freebsd-skq/sys/powerpc/aim/vm_machdep.c
Poul-Henning Kamp 21144e3bf1 Remove B_READ, B_WRITE and B_FREEBUF and replace them with a new
field in struct buf: b_iocmd.  The b_iocmd is enforced to have
exactly one bit set.

B_WRITE was bogusly defined as zero giving rise to obvious coding
mistakes.

Also eliminate the redundant struct buf flag B_CALL, it can just
as efficiently be done by comparing b_iodone to NULL.

Should you get a panic or drop into the debugger, complaining about
"b_iocmd", don't continue.  It is likely to write on your disk
where it should have been reading.

This change is a step in the direction towards a stackable BIO capability.

A lot of this patch were machine generated (Thanks to style(9) compliance!)

Vinum users:  Greg has not had time to test this yet, be careful.
2000-03-20 10:44:49 +00:00

490 lines
13 KiB
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 $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
* $FreeBSD$
*/
/*
* Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Chris G. Demetriou
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/vmmeter.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/unistd.h>
#include <machine/clock.h>
#include <machine/cpu.h>
#include <machine/fpu.h>
#include <machine/md_var.h>
#include <machine/prom.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <sys/lock.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>
#include <vm/vm_map.h>
#include <vm/vm_extern.h>
#include <sys/user.h>
/*
* quick version of vm_fault
*/
int
vm_fault_quick(v, prot)
caddr_t v;
int prot;
{
int r;
if (prot & VM_PROT_WRITE)
r = subyte(v, fubyte(v));
else
r = fubyte(v);
return(r);
}
/*
* 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(p1, p2, flags)
register struct proc *p1, *p2;
int flags;
{
struct user *up = p2->p_addr;
if ((flags & RFPROC) == 0)
return;
p2->p_md.md_tf = p1->p_md.md_tf;
p2->p_md.md_flags = p1->p_md.md_flags & (MDP_FPUSED | MDP_UAC_MASK);
/*
* Cache the physical address of the pcb, so we can
* swap to it easily.
*/
p2->p_md.md_pcbpaddr = (void*) vtophys((vm_offset_t) &up->u_pcb);
/*
* Copy floating point state from the FP chip to the PCB
* if this process has state stored there.
*/
alpha_fpstate_save(p1, 0);
/*
* Copy pcb and stack from proc p1 to p2. We do this as
* cheaply as possible, copying only the active part of the
* stack. The stack and pcb need to agree. Make sure that the
* new process has FEN disabled.
*/
p2->p_addr->u_pcb = p1->p_addr->u_pcb;
p2->p_addr->u_pcb.pcb_hw.apcb_usp = alpha_pal_rdusp();
p2->p_addr->u_pcb.pcb_hw.apcb_flags &= ~ALPHA_PCB_FLAGS_FEN;
/*
* Set the floating point state.
*/
if ((p2->p_addr->u_pcb.pcb_fp_control & IEEE_INHERIT) == 0) {
p2->p_addr->u_pcb.pcb_fp_control = 0;
p2->p_addr->u_pcb.pcb_fp.fpr_cr = (FPCR_DYN_NORMAL
| FPCR_INVD | FPCR_DZED
| FPCR_OVFD | FPCR_INED
| FPCR_UNFD);
}
/*
* Arrange for a non-local goto when the new process
* is started, to resume here, returning nonzero from setjmp.
*/
#ifdef DIAGNOSTIC
if (p1 != curproc)
panic("cpu_fork: curproc");
alpha_fpstate_check(p1);
#endif
/*
* create the child's kernel stack, from scratch.
*/
{
struct trapframe *p2tf;
/*
* Pick a stack pointer, leaving room for a trapframe;
* copy trapframe from parent so return to user mode
* will be to right address, with correct registers.
*/
p2tf = p2->p_md.md_tf = (struct trapframe *)
((char *)p2->p_addr + USPACE - sizeof(struct trapframe));
bcopy(p1->p_md.md_tf, p2->p_md.md_tf,
sizeof(struct trapframe));
/*
* Set up return-value registers as fork() libc stub expects.
*/
p2tf->tf_regs[FRAME_V0] = 0; /* child's pid (linux) */
p2tf->tf_regs[FRAME_A3] = 0; /* no error */
p2tf->tf_regs[FRAME_A4] = 1; /* is child (FreeBSD) */
/*
* Arrange for continuation at child_return(), which
* will return to exception_return(). Note that the child
* process doesn't stay in the kernel for long!
*
* This is an inlined version of cpu_set_kpc.
*/
up->u_pcb.pcb_hw.apcb_ksp = (u_int64_t)p2tf;
up->u_pcb.pcb_context[0] =
(u_int64_t)child_return; /* s0: pc */
up->u_pcb.pcb_context[1] =
(u_int64_t)exception_return; /* s1: ra */
up->u_pcb.pcb_context[2] = (u_long) p2; /* s2: a0 */
up->u_pcb.pcb_context[7] =
(u_int64_t)switch_trampoline; /* ra: assembly magic */
}
}
/*
* 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(p, func, arg)
struct proc *p;
void (*func) __P((void *));
void *arg;
{
/*
* Note that the trap frame follows the args, so the function
* is really called like this: func(arg, frame);
*/
p->p_addr->u_pcb.pcb_context[0] = (u_long) func;
p->p_addr->u_pcb.pcb_context[2] = (u_long) arg;
}
/*
* cpu_exit is called as the last action during exit.
* We release the address space of the process, block interrupts,
* and call switch_exit. switch_exit switches to proc0's PCB and stack,
* then jumps into the middle of cpu_switch, as if it were switching
* from proc0.
*/
void
cpu_exit(p)
register struct proc *p;
{
alpha_fpstate_drop(p);
(void) splhigh();
cnt.v_swtch++;
cpu_switch(p);
panic("cpu_exit");
}
void
cpu_wait(p)
struct proc *p;
{
/* drop per-process resources */
pmap_dispose_proc(p);
/* and clean-out the vmspace */
vmspace_free(p->p_vmspace);
}
/*
* Dump the machine specific header information at the start of a core dump.
*/
int
cpu_coredump(p, vp, cred)
struct proc *p;
struct vnode *vp;
struct ucred *cred;
{
return (vn_rdwr(UIO_WRITE, vp, (caddr_t) p->p_addr, ctob(UPAGES),
(off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *)NULL,
p));
}
#ifdef notyet
static void
setredzone(pte, vaddr)
u_short *pte;
caddr_t vaddr;
{
/* eventually do this by setting up an expand-down stack segment
for ss0: selector, allowing stack access down to top of u.
this means though that protection violations need to be handled
thru a double fault exception that must do an integral task
switch to a known good context, within which a dump can be
taken. a sensible scheme might be to save the initial context
used by sched (that has physical memory mapped 1:1 at bottom)
and take the dump while still in mapped mode */
}
#endif
/*
* Map an IO request into kernel virtual address space.
*
* All requests are (re)mapped into kernel VA space.
* Notice that we use b_bufsize for the size of the buffer
* to be mapped. b_bcount might be modified by the driver.
*/
void
vmapbuf(bp)
register struct buf *bp;
{
register caddr_t addr, v, kva;
vm_offset_t pa;
if ((bp->b_flags & B_PHYS) == 0)
panic("vmapbuf");
for (v = bp->b_saveaddr, addr = (caddr_t)trunc_page(bp->b_data);
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE, v += PAGE_SIZE) {
/*
* Do the vm_fault if needed; do the copy-on-write thing
* when reading stuff off device into memory.
*/
vm_fault_quick(addr,
(bp->b_iocmd == BIO_READ)?(VM_PROT_READ|VM_PROT_WRITE):VM_PROT_READ);
pa = trunc_page(pmap_kextract((vm_offset_t) addr));
if (pa == 0)
panic("vmapbuf: page not present");
vm_page_hold(PHYS_TO_VM_PAGE(pa));
pmap_kenter((vm_offset_t) v, pa);
}
kva = bp->b_saveaddr;
bp->b_saveaddr = bp->b_data;
bp->b_data = kva + (((vm_offset_t) bp->b_data) & PAGE_MASK);
}
/*
* Free the io map PTEs associated with this IO operation.
* We also invalidate the TLB entries and restore the original b_addr.
*/
void
vunmapbuf(bp)
register struct buf *bp;
{
register caddr_t addr;
vm_offset_t pa;
if ((bp->b_flags & B_PHYS) == 0)
panic("vunmapbuf");
for (addr = (caddr_t)trunc_page(bp->b_data);
addr < bp->b_data + bp->b_bufsize;
addr += PAGE_SIZE) {
pa = trunc_page(pmap_kextract((vm_offset_t) addr));
pmap_kremove((vm_offset_t) addr);
vm_page_unhold(PHYS_TO_VM_PAGE(pa));
}
bp->b_data = bp->b_saveaddr;
}
/*
* Force reset the processor by invalidating the entire address space!
*/
void
cpu_reset()
{
prom_halt(0);
}
int
grow_stack(p, sp)
struct proc *p;
size_t sp;
{
int rv;
rv = vm_map_growstack (p, sp);
if (rv != KERN_SUCCESS)
return (0);
return (1);
}
static int cnt_prezero;
SYSCTL_INT(_machdep, OID_AUTO, cnt_prezero, CTLFLAG_RD, &cnt_prezero, 0, "");
/*
* Implement the pre-zeroed page mechanism.
* This routine is called from the idle loop.
*/
#define ZIDLE_LO(v) ((v) * 2 / 3)
#define ZIDLE_HI(v) ((v) * 4 / 5)
int
vm_page_zero_idle()
{
static int free_rover;
static int zero_state;
vm_page_t m;
int s;
/*
* Attempt to maintain approximately 1/2 of our free pages in a
* PG_ZERO'd state. Add some hysteresis to (attempt to) avoid
* generally zeroing a page when the system is near steady-state.
* Otherwise we might get 'flutter' during disk I/O / IPC or
* fast sleeps. We also do not want to be continuously zeroing
* pages because doing so may flush our L1 and L2 caches too much.
*/
if (zero_state && vm_page_zero_count >= ZIDLE_LO(cnt.v_free_count))
return(0);
if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
return(0);
#ifdef SMP
if (try_mplock()) {
#endif
s = splvm();
m = vm_page_list_find(PQ_FREE, free_rover, FALSE);
zero_state = 0;
if (m != NULL && (m->flags & PG_ZERO) == 0) {
vm_page_queues[m->queue].lcnt--;
TAILQ_REMOVE(&vm_page_queues[m->queue].pl, m, pageq);
m->queue = PQ_NONE;
splx(s);
#if 0
rel_mplock();
#endif
pmap_zero_page(VM_PAGE_TO_PHYS(m));
#if 0
get_mplock();
#endif
(void)splvm();
vm_page_flag_set(m, PG_ZERO);
m->queue = PQ_FREE + m->pc;
vm_page_queues[m->queue].lcnt++;
TAILQ_INSERT_TAIL(&vm_page_queues[m->queue].pl, m,
pageq);
++vm_page_zero_count;
++cnt_prezero;
if (vm_page_zero_count >= ZIDLE_HI(cnt.v_free_count))
zero_state = 1;
}
free_rover = (free_rover + PQ_PRIME2) & PQ_L2_MASK;
splx(s);
#ifdef SMP
rel_mplock();
#endif
return (1);
#ifdef SMP
}
#endif
return (0);
}
/*
* Software interrupt handler for queued VM system processing.
*/
void
swi_vm()
{
#if 0
if (busdma_swi_pending != 0)
busdma_swi();
#endif
}
/*
* 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(addr)
vm_offset_t addr;
{
/*
* stuff other tests for known memory-mapped devices (PCI?)
* here
*/
return 1;
}