/os/sundep.c index cfb4552287..34e0a03d68 100644 --- a/usr/src/uts/intel/ia32/os/sundep.c +++ b/usr/src/uts/intel/ia32/os/sundep.c @@ -20,7 +20,7 @@ */ /* * Copyright (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved. - * Copyright 2018 Joyent, Inc. + * Copyright 2019 Joyent, Inc. */ /* Copyright (c) 1990, 1991 UNIX System Laboratories, Inc. */ @@ -551,16 +551,19 @@ update_sregs(struct regs *rp, klwp_t *lwp) * * We've just mucked up the kernel's gsbase. Oops. In * particular we can't take any traps at all. Make the newly - * computed gsbase be the hidden gs via __swapgs, and fix + * computed gsbase be the hidden gs via swapgs, and fix * the kernel's gsbase back again. Later, when we return to * userland we'll swapgs again restoring gsbase just loaded * above. */ - __swapgs(); + __asm__ __volatile__("mfence; swapgs"); + rp->r_gs = pcb->pcb_gs; /* - * restore kernel's gsbase + * Restore kernel's gsbase. Note that this also serializes any + * attempted speculation from loading the user-controlled + * %gsbase. */ wrmsr(MSR_AMD_GSBASE, kgsbase); |