minix/servers/vm/pagefaults.c

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#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 <pagefaults.h>
#include "glo.h"
#include "proto.h"
#include "memory.h"
#include "util.h"
#include "region.h"
/*===========================================================================*
* pf_errstr *
*===========================================================================*/
char *pf_errstr(u32_t err)
{
static char buf[100];
Build NetBSD libc library in world in ELF mode. 3 sets of libraries are built now: . ack: all libraries that ack can compile (/usr/lib/i386/) . clang+elf: all libraries with minix headers (/usr/lib/) . clang+elf: all libraries with netbsd headers (/usr/netbsd/) Once everything can be compiled with netbsd libraries and headers, the /usr/netbsd hierarchy will be obsolete and its libraries compiled with netbsd headers will be installed in /usr/lib, and its headers in /usr/include. (i.e. minix libc and current minix headers set will be gone.) To use the NetBSD libc system (libraries + headers) before it is the default libc, see: http://wiki.minix3.org/en/DevelopersGuide/UsingNetBSDCode This wiki page also documents the maintenance of the patch files of minix-specific changes to imported NetBSD code. Changes in this commit: . libsys: Add NBSD compilation and create a safe NBSD-based libc. . Port rest of libraries (except libddekit) to new header system. . Enable compilation of libddekit with new headers. . Enable kernel compilation with new headers. . Enable drivers compilation with new headers. . Port legacy commands to new headers and libc. . Port servers to new headers. . Add <sys/sigcontext.h> in compat library. . Remove dependency file in tree. . Enable compilation of common/lib/libc/atomic in libsys . Do not generate RCSID strings in libc. . Temporarily disable zoneinfo as they are incompatible with NetBSD format . obj-nbsd for .gitignore . Procfs: use only integer arithmetic. (Antoine Leca) . Increase ramdisk size to create NBSD-based images. . Remove INCSYMLINKS handling hack. . Add nbsd_include/sys/exec_elf.h . Enable ELF compilation with NBSD libc. . Add 'make nbsdsrc' in tools to download reference NetBSD sources. . Automate minix-port.patch creation. . Avoid using fstavfs() as it is *extremely* slow and unneeded. . Set err() as PRIVATE to avoid name clash with libc. . [NBSD] servers/vm: remove compilation warnings. . u32 is not a long in NBSD headers. . UPDATING info on netbsd hierarchy . commands fixes for netbsd libc
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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;
}
/*===========================================================================*
* do_pagefaults *
*===========================================================================*/
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void do_pagefaults(message *m)
{
endpoint_t ep = m->m_source;
u32_t addr = m->VPF_ADDR;
u32_t err = m->VPF_FLAGS;
struct vmproc *vmp;
int s;
struct vir_region *region;
vir_bytes offset;
int p, wr = PFERR_WRITE(err);
if(vm_isokendpt(ep, &p) != OK)
panic("do_pagefaults: 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))) {
assert(PFERR_NOPAGE(err));
printf("VM: pagefault: SIGSEGV %d bad addr %s; %s\n",
ep, arch_map2str(vmp, 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;
}
/* Make sure this isn't a region that isn't supposed
* to cause pagefaults.
*/
assert(!(region->flags & VR_NOPF));
/* 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, arch_map2vir(vmp, 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((map_pf(vmp, region, offset, wr)) != OK) {
printf("VM: pagefault: SIGSEGV %d pagefault not handled\n", 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;
}
/* 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);
}
/*===========================================================================*
* do_memory *
*===========================================================================*/
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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:
if(vm_isokendpt(who, &p) != OK)
panic("do_memory: bad endpoint: %d", who);
vmp = &vmproc[p];
r = handle_memory(vmp, mem, len, wrflag);
break;
case VMPTYPE_COWMAP:
r = map_memory(who_s, who, mem_s, mem, len, -1);
break;
case VMPTYPE_SMAP:
r = map_memory(who_s, who, mem_s, mem, len, wrflag);
break;
case VMPTYPE_SUNMAP:
r = unmap_memory(who_s, who, mem_s, mem, len, wrflag);
break;
default:
return;
}
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)
{
struct vir_region *region;
vir_bytes o;
/* 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))) {
#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->flags & VR_NOPF));
assert(!(region->vaddr % VM_PAGE_SIZE));
offset = mem - region->vaddr;
sublen = len;
if(offset + sublen > region->length)
sublen = region->length - offset;
r = map_handle_memory(vmp, region, offset,
sublen, wrflag);
len -= sublen;
mem += sublen;
}
if(r != OK) {
#if VERBOSE
printf("VM: memory range 0x%lx-0x%lx not available in %d\n",
arch_map2vir(vmp, mem), arch_map2vir(vmp, mem+len),
vmp->vm_endpoint);
#endif
return r;
}
}
return OK;
}
New RS and new signal handling for system processes. UPDATING INFO: 20100317: /usr/src/etc/system.conf updated to ignore default kernel calls: copy it (or merge it) to /etc/system.conf. The hello driver (/dev/hello) added to the distribution: # cd /usr/src/commands/scripts && make clean install # cd /dev && MAKEDEV hello KERNEL CHANGES: - Generic signal handling support. The kernel no longer assumes PM as a signal manager for every process. The signal manager of a given process can now be specified in its privilege slot. When a signal has to be delivered, the kernel performs the lookup and forwards the signal to the appropriate signal manager. PM is the default signal manager for user processes, RS is the default signal manager for system processes. To enable ptrace()ing for system processes, it is sufficient to change the default signal manager to PM. This will temporarily disable crash recovery, though. - sys_exit() is now split into sys_exit() (i.e. exit() for system processes, which generates a self-termination signal), and sys_clear() (i.e. used by PM to ask the kernel to clear a process slot when a process exits). - Added a new kernel call (i.e. sys_update()) to swap two process slots and implement live update. PM CHANGES: - Posix signal handling is no longer allowed for system processes. System signals are split into two fixed categories: termination and non-termination signals. When a non-termination signaled is processed, PM transforms the signal into an IPC message and delivers the message to the system process. When a termination signal is processed, PM terminates the process. - PM no longer assumes itself as the signal manager for system processes. It now makes sure that every system signal goes through the kernel before being actually processes. The kernel will then dispatch the signal to the appropriate signal manager which may or may not be PM. SYSLIB CHANGES: - Simplified SEF init and LU callbacks. - Added additional predefined SEF callbacks to debug crash recovery and live update. - Fixed a temporary ack in the SEF init protocol. SEF init reply is now completely synchronous. - Added SEF signal event type to provide a uniform interface for system processes to deal with signals. A sef_cb_signal_handler() callback is available for system processes to handle every received signal. A sef_cb_signal_manager() callback is used by signal managers to process system signals on behalf of the kernel. - Fixed a few bugs with memory mapping and DS. VM CHANGES: - Page faults and memory requests coming from the kernel are now implemented using signals. - Added a new VM call to swap two process slots and implement live update. - The call is used by RS at update time and in turn invokes the kernel call sys_update(). RS CHANGES: - RS has been reworked with a better functional decomposition. - Better kernel call masks. com.h now defines the set of very basic kernel calls every system service is allowed to use. This makes system.conf simpler and easier to maintain. In addition, this guarantees a higher level of isolation for system libraries that use one or more kernel calls internally (e.g. printf). - RS is the default signal manager for system processes. By default, RS intercepts every signal delivered to every system process. This makes crash recovery possible before bringing PM and friends in the loop. - RS now supports fast rollback when something goes wrong while initializing the new version during a live update. - Live update is now implemented by keeping the two versions side-by-side and swapping the process slots when the old version is ready to update. - Crash recovery is now implemented by keeping the two versions side-by-side and cleaning up the old version only when the recovery process is complete. DS CHANGES: - Fixed a bug when the process doing ds_publish() or ds_delete() is not known by DS. - Fixed the completely broken support for strings. String publishing is now implemented in the system library and simply wraps publishing of memory ranges. Ideally, we should adopt a similar approach for other data types as well. - Test suite fixed. DRIVER CHANGES: - The hello driver has been added to the Minix distribution to demonstrate basic live update and crash recovery functionalities. - Other drivers have been adapted to conform the new SEF interface.
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