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| Current File : //sys/i386/i386/vm_machdep.c |
/*-
* Copyright (c) 1982, 1986 The Regents of the University of California.
* Copyright (c) 1989, 1990 William Jolitz
* Copyright (c) 1994 John Dyson
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department, and William Jolitz.
*
* 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 the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
* from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/i386/i386/vm_machdep.c 223758 2011-07-04 12:04:52Z attilio $");
#include "opt_isa.h"
#include "opt_npx.h"
#include "opt_reset.h"
#include "opt_cpu.h"
#include "opt_xbox.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/pioctl.h>
#include <sys/proc.h>
#include <sys/sysent.h>
#include <sys/sf_buf.h>
#include <sys/smp.h>
#include <sys/sched.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <machine/cpu.h>
#include <machine/cputypes.h>
#include <machine/md_var.h>
#include <machine/pcb.h>
#include <machine/pcb_ext.h>
#include <machine/smp.h>
#include <machine/vm86.h>
#ifdef CPU_ELAN
#include <machine/elan_mmcr.h>
#endif
#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_param.h>
#ifdef XEN
#include <xen/hypervisor.h>
#endif
#ifdef PC98
#include <pc98/cbus/cbus.h>
#else
#include <x86/isa/isa.h>
#endif
#ifdef XBOX
#include <machine/xbox.h>
#endif
#ifndef NSFBUFS
#define NSFBUFS (512 + maxusers * 16)
#endif
static void cpu_reset_real(void);
#ifdef SMP
static void cpu_reset_proxy(void);
static u_int cpu_reset_proxyid;
static volatile u_int cpu_reset_proxy_active;
#endif
static void sf_buf_init(void *arg);
SYSINIT(sock_sf, SI_SUB_MBUF, SI_ORDER_ANY, sf_buf_init, NULL);
LIST_HEAD(sf_head, sf_buf);
/*
* A hash table of active sendfile(2) buffers
*/
static struct sf_head *sf_buf_active;
static u_long sf_buf_hashmask;
#define SF_BUF_HASH(m) (((m) - vm_page_array) & sf_buf_hashmask)
static TAILQ_HEAD(, sf_buf) sf_buf_freelist;
static u_int sf_buf_alloc_want;
/*
* A lock used to synchronize access to the hash table and free list
*/
static struct mtx sf_buf_lock;
extern int _ucodesel, _udatasel;
/*
* Finish a fork operation, with process p2 nearly set up.
* Copy and update the pcb, set up the stack so that the child
* ready to run and return to user mode.
*/
void
cpu_fork(td1, p2, td2, flags)
register struct thread *td1;
register struct proc *p2;
struct thread *td2;
int flags;
{
register struct proc *p1;
struct pcb *pcb2;
struct mdproc *mdp2;
p1 = td1->td_proc;
if ((flags & RFPROC) == 0) {
if ((flags & RFMEM) == 0) {
/* unshare user LDT */
struct mdproc *mdp1 = &p1->p_md;
struct proc_ldt *pldt, *pldt1;
mtx_lock_spin(&dt_lock);
if ((pldt1 = mdp1->md_ldt) != NULL &&
pldt1->ldt_refcnt > 1) {
pldt = user_ldt_alloc(mdp1, pldt1->ldt_len);
if (pldt == NULL)
panic("could not copy LDT");
mdp1->md_ldt = pldt;
set_user_ldt(mdp1);
user_ldt_deref(pldt1);
} else
mtx_unlock_spin(&dt_lock);
}
return;
}
/* Ensure that td1's pcb is up to date. */
if (td1 == curthread)
td1->td_pcb->pcb_gs = rgs();
#ifdef DEV_NPX
critical_enter();
if (PCPU_GET(fpcurthread) == td1)
npxsave(td1->td_pcb->pcb_save);
critical_exit();
#endif
/* Point the pcb to the top of the stack */
pcb2 = (struct pcb *)(td2->td_kstack +
td2->td_kstack_pages * PAGE_SIZE) - 1;
td2->td_pcb = pcb2;
/* Copy td1's pcb */
bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
/* Properly initialize pcb_save */
pcb2->pcb_save = &pcb2->pcb_user_save;
/* Point mdproc and then copy over td1's contents */
mdp2 = &p2->p_md;
bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
/*
* Create a new fresh stack for the new process.
* Copy the trap frame for the return to user mode as if from a
* syscall. This copies most of the user mode register values.
* The -16 is so we can expand the trapframe if we go to vm86.
*/
td2->td_frame = (struct trapframe *)((caddr_t)td2->td_pcb - 16) - 1;
bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
td2->td_frame->tf_eax = 0; /* Child returns zero */
td2->td_frame->tf_eflags &= ~PSL_C; /* success */
td2->td_frame->tf_edx = 1;
/*
* If the parent process has the trap bit set (i.e. a debugger had
* single stepped the process to the system call), we need to clear
* the trap flag from the new frame unless the debugger had set PF_FORK
* on the parent. Otherwise, the child will receive a (likely
* unexpected) SIGTRAP when it executes the first instruction after
* returning to userland.
*/
if ((p1->p_pfsflags & PF_FORK) == 0)
td2->td_frame->tf_eflags &= ~PSL_T;
/*
* Set registers for trampoline to user mode. Leave space for the
* return address on stack. These are the kernel mode register values.
*/
#ifdef PAE
pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdpt);
#else
pcb2->pcb_cr3 = vtophys(vmspace_pmap(p2->p_vmspace)->pm_pdir);
#endif
pcb2->pcb_edi = 0;
pcb2->pcb_esi = (int)fork_return; /* fork_trampoline argument */
pcb2->pcb_ebp = 0;
pcb2->pcb_esp = (int)td2->td_frame - sizeof(void *);
pcb2->pcb_ebx = (int)td2; /* fork_trampoline argument */
pcb2->pcb_eip = (int)fork_trampoline;
pcb2->pcb_psl = PSL_KERNEL; /* ints disabled */
/*-
* pcb2->pcb_dr*: cloned above.
* pcb2->pcb_savefpu: cloned above.
* pcb2->pcb_flags: cloned above.
* pcb2->pcb_onfault: cloned above (always NULL here?).
* pcb2->pcb_gs: cloned above.
* pcb2->pcb_ext: cleared below.
*/
/*
* XXX don't copy the i/o pages. this should probably be fixed.
*/
pcb2->pcb_ext = 0;
/* Copy the LDT, if necessary. */
mtx_lock_spin(&dt_lock);
if (mdp2->md_ldt != NULL) {
if (flags & RFMEM) {
mdp2->md_ldt->ldt_refcnt++;
} else {
mdp2->md_ldt = user_ldt_alloc(mdp2,
mdp2->md_ldt->ldt_len);
if (mdp2->md_ldt == NULL)
panic("could not copy LDT");
}
}
mtx_unlock_spin(&dt_lock);
/* Setup to release spin count in fork_exit(). */
td2->td_md.md_spinlock_count = 1;
/*
* XXX XEN need to check on PSL_USER is handled
*/
td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
/*
* Now, cpu_switch() can schedule the new process.
* pcb_esp is loaded pointing to the cpu_switch() stack frame
* containing the return address when exiting cpu_switch.
* This will normally be to fork_trampoline(), which will have
* %ebx loaded with the new proc's pointer. fork_trampoline()
* will set up a stack to call fork_return(p, frame); to complete
* the return to user-mode.
*/
}
/*
* Intercept the return address from a freshly forked process that has NOT
* been scheduled yet.
*
* This is needed to make kernel threads stay in kernel mode.
*/
void
cpu_set_fork_handler(td, func, arg)
struct thread *td;
void (*func)(void *);
void *arg;
{
/*
* Note that the trap frame follows the args, so the function
* is really called like this: func(arg, frame);
*/
td->td_pcb->pcb_esi = (int) func; /* function */
td->td_pcb->pcb_ebx = (int) arg; /* first arg */
}
void
cpu_exit(struct thread *td)
{
/*
* If this process has a custom LDT, release it. Reset pc->pcb_gs
* and %gs before we free it in case they refer to an LDT entry.
*/
mtx_lock_spin(&dt_lock);
if (td->td_proc->p_md.md_ldt) {
td->td_pcb->pcb_gs = _udatasel;
load_gs(_udatasel);
user_ldt_free(td);
} else
mtx_unlock_spin(&dt_lock);
}
void
cpu_thread_exit(struct thread *td)
{
#ifdef DEV_NPX
critical_enter();
if (td == PCPU_GET(fpcurthread))
npxdrop();
critical_exit();
#endif
/* Disable any hardware breakpoints. */
if (td->td_pcb->pcb_flags & PCB_DBREGS) {
reset_dbregs();
td->td_pcb->pcb_flags &= ~PCB_DBREGS;
}
}
void
cpu_thread_clean(struct thread *td)
{
struct pcb *pcb;
pcb = td->td_pcb;
if (pcb->pcb_ext != NULL) {
/* if (pcb->pcb_ext->ext_refcount-- == 1) ?? */
/*
* XXX do we need to move the TSS off the allocated pages
* before freeing them? (not done here)
*/
kmem_free(kernel_map, (vm_offset_t)pcb->pcb_ext,
ctob(IOPAGES + 1));
pcb->pcb_ext = NULL;
}
}
void
cpu_thread_swapin(struct thread *td)
{
}
void
cpu_thread_swapout(struct thread *td)
{
}
void
cpu_thread_alloc(struct thread *td)
{
td->td_pcb = (struct pcb *)(td->td_kstack +
td->td_kstack_pages * PAGE_SIZE) - 1;
td->td_frame = (struct trapframe *)((caddr_t)td->td_pcb - 16) - 1;
td->td_pcb->pcb_ext = NULL;
td->td_pcb->pcb_save = &td->td_pcb->pcb_user_save;
}
void
cpu_thread_free(struct thread *td)
{
cpu_thread_clean(td);
}
void
cpu_set_syscall_retval(struct thread *td, int error)
{
switch (error) {
case 0:
td->td_frame->tf_eax = td->td_retval[0];
td->td_frame->tf_edx = td->td_retval[1];
td->td_frame->tf_eflags &= ~PSL_C;
break;
case ERESTART:
/*
* Reconstruct pc, assuming lcall $X,y is 7 bytes, int
* 0x80 is 2 bytes. We saved this in tf_err.
*/
td->td_frame->tf_eip -= td->td_frame->tf_err;
break;
case EJUSTRETURN:
break;
default:
if (td->td_proc->p_sysent->sv_errsize) {
if (error >= td->td_proc->p_sysent->sv_errsize)
error = -1; /* XXX */
else
error = td->td_proc->p_sysent->sv_errtbl[error];
}
td->td_frame->tf_eax = error;
td->td_frame->tf_eflags |= PSL_C;
break;
}
}
/*
* Initialize machine state (pcb and trap frame) for a new thread about to
* upcall. Put enough state in the new thread's PCB to get it to go back
* userret(), where we can intercept it again to set the return (upcall)
* Address and stack, along with those from upcals that are from other sources
* such as those generated in thread_userret() itself.
*/
void
cpu_set_upcall(struct thread *td, struct thread *td0)
{
struct pcb *pcb2;
/* Point the pcb to the top of the stack. */
pcb2 = td->td_pcb;
/*
* Copy the upcall pcb. This loads kernel regs.
* Those not loaded individually below get their default
* values here.
*/
bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
pcb2->pcb_flags &= ~(PCB_NPXINITDONE | PCB_NPXUSERINITDONE);
pcb2->pcb_save = &pcb2->pcb_user_save;
/*
* Create a new fresh stack for the new thread.
*/
bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
/* If the current thread has the trap bit set (i.e. a debugger had
* single stepped the process to the system call), we need to clear
* the trap flag from the new frame. Otherwise, the new thread will
* receive a (likely unexpected) SIGTRAP when it executes the first
* instruction after returning to userland.
*/
td->td_frame->tf_eflags &= ~PSL_T;
/*
* Set registers for trampoline to user mode. Leave space for the
* return address on stack. These are the kernel mode register values.
*/
pcb2->pcb_edi = 0;
pcb2->pcb_esi = (int)fork_return; /* trampoline arg */
pcb2->pcb_ebp = 0;
pcb2->pcb_esp = (int)td->td_frame - sizeof(void *); /* trampoline arg */
pcb2->pcb_ebx = (int)td; /* trampoline arg */
pcb2->pcb_eip = (int)fork_trampoline;
pcb2->pcb_psl &= ~(PSL_I); /* interrupts must be disabled */
pcb2->pcb_gs = rgs();
/*
* If we didn't copy the pcb, we'd need to do the following registers:
* pcb2->pcb_cr3: cloned above.
* pcb2->pcb_dr*: cloned above.
* pcb2->pcb_savefpu: cloned above.
* pcb2->pcb_flags: cloned above.
* pcb2->pcb_onfault: cloned above (always NULL here?).
* pcb2->pcb_gs: cloned above.
* pcb2->pcb_ext: cleared below.
*/
pcb2->pcb_ext = NULL;
/* Setup to release spin count in fork_exit(). */
td->td_md.md_spinlock_count = 1;
td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
}
/*
* Set that machine state for performing an upcall that has to
* be done in thread_userret() so that those upcalls generated
* in thread_userret() itself can be done as well.
*/
void
cpu_set_upcall_kse(struct thread *td, void (*entry)(void *), void *arg,
stack_t *stack)
{
/*
* Do any extra cleaning that needs to be done.
* The thread may have optional components
* that are not present in a fresh thread.
* This may be a recycled thread so make it look
* as though it's newly allocated.
*/
cpu_thread_clean(td);
/*
* Set the trap frame to point at the beginning of the uts
* function.
*/
td->td_frame->tf_ebp = 0;
td->td_frame->tf_esp =
(((int)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
td->td_frame->tf_eip = (int)entry;
/*
* Pass the address of the mailbox for this kse to the uts
* function as a parameter on the stack.
*/
suword((void *)(td->td_frame->tf_esp + sizeof(void *)),
(int)arg);
}
int
cpu_set_user_tls(struct thread *td, void *tls_base)
{
struct segment_descriptor sd;
uint32_t base;
/*
* Construct a descriptor and store it in the pcb for
* the next context switch. Also store it in the gdt
* so that the load of tf_fs into %fs will activate it
* at return to userland.
*/
base = (uint32_t)tls_base;
sd.sd_lobase = base & 0xffffff;
sd.sd_hibase = (base >> 24) & 0xff;
sd.sd_lolimit = 0xffff; /* 4GB limit, wraps around */
sd.sd_hilimit = 0xf;
sd.sd_type = SDT_MEMRWA;
sd.sd_dpl = SEL_UPL;
sd.sd_p = 1;
sd.sd_xx = 0;
sd.sd_def32 = 1;
sd.sd_gran = 1;
critical_enter();
/* set %gs */
td->td_pcb->pcb_gsd = sd;
if (td == curthread) {
PCPU_GET(fsgs_gdt)[1] = sd;
load_gs(GSEL(GUGS_SEL, SEL_UPL));
}
critical_exit();
return (0);
}
/*
* Convert kernel VA to physical address
*/
vm_paddr_t
kvtop(void *addr)
{
vm_paddr_t pa;
pa = pmap_kextract((vm_offset_t)addr);
if (pa == 0)
panic("kvtop: zero page frame");
return (pa);
}
#ifdef SMP
static void
cpu_reset_proxy()
{
cpuset_t tcrp;
cpu_reset_proxy_active = 1;
while (cpu_reset_proxy_active == 1)
; /* Wait for other cpu to see that we've started */
CPU_SETOF(cpu_reset_proxyid, &tcrp);
stop_cpus(tcrp);
printf("cpu_reset_proxy: Stopped CPU %d\n", cpu_reset_proxyid);
DELAY(1000000);
cpu_reset_real();
}
#endif
void
cpu_reset()
{
#ifdef XBOX
if (arch_i386_is_xbox) {
/* Kick the PIC16L, it can reboot the box */
pic16l_reboot();
for (;;);
}
#endif
#ifdef SMP
cpuset_t map;
u_int cnt;
if (smp_active) {
map = all_cpus;
CPU_CLR(PCPU_GET(cpuid), &map);
CPU_NAND(&map, &stopped_cpus);
if (!CPU_EMPTY(&map)) {
printf("cpu_reset: Stopping other CPUs\n");
stop_cpus(map);
}
if (PCPU_GET(cpuid) != 0) {
cpu_reset_proxyid = PCPU_GET(cpuid);
cpustop_restartfunc = cpu_reset_proxy;
cpu_reset_proxy_active = 0;
printf("cpu_reset: Restarting BSP\n");
/* Restart CPU #0. */
/* XXX: restart_cpus(1 << 0); */
CPU_SETOF(0, &started_cpus);
wmb();
cnt = 0;
while (cpu_reset_proxy_active == 0 && cnt < 10000000)
cnt++; /* Wait for BSP to announce restart */
if (cpu_reset_proxy_active == 0)
printf("cpu_reset: Failed to restart BSP\n");
enable_intr();
cpu_reset_proxy_active = 2;
while (1);
/* NOTREACHED */
}
DELAY(1000000);
}
#endif
cpu_reset_real();
/* NOTREACHED */
}
static void
cpu_reset_real()
{
struct region_descriptor null_idt;
#ifndef PC98
int b;
#endif
disable_intr();
#ifdef XEN
if (smp_processor_id() == 0)
HYPERVISOR_shutdown(SHUTDOWN_reboot);
else
HYPERVISOR_shutdown(SHUTDOWN_poweroff);
#endif
#ifdef CPU_ELAN
if (elan_mmcr != NULL)
elan_mmcr->RESCFG = 1;
#endif
if (cpu == CPU_GEODE1100) {
/* Attempt Geode's own reset */
outl(0xcf8, 0x80009044ul);
outl(0xcfc, 0xf);
}
#ifdef PC98
/*
* Attempt to do a CPU reset via CPU reset port.
*/
if ((inb(0x35) & 0xa0) != 0xa0) {
outb(0x37, 0x0f); /* SHUT0 = 0. */
outb(0x37, 0x0b); /* SHUT1 = 0. */
}
outb(0xf0, 0x00); /* Reset. */
#else
#if !defined(BROKEN_KEYBOARD_RESET)
/*
* Attempt to do a CPU reset via the keyboard controller,
* do not turn off GateA20, as any machine that fails
* to do the reset here would then end up in no man's land.
*/
outb(IO_KBD + 4, 0xFE);
DELAY(500000); /* wait 0.5 sec to see if that did it */
#endif
/*
* Attempt to force a reset via the Reset Control register at
* I/O port 0xcf9. Bit 2 forces a system reset when it
* transitions from 0 to 1. Bit 1 selects the type of reset
* to attempt: 0 selects a "soft" reset, and 1 selects a
* "hard" reset. We try a "hard" reset. The first write sets
* bit 1 to select a "hard" reset and clears bit 2. The
* second write forces a 0 -> 1 transition in bit 2 to trigger
* a reset.
*/
outb(0xcf9, 0x2);
outb(0xcf9, 0x6);
DELAY(500000); /* wait 0.5 sec to see if that did it */
/*
* Attempt to force a reset via the Fast A20 and Init register
* at I/O port 0x92. Bit 1 serves as an alternate A20 gate.
* Bit 0 asserts INIT# when set to 1. We are careful to only
* preserve bit 1 while setting bit 0. We also must clear bit
* 0 before setting it if it isn't already clear.
*/
b = inb(0x92);
if (b != 0xff) {
if ((b & 0x1) != 0)
outb(0x92, b & 0xfe);
outb(0x92, b | 0x1);
DELAY(500000); /* wait 0.5 sec to see if that did it */
}
#endif /* PC98 */
printf("No known reset method worked, attempting CPU shutdown\n");
DELAY(1000000); /* wait 1 sec for printf to complete */
/* Wipe the IDT. */
null_idt.rd_limit = 0;
null_idt.rd_base = 0;
lidt(&null_idt);
/* "good night, sweet prince .... <THUNK!>" */
breakpoint();
/* NOTREACHED */
while(1);
}
/*
* Allocate a pool of sf_bufs (sendfile(2) or "super-fast" if you prefer. :-))
*/
static void
sf_buf_init(void *arg)
{
struct sf_buf *sf_bufs;
vm_offset_t sf_base;
int i;
nsfbufs = NSFBUFS;
TUNABLE_INT_FETCH("kern.ipc.nsfbufs", &nsfbufs);
sf_buf_active = hashinit(nsfbufs, M_TEMP, &sf_buf_hashmask);
TAILQ_INIT(&sf_buf_freelist);
sf_base = kmem_alloc_nofault(kernel_map, nsfbufs * PAGE_SIZE);
sf_bufs = malloc(nsfbufs * sizeof(struct sf_buf), M_TEMP,
M_NOWAIT | M_ZERO);
for (i = 0; i < nsfbufs; i++) {
sf_bufs[i].kva = sf_base + i * PAGE_SIZE;
TAILQ_INSERT_TAIL(&sf_buf_freelist, &sf_bufs[i], free_entry);
}
sf_buf_alloc_want = 0;
mtx_init(&sf_buf_lock, "sf_buf", NULL, MTX_DEF);
}
/*
* Invalidate the cache lines that may belong to the page, if
* (possibly old) mapping of the page by sf buffer exists. Returns
* TRUE when mapping was found and cache invalidated.
*/
boolean_t
sf_buf_invalidate_cache(vm_page_t m)
{
struct sf_head *hash_list;
struct sf_buf *sf;
boolean_t ret;
hash_list = &sf_buf_active[SF_BUF_HASH(m)];
ret = FALSE;
mtx_lock(&sf_buf_lock);
LIST_FOREACH(sf, hash_list, list_entry) {
if (sf->m == m) {
/*
* Use pmap_qenter to update the pte for
* existing mapping, in particular, the PAT
* settings are recalculated.
*/
pmap_qenter(sf->kva, &m, 1);
pmap_invalidate_cache_range(sf->kva, sf->kva +
PAGE_SIZE);
ret = TRUE;
break;
}
}
mtx_unlock(&sf_buf_lock);
return (ret);
}
/*
* Get an sf_buf from the freelist. May block if none are available.
*/
struct sf_buf *
sf_buf_alloc(struct vm_page *m, int flags)
{
pt_entry_t opte, *ptep;
struct sf_head *hash_list;
struct sf_buf *sf;
#ifdef SMP
cpuset_t other_cpus;
u_int cpuid;
#endif
int error;
KASSERT(curthread->td_pinned > 0 || (flags & SFB_CPUPRIVATE) == 0,
("sf_buf_alloc(SFB_CPUPRIVATE): curthread not pinned"));
hash_list = &sf_buf_active[SF_BUF_HASH(m)];
mtx_lock(&sf_buf_lock);
LIST_FOREACH(sf, hash_list, list_entry) {
if (sf->m == m) {
sf->ref_count++;
if (sf->ref_count == 1) {
TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
nsfbufsused++;
nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
}
#ifdef SMP
goto shootdown;
#else
goto done;
#endif
}
}
while ((sf = TAILQ_FIRST(&sf_buf_freelist)) == NULL) {
if (flags & SFB_NOWAIT)
goto done;
sf_buf_alloc_want++;
mbstat.sf_allocwait++;
error = msleep(&sf_buf_freelist, &sf_buf_lock,
(flags & SFB_CATCH) ? PCATCH | PVM : PVM, "sfbufa", 0);
sf_buf_alloc_want--;
/*
* If we got a signal, don't risk going back to sleep.
*/
if (error)
goto done;
}
TAILQ_REMOVE(&sf_buf_freelist, sf, free_entry);
if (sf->m != NULL)
LIST_REMOVE(sf, list_entry);
LIST_INSERT_HEAD(hash_list, sf, list_entry);
sf->ref_count = 1;
sf->m = m;
nsfbufsused++;
nsfbufspeak = imax(nsfbufspeak, nsfbufsused);
/*
* Update the sf_buf's virtual-to-physical mapping, flushing the
* virtual address from the TLB. Since the reference count for
* the sf_buf's old mapping was zero, that mapping is not
* currently in use. Consequently, there is no need to exchange
* the old and new PTEs atomically, even under PAE.
*/
ptep = vtopte(sf->kva);
opte = *ptep;
#ifdef XEN
PT_SET_MA(sf->kva, xpmap_ptom(VM_PAGE_TO_PHYS(m)) | pgeflag
| PG_RW | PG_V | pmap_cache_bits(m->md.pat_mode, 0));
#else
*ptep = VM_PAGE_TO_PHYS(m) | pgeflag | PG_RW | PG_V |
pmap_cache_bits(m->md.pat_mode, 0);
#endif
/*
* Avoid unnecessary TLB invalidations: If the sf_buf's old
* virtual-to-physical mapping was not used, then any processor
* that has invalidated the sf_buf's virtual address from its TLB
* since the last used mapping need not invalidate again.
*/
#ifdef SMP
if ((opte & (PG_V | PG_A)) == (PG_V | PG_A))
CPU_ZERO(&sf->cpumask);
shootdown:
sched_pin();
cpuid = PCPU_GET(cpuid);
if (!CPU_ISSET(cpuid, &sf->cpumask)) {
CPU_SET(cpuid, &sf->cpumask);
invlpg(sf->kva);
}
if ((flags & SFB_CPUPRIVATE) == 0) {
other_cpus = all_cpus;
CPU_CLR(cpuid, &other_cpus);
CPU_NAND(&other_cpus, &sf->cpumask);
if (!CPU_EMPTY(&other_cpus)) {
CPU_OR(&sf->cpumask, &other_cpus);
smp_masked_invlpg(other_cpus, sf->kva);
}
}
sched_unpin();
#else
if ((opte & (PG_V | PG_A)) == (PG_V | PG_A))
pmap_invalidate_page(kernel_pmap, sf->kva);
#endif
done:
mtx_unlock(&sf_buf_lock);
return (sf);
}
/*
* Remove a reference from the given sf_buf, adding it to the free
* list when its reference count reaches zero. A freed sf_buf still,
* however, retains its virtual-to-physical mapping until it is
* recycled or reactivated by sf_buf_alloc(9).
*/
void
sf_buf_free(struct sf_buf *sf)
{
mtx_lock(&sf_buf_lock);
sf->ref_count--;
if (sf->ref_count == 0) {
TAILQ_INSERT_TAIL(&sf_buf_freelist, sf, free_entry);
nsfbufsused--;
#ifdef XEN
/*
* Xen doesn't like having dangling R/W mappings
*/
pmap_qremove(sf->kva, 1);
sf->m = NULL;
LIST_REMOVE(sf, list_entry);
#endif
if (sf_buf_alloc_want > 0)
wakeup(&sf_buf_freelist);
}
mtx_unlock(&sf_buf_lock);
}
/*
* Software interrupt handler for queued VM system processing.
*/
void
swi_vm(void *dummy)
{
if (busdma_swi_pending != 0)
busdma_swi();
}
/*
* Tell whether this address is in some physical memory region.
* Currently used by the kernel coredump code in order to avoid
* dumping the ``ISA memory hole'' which could cause indefinite hangs,
* or other unpredictable behaviour.
*/
int
is_physical_memory(vm_paddr_t addr)
{
#ifdef DEV_ISA
/* The ISA ``memory hole''. */
if (addr >= 0xa0000 && addr < 0x100000)
return 0;
#endif
/*
* stuff other tests for known memory-mapped devices (PCI?)
* here
*/
return 1;
}