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make kernel leave a page-sized gap in its code and data to not be

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mapped in if so configured.
This commit is contained in:
Ben Gras 2008-12-18 14:30:55 +00:00
parent 834d9d34e8
commit f0000078c3
4 changed files with 32 additions and 2 deletions
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1
include/minix/com.h
View file

@ -593,6 +593,7 @@
#define VMCTL_MEMREQ_REPLY 15
#define VMCTL_INCSP 16
#define VMCTL_STACKTRACE 17
#define VMCTL_NOPAGEZERO 18
/*===========================================================================*
* Messages for the Reincarnation Server *

3
include/minix/config.h
View file

@ -95,4 +95,7 @@
#define SPROFILE 1 /* statistical profiling */
#define CPROFILE 0 /* call profiling */
/* Compile kernel so that first page of code and data can be unmapped. */
#define VM_KERN_NOPAGEZERO 1
#endif /* _CONFIG_H */

25
kernel/arch/i386/memory.c
View file

@ -45,6 +45,7 @@ PUBLIC void vm_init(void)
u32_t entry;
unsigned pages;
struct proc* rp;
struct proc *sys = proc_addr(SYSTEM);
if (!vm_size)
minix_panic("i386_vm_init: no space for page tables", NO_NUM);
@ -77,6 +78,12 @@ PUBLIC void vm_init(void)
I386_VM_PRESENT;
if (phys_mem >= vm_mem_high)
entry= 0;
#if VM_KERN_NOPAGEZERO
if (phys_mem == (sys->p_memmap[T].mem_phys << CLICK_SHIFT) ||
phys_mem == (sys->p_memmap[D].mem_phys << CLICK_SHIFT)) {
entry = 0;
}
#endif
phys_put32(vm_pt_base + p*I386_VM_PT_ENT_SIZE, entry);
}
@ -471,6 +478,7 @@ PUBLIC int vm_checkrange(struct proc *caller, struct proc *target,
vmassert(vm_running);
/* If caller has had a reply to this request, return it. */
if(RTS_ISSET(caller, VMREQUEST)) {
if(caller->p_vmrequest.who == target->p_endpoint) {
@ -522,8 +530,9 @@ PUBLIC int vm_checkrange(struct proc *caller, struct proc *target,
target->p_name, target->p_endpoint, v, wrfl, flags, phys);
}
if(checkonly)
if(checkonly) {
return VMSUSPEND;
}
/* This range is not OK for this process. Set parameters
* of the request and notify VM about the pending request.
@ -544,7 +553,19 @@ PUBLIC int vm_checkrange(struct proc *caller, struct proc *target,
/* Connect caller on vmrequest wait queue. */
caller->p_vmrequest.nextrequestor = vmrequest;
vmrequest = caller;
soft_notify(VM_PROC_NR);
if(!caller->p_vmrequest.nextrequestor) {
int n = 0;
struct proc *vmr;
for(vmr = vmrequest; vmr; vmr = vmr->p_vmrequest.nextrequestor)
n++;
soft_notify(VM_PROC_NR);
#if 0
kprintf("(%d) ", n);
kprintf("%d/%d ",
caller->p_endpoint, target->p_endpoint);
util_stacktrace();
#endif
}
#if 0
kprintf("SYSTEM: vm_checkrange: range bad for "

5
kernel/system/do_vmctl.c
View file

@ -11,6 +11,7 @@
#include "../vm.h"
#include "../debug.h"
#include <minix/type.h>
#include <minix/config.h>
/*===========================================================================*
* do_vmctl *
@ -92,6 +93,10 @@ kprintf("SYSTEM: request %d:0x%lx-0x%lx, wrflag %d, failed\n",
}
#endif
return OK;
#if VM_KERN_NOPAGEZERO
case VMCTL_NOPAGEZERO:
return OK;
#endif
case VMCTL_STACKTRACE:
kprintf("vmctl stacktrace ");
proc_stacktrace(p);