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[/] [c0or1k/] [trunk/] [conts/] [posix/] [libposix/] [shpage.c] - Rev 7
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/* * Initialise posix-related structures. * * Copyright (C) 2007-2009 Bahadir Balban */ #include <l4lib/kip.h> #include <l4lib/ipcdefs.h> #include <l4/macros.h> #include <stdio.h> #include <shpage.h> #include <sys/types.h> #include <sys/shm.h> #include <shpage.h> #include <libposix.h> #include INC_GLUE(memlayout.h) #if 0 /* * Shared page initialisation of posix-like tasks. * * POSIX tasks currently use a default shared page for communciation. * This could have been also done by long ipc calls. */ /* * Shared page for this task. Used for passing data among ipc * parties when message registers are not big enough. Every thread * has right to own one, and it has an address unique to every * thread. It must be explicitly mapped by both parties of the ipc * in order to be useful. */ void *shared_page; /* * Obtains a unique address for the task's shared page. Note this * just returns the address. This address is used as an shm key * to map it via shmget()/shmat() later on. */ static void *shared_page_address(void) { void *addr; int err; /* We're asking it for ourself. */ write_mr(L4SYS_ARG0, self_tid()); /* Call pager with utcb address request. Check ipc error. */ if ((err = l4_sendrecv(pagerid, pagerid, L4_IPC_TAG_SHPAGE)) < 0) { print_err("%s: L4 IPC Error: %d.\n", __FUNCTION__, err); return PTR_ERR(err); } /* Check if syscall itself was successful */ if (IS_ERR(addr = (void *)l4_get_retval())) { print_err("%s: Request UTCB Address Error: %d.\n", __FUNCTION__, (int)addr); return addr; } return addr; } /* * Initialises a non-pager task's default shared memory page * using posix semantics. Used during task initialisation * and by child tasks after a fork. */ int shared_page_init(void) { int shmid; void *shmaddr; /* * Initialise shared page only if we're not the pager. * The pager does it differently for itself. */ BUG_ON(self_tid() == pagerid); /* Obtain our shared page address */ shared_page = shared_page_address(); //print_err("%s: UTCB Read from mm0 as: 0x%x\n", __FUNCTION__, // (unsigned long)shared_page); /* Use it as a key to create a shared memory region */ BUG_ON((shmid = shmget((key_t)shared_page, PAGE_SIZE, IPC_CREAT)) < 0); /* Attach to the region */ BUG_ON((shmaddr = shmat(shmid, shared_page, 0)) < 0); BUG_ON(shmaddr != shared_page); return 0; } #endif
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