diff options
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/arch/amd64/amd64/locore.S | 33 | ||||
| -rw-r--r-- | sys/arch/amd64/conf/Makefile.amd64 | 10 |
2 files changed, 31 insertions, 12 deletions
diff --git a/sys/arch/amd64/amd64/locore.S b/sys/arch/amd64/amd64/locore.S index 62ec81239f4..ecc9eedc05d 100644 --- a/sys/arch/amd64/amd64/locore.S +++ b/sys/arch/amd64/amd64/locore.S @@ -1,4 +1,4 @@ -/* $OpenBSD: locore.S,v 1.107 2018/07/24 02:42:25 guenther Exp $ */ +/* $OpenBSD: locore.S,v 1.108 2018/09/09 22:09:36 guenther Exp $ */ /* $NetBSD: locore.S,v 1.13 2004/03/25 18:33:17 drochner Exp $ */ /* @@ -860,10 +860,31 @@ intr_user_exit_post_ast: movq CPUVAR(USER_CR3),%rax movq %rax,%cr3 Xiretq_trampback: +KTEXT_PAGE_END +/* the movq %cr3 switches to this "KUTEXT" page */ +KUTEXT_PAGE_START + .space (Xiretq_trampback - Xsyscall_meltdown) - \ + (. - XUsyscall_meltdown), 0xcc + movq CPUVAR(SCRATCH),%rax +.Liretq_swapgs: + swapgs +doreti_iret_meltdown: + iretq +KUTEXT_PAGE_END +/* + * Back to the "KTEXT" page to fill in the speculation trap and the + * swapgs+iretq used for non-Meltdown kernels. This switching back + * and forth between segments is so that we can do the .space + * calculation below to guarantee the iretq's above and below line + * up, so the 'doreti_iret' label lines up with the iretq whether + * the CPU is affected by Meltdown or not. + */ +KTEXT_PAGE_START 0: pause lfence jmp 0b - .space 5,0xcc /* pad to match "movq CPUVAR(SCRATCH),%rax" */ + .space (.Liretq_swapgs - XUsyscall_meltdown) - \ + (. - Xsyscall_meltdown), 0xcc CODEPATCH_END(CPTAG_MELTDOWN_NOP) swapgs @@ -872,14 +893,6 @@ _C_LABEL(doreti_iret): iretq KTEXT_PAGE_END -KUTEXT_PAGE_START - .space (Xiretq_trampback - Xsyscall_meltdown) - \ - (. - XUsyscall_meltdown), 0xcc - movq CPUVAR(SCRATCH),%rax - swapgs - iretq -KUTEXT_PAGE_END - .text _ALIGN_TRAPS .Lintr_restore_xstate: /* CPU doesn't have curproc's xstate */ diff --git a/sys/arch/amd64/conf/Makefile.amd64 b/sys/arch/amd64/conf/Makefile.amd64 index bd1d63d12c5..270559f14f3 100644 --- a/sys/arch/amd64/conf/Makefile.amd64 +++ b/sys/arch/amd64/conf/Makefile.amd64 @@ -1,4 +1,4 @@ -# $OpenBSD: Makefile.amd64,v 1.101 2018/08/21 18:06:12 anton Exp $ +# $OpenBSD: Makefile.amd64,v 1.102 2018/09/09 22:09:36 guenther Exp $ # For instructions on building kernels consult the config(8) and options(4) # manual pages. @@ -125,6 +125,12 @@ mcount.o: $S/lib/libkern/mcount.c Makefile ioconf.o: ioconf.c ${NORMAL_C} +locore.o: assym.h + ${NORMAL_S} + @[[ -n `objdump -D $@ | grep -A1 doreti_iret | sort | uniq -d` ]] || \ + { rm -f $@; echo "ERROR: overlaid iretq instructions don't line up"; \ + echo "#GP-on-iretq fault handling would be broken"; exit 1; } + ld.script: ${_machdir}/conf/ld.script cp ${_machdir}/conf/ld.script $@ @@ -155,7 +161,7 @@ cleandir: clean depend obj: locore0.o: ${_machdir}/${_mach}/locore0.S assym.h -locore.o mutex.o vector.o copy.o spl.o: assym.h +mutex.o vector.o copy.o spl.o: assym.h mptramp.o acpi_wakecode.o vmm_support.o: assym.h hardlink-obsd: |