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Prefaulting of utcb pages seem to work.

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Next: fs0 should shmat() on others' utcbs.
This commit is contained in:
Bahadir Balban
2008-03-22 15:57:20 +00:00
parent 0dfbde6bc0
commit 82a7228d89
9 changed files with 211 additions and 78 deletions
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40
tasks/mm0/src/utcb.c
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@@ -11,6 +11,7 @@
#include <l4lib/arch/syscalls.h>
#include <l4lib/arch/syslib.h>
#include <task.h>
#include <vm_area.h>
#include INC_GLUE(memlayout.h)
static struct address_pool utcb_vaddr_pool;
@@ -35,7 +36,8 @@ void *utcb_vaddr_new(void)
/*
* Sends utcb address information to requester task, allocates
* an address if it doesn't exist and the requester is asking
* for its own.
* for its own. The requester then uses this address as a shm key and
* maps its own utcb via shmget/shmat.
*/
int task_send_utcb_address(l4id_t sender, l4id_t taskid)
{
@@ -69,5 +71,41 @@ int task_send_utcb_address(l4id_t sender, l4id_t taskid)
return 0;
}
/*
* Triggered during a sys_shmat() by a client task when mapping its utcb.
* This prefaults the utcb and maps it in to mm0 so that it can freely
* access it anytime later.
*/
int utcb_prefault(struct tcb *task, unsigned int vmflags)
{
int err;
struct page *pg;
/* First map in the page to task with given flags, e.g. read/write */
if ((err = prefault_page(task, task->utcb_address, vmflags)) < 0) {
printf("%s: Failed: %d\n", __FUNCTION__, err);
return err;
}
/*
* Get the topmost page. Since we did both a VM_READ and VM_WRITE
* prefault, this gets a writeable instead of a read-only page.
*/
pg = task_virt_to_page(task, task->utcb_address);
if (!pg || IS_ERR(pg)) {
printf("%s: Cannot retrieve task %d's utcb page.\n",
__FUNCTION__, task->tid);
BUG();
}
/* Map it in to self */
l4_map((void *)page_to_phys(pg), (void *)task->utcb_address, 1,
MAP_USR_RW_FLAGS, self_tid());
/* Flag that says this task's utcb is mapped to mm0 as r/w */
task->utcb_mapped = 1;
return 0;
}