minix/servers/vm/pagefaults.c
Ben Gras b538531449 vm: make WARNS=5 proof
Change-Id: I737ded223daf04f1c0c85a2e8e6b36c8fdcd07db
2013-09-06 11:51:20 +02:00

299 lines
7.2 KiB
C

#define _SYSTEM 1
#include <minix/callnr.h>
#include <minix/com.h>
#include <minix/config.h>
#include <minix/const.h>
#include <minix/ds.h>
#include <minix/endpoint.h>
#include <minix/keymap.h>
#include <minix/minlib.h>
#include <minix/type.h>
#include <minix/ipc.h>
#include <minix/sysutil.h>
#include <minix/syslib.h>
#include <minix/safecopies.h>
#include <minix/bitmap.h>
#include <errno.h>
#include <string.h>
#include <env.h>
#include <stdio.h>
#include <fcntl.h>
#include <signal.h>
#include <assert.h>
#include "glo.h"
#include "proto.h"
#include "util.h"
#include "region.h"
/*===========================================================================*
* pf_errstr *
*===========================================================================*/
char *pf_errstr(u32_t err)
{
static char buf[100];
sprintf(buf, "err 0x%lx ", (long)err);
if(PFERR_NOPAGE(err)) strcat(buf, "nopage ");
if(PFERR_PROT(err)) strcat(buf, "protection ");
if(PFERR_WRITE(err)) strcat(buf, "write");
if(PFERR_READ(err)) strcat(buf, "read");
return buf;
}
struct pf_state {
endpoint_t ep;
vir_bytes vaddr;
u32_t err;
};
struct hm_state {
endpoint_t requestor;
struct vmproc *vmp;
vir_bytes mem;
vir_bytes len;
int wrflag;
};
static void pf_cont(struct vmproc *vmp, message *m, void *arg, void *statearg);
static void hm_cont(struct vmproc *vmp, message *m, void *arg, void *statearg);
static void handle_pagefault(endpoint_t ep, vir_bytes addr, u32_t err, int retry)
{
struct vmproc *vmp;
int s, result;
struct vir_region *region;
vir_bytes offset;
int p, wr = PFERR_WRITE(err);
int io = 0;
if(vm_isokendpt(ep, &p) != OK)
panic("handle_pagefault: endpoint wrong: %d", ep);
vmp = &vmproc[p];
assert(vmp->vm_flags & VMF_INUSE);
/* See if address is valid at all. */
if(!(region = map_lookup(vmp, addr, NULL))) {
if(PFERR_PROT(err)) {
printf("VM: pagefault: SIGSEGV %d protected addr 0x%lx; %s\n",
ep, addr, pf_errstr(err));
} else {
assert(PFERR_NOPAGE(err));
printf("VM: pagefault: SIGSEGV %d bad addr 0x%lx; %s\n",
ep, addr, pf_errstr(err));
sys_sysctl_stacktrace(ep);
}
if((s=sys_kill(vmp->vm_endpoint, SIGSEGV)) != OK)
panic("sys_kill failed: %d", s);
if((s=sys_vmctl(ep, VMCTL_CLEAR_PAGEFAULT, 0 /*unused*/)) != OK)
panic("do_pagefaults: sys_vmctl failed: %d", ep);
return;
}
/* If process was writing, see if it's writable. */
if(!(region->flags & VR_WRITABLE) && wr) {
printf("VM: pagefault: SIGSEGV %d ro map 0x%lx %s\n",
ep, addr, pf_errstr(err));
if((s=sys_kill(vmp->vm_endpoint, SIGSEGV)) != OK)
panic("sys_kill failed: %d", s);
if((s=sys_vmctl(ep, VMCTL_CLEAR_PAGEFAULT, 0 /*unused*/)) != OK)
panic("do_pagefaults: sys_vmctl failed: %d", ep);
return;
}
assert(addr >= region->vaddr);
offset = addr - region->vaddr;
/* Access is allowed; handle it. */
if(retry) {
result = map_pf(vmp, region, offset, wr, NULL, NULL, 0, &io);
assert(result != SUSPEND);
} else {
struct pf_state state;
state.ep = ep;
state.vaddr = addr;
state.err = err;
result = map_pf(vmp, region, offset, wr, pf_cont,
&state, sizeof(state), &io);
}
if (io)
vmp->vm_major_page_fault++;
else
vmp->vm_minor_page_fault++;
if(result == SUSPEND) {
return;
}
if(result != OK) {
printf("VM: pagefault: SIGSEGV %d pagefault not handled\n", ep);
if((s=sys_kill(ep, SIGSEGV)) != OK)
panic("sys_kill failed: %d", s);
if((s=sys_vmctl(ep, VMCTL_CLEAR_PAGEFAULT, 0 /*unused*/)) != OK)
panic("do_pagefaults: sys_vmctl failed: %d", ep);
return;
}
pt_clearmapcache();
/* Pagefault is handled, so now reactivate the process. */
if((s=sys_vmctl(ep, VMCTL_CLEAR_PAGEFAULT, 0 /*unused*/)) != OK)
panic("do_pagefaults: sys_vmctl failed: %d", ep);
}
static void pf_cont(struct vmproc *vmp, message *m,
void *arg, void *statearg)
{
struct pf_state *state = statearg;
int p;
if(vm_isokendpt(state->ep, &p) != OK) return; /* signal */
handle_pagefault(state->ep, state->vaddr, state->err, 1);
}
static void hm_cont(struct vmproc *vmp, message *m,
void *arg, void *statearg)
{
int r;
struct hm_state *state = statearg;
printf("hm_cont: result %d\n", m->VMV_RESULT);
r = handle_memory(vmp, state->mem, state->len, state->wrflag,
hm_cont, &state, sizeof(state));
if(r == SUSPEND) {
printf("VM: hm_cont: damnit: hm_cont: more SUSPEND\n");
return;
}
printf("VM: hm_cont: ok, result %d, requestor %d\n", r, state->requestor);
if(sys_vmctl(state->requestor, VMCTL_MEMREQ_REPLY, r) != OK)
panic("hm_cont: sys_vmctl failed: %d", r);
printf("MEMREQ_REPLY sent\n");
}
/*===========================================================================*
* do_pagefaults *
*===========================================================================*/
void do_pagefaults(message *m)
{
handle_pagefault(m->m_source, m->VPF_ADDR, m->VPF_FLAGS, 0);
}
/*===========================================================================*
* do_memory *
*===========================================================================*/
void do_memory(void)
{
endpoint_t who, who_s, requestor;
vir_bytes mem, mem_s;
vir_bytes len;
int wrflag;
while(1) {
int p, r = OK;
struct vmproc *vmp;
r = sys_vmctl_get_memreq(&who, &mem, &len, &wrflag, &who_s,
&mem_s, &requestor);
switch(r) {
case VMPTYPE_CHECK:
{
struct hm_state state;
if(vm_isokendpt(who, &p) != OK)
panic("do_memory: bad endpoint: %d", who);
vmp = &vmproc[p];
state.vmp = vmp;
state.mem = mem;
state.len = len;
state.wrflag = wrflag;
state.requestor = requestor;
r = handle_memory(vmp, mem, len,
wrflag, hm_cont, &state, sizeof(state));
break;
}
default:
return;
}
if(r != SUSPEND) {
if(sys_vmctl(requestor, VMCTL_MEMREQ_REPLY, r) != OK)
panic("do_memory: sys_vmctl failed: %d", r);
}
}
}
int handle_memory(struct vmproc *vmp, vir_bytes mem, vir_bytes len, int wrflag,
vfs_callback_t callback, void *state, int statelen)
{
struct vir_region *region;
vir_bytes o;
struct hm_state *hmstate = (struct hm_state *) state;
/* Page-align memory and length. */
o = mem % VM_PAGE_SIZE;
mem -= o;
len += o;
o = len % VM_PAGE_SIZE;
if(o > 0) len += VM_PAGE_SIZE - o;
while(len > 0) {
int r;
if(!(region = map_lookup(vmp, mem, NULL))) {
#if VERBOSE
map_printmap(vmp);
printf("VM: do_memory: memory doesn't exist\n");
#endif
r = EFAULT;
} else if(!(region->flags & VR_WRITABLE) && wrflag) {
#if VERBOSE
printf("VM: do_memory: write to unwritable map\n");
#endif
r = EFAULT;
} else {
vir_bytes offset, sublen;
assert(region->vaddr <= mem);
assert(!(region->vaddr % VM_PAGE_SIZE));
offset = mem - region->vaddr;
sublen = len;
if(offset + sublen > region->length)
sublen = region->length - offset;
if(hmstate && hmstate->requestor == VFS_PROC_NR
&& region->def_memtype == &mem_type_mappedfile) {
r = map_handle_memory(vmp, region, offset,
sublen, wrflag, NULL, NULL, 0);
} else {
r = map_handle_memory(vmp, region, offset,
sublen, wrflag, callback, state, sizeof(state));
}
len -= sublen;
mem += sublen;
}
if(r != OK) {
#if VERBOSE
printf("VM: memory range 0x%lx-0x%lx not available in %d\n",
mem, mem+len, vmp->vm_endpoint);
#endif
return r;
}
}
return OK;
}