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[src/trunk]: src/sys/arch Change the way SVS is disabled. Now you have to pas...



details:   https://anonhg.NetBSD.org/src/rev/261762cf4c3c
branches:  trunk
changeset: 841445:261762cf4c3c
user:      maxv <maxv%NetBSD.org@localhost>
date:      Wed May 15 17:31:41 2019 +0000

description:
Change the way SVS is disabled. Now you have to pass "boot -3" from the
bootloader. The machdep.svs.enabled sysctl becomes read-only, and just
indicates whether SVS is enabled.

Sent on port-amd64@.

diffstat:

 sys/arch/amd64/amd64/locore.S  |   30 +-------
 sys/arch/x86/x86/svs.c         |  151 +---------------------------------------
 sys/arch/x86/x86/x86_machdep.c |    9 +-
 3 files changed, 12 insertions(+), 178 deletions(-)

diffs (278 lines):

diff -r 5618a41fc76b -r 261762cf4c3c sys/arch/amd64/amd64/locore.S
--- a/sys/arch/amd64/amd64/locore.S     Wed May 15 16:59:10 2019 +0000
+++ b/sys/arch/amd64/amd64/locore.S     Wed May 15 17:31:41 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: locore.S,v 1.181 2019/05/14 16:59:25 maxv Exp $        */
+/*     $NetBSD: locore.S,v 1.182 2019/05/15 17:31:41 maxv Exp $        */
 
 /*
  * Copyright-o-rama!
@@ -1621,10 +1621,6 @@
        .globl  svs_enter_altstack, svs_enter_altstack_end
        .globl  svs_leave, svs_leave_end
        .globl  svs_leave_altstack, svs_leave_altstack_end
-       .globl  nosvs_enter, nosvs_enter_end
-       .globl  nosvs_enter_altstack, nosvs_enter_altstack_end
-       .globl  nosvs_leave, nosvs_leave_end
-       .globl  nosvs_leave_altstack, nosvs_leave_altstack_end
 
 LABEL(svs_enter)
        movabs  SVS_UTLS+UTLS_KPDIRPA,%rax
@@ -1668,30 +1664,6 @@
        movq    (FRAMESIZE+1*8)(%rsp),%rax      /* nmistore->scratch */
        movq    %rax,%cr3
 LABEL(svs_leave_nmi_end)
-
-LABEL(nosvs_enter)
-       NOSVS_ENTER
-LABEL(nosvs_enter_end)
-
-LABEL(nosvs_enter_altstack)
-       NOSVS_ENTER_ALTSTACK
-LABEL(nosvs_enter_altstack_end)
-
-LABEL(nosvs_enter_nmi)
-       NOSVS_ENTER_NMI
-LABEL(nosvs_enter_nmi_end)
-
-LABEL(nosvs_leave)
-       NOSVS_LEAVE
-LABEL(nosvs_leave_end)
-
-LABEL(nosvs_leave_altstack)
-       NOSVS_LEAVE_ALTSTACK
-LABEL(nosvs_leave_altstack_end)
-
-LABEL(nosvs_leave_nmi)
-       NOSVS_LEAVE_NMI
-LABEL(nosvs_leave_nmi_end)
 #endif
 
        .globl  ibrs_enter, ibrs_enter_end
diff -r 5618a41fc76b -r 261762cf4c3c sys/arch/x86/x86/svs.c
--- a/sys/arch/x86/x86/svs.c    Wed May 15 16:59:10 2019 +0000
+++ b/sys/arch/x86/x86/svs.c    Wed May 15 17:31:41 2019 +0000
@@ -1,7 +1,7 @@
-/*     $NetBSD: svs.c,v 1.25 2019/04/21 06:37:21 maxv Exp $    */
+/*     $NetBSD: svs.c,v 1.26 2019/05/15 17:31:41 maxv Exp $    */
 
 /*
- * Copyright (c) 2018 The NetBSD Foundation, Inc.
+ * Copyright (c) 2018-2019 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: svs.c,v 1.25 2019/04/21 06:37:21 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: svs.c,v 1.26 2019/05/15 17:31:41 maxv Exp $");
 
 #include "opt_svs.h"
 
@@ -41,6 +41,7 @@
 #include <sys/kauth.h>
 #include <sys/sysctl.h>
 #include <sys/xcall.h>
+#include <sys/reboot.h>
 
 #include <x86/cputypes.h>
 #include <machine/cpuvar.h>
@@ -611,147 +612,6 @@
        x86_patch_window_close(psl, cr0);
 }
 
-static void
-svs_disable_hotpatch(void)
-{
-       extern uint8_t nosvs_enter, nosvs_enter_end;
-       extern uint8_t nosvs_enter_altstack, nosvs_enter_altstack_end;
-       extern uint8_t nosvs_enter_nmi, nosvs_enter_nmi_end;
-       extern uint8_t nosvs_leave, nosvs_leave_end;
-       extern uint8_t nosvs_leave_altstack, nosvs_leave_altstack_end;
-       extern uint8_t nosvs_leave_nmi, nosvs_leave_nmi_end;
-       u_long psl, cr0;
-       uint8_t *bytes;
-       size_t size;
-
-       x86_patch_window_open(&psl, &cr0);
-
-       bytes = &nosvs_enter;
-       size = (size_t)&nosvs_enter_end - (size_t)&nosvs_enter;
-       x86_hotpatch(HP_NAME_SVS_ENTER, bytes, size);
-
-       bytes = &nosvs_enter_altstack;
-       size = (size_t)&nosvs_enter_altstack_end -
-           (size_t)&nosvs_enter_altstack;
-       x86_hotpatch(HP_NAME_SVS_ENTER_ALT, bytes, size);
-
-       bytes = &nosvs_enter_nmi;
-       size = (size_t)&nosvs_enter_nmi_end -
-           (size_t)&nosvs_enter_nmi;
-       x86_hotpatch(HP_NAME_SVS_ENTER_NMI, bytes, size);
-
-       bytes = &nosvs_leave;
-       size = (size_t)&nosvs_leave_end - (size_t)&nosvs_leave;
-       x86_hotpatch(HP_NAME_SVS_LEAVE, bytes, size);
-
-       bytes = &nosvs_leave_altstack;
-       size = (size_t)&nosvs_leave_altstack_end -
-           (size_t)&nosvs_leave_altstack;
-       x86_hotpatch(HP_NAME_SVS_LEAVE_ALT, bytes, size);
-
-       bytes = &nosvs_leave_nmi;
-       size = (size_t)&nosvs_leave_nmi_end -
-           (size_t)&nosvs_leave_nmi;
-       x86_hotpatch(HP_NAME_SVS_LEAVE_NMI, bytes, size);
-
-       x86_patch_window_close(psl, cr0);
-}
-
-static volatile unsigned long svs_cpu_barrier1 __cacheline_aligned;
-static volatile unsigned long svs_cpu_barrier2 __cacheline_aligned;
-typedef void (vector)(void);
-
-static void
-svs_disable_cpu(void *arg1, void *arg2)
-{
-       struct cpu_info *ci = curcpu();
-       extern vector Xsyscall;
-       u_long psl;
-
-       psl = x86_read_psl();
-       x86_disable_intr();
-
-       atomic_dec_ulong(&svs_cpu_barrier1);
-       while (atomic_cas_ulong(&svs_cpu_barrier1, 0, 0) != 0) {
-               x86_pause();
-       }
-
-       /* cpu0 is the one that does the hotpatch job */
-       if (ci == &cpu_info_primary) {
-               svs_enabled = false;
-               svs_disable_hotpatch();
-       }
-
-       /* put back the non-SVS syscall entry point */
-       wrmsr(MSR_LSTAR, (uint64_t)Xsyscall);
-
-       /* enable global pages */
-       if (cpu_feature[0] & CPUID_PGE)
-               lcr4(rcr4() | CR4_PGE);
-
-       atomic_dec_ulong(&svs_cpu_barrier2);
-       while (atomic_cas_ulong(&svs_cpu_barrier2, 0, 0) != 0) {
-               x86_pause();
-       }
-
-       /* Write back and invalidate cache, flush pipelines. */
-       wbinvd();
-       x86_flush();
-
-       x86_write_psl(psl);
-}
-
-static int
-svs_disable(void)
-{
-       uint64_t xc;
-
-       svs_cpu_barrier1 = ncpu;
-       svs_cpu_barrier2 = ncpu;
-
-       printf("[+] Disabling SVS...");
-       xc = xc_broadcast(0, svs_disable_cpu, NULL, NULL);
-       xc_wait(xc);
-       printf(" done!\n");
-
-       return 0;
-}
-
-int sysctl_machdep_svs_enabled(SYSCTLFN_ARGS);
-
-int
-sysctl_machdep_svs_enabled(SYSCTLFN_ARGS)
-{
-       struct sysctlnode node;
-       int error;
-       bool val;
-
-       val = *(bool *)rnode->sysctl_data;
-
-       node = *rnode;
-       node.sysctl_data = &val;
-
-       error = sysctl_lookup(SYSCTLFN_CALL(&node));
-       if (error != 0 || newp == NULL)
-               return error;
-
-       if (val == 1) {
-               if (svs_enabled)
-                       error = 0;
-               else
-                       error = EOPNOTSUPP;
-       } else if (svs_enabled) {
-               error = kauth_authorize_machdep(kauth_cred_get(),
-                   KAUTH_MACHDEP_SVS_DISABLE, NULL, NULL, NULL, NULL);
-               if (!error)
-                       error = svs_disable();
-       } else {
-               error = 0;
-       }
-
-       return error;
-}
-
 void
 svs_init(void)
 {
@@ -760,6 +620,9 @@
        if (cpu_vendor != CPUVENDOR_INTEL) {
                return;
        }
+       if (boothowto & RB_MD3) {
+               return;
+       }
        if (cpu_info_primary.ci_feat_val[7] & CPUID_SEF_ARCH_CAP) {
                msr = rdmsr(MSR_IA32_ARCH_CAPABILITIES);
                if (msr & IA32_ARCH_RDCL_NO) {
diff -r 5618a41fc76b -r 261762cf4c3c sys/arch/x86/x86/x86_machdep.c
--- a/sys/arch/x86/x86/x86_machdep.c    Wed May 15 16:59:10 2019 +0000
+++ b/sys/arch/x86/x86/x86_machdep.c    Wed May 15 17:31:41 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: x86_machdep.c,v 1.124 2019/02/15 08:54:01 nonaka Exp $ */
+/*     $NetBSD: x86_machdep.c,v 1.125 2019/05/15 17:31:41 maxv Exp $   */
 
 /*-
  * Copyright (c) 2002, 2006, 2007 YAMAMOTO Takashi,
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: x86_machdep.c,v 1.124 2019/02/15 08:54:01 nonaka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: x86_machdep.c,v 1.125 2019/05/15 17:31:41 maxv Exp $");
 
 #include "opt_modular.h"
 #include "opt_physmem.h"
@@ -1287,7 +1287,6 @@
                       sysctl_machdep_hypervisor, 0, NULL, 0,
                       CTL_MACHDEP, CTL_CREATE, CTL_EOL);
 #ifdef SVS
-       int sysctl_machdep_svs_enabled(SYSCTLFN_ARGS);
        const struct sysctlnode *svs_rnode = NULL;
        sysctl_createv(clog, 0, NULL, &svs_rnode,
                       CTLFLAG_PERMANENT,
@@ -1295,10 +1294,10 @@
                       NULL, 0, NULL, 0,
                       CTL_MACHDEP, CTL_CREATE);
        sysctl_createv(clog, 0, &svs_rnode, &svs_rnode,
-                      CTLFLAG_READWRITE,
+                      CTLFLAG_PERMANENT,
                       CTLTYPE_BOOL, "enabled",
                       SYSCTL_DESCR("Whether the kernel uses SVS"),
-                      sysctl_machdep_svs_enabled, 0, &svs_enabled, 0,
+                      NULL, 0, &svs_enabled, 0,
                       CTL_CREATE, CTL_EOL);
 #endif
 



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