minix3/kernel/system/do_umap_remote.c

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2020-02-21 00:59:27 +05:30
/* The kernel call implemented in this file:
* m_type: SYS_UMAP_REMOTE
*
* The parameters for this kernel call are:
* m_lsys_krn_sys_umap.src_endpt (process number)
* m_lsys_krn_sys_umap.segment (segment where address is: T, D, or S)
* m_lsys_krn_sys_umap.src_addr (virtual address)
* m_lsys_krn_sys_umap.dst_endpt (process number of grantee to check access for)
* m_krn_lsys_sys_umap.dst_addr (returns physical address)
* m_lsys_krn_sys_umap.nr_bytes (size of datastructure)
*/
#include "kernel/system.h"
#include <minix/endpoint.h>
#if USE_UMAP || USE_UMAP_REMOTE
#if ! USE_UMAP_REMOTE
#undef do_umap_remote
#endif
/*==========================================================================*
* do_umap_remote *
*==========================================================================*/
int do_umap_remote(struct proc * caller, message * m_ptr)
{
/* Map virtual address to physical, for non-kernel processes. */
int seg_type = m_ptr->m_lsys_krn_sys_umap.segment & SEGMENT_TYPE;
int seg_index = m_ptr->m_lsys_krn_sys_umap.segment & SEGMENT_INDEX;
vir_bytes offset = m_ptr->m_lsys_krn_sys_umap.src_addr;
int count = m_ptr->m_lsys_krn_sys_umap.nr_bytes;
endpoint_t endpt = m_ptr->m_lsys_krn_sys_umap.src_endpt;
endpoint_t grantee = m_ptr->m_lsys_krn_sys_umap.dst_endpt;
int proc_nr, proc_nr_grantee;
phys_bytes phys_addr = 0, lin_addr = 0;
struct proc *targetpr;
/* Verify process number. */
if (endpt == SELF)
okendpt(caller->p_endpoint, &proc_nr);
else
if (! isokendpt(endpt, &proc_nr))
return(EINVAL);
targetpr = proc_addr(proc_nr);
/* Verify grantee endpoint */
if (grantee == SELF) {
grantee = caller->p_endpoint;
} else if (grantee == NONE ||
grantee == ANY ||
seg_index != MEM_GRANT ||
!isokendpt(grantee, &proc_nr_grantee)) {
return EINVAL;
}
/* See which mapping should be made. */
switch(seg_type) {
case LOCAL_VM_SEG:
if(seg_index == MEM_GRANT) {
vir_bytes newoffset;
endpoint_t newep;
int new_proc_nr;
cp_grant_id_t grant = (cp_grant_id_t) offset;
if(verify_grant(targetpr->p_endpoint, grantee, grant, count,
0, 0, &newoffset, &newep, NULL) != OK) {
printf("SYSTEM: do_umap: verify_grant in %s, grant %d, bytes 0x%lx, failed, caller %s\n", targetpr->p_name, offset, count, caller->p_name);
proc_stacktrace(caller);
return EFAULT;
}
if(!isokendpt(newep, &new_proc_nr)) {
printf("SYSTEM: do_umap: isokendpt failed\n");
return EFAULT;
}
/* New lookup. */
offset = newoffset;
targetpr = proc_addr(new_proc_nr);
seg_index = VIR_ADDR;
}
if(seg_index == VIR_ADDR) {
phys_addr = lin_addr = offset;
} else {
printf("SYSTEM: bogus seg type 0x%lx\n", seg_index);
return EFAULT;
}
if(!lin_addr) {
printf("SYSTEM:do_umap: umap_local failed\n");
return EFAULT;
}
if(vm_lookup(targetpr, lin_addr, &phys_addr, NULL) != OK) {
printf("SYSTEM:do_umap: vm_lookup failed\n");
return EFAULT;
}
if(phys_addr == 0)
panic("vm_lookup returned zero physical address");
break;
default:
printf("umap: peculiar type\n");
return EINVAL;
}
if(vm_running && vm_lookup_range(targetpr, lin_addr, NULL, count) != count) {
printf("SYSTEM:do_umap: not contiguous\n");
return EFAULT;
}
m_ptr->m_krn_lsys_sys_umap.dst_addr = phys_addr;
if(phys_addr == 0) {
printf("kernel: umap 0x%x done by %d / %s, pc 0x%lx, 0x%lx -> 0x%lx\n",
seg_type, caller->p_endpoint, caller->p_name,
caller->p_reg.pc, offset, phys_addr);
printf("caller stack: ");
proc_stacktrace(caller);
}
return (phys_addr == 0) ? EFAULT: OK;
}
#endif /* USE_UMAP || USE_UMAP_REMOTE */