sys_umap now supports only: - looking up the physical address of a virtual address in the address space of the caller; - looking up the physical address of a grant for which the caller is the grantee. This is enough for nearly all umap users. The new sys_umap_remote supports lookups in arbitrary address spaces and grants for arbitrary grantees.
		
			
				
	
	
		
			131 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			131 lines
		
	
	
		
			3.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* The kernel call implemented in this file:
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 *   m_type:	SYS_UMAP_REMOTE
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 *
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 * The parameters for this kernel call are:
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 *    m5_i1:	CP_SRC_PROC_NR	(process number)
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 *    m5_s1:	CP_SRC_SPACE	(segment where address is: T, D, or S)
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 *    m5_l1:	CP_SRC_ADDR	(virtual address)
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 *    m5_i2:	CP_DST_ENDPT	(process number of grantee to check access for)
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 *    m5_l2:	CP_DST_ADDR	(returns physical address)
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 *    m5_l3:	CP_NR_BYTES	(size of datastructure)
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 */
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#include "kernel/system.h"
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#include <minix/endpoint.h>
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#if USE_UMAP || USE_UMAP_REMOTE
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#if ! USE_UMAP_REMOTE
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#undef do_umap_remote
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#endif
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/*==========================================================================*
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 *				do_umap_remote				    *
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 *==========================================================================*/
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PUBLIC int do_umap_remote(struct proc * caller, message * m_ptr)
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{
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/* Map virtual address to physical, for non-kernel processes. */
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  int seg_type = m_ptr->CP_SRC_SPACE & SEGMENT_TYPE;
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  int seg_index = m_ptr->CP_SRC_SPACE & SEGMENT_INDEX;
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  vir_bytes offset = m_ptr->CP_SRC_ADDR;
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  int count = m_ptr->CP_NR_BYTES;
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  int endpt = (int) m_ptr->CP_SRC_ENDPT;
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  endpoint_t grantee = (endpoint_t) m_ptr->CP_DST_ENDPT;
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  int proc_nr, proc_nr_grantee, r;
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  int naughty = 0;
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  phys_bytes phys_addr = 0, lin_addr = 0;
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  struct proc *targetpr;
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  /* Verify process number. */
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  if (endpt == SELF)
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	proc_nr = _ENDPOINT_P(caller->p_endpoint);
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  else
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	if (! isokendpt(endpt, &proc_nr))
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		return(EINVAL);
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  targetpr = proc_addr(proc_nr);
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  /* Verify grantee endpoint */
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  if (grantee == SELF) {
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	grantee = caller->p_endpoint;
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  } else if (grantee == NONE ||
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	grantee == ANY ||
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	seg_index != MEM_GRANT ||
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	!isokendpt(grantee, &proc_nr_grantee)) {
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	return EINVAL;
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  }
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  /* See which mapping should be made. */
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  switch(seg_type) {
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  case LOCAL_SEG:
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      phys_addr = lin_addr = umap_local(targetpr, seg_index, offset, count);
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      if(!lin_addr) return EFAULT;
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      naughty = 1;
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      break;
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  case LOCAL_VM_SEG:
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    if(seg_index == MEM_GRANT) {
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	vir_bytes newoffset;
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	endpoint_t newep;
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	int new_proc_nr;
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	cp_grant_id_t grant = (cp_grant_id_t) offset;
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        if(verify_grant(targetpr->p_endpoint, grantee, grant, count,
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                0, 0, &newoffset, &newep) != OK) {
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                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);
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		proc_stacktrace(caller);
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                return EFAULT;
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        }
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        if(!isokendpt(newep, &new_proc_nr)) {
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                printf("SYSTEM: do_umap: isokendpt failed\n");
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                return EFAULT;
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        }
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	/* New lookup. */
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	offset = newoffset;
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	targetpr = proc_addr(new_proc_nr);
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	seg_index = D;
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      }
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      if(seg_index == T || seg_index == D || seg_index == S) {
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        phys_addr = lin_addr = umap_local(targetpr, seg_index, offset, count);
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      } else {
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	printf("SYSTEM: bogus seg type 0x%lx\n", seg_index);
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	return EFAULT;
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      }
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      if(!lin_addr) {
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	printf("SYSTEM:do_umap: umap_local failed\n");
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	return EFAULT;
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      }
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      if(vm_lookup(targetpr, lin_addr, &phys_addr, NULL) != OK) {
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	printf("SYSTEM:do_umap: vm_lookup failed\n");
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	return EFAULT;
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      }
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      if(phys_addr == 0)
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	panic("vm_lookup returned zero physical address");
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      break;
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  default:
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      if((r=arch_umap(targetpr, offset, count, seg_type, &lin_addr))
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	!= OK)
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	return r;
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      phys_addr = lin_addr;
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  }
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  if(vm_running && !vm_contiguous(targetpr, lin_addr, count)) {
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	printf("SYSTEM:do_umap: not contiguous\n");
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	return EFAULT;
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  }
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  m_ptr->CP_DST_ADDR = phys_addr;
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  if(naughty || phys_addr == 0) {
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	  printf("kernel: umap 0x%x done by %d / %s, pc 0x%lx, 0x%lx -> 0x%lx\n",
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		seg_type, caller->p_endpoint, caller->p_name,
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		caller->p_reg.pc, offset, phys_addr);
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	printf("caller stack: ");
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	proc_stacktrace(caller);
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  }
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  return (phys_addr == 0) ? EFAULT: OK;
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}
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#endif /* USE_UMAP || USE_UMAP_REMOTE */
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