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Use the ABI-mandated thread pointer register (r2 for ppc32, r13 for ppc64)

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instead of a PCPU field for curthread. This averts a race on SMP systems
with a high interrupt rate where the thread looking up the value of
curthread could be preempted and migrated between obtaining the PCPU
pointer and reading the value of pc_curthread, resulting in curthread being
observed to be the current thread on the thread's original CPU. This played
merry havoc with the system, in particular with mutexes. Many thanks to
jhb for helping me work this one out.

Note that Book-E is in principle susceptible to the same problem, but has
not been modified yet due to lack of Book-E hardware.

MFC after:	2 weeks
This commit is contained in:
Nathan Whitehorn 2011-06-23 22:21:28 +00:00
parent 6a4ba2279d
commit e69dff491d
16 changed files with 82 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
sys/powerpc/aim/copyinout.c
View File

@ -142,7 +142,7 @@ copyout(const void *kaddr, void *udaddr, size_t len)
char *up, *p;
size_t l;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
if (setfault(env)) {
@ -183,7 +183,7 @@ copyin(const void *udaddr, void *kaddr, size_t len)
char *kp, *p;
size_t l;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
if (setfault(env)) {
@ -225,7 +225,7 @@ copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done)
size_t l;
int rv, c;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
if (setfault(env)) {
@ -267,7 +267,7 @@ subyte(void *addr, int byte)
faultbuf env;
char *p;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (char *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -293,7 +293,7 @@ suword32(void *addr, int word)
faultbuf env;
int *p;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (int *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -319,7 +319,7 @@ suword(void *addr, long word)
faultbuf env;
long *p;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (long *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -359,7 +359,7 @@ fubyte(const void *addr)
u_char *p;
int val;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (u_char *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -385,7 +385,7 @@ fuword32(const void *addr)
faultbuf env;
int32_t *p, val;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (int32_t *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -411,7 +411,7 @@ fuword(const void *addr)
faultbuf env;
long *p, val;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (long *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -444,7 +444,7 @@ casuword32(volatile uint32_t *addr, uint32_t old, uint32_t new)
faultbuf env;
uint32_t *p, val;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (uint32_t *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));
@ -489,7 +489,7 @@ casuword(volatile u_long *addr, u_long old, u_long new)
faultbuf env;
u_long *p, val;
td = PCPU_GET(curthread);
td = curthread;
pm = &td->td_proc->p_vmspace->vm_pmap;
p = (u_long *)(USER_ADDR + ((uintptr_t)addr & ~SEGMENT_MASK));

3
sys/powerpc/aim/locore32.S
View File

@ -181,8 +181,7 @@ setfault:
mflr 0
mfcr 12
mfsprg 4,0
lwz 4,PC_CURTHREAD(4)
lwz 4,TD_PCB(4)
lwz 4,TD_PCB(2) /* curthread = r2 */
stw 3,PCB_ONFAULT(4)
stw 0,0(3)
stw 1,4(3)

3
sys/powerpc/aim/locore64.S
View File

@ -203,8 +203,7 @@ ASENTRY(setfault)
mflr 0
mfcr 12
mfsprg 4,0
ld 4,PC_CURTHREAD(4)
ld 4,TD_PCB(4)
ld 4,TD_PCB(13) /* curthread = r13 */
std 3,PCB_ONFAULT(4)
std 0,0(3)
std 1,8(3)

4
sys/powerpc/aim/machdep.c
View File

@ -303,7 +303,7 @@ powerpc_init(vm_offset_t startkernel, vm_offset_t endkernel,
*/
pc = __pcpu;
pcpu_init(pc, 0, sizeof(struct pcpu));
pc->pc_curthread = &thread0;
curthread_reg = pc->pc_curthread = &thread0;
pc->pc_cpuid = 0;
__asm __volatile("mtsprg 0, %0" :: "r"(pc));
@ -745,7 +745,7 @@ kcopy(const void *src, void *dst, size_t len)
faultbuf env, *oldfault;
int rv;
td = PCPU_GET(curthread);
td = curthread;
oldfault = td->td_pcb->pcb_onfault;
if ((rv = setfault(env)) != 0) {
td->td_pcb->pcb_onfault = oldfault;

2
sys/powerpc/aim/mp_cpudep.c
View File

@ -88,7 +88,7 @@ cpudep_ap_bootstrap(void)
msr = PSL_KERNSET & ~PSL_EE;
mtmsr(msr);
pcpup->pc_curthread = pcpup->pc_idlethread;
curthread_reg = pcpup->pc_curthread = pcpup->pc_idlethread;
pcpup->pc_curpcb = pcpup->pc_curthread->td_pcb;
sp = pcpup->pc_curpcb->pcb_sp;

18
sys/powerpc/aim/swtch32.S
View File

@ -69,7 +69,7 @@
* void cpu_throw(struct thread *old, struct thread *new)
*/
ENTRY(cpu_throw)
mr %r15, %r4
mr %r2, %r4
b cpu_switchin
/*
@ -89,10 +89,9 @@ ENTRY(cpu_switch)
mflr %r16 /* Save the link register */
stw %r16,PCB_LR(%r6)
stw %r1,PCB_SP(%r6) /* Save the stack pointer */
stw %r2,PCB_TOC(%r6) /* Save the TOC pointer */
mr %r14,%r3 /* Copy the old thread ptr... */
mr %r15,%r4 /* and the new thread ptr in scratch */
mr %r2,%r4 /* and the new thread ptr in curthread */
mr %r16,%r5 /* and the new lock */
mr %r17,%r6 /* and the PCB */
@ -122,24 +121,24 @@ cpu_switchin:
lis %r6,blocked_lock@ha
addi %r6,%r6,blocked_lock@l
blocked_loop:
lwz %r7,TD_LOCK(%r15)
lwz %r7,TD_LOCK(%r2)
cmpw %r6,%r7
beq blocked_loop
#endif
mfsprg %r7,0 /* Get the pcpu pointer */
stw %r15,PC_CURTHREAD(%r7) /* Store new current thread */
lwz %r17,TD_PCB(%r15) /* Store new current PCB */
stw %r2,PC_CURTHREAD(%r7) /* Store new current thread */
lwz %r17,TD_PCB(%r2) /* Store new current PCB */
stw %r17,PC_CURPCB(%r7)
mr %r3,%r15 /* Get new thread ptr */
mr %r3,%r2 /* Get new thread ptr */
bl pmap_activate /* Activate the new address space */
lwz %r6, PCB_FLAGS(%r17)
/* Restore FPU context if needed */
andi. %r6, %r6, PCB_FPU
beq .L3
mr %r3,%r15 /* Pass curthread to enable_fpu */
mr %r3,%r2 /* Pass curthread to enable_fpu */
bl enable_fpu
.L3:
@ -147,7 +146,7 @@ blocked_loop:
/* Restore Altivec context if needed */
andi. %r6, %r6, PCB_VEC
beq .L4
mr %r3,%r15 /* Pass curthread to enable_vec */
mr %r3,%r2 /* Pass curthread to enable_vec */
bl enable_vec
/* thread to restore is in r3 */
@ -163,7 +162,6 @@ blocked_loop:
mtsr USER_SR,%r5
isync
lwz %r1,PCB_SP(%r3) /* Load the stack pointer */
lwz %r2,PCB_TOC(%r3) /* Load the TOC pointer */
/*
* Perform a dummy stwcx. to clear any reservations we may have
* inherited from the previous thread. It doesn't matter if the

18
sys/powerpc/aim/swtch64.S
View File

@ -69,7 +69,7 @@
* void cpu_throw(struct thread *old, struct thread *new)
*/
ENTRY(cpu_throw)
mr %r15, %r4
mr %r13, %r4
b cpu_switchin
/*
@ -83,7 +83,6 @@ ENTRY(cpu_switch)
ld %r6,TD_PCB(%r3) /* Get the old thread's PCB ptr */
std %r12,PCB_CONTEXT(%r6) /* Save the non-volatile GP regs.
These can now be used for scratch */
std %r13,PCB_CONTEXT+1*8(%r6)
std %r14,PCB_CONTEXT+2*8(%r6)
std %r15,PCB_CONTEXT+3*8(%r6)
std %r16,PCB_CONTEXT+4*8(%r6)
@ -111,7 +110,7 @@ ENTRY(cpu_switch)
std %r2,PCB_TOC(%r6) /* Save the TOC pointer */
mr %r14,%r3 /* Copy the old thread ptr... */
mr %r15,%r4 /* and the new thread ptr in scratch */
mr %r13,%r4 /* and the new thread ptr in curthread*/
mr %r16,%r5 /* and the new lock */
mr %r17,%r6 /* and the PCB */
@ -148,19 +147,19 @@ cpu_switchin:
lis %r6,blocked_lock@ha
addi %r6,%r6,blocked_lock@l
blocked_loop:
ld %r7,TD_LOCK(%r15)
ld %r7,TD_LOCK(%r13)
cmpd %r6,%r7
beq blocked_loop
#endif
mfsprg %r7,0 /* Get the pcpu pointer */
std %r15,PC_CURTHREAD(%r7) /* Store new current thread */
ld %r17,TD_PCB(%r15) /* Store new current PCB */
std %r13,PC_CURTHREAD(%r7) /* Store new current thread */
ld %r17,TD_PCB(%r13) /* Store new current PCB */
std %r17,PC_CURPCB(%r7)
stdu %r1,-48(%r1)
mr %r3,%r15 /* Get new thread ptr */
mr %r3,%r13 /* Get new thread ptr */
bl pmap_activate /* Activate the new address space */
nop
@ -168,7 +167,7 @@ blocked_loop:
/* Restore FPU context if needed */
andi. %r6, %r6, PCB_FPU
beq .L3
mr %r3,%r15 /* Pass curthread to enable_fpu */
mr %r3,%r13 /* Pass curthread to enable_fpu */
bl enable_fpu
nop
@ -177,7 +176,7 @@ blocked_loop:
/* Restore Altivec context if needed */
andi. %r6, %r6, PCB_VEC
beq .L4
mr %r3,%r15 /* Pass curthread to enable_vec */
mr %r3,%r13 /* Pass curthread to enable_vec */
bl enable_vec
nop
@ -186,7 +185,6 @@ blocked_loop:
addi %r1,%r1,48
mr %r3,%r17 /* Recover PCB ptr */
ld %r12,PCB_CONTEXT(%r3) /* Load the non-volatile GP regs. */
ld %r13,PCB_CONTEXT+1*8(%r3)
ld %r14,PCB_CONTEXT+2*8(%r3)
ld %r15,PCB_CONTEXT+3*8(%r3)
ld %r16,PCB_CONTEXT+4*8(%r3)

6
sys/powerpc/aim/trap.c
View File

@ -149,7 +149,7 @@ trap(struct trapframe *frame)
PCPU_INC(cnt.v_trap);
td = PCPU_GET(curthread);
td = curthread;
p = td->td_proc;
type = ucode = frame->exc;
@ -452,7 +452,7 @@ syscall(struct trapframe *frame)
struct syscall_args sa;
int error;
td = PCPU_GET(curthread);
td = curthread;
td->td_frame = frame;
#ifdef __powerpc64__
@ -600,7 +600,7 @@ badaddr_read(void *addr, size_t size, int *rptr)
/* Get rid of any stale machine checks that have been waiting. */
__asm __volatile ("sync; isync");
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = 0;

14
sys/powerpc/aim/trap_subr32.S
View File

@ -155,9 +155,15 @@
stw %r28,FRAME_AIM_DAR+8(1); \
stw %r29,FRAME_AIM_DSISR+8(1); /* save dsisr/srr0/srr1 */ \
stw %r30,FRAME_SRR0+8(1); \
stw %r31,FRAME_SRR1+8(1)
stw %r31,FRAME_SRR1+8(1); \
lwz %r2,PC_CURTHREAD(%r2) /* set curthread pointer */
#define FRAME_LEAVE(savearea) \
/* Disable exceptions: */ \
mfmsr %r2; \
andi. %r2,%r2,~PSL_EE@l; \
mtmsr %r2; \
isync; \
/* Now restore regs: */ \
lwz %r2,FRAME_SRR0+8(%r1); \
lwz %r3,FRAME_SRR1+8(%r1); \
@ -209,7 +215,7 @@
mtsprg3 %r3; \
/* Disable translation, machine check and recoverability: */ \
mfmsr %r2; \
andi. %r2,%r2,~(PSL_DR|PSL_IR|PSL_EE|PSL_ME|PSL_RI)@l; \
andi. %r2,%r2,~(PSL_DR|PSL_IR|PSL_ME|PSL_RI)@l; \
mtmsr %r2; \
isync; \
/* Decide whether we return to user mode: */ \
@ -764,8 +770,8 @@ CNAME(trapexit):
bf 17,1f /* branch if PSL_PR is false */
GET_CPUINFO(%r3) /* get per-CPU pointer */
lwz %r4, PC_CURTHREAD(%r3) /* deref to get curthread */
lwz %r4, TD_FLAGS(%r4) /* get thread flags value */
lwz %r4, TD_FLAGS(%r2) /* get thread flags value
* (r2 is curthread) */
lis %r5, (TDF_ASTPENDING|TDF_NEEDRESCHED)@h
ori %r5,%r5, (TDF_ASTPENDING|TDF_NEEDRESCHED)@l
and. %r4,%r4,%r5

13
sys/powerpc/aim/trap_subr64.S
View File

@ -179,9 +179,15 @@ restore_kernsrs:
std %r28,FRAME_AIM_DAR+48(1); \
std %r29,FRAME_AIM_DSISR+48(1); /* save dsisr/srr0/srr1 */ \
std %r30,FRAME_SRR0+48(1); \
std %r31,FRAME_SRR1+48(1)
std %r31,FRAME_SRR1+48(1); \
ld %r13,PC_CURTHREAD(%r2) /* set kernel curthread */
#define FRAME_LEAVE(savearea) \
/* Disable exceptions: */ \
mfmsr %r2; \
andi. %r2,%r2,~PSL_EE@l; \
mtmsr %r2; \
isync; \
/* Now restore regs: */ \
ld %r2,FRAME_SRR0+48(%r1); \
ld %r3,FRAME_SRR1+48(%r1); \
@ -233,7 +239,7 @@ restore_kernsrs:
mtsprg3 %r3; \
/* Disable translation, machine check and recoverability: */ \
mfmsr %r2; \
andi. %r2,%r2,~(PSL_DR|PSL_IR|PSL_EE|PSL_ME|PSL_RI)@l; \
andi. %r2,%r2,~(PSL_DR|PSL_IR|PSL_ME|PSL_RI)@l; \
mtmsr %r2; \
isync; \
/* Decide whether we return to user mode: */ \
@ -526,8 +532,7 @@ CNAME(trapexit):
bf 17,1f /* branch if PSL_PR is false */
GET_CPUINFO(%r3) /* get per-CPU pointer */
ld %r4, PC_CURTHREAD(%r3) /* deref to get curthread */
lwz %r4, TD_FLAGS(%r4) /* get thread flags value */
lwz %r4, TD_FLAGS(%r13) /* get thread flags value */
lis %r5, (TDF_ASTPENDING|TDF_NEEDRESCHED)@h
ori %r5,%r5, (TDF_ASTPENDING|TDF_NEEDRESCHED)@l
and. %r4,%r4,%r5

16
sys/powerpc/booke/copyinout.c
View File

@ -87,7 +87,7 @@ copyout(const void *kaddr, void *udaddr, size_t len)
if (!is_uaddr(udaddr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -109,7 +109,7 @@ copyin(const void *udaddr, void *kaddr, size_t len)
if (!is_uaddr(udaddr) || is_uaddr(kaddr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -135,7 +135,7 @@ copyinstr(const void *udaddr, void *kaddr, size_t len, size_t *done)
if (!is_uaddr(udaddr) || is_uaddr(kaddr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -175,7 +175,7 @@ subyte(void *addr, int byte)
if (!is_uaddr(addr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -197,7 +197,7 @@ suword(void *addr, long word)
if (!is_uaddr(addr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -228,7 +228,7 @@ fubyte(const void *addr)
if (!is_uaddr(addr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -251,7 +251,7 @@ fuword(const void *addr)
if (!is_uaddr(addr))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;
@ -288,7 +288,7 @@ casuword(volatile u_long *addr, u_long old, u_long new)
if (!((vm_offset_t)addr <= VM_MAXUSER_ADDRESS))
return (EFAULT);
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = NULL;

2
sys/powerpc/booke/interrupt.c
View File

@ -118,7 +118,7 @@ powerpc_decr_interrupt(struct trapframe *framep)
struct thread *td;
struct trapframe *oldframe;
td = PCPU_GET(curthread);
td = curthread;
critical_enter();
atomic_add_int(&td->td_intr_nesting_level, 1);
oldframe = td->td_intr_frame;

6
sys/powerpc/booke/trap.c
View File

@ -145,7 +145,7 @@ trap(struct trapframe *frame)
PCPU_INC(cnt.v_trap);
td = PCPU_GET(curthread);
td = curthread;
p = td->td_proc;
type = frame->exc;
@ -382,7 +382,7 @@ syscall(struct trapframe *frame)
struct syscall_args sa;
int error;
td = PCPU_GET(curthread);
td = curthread;
td->td_frame = frame;
error = syscallenter(td, &sa);
@ -480,7 +480,7 @@ badaddr_read(void *addr, size_t size, int *rptr)
/* Get rid of any stale machine checks that have been waiting. */
__asm __volatile ("sync; isync");
td = PCPU_GET(curthread);
td = curthread;
if (setfault(env)) {
td->td_pcb->pcb_onfault = 0;

8
sys/powerpc/include/pcpu.h
View File

@ -135,6 +135,14 @@ struct pmap;
#ifdef _KERNEL
#define pcpup ((struct pcpu *) powerpc_get_pcpup())
#ifdef __powerpc64__
register struct thread *curthread_reg __asm("%r13");
#else
register struct thread *curthread_reg __asm("%r2");
#endif
#ifdef AIM /* Book-E not yet adapted */
#define curthread curthread_reg
#endif
#define PCPU_GET(member) (pcpup->pc_ ## member)

14
sys/powerpc/ofw/ofwcall32.S
View File

@ -87,10 +87,11 @@ ASENTRY(ofwcall)
* later.
*/
mr %r5,%r1
lis %r1,(ofwstk+OFWSTKSZ-16)@ha
addi %r1,%r1,(ofwstk+OFWSTKSZ-16)@l
stw %r5,8(%r1) /* Save real stack pointer */
stw %r6,12(%r1) /* Save old MSR */
lis %r1,(ofwstk+OFWSTKSZ-32)@ha
addi %r1,%r1,(ofwstk+OFWSTKSZ-32)@l
stw %r5,20(%r1) /* Save real stack pointer */
stw %r2,24(%r1) /* Save curthread */
stw %r6,28(%r1) /* Save old MSR */
li %r5,0
stw %r5,4(%r1)
stw %r5,0(%r1)
@ -100,8 +101,9 @@ ASENTRY(ofwcall)
bctrl
/* Reload stack pointer and MSR from the OFW stack */
lwz %r6,12(%r1)
lwz %r1,8(%r1)
lwz %r6,28(%r1)
lwz %r2,24(%r1)
lwz %r1,20(%r1)
/* Now set the real MSR */
mtmsr %r6

4
sys/powerpc/powerpc/mp_machdep.c
View File

@ -96,10 +96,6 @@ machdep_ap_bootstrap(void)
printf("SMP: AP CPU #%d launched\n", PCPU_GET(cpuid));
mtx_unlock_spin(&ap_boot_mtx);
/* Initialize curthread */
PCPU_SET(curthread, PCPU_GET(idlethread));
PCPU_SET(curpcb, curthread->td_pcb);
/* Start per-CPU event timers. */
cpu_initclocks_ap();