page_access.cxx

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/*
  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
*/
 
#include "CxxUtils/page_access.h"
#include <unistd.h>
#include <limits.h>
namespace athena{
  const size_t PAGESIZE = sysconf(_SC_PAGE_SIZE);
 
  const void* page_address(const void* addr) { 
    return (const void*)((long)addr & ~(PAGESIZE-1)); 
  }
  void* page_address(void* addr) { 
    return (void*)((long)addr & ~(PAGESIZE-1)); 
  }
  void* next_page_address(void* addr) { 
    return (void*)(((long)addr & ~(PAGESIZE-1)) + PAGESIZE); 
  }
 
  int page_protect(void* addr, int prot) {
    int rc=mprotect(page_address(addr), PAGESIZE, prot);
    if (rc) printf("page_protect WARNING: mprotect heap failed for void *address %p\n", addr);
#ifdef DEBUG
    else printf("page_protect DEBUG: set protection @%i for range @%zx - @%zx containing void* addr=%p\n",
        prot,(size_t)page_address(addr), 
        (size_t)page_address(addr) + PAGESIZE, addr);
#endif
    return rc;
  }
}