freebsd-skq/sys/powerpc/aim/aim_machdep.c
jhibbits 96915338d5 Add hypervisor trap handling, using HSRR0/HSRR1
Summary:
Some hypervisor exceptions on POWER architecture only save state to HSRR0/HSRR1.
Until we have bhyve on POWER, use a lightweight exception frontend which copies
HSRR0/HSRR1 into SRR0/SRR1, and run the normal trap handler.

The first user of this is the Hypervisor Virtualization Interrupt, which targets
the XIVE interrupt controller on POWER9.

Reviewed By: nwhitehorn
Differential Revision: https://reviews.freebsd.org/D15487
2018-05-19 04:21:50 +00:00

694 lines
18 KiB
C

/*-
* Copyright (C) 1995, 1996 Wolfgang Solfrank.
* Copyright (C) 1995, 1996 TooLs GmbH.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by TooLs GmbH.
* 4. The name of TooLs GmbH may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*-
* Copyright (C) 2001 Benno Rice
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY Benno Rice ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
* $NetBSD: machdep.c,v 1.74.2.1 2000/11/01 16:13:48 tv Exp $
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ddb.h"
#include "opt_kstack_pages.h"
#include "opt_platform.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/bus.h>
#include <sys/cons.h>
#include <sys/cpu.h>
#include <sys/eventhandler.h>
#include <sys/exec.h>
#include <sys/imgact.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/msgbuf.h>
#include <sys/mutex.h>
#include <sys/ptrace.h>
#include <sys/reboot.h>
#include <sys/rwlock.h>
#include <sys/signalvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/ucontext.h>
#include <sys/uio.h>
#include <sys/vmmeter.h>
#include <sys/vnode.h>
#include <net/netisr.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <machine/altivec.h>
#ifndef __powerpc64__
#include <machine/bat.h>
#endif
#include <machine/cpu.h>
#include <machine/elf.h>
#include <machine/fpu.h>
#include <machine/hid.h>
#include <machine/kdb.h>
#include <machine/md_var.h>
#include <machine/metadata.h>
#include <machine/mmuvar.h>
#include <machine/pcb.h>
#include <machine/reg.h>
#include <machine/sigframe.h>
#include <machine/spr.h>
#include <machine/trap.h>
#include <machine/vmparam.h>
#include <machine/ofw_machdep.h>
#include <ddb/ddb.h>
#include <dev/ofw/openfirm.h>
#ifdef __powerpc64__
#include "mmu_oea64.h"
#endif
#ifndef __powerpc64__
struct bat battable[16];
#endif
#ifndef __powerpc64__
/* Bits for running on 64-bit systems in 32-bit mode. */
extern void *testppc64, *testppc64size;
extern void *restorebridge, *restorebridgesize;
extern void *rfid_patch, *rfi_patch1, *rfi_patch2;
extern void *trapcode64;
extern Elf_Addr _GLOBAL_OFFSET_TABLE_[];
#endif
extern void *rstcode, *rstcodeend;
extern void *trapcode, *trapcodeend;
extern void *hypertrapcode, *hypertrapcodeend;
extern void *generictrap, *generictrap64;
extern void *alitrap, *aliend;
extern void *dsitrap, *dsiend;
extern void *decrint, *decrsize;
extern void *extint, *extsize;
extern void *dblow, *dbend;
extern void *imisstrap, *imisssize;
extern void *dlmisstrap, *dlmisssize;
extern void *dsmisstrap, *dsmisssize;
extern void *ap_pcpu;
extern void __restartkernel(vm_offset_t, vm_offset_t, vm_offset_t, void *, uint32_t, register_t offset, register_t msr);
void aim_early_init(vm_offset_t fdt, vm_offset_t toc, vm_offset_t ofentry,
void *mdp, uint32_t mdp_cookie);
void aim_cpu_init(vm_offset_t toc);
void
aim_early_init(vm_offset_t fdt, vm_offset_t toc, vm_offset_t ofentry, void *mdp,
uint32_t mdp_cookie)
{
register_t scratch;
/*
* If running from an FDT, make sure we are in real mode to avoid
* tromping on firmware page tables. Everything in the kernel assumes
* 1:1 mappings out of firmware, so this won't break anything not
* already broken. This doesn't work if there is live OF, since OF
* may internally use non-1:1 mappings.
*/
if (ofentry == 0)
mtmsr(mfmsr() & ~(PSL_IR | PSL_DR));
#ifdef __powerpc64__
/*
* If in real mode, relocate to high memory so that the kernel
* can execute from the direct map.
*/
if (!(mfmsr() & PSL_DR) &&
(vm_offset_t)&aim_early_init < DMAP_BASE_ADDRESS)
__restartkernel(fdt, 0, ofentry, mdp, mdp_cookie,
DMAP_BASE_ADDRESS, mfmsr());
#endif
/* Various very early CPU fix ups */
switch (mfpvr() >> 16) {
/*
* PowerPC 970 CPUs have a misfeature requested by Apple that
* makes them pretend they have a 32-byte cacheline. Turn this
* off before we measure the cacheline size.
*/
case IBM970:
case IBM970FX:
case IBM970MP:
case IBM970GX:
scratch = mfspr(SPR_HID5);
scratch &= ~HID5_970_DCBZ_SIZE_HI;
mtspr(SPR_HID5, scratch);
break;
#ifdef __powerpc64__
case IBMPOWER7:
case IBMPOWER7PLUS:
case IBMPOWER8:
case IBMPOWER8E:
case IBMPOWER9:
/* XXX: get from ibm,slb-size in device tree */
n_slbs = 32;
break;
#endif
}
}
void
aim_cpu_init(vm_offset_t toc)
{
size_t trap_offset, trapsize;
vm_offset_t trap;
register_t msr;
uint8_t *cache_check;
int cacheline_warn;
#ifndef __powerpc64__
register_t scratch;
int ppc64;
#endif
trap_offset = 0;
cacheline_warn = 0;
/* General setup for AIM CPUs */
psl_kernset = PSL_EE | PSL_ME | PSL_IR | PSL_DR | PSL_RI;
#ifdef __powerpc64__
psl_kernset |= PSL_SF;
if (mfmsr() & PSL_HV)
psl_kernset |= PSL_HV;
#endif
psl_userset = psl_kernset | PSL_PR;
#ifdef __powerpc64__
psl_userset32 = psl_userset & ~PSL_SF;
#endif
/* Bits that users aren't allowed to change */
psl_userstatic = ~(PSL_VEC | PSL_FP | PSL_FE0 | PSL_FE1);
/*
* Mask bits from the SRR1 that aren't really the MSR:
* Bits 1-4, 10-15 (ppc32), 33-36, 42-47 (ppc64)
*/
psl_userstatic &= ~0x783f0000UL;
/*
* Initialize the interrupt tables and figure out our cache line
* size and whether or not we need the 64-bit bridge code.
*/
/*
* Disable translation in case the vector area hasn't been
* mapped (G5). Note that no OFW calls can be made until
* translation is re-enabled.
*/
msr = mfmsr();
mtmsr((msr & ~(PSL_IR | PSL_DR)) | PSL_RI);
/*
* Measure the cacheline size using dcbz
*
* Use EXC_PGM as a playground. We are about to overwrite it
* anyway, we know it exists, and we know it is cache-aligned.
*/
cache_check = (void *)EXC_PGM;
for (cacheline_size = 0; cacheline_size < 0x100; cacheline_size++)
cache_check[cacheline_size] = 0xff;
__asm __volatile("dcbz 0,%0":: "r" (cache_check) : "memory");
/* Find the first byte dcbz did not zero to get the cache line size */
for (cacheline_size = 0; cacheline_size < 0x100 &&
cache_check[cacheline_size] == 0; cacheline_size++);
/* Work around psim bug */
if (cacheline_size == 0) {
cacheline_warn = 1;
cacheline_size = 32;
}
#ifndef __powerpc64__
/*
* Figure out whether we need to use the 64 bit PMAP. This works by
* executing an instruction that is only legal on 64-bit PPC (mtmsrd),
* and setting ppc64 = 0 if that causes a trap.
*/
ppc64 = 1;
bcopy(&testppc64, (void *)EXC_PGM, (size_t)&testppc64size);
__syncicache((void *)EXC_PGM, (size_t)&testppc64size);
__asm __volatile("\
mfmsr %0; \
mtsprg2 %1; \
\
mtmsrd %0; \
mfsprg2 %1;"
: "=r"(scratch), "=r"(ppc64));
if (ppc64)
cpu_features |= PPC_FEATURE_64;
/*
* Now copy restorebridge into all the handlers, if necessary,
* and set up the trap tables.
*/
if (cpu_features & PPC_FEATURE_64) {
/* Patch the two instances of rfi -> rfid */
bcopy(&rfid_patch,&rfi_patch1,4);
#ifdef KDB
/* rfi_patch2 is at the end of dbleave */
bcopy(&rfid_patch,&rfi_patch2,4);
#endif
}
#else /* powerpc64 */
cpu_features |= PPC_FEATURE_64;
#endif
trapsize = (size_t)&trapcodeend - (size_t)&trapcode;
/*
* Copy generic handler into every possible trap. Special cases will get
* different ones in a minute.
*/
for (trap = EXC_RST; trap < EXC_LAST; trap += 0x20)
bcopy(&trapcode, (void *)trap, trapsize);
#ifndef __powerpc64__
if (cpu_features & PPC_FEATURE_64) {
/*
* Copy a code snippet to restore 32-bit bridge mode
* to the top of every non-generic trap handler
*/
trap_offset += (size_t)&restorebridgesize;
bcopy(&restorebridge, (void *)EXC_RST, trap_offset);
bcopy(&restorebridge, (void *)EXC_DSI, trap_offset);
bcopy(&restorebridge, (void *)EXC_ALI, trap_offset);
bcopy(&restorebridge, (void *)EXC_PGM, trap_offset);
bcopy(&restorebridge, (void *)EXC_MCHK, trap_offset);
bcopy(&restorebridge, (void *)EXC_TRC, trap_offset);
bcopy(&restorebridge, (void *)EXC_BPT, trap_offset);
}
#else
trapsize = (size_t)&hypertrapcodeend - (size_t)&hypertrapcode;
bcopy(&hypertrapcode, (void *)(EXC_HEA + trap_offset), trapsize);
bcopy(&hypertrapcode, (void *)(EXC_HMI + trap_offset), trapsize);
bcopy(&hypertrapcode, (void *)(EXC_HVI + trap_offset), trapsize);
#endif
bcopy(&rstcode, (void *)(EXC_RST + trap_offset), (size_t)&rstcodeend -
(size_t)&rstcode);
#ifdef KDB
bcopy(&dblow, (void *)(EXC_MCHK + trap_offset), (size_t)&dbend -
(size_t)&dblow);
bcopy(&dblow, (void *)(EXC_PGM + trap_offset), (size_t)&dbend -
(size_t)&dblow);
bcopy(&dblow, (void *)(EXC_TRC + trap_offset), (size_t)&dbend -
(size_t)&dblow);
bcopy(&dblow, (void *)(EXC_BPT + trap_offset), (size_t)&dbend -
(size_t)&dblow);
#endif
bcopy(&alitrap, (void *)(EXC_ALI + trap_offset), (size_t)&aliend -
(size_t)&alitrap);
bcopy(&dsitrap, (void *)(EXC_DSI + trap_offset), (size_t)&dsiend -
(size_t)&dsitrap);
#ifdef __powerpc64__
/* Set TOC base so that the interrupt code can get at it */
*((void **)TRAP_GENTRAP) = &generictrap;
*((register_t *)TRAP_TOCBASE) = toc;
#else
/* Set branch address for trap code */
if (cpu_features & PPC_FEATURE_64)
*((void **)TRAP_GENTRAP) = &generictrap64;
else
*((void **)TRAP_GENTRAP) = &generictrap;
*((void **)TRAP_TOCBASE) = _GLOBAL_OFFSET_TABLE_;
/* G2-specific TLB miss helper handlers */
bcopy(&imisstrap, (void *)EXC_IMISS, (size_t)&imisssize);
bcopy(&dlmisstrap, (void *)EXC_DLMISS, (size_t)&dlmisssize);
bcopy(&dsmisstrap, (void *)EXC_DSMISS, (size_t)&dsmisssize);
#endif
__syncicache(EXC_RSVD, EXC_LAST - EXC_RSVD);
/*
* Restore MSR
*/
mtmsr(msr);
/* Warn if cachline size was not determined */
if (cacheline_warn == 1) {
printf("WARNING: cacheline size undetermined, setting to 32\n");
}
/*
* Initialise virtual memory. Use BUS_PROBE_GENERIC priority
* in case the platform module had a better idea of what we
* should do.
*/
if (cpu_features & PPC_FEATURE_64)
pmap_mmu_install(MMU_TYPE_G5, BUS_PROBE_GENERIC);
else
pmap_mmu_install(MMU_TYPE_OEA, BUS_PROBE_GENERIC);
}
/*
* Shutdown the CPU as much as possible.
*/
void
cpu_halt(void)
{
OF_exit();
}
int
ptrace_single_step(struct thread *td)
{
struct trapframe *tf;
tf = td->td_frame;
tf->srr1 |= PSL_SE;
return (0);
}
int
ptrace_clear_single_step(struct thread *td)
{
struct trapframe *tf;
tf = td->td_frame;
tf->srr1 &= ~PSL_SE;
return (0);
}
void
kdb_cpu_clear_singlestep(void)
{
kdb_frame->srr1 &= ~PSL_SE;
}
void
kdb_cpu_set_singlestep(void)
{
kdb_frame->srr1 |= PSL_SE;
}
/*
* Initialise a struct pcpu.
*/
void
cpu_pcpu_init(struct pcpu *pcpu, int cpuid, size_t sz)
{
#ifdef __powerpc64__
/* Copy the SLB contents from the current CPU */
memcpy(pcpu->pc_aim.slb, PCPU_GET(aim.slb), sizeof(pcpu->pc_aim.slb));
#endif
}
#ifndef __powerpc64__
uint64_t
va_to_vsid(pmap_t pm, vm_offset_t va)
{
return ((pm->pm_sr[(uintptr_t)va >> ADDR_SR_SHFT]) & SR_VSID_MASK);
}
#endif
/*
* These functions need to provide addresses that both (a) work in real mode
* (or whatever mode/circumstances the kernel is in in early boot (now)) and
* (b) can still, in principle, work once the kernel is going. Because these
* rely on existing mappings/real mode, unmap is a no-op.
*/
vm_offset_t
pmap_early_io_map(vm_paddr_t pa, vm_size_t size)
{
KASSERT(!pmap_bootstrapped, ("Not available after PMAP started!"));
/*
* If we have the MMU up in early boot, assume it is 1:1. Otherwise,
* try to get the address in a memory region compatible with the
* direct map for efficiency later.
*/
if (mfmsr() & PSL_DR)
return (pa);
else
return (DMAP_BASE_ADDRESS + pa);
}
void
pmap_early_io_unmap(vm_offset_t va, vm_size_t size)
{
KASSERT(!pmap_bootstrapped, ("Not available after PMAP started!"));
}
/* From p3-53 of the MPC7450 RISC Microprocessor Family Reference Manual */
void
flush_disable_caches(void)
{
register_t msr;
register_t msscr0;
register_t cache_reg;
volatile uint32_t *memp;
uint32_t temp;
int i;
int x;
msr = mfmsr();
powerpc_sync();
mtmsr(msr & ~(PSL_EE | PSL_DR));
msscr0 = mfspr(SPR_MSSCR0);
msscr0 &= ~MSSCR0_L2PFE;
mtspr(SPR_MSSCR0, msscr0);
powerpc_sync();
isync();
__asm__ __volatile__("dssall; sync");
powerpc_sync();
isync();
__asm__ __volatile__("dcbf 0,%0" :: "r"(0));
__asm__ __volatile__("dcbf 0,%0" :: "r"(0));
__asm__ __volatile__("dcbf 0,%0" :: "r"(0));
/* Lock the L1 Data cache. */
mtspr(SPR_LDSTCR, mfspr(SPR_LDSTCR) | 0xFF);
powerpc_sync();
isync();
mtspr(SPR_LDSTCR, 0);
/*
* Perform this in two stages: Flush the cache starting in RAM, then do it
* from ROM.
*/
memp = (volatile uint32_t *)0x00000000;
for (i = 0; i < 128 * 1024; i++) {
temp = *memp;
__asm__ __volatile__("dcbf 0,%0" :: "r"(memp));
memp += 32/sizeof(*memp);
}
memp = (volatile uint32_t *)0xfff00000;
x = 0xfe;
for (; x != 0xff;) {
mtspr(SPR_LDSTCR, x);
for (i = 0; i < 128; i++) {
temp = *memp;
__asm__ __volatile__("dcbf 0,%0" :: "r"(memp));
memp += 32/sizeof(*memp);
}
x = ((x << 1) | 1) & 0xff;
}
mtspr(SPR_LDSTCR, 0);
cache_reg = mfspr(SPR_L2CR);
if (cache_reg & L2CR_L2E) {
cache_reg &= ~(L2CR_L2IO_7450 | L2CR_L2DO_7450);
mtspr(SPR_L2CR, cache_reg);
powerpc_sync();
mtspr(SPR_L2CR, cache_reg | L2CR_L2HWF);
while (mfspr(SPR_L2CR) & L2CR_L2HWF)
; /* Busy wait for cache to flush */
powerpc_sync();
cache_reg &= ~L2CR_L2E;
mtspr(SPR_L2CR, cache_reg);
powerpc_sync();
mtspr(SPR_L2CR, cache_reg | L2CR_L2I);
powerpc_sync();
while (mfspr(SPR_L2CR) & L2CR_L2I)
; /* Busy wait for L2 cache invalidate */
powerpc_sync();
}
cache_reg = mfspr(SPR_L3CR);
if (cache_reg & L3CR_L3E) {
cache_reg &= ~(L3CR_L3IO | L3CR_L3DO);
mtspr(SPR_L3CR, cache_reg);
powerpc_sync();
mtspr(SPR_L3CR, cache_reg | L3CR_L3HWF);
while (mfspr(SPR_L3CR) & L3CR_L3HWF)
; /* Busy wait for cache to flush */
powerpc_sync();
cache_reg &= ~L3CR_L3E;
mtspr(SPR_L3CR, cache_reg);
powerpc_sync();
mtspr(SPR_L3CR, cache_reg | L3CR_L3I);
powerpc_sync();
while (mfspr(SPR_L3CR) & L3CR_L3I)
; /* Busy wait for L3 cache invalidate */
powerpc_sync();
}
mtspr(SPR_HID0, mfspr(SPR_HID0) & ~HID0_DCE);
powerpc_sync();
isync();
mtmsr(msr);
}
void
cpu_sleep()
{
static u_quad_t timebase = 0;
static register_t sprgs[4];
static register_t srrs[2];
jmp_buf resetjb;
struct thread *fputd;
struct thread *vectd;
register_t hid0;
register_t msr;
register_t saved_msr;
ap_pcpu = pcpup;
PCPU_SET(restore, &resetjb);
saved_msr = mfmsr();
fputd = PCPU_GET(fputhread);
vectd = PCPU_GET(vecthread);
if (fputd != NULL)
save_fpu(fputd);
if (vectd != NULL)
save_vec(vectd);
if (setjmp(resetjb) == 0) {
sprgs[0] = mfspr(SPR_SPRG0);
sprgs[1] = mfspr(SPR_SPRG1);
sprgs[2] = mfspr(SPR_SPRG2);
sprgs[3] = mfspr(SPR_SPRG3);
srrs[0] = mfspr(SPR_SRR0);
srrs[1] = mfspr(SPR_SRR1);
timebase = mftb();
powerpc_sync();
flush_disable_caches();
hid0 = mfspr(SPR_HID0);
hid0 = (hid0 & ~(HID0_DOZE | HID0_NAP)) | HID0_SLEEP;
powerpc_sync();
isync();
msr = mfmsr() | PSL_POW;
mtspr(SPR_HID0, hid0);
powerpc_sync();
while (1)
mtmsr(msr);
}
platform_smp_timebase_sync(timebase, 0);
PCPU_SET(curthread, curthread);
PCPU_SET(curpcb, curthread->td_pcb);
pmap_activate(curthread);
powerpc_sync();
mtspr(SPR_SPRG0, sprgs[0]);
mtspr(SPR_SPRG1, sprgs[1]);
mtspr(SPR_SPRG2, sprgs[2]);
mtspr(SPR_SPRG3, sprgs[3]);
mtspr(SPR_SRR0, srrs[0]);
mtspr(SPR_SRR1, srrs[1]);
mtmsr(saved_msr);
if (fputd == curthread)
enable_fpu(curthread);
if (vectd == curthread)
enable_vec(curthread);
powerpc_sync();
}