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minix/servers/vm/exec.c
Ben Gras 68d0c4defe - code shared with exec() letting boot-time processes have 
their own fully fledged virtual address space and freeing
   their pre-allocated heap+stack area (necessary to let memory
   driver map in arbitrary areas of memory for /dev/mem without
   sys_vm_map)
 - small optimization preallocating memory on exec
 - finished VR_DIRECT physical mapping code
2008-12-08 16:43:20 +00:00

445 lines
14 KiB
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/const.h>
#include <errno.h>
#include <assert.h>
#include <env.h>
#include <pagetable.h>
#include "glo.h"
#include "proto.h"
#include "util.h"
#include "vm.h"
#include "region.h"
#include "sanitycheck.h"
#include "memory.h"
FORWARD _PROTOTYPE( int new_mem, (struct vmproc *vmp, struct vmproc *sh_vmp,
vir_bytes text_bytes, vir_bytes data_bytes, vir_bytes bss_bytes,
vir_bytes stk_bytes, phys_bytes tot_bytes) );
/*===========================================================================*
* find_share *
*===========================================================================*/
PUBLIC struct vmproc *find_share(vmp_ign, ino, dev, ctime)
struct vmproc *vmp_ign; /* process that should not be looked at */
ino_t ino; /* parameters that uniquely identify a file */
dev_t dev;
time_t ctime;
{
/* Look for a process that is the file <ino, dev, ctime> in execution. Don't
* accidentally "find" vmp_ign, because it is the process on whose behalf this
* call is made.
*/
struct vmproc *vmp;
for (vmp = &vmproc[0]; vmp < &vmproc[NR_PROCS]; vmp++) {
if (!(vmp->vm_flags & VMF_INUSE)) continue;
if (!(vmp->vm_flags & VMF_SEPARATE)) continue;
if (vmp->vm_flags & VMF_HASPT) continue;
if (vmp == vmp_ign) continue;
if (vmp->vm_ino != ino) continue;
if (vmp->vm_dev != dev) continue;
if (vmp->vm_ctime != ctime) continue;
return vmp;
}
return(NULL);
}
/*===========================================================================*
* exec_newmem *
*===========================================================================*/
PUBLIC int do_exec_newmem(message *msg)
{
int r, proc_e, proc_n;
vir_bytes stack_top;
vir_clicks tc, dc, sc, totc, dvir, s_vir;
struct vmproc *vmp, *sh_mp;
char *ptr;
struct exec_newmem args;
SANITYCHECK(SCL_FUNCTIONS);
proc_e= msg->VMEN_ENDPOINT;
if (vm_isokendpt(proc_e, &proc_n) != OK)
{
printf("VM:exec_newmem: bad endpoint %d from %d\n",
proc_e, msg->m_source);
return ESRCH;
}
vmp= &vmproc[proc_n];
ptr= msg->VMEN_ARGSPTR;
if(msg->VMEN_ARGSSIZE != sizeof(args)) {
printf("VM:exec_newmem: args size %d != %ld\n",
msg->VMEN_ARGSSIZE, sizeof(args));
return EINVAL;
}
SANITYCHECK(SCL_DETAIL);
r= sys_datacopy(msg->m_source, (vir_bytes)ptr,
SELF, (vir_bytes)&args, sizeof(args));
if (r != OK)
vm_panic("exec_newmem: sys_datacopy failed", r);
/* Check to see if segment sizes are feasible. */
tc = ((unsigned long) args.text_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
dc = (args.data_bytes+args.bss_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
totc = (args.tot_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
sc = (args.args_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
if (dc >= totc) return(ENOEXEC); /* stack must be at least 1 click */
dvir = (args.sep_id ? 0 : tc);
s_vir = dvir + (totc - sc);
r = (dvir + dc > s_vir) ? ENOMEM : OK;
if (r != OK)
return r;
/* Can the process' text be shared with that of one already running? */
if(!vm_paged) {
sh_mp = find_share(vmp, args.st_ino, args.st_dev, args.st_ctime);
} else {
sh_mp = NULL;
}
/* Allocate new memory and release old memory. Fix map and tell
* kernel.
*/
r = new_mem(vmp, sh_mp, args.text_bytes, args.data_bytes,
args.bss_bytes, args.args_bytes, args.tot_bytes);
if (r != OK) return(r);
/* Save file identification to allow it to be shared. */
vmp->vm_ino = args.st_ino;
vmp->vm_dev = args.st_dev;
vmp->vm_ctime = args.st_ctime;
stack_top= ((vir_bytes)vmp->vm_arch.vm_seg[S].mem_vir << CLICK_SHIFT) +
((vir_bytes)vmp->vm_arch.vm_seg[S].mem_len << CLICK_SHIFT);
/* set/clear separate I&D flag */
if (args.sep_id)
vmp->vm_flags |= VMF_SEPARATE;
else
vmp->vm_flags &= ~VMF_SEPARATE;
msg->VMEN_STACK_TOP = (void *) stack_top;
msg->VMEN_FLAGS = 0;
if (!sh_mp) /* Load text if sh_mp = NULL */
msg->VMEN_FLAGS |= EXC_NM_RF_LOAD_TEXT;
return OK;
}
/*===========================================================================*
* new_mem *
*===========================================================================*/
PRIVATE int new_mem(rmp, sh_mp, text_bytes, data_bytes,
bss_bytes,stk_bytes,tot_bytes)
struct vmproc *rmp; /* process to get a new memory map */
struct vmproc *sh_mp; /* text can be shared with this process */
vir_bytes text_bytes; /* text segment size in bytes */
vir_bytes data_bytes; /* size of initialized data in bytes */
vir_bytes bss_bytes; /* size of bss in bytes */
vir_bytes stk_bytes; /* size of initial stack segment in bytes */
phys_bytes tot_bytes; /* total memory to allocate, including gap */
{
/* Allocate new memory and release the old memory. Change the map and report
* the new map to the kernel. Zero the new core image's bss, gap and stack.
*/
vir_clicks text_clicks, data_clicks, gap_clicks, stack_clicks, tot_clicks;
phys_bytes bytes, base, bss_offset;
int s, r2;
SANITYCHECK(SCL_FUNCTIONS);
/* No need to allocate text if it can be shared. */
if (sh_mp != NULL) {
text_bytes = 0;
vm_assert(!vm_paged);
}
/* Acquire the new memory. Each of the 4 parts: text, (data+bss), gap,
* and stack occupies an integral number of clicks, starting at click
* boundary. The data and bss parts are run together with no space.
*/
text_clicks = ((unsigned long) text_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
data_clicks = (data_bytes + bss_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
stack_clicks = (stk_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
tot_clicks = (tot_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
gap_clicks = tot_clicks - data_clicks - stack_clicks;
if ( (int) gap_clicks < 0) return(ENOMEM);
SANITYCHECK(SCL_DETAIL);
/* We've got memory for the new core image. Release the old one. */
if(rmp->vm_flags & VMF_HASPT) {
/* Free page table and memory allocated by pagetable functions. */
rmp->vm_flags &= ~VMF_HASPT;
free_proc(rmp);
} else {
if (find_share(rmp, rmp->vm_ino, rmp->vm_dev, rmp->vm_ctime) == NULL) {
/* No other process shares the text segment, so free it. */
FREE_MEM(rmp->vm_arch.vm_seg[T].mem_phys, rmp->vm_arch.vm_seg[T].mem_len);
}
/* Free the data and stack segments. */
FREE_MEM(rmp->vm_arch.vm_seg[D].mem_phys,
rmp->vm_arch.vm_seg[S].mem_vir
+ rmp->vm_arch.vm_seg[S].mem_len
- rmp->vm_arch.vm_seg[D].mem_vir);
}
/* We have now passed the point of no return. The old core image has been
* forever lost, memory for a new core image has been allocated. Set up
* and report new map.
*/
if(vm_paged) {
if(pt_new(&rmp->vm_pt) != OK)
vm_panic("exec_newmem: no new pagetable", NO_NUM);
SANITYCHECK(SCL_DETAIL);
proc_new(rmp,
kernel_top_bytes, /* where to start the process in the page table */
CLICK2ABS(text_clicks),/* how big is the text in bytes, page-aligned */
CLICK2ABS(data_clicks),/* how big is data+bss, page-aligned */
CLICK2ABS(stack_clicks),/* how big is stack, page-aligned */
CLICK2ABS(gap_clicks), /* how big is gap, page-aligned */
0,0, /* not preallocated */
VM_STACKTOP /* regular stack top */
);
SANITYCHECK(SCL_DETAIL);
} else {
phys_clicks new_base;
new_base = ALLOC_MEM(text_clicks + tot_clicks, 0);
if (new_base == NO_MEM) return(ENOMEM);
if (sh_mp != NULL) {
/* Share the text segment. */
rmp->vm_arch.vm_seg[T] = sh_mp->vm_arch.vm_seg[T];
} else {
rmp->vm_arch.vm_seg[T].mem_phys = new_base;
rmp->vm_arch.vm_seg[T].mem_vir = 0;
rmp->vm_arch.vm_seg[T].mem_len = text_clicks;
if (text_clicks > 0)
{
/* Zero the last click of the text segment. Otherwise the
* part of that click may remain unchanged.
*/
base = (phys_bytes)(new_base+text_clicks-1) << CLICK_SHIFT;
if ((s= sys_memset(0, base, CLICK_SIZE)) != OK)
vm_panic("new_mem: sys_memset failed", s);
}
}
/* No paging stuff. */
rmp->vm_flags &= ~VMF_HASPT;
rmp->vm_regions = NULL;
rmp->vm_arch.vm_seg[D].mem_phys = new_base + text_clicks;
rmp->vm_arch.vm_seg[D].mem_vir = 0;
rmp->vm_arch.vm_seg[D].mem_len = data_clicks;
rmp->vm_arch.vm_seg[S].mem_phys = rmp->vm_arch.vm_seg[D].mem_phys +
data_clicks + gap_clicks;
rmp->vm_arch.vm_seg[S].mem_vir = rmp->vm_arch.vm_seg[D].mem_vir +
data_clicks + gap_clicks;
rmp->vm_arch.vm_seg[S].mem_len = stack_clicks;
rmp->vm_stacktop =
CLICK2ABS(rmp->vm_arch.vm_seg[S].mem_vir +
rmp->vm_arch.vm_seg[S].mem_len);
rmp->vm_arch.vm_data_top =
(rmp->vm_arch.vm_seg[S].mem_vir +
rmp->vm_arch.vm_seg[S].mem_len) << CLICK_SHIFT;
if((r2=sys_newmap(rmp->vm_endpoint, rmp->vm_arch.vm_seg)) != OK) {
/* report new map to the kernel */
vm_panic("sys_newmap failed", r2);
}
/* Zero the bss, gap, and stack segment. */
bytes = (phys_bytes)(data_clicks + gap_clicks + stack_clicks) << CLICK_SHIFT;
base = (phys_bytes) rmp->vm_arch.vm_seg[D].mem_phys << CLICK_SHIFT;
bss_offset = (data_bytes >> CLICK_SHIFT) << CLICK_SHIFT;
base += bss_offset;
bytes -= bss_offset;
if ((s=sys_memset(0, base, bytes)) != OK) {
vm_panic("new_mem can't zero", s);
}
/* Tell kernel this thing has no page table. */
if((s=pt_bind(NULL, rmp)) != OK)
vm_panic("exec_newmem: pt_bind failed", s);
}
SANITYCHECK(SCL_FUNCTIONS);
return(OK);
}
/*===========================================================================*
* find_kernel_top *
*===========================================================================*/
PUBLIC phys_bytes find_kernel_top(void)
{
/* Find out where the kernel is, so we know where to start mapping
* user processes.
*/
u32_t kernel_top = 0;
#define MEMTOP(v, i) \
(vmproc[v].vm_arch.vm_seg[i].mem_phys + vmproc[v].vm_arch.vm_seg[i].mem_len)
vm_assert(vmproc[VMP_SYSTEM].vm_flags & VMF_INUSE);
kernel_top = MEMTOP(VMP_SYSTEM, T);
kernel_top = MAX(kernel_top, MEMTOP(VMP_SYSTEM, D));
kernel_top = MAX(kernel_top, MEMTOP(VMP_SYSTEM, S));
vm_assert(kernel_top);
return CLICK2ABS(kernel_top);
}
/*===========================================================================*
* proc_new *
*===========================================================================*/
PUBLIC int proc_new(struct vmproc *vmp,
phys_bytes vstart, /* where to start the process in page table */
phys_bytes text_bytes, /* how much code, in bytes but page aligned */
phys_bytes data_bytes, /* how much data + bss, in bytes but page aligned */
phys_bytes stack_bytes, /* stack space to reserve, in bytes, page aligned */
phys_bytes gap_bytes, /* gap bytes, page aligned */
phys_bytes text_start, /* text starts here, if preallocated, otherwise 0 */
phys_bytes data_start, /* data starts here, if preallocated, otherwise 0 */
phys_bytes stacktop
)
{
int s;
vir_bytes hole_bytes;
int prealloc;
vm_assert(!(vstart % VM_PAGE_SIZE));
vm_assert(!(text_bytes % VM_PAGE_SIZE));
vm_assert(!(data_bytes % VM_PAGE_SIZE));
vm_assert(!(stack_bytes % VM_PAGE_SIZE));
vm_assert(!(gap_bytes % VM_PAGE_SIZE));
vm_assert(!(text_start % VM_PAGE_SIZE));
vm_assert(!(data_start % VM_PAGE_SIZE));
vm_assert((!text_start && !data_start) || (text_start && data_start));
if(!map_proc_kernel(vmp)) {
printf("VM: exec: map_proc_kernel failed\n");
return ENOMEM;
}
/* Place text at start of process. */
vmp->vm_arch.vm_seg[T].mem_phys = ABS2CLICK(vstart);
vmp->vm_arch.vm_seg[T].mem_vir = 0;
vmp->vm_arch.vm_seg[T].mem_len = ABS2CLICK(text_bytes);
vmp->vm_offset = vstart;
/* page mapping flags for code */
#define TEXTFLAGS (PTF_PRESENT | PTF_USER | PTF_WRITE)
SANITYCHECK(SCL_DETAIL);
if(text_bytes > 0) {
if(!map_page_region(vmp, vstart, 0, text_bytes,
text_start ? text_start : MAP_NONE,
VR_ANON | VR_WRITABLE, text_start ? 0 : MF_PREALLOC)) {
SANITYCHECK(SCL_DETAIL);
printf("VM: proc_new: map_page_region failed (text)\n");
return(ENOMEM);
}
SANITYCHECK(SCL_DETAIL);
}
SANITYCHECK(SCL_DETAIL);
/* Allocate memory for data (including bss, but not including gap
* or stack), make sure it's cleared, and map it in after text
* (if any).
*/
if(!(vmp->vm_heap = map_page_region(vmp, vstart + text_bytes, 0,
data_bytes, data_start ? data_start : MAP_NONE, VR_ANON | VR_WRITABLE,
data_start ? 0 : MF_PREALLOC))) {
printf("VM: exec: map_page_region for data failed\n");
return ENOMEM;
}
/* Tag the heap so brk() call knows which region to extend. */
map_region_set_tag(vmp->vm_heap, VRT_HEAP);
/* How many address space clicks between end of data
* and start of stack?
* stacktop is the first address after the stack, as addressed
* from within the user process.
*/
hole_bytes = stacktop - data_bytes - stack_bytes - gap_bytes;
if(!map_page_region(vmp, vstart + text_bytes + data_bytes + hole_bytes,
0, stack_bytes + gap_bytes, MAP_NONE,
VR_ANON | VR_WRITABLE, 0) != OK) {
vm_panic("map_page_region failed for stack", NO_NUM);
}
vmp->vm_arch.vm_seg[D].mem_phys = ABS2CLICK(vstart + text_bytes);
vmp->vm_arch.vm_seg[D].mem_vir = 0;
vmp->vm_arch.vm_seg[D].mem_len = ABS2CLICK(data_bytes);
vmp->vm_arch.vm_seg[S].mem_phys = ABS2CLICK(vstart +
text_bytes + data_bytes + gap_bytes + hole_bytes);
vmp->vm_arch.vm_seg[S].mem_vir = ABS2CLICK(data_bytes + gap_bytes + hole_bytes);
/* Pretend the stack is the full size of the data segment, so
* we get a full-sized data segment, up to VM_DATATOP.
* After sys_newmap(), change the stack to what we know the
* stack to be (up to stacktop).
*/
vmp->vm_arch.vm_seg[S].mem_len = (VM_DATATOP >> CLICK_SHIFT) -
vmp->vm_arch.vm_seg[S].mem_vir - ABS2CLICK(vstart) - ABS2CLICK(text_bytes);
/* Where are we allowed to start using the rest of the virtual
* address space?
*/
vmp->vm_stacktop = stacktop;
/* What is the final size of the data segment in bytes? */
vmp->vm_arch.vm_data_top =
(vmp->vm_arch.vm_seg[S].mem_vir +
vmp->vm_arch.vm_seg[S].mem_len) << CLICK_SHIFT;
vmp->vm_flags |= VMF_HASPT;
if((s=sys_newmap(vmp->vm_endpoint, vmp->vm_arch.vm_seg)) != OK) {
vm_panic("sys_newmap (vm) failed", s);
}
/* This is the real stack clicks. */
vmp->vm_arch.vm_seg[S].mem_len = ABS2CLICK(stack_bytes);
if((s=pt_bind(&vmp->vm_pt, vmp)) != OK)
vm_panic("exec_newmem: pt_bind failed", s);
return OK;
}
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