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Cleaner allocation, mapping and prefaulting of utcb shm segments.

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A function has been defined that handles all utcb operations.
This commit is contained in:
Bahadir Balban
2008-10-24 17:20:42 +03:00
parent 46fcdc9b31
commit d43a98b4af
4 changed files with 52 additions and 63 deletions
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9
tasks/mm0/include/utcb.h
View File

@@ -3,14 +3,21 @@
#include <l4lib/types.h> #include <l4lib/types.h>
#include <task.h> #include <task.h>
#define UTCB_PREFAULT (1 << 0) /* Prefaults utcb pages after mapping */
#define UTCB_NEW_SHM (1 << 1) /* Creates a new shm segment for utcb */
#define UTCB_NEW_ADDRESS (1 << 2) /* Allocates a virtual address for utcb */
int utcb_pool_init(void); int utcb_pool_init(void);
void *utcb_new_address(void); void *utcb_new_address(void);
int utcb_delete_address(void *utcb_addr); int utcb_delete_address(void *utcb_addr);
/* IPC to send utcb address information to tasks */ /* IPC to send utcb address information to tasks */
void *task_send_utcb_address(struct tcb *sender, l4id_t taskid); void *task_send_utcb_address(struct tcb *sender, l4id_t taskid);
int utcb_map_to_task(struct tcb *owner, struct tcb *mapper, unsigned int flags);
int utcb_unmap_from_task(struct tcb *owner, struct tcb *mapper);
/* Prefault an *mmaped* utcb */ /* Prefault an *mmaped* utcb */
int utcb_prefault(struct tcb *task, unsigned int vmflags); int utcb_prefault(struct tcb *task, unsigned int vmflags);

44
tasks/mm0/src/clone.c
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@@ -55,11 +55,10 @@ int sys_fork(struct tcb *parent)
int err; int err;
struct tcb *child; struct tcb *child;
struct exregs_data exregs; struct exregs_data exregs;
struct vm_file *utcb_shm;
struct task_ids ids = { struct task_ids ids = {
.tid = TASK_ID_INVALID, .tid = TASK_ID_INVALID,
.spid = parent->spid, .spid = parent->spid,
.tgid = TASK_ID_INVALID /* FIXME: !!! FIX THIS */ .tgid = TASK_ID_INVALID, /* FIXME: !!! FIX THIS */
}; };
/* Make all shadows in this task read-only */ /* Make all shadows in this task read-only */
@@ -76,25 +75,14 @@ int sys_fork(struct tcb *parent)
/* Set child's fork return value to 0 */ /* Set child's fork return value to 0 */
memset(&exregs, 0, sizeof(exregs)); memset(&exregs, 0, sizeof(exregs));
exregs_set_mr(&exregs, MR_RETURN, 0); exregs_set_mr(&exregs, MR_RETURN, 0);
/* Do the actual exregs call to c0 */
if ((err = l4_exchange_registers(&exregs, child->tid)) < 0) if ((err = l4_exchange_registers(&exregs, child->tid)) < 0)
BUG(); BUG();
/* Create new utcb for child since it can't use its parent's */ /* Create and prefault a utcb for child and map it to vfs task */
child->utcb = utcb_new_address(); utcb_map_to_task(child, find_task(VFS_TID),
UTCB_NEW_ADDRESS | UTCB_NEW_SHM | UTCB_PREFAULT);
/*
* Create the utcb shared memory segment
* available for child to shmat()
*/
if (IS_ERR(utcb_shm = shm_new((key_t)child->utcb,
__pfn(DEFAULT_UTCB_SIZE))))
return (int)utcb_shm;
/*
* Map and prefault child utcb to vfs so that vfs need not
* call us to map it.
*/
task_map_prefault_utcb(find_task(VFS_TID), child);
/* We can now notify vfs about forked process */ /* We can now notify vfs about forked process */
vfs_notify_fork(child, parent); vfs_notify_fork(child, parent);
@@ -112,7 +100,6 @@ int sys_fork(struct tcb *parent)
int sys_clone(struct tcb *parent, void *child_stack, unsigned int flags) int sys_clone(struct tcb *parent, void *child_stack, unsigned int flags)
{ {
struct task_ids ids; struct task_ids ids;
struct vm_file *utcb_shm;
struct tcb *child; struct tcb *child;
ids.tid = TASK_ID_INVALID; ids.tid = TASK_ID_INVALID;
@@ -123,19 +110,9 @@ int sys_clone(struct tcb *parent, void *child_stack, unsigned int flags)
TCB_SHARED_VM | TCB_SHARED_FILES))) TCB_SHARED_VM | TCB_SHARED_FILES)))
return (int)child; return (int)child;
/* Allocate a unique utcb address for child */ /* Create and prefault a utcb for child and map it to vfs task */
child->utcb = utcb_new_address(); utcb_map_to_task(child, find_task(VFS_TID),
UTCB_NEW_ADDRESS | UTCB_NEW_SHM | UTCB_PREFAULT);
/*
* Create the utcb shared memory segment
* available for child to shmat()
*/
if (IS_ERR(utcb_shm = shm_new((key_t)child->utcb,
__pfn(DEFAULT_UTCB_SIZE))))
return (int)utcb_shm;
/* Map and prefault child's utcb to vfs task */
task_map_prefault_utcb(find_task(VFS_TID), child);
/* Set up child stack marks with given stack argument */ /* Set up child stack marks with given stack argument */
child->stack_end = (unsigned long)child_stack; child->stack_end = (unsigned long)child_stack;
@@ -158,6 +135,3 @@ int sys_clone(struct tcb *parent, void *child_stack, unsigned int flags)

28
tasks/mm0/src/task.c
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@@ -444,27 +444,6 @@ struct tcb *task_exec(struct vm_file *f, unsigned long task_region_start,
return task; return task;
} }
/* Maps and prefaults the utcb of a task into another task */
void task_map_prefault_utcb(struct tcb *mapper, struct tcb *owner)
{
BUG_ON(!owner->utcb);
/*
* First internally map the utcb as a shm area. We use
* such posix semantics on purpose to have a unified
* way of doing similar operations.
*/
BUG_ON(IS_ERR(shmat_shmget_internal(mapper,
(key_t)owner->utcb,
owner->utcb)));
/* Prefault the owner's utcb to mapper's address space */
for (int i = 0; i < __pfn(DEFAULT_UTCB_SIZE); i++)
prefault_page(mapper, (unsigned long)owner->utcb +
__pfn_to_addr(i), VM_READ | VM_WRITE);
}
/* /*
* During its initialisation FS0 wants to learn how many boot tasks * During its initialisation FS0 wants to learn how many boot tasks
* are running, and their tids, which includes itself. This function * are running, and their tids, which includes itself. This function
@@ -487,12 +466,7 @@ int send_task_data(struct tcb *vfs)
BUG_ON(!vfs->utcb); BUG_ON(!vfs->utcb);
/* Attach mm0 to vfs's utcb segment just like a normal task */ /* Attach mm0 to vfs's utcb segment just like a normal task */
BUG_ON(IS_ERR(shmat_shmget_internal(self, (key_t)vfs->utcb, vfs->utcb))); utcb_map_to_task(vfs, self, UTCB_PREFAULT);
/* Prefault those pages to self. */
for (int i = 0; i < __pfn(DEFAULT_UTCB_SIZE); i++)
prefault_page(self, (unsigned long)vfs->utcb + __pfn_to_addr(i),
VM_READ | VM_WRITE);
/* Write all requested task information to utcb's user buffer area */ /* Write all requested task information to utcb's user buffer area */
tdata_head = (struct task_data_head *)vfs->utcb; tdata_head = (struct task_data_head *)vfs->utcb;

34
tasks/mm0/src/utcb.c
View File

@@ -10,6 +10,7 @@
#include <l4lib/arch/syscalls.h> #include <l4lib/arch/syscalls.h>
#include <l4lib/arch/syslib.h> #include <l4lib/arch/syslib.h>
#include <task.h> #include <task.h>
#include <shm.h>
#include <vm_area.h> #include <vm_area.h>
#include INC_GLUE(memlayout.h) #include INC_GLUE(memlayout.h)
@@ -70,3 +71,36 @@ void *task_send_utcb_address(struct tcb *sender, l4id_t taskid)
return 0; return 0;
} }
int utcb_map_to_task(struct tcb *owner, struct tcb *mapper, unsigned int flags)
{
struct vm_file *utcb_shm;
/* Allocate a new utcb address */
if (flags & UTCB_NEW_ADDRESS)
owner->utcb = utcb_new_address();
else if (!owner->utcb)
BUG();
/* Create a new shared memory segment for utcb */
if (flags & UTCB_NEW_SHM)
if (IS_ERR(utcb_shm = shm_new((key_t)owner->utcb,
__pfn(DEFAULT_UTCB_SIZE))))
return (int)utcb_shm;
/* Map the utcb to mapper */
if (IS_ERR(shmat_shmget_internal(mapper, (key_t)owner->utcb,
owner->utcb)))
BUG();
/* Prefault the owner's utcb to mapper's address space */
if (flags & UTCB_PREFAULT)
for (int i = 0; i < __pfn(DEFAULT_UTCB_SIZE); i++)
prefault_page(mapper, (unsigned long)owner->utcb +
__pfn_to_addr(i), VM_READ | VM_WRITE);
return 0;
}
int utcb_unmap_from_task(struct tcb *owner, struct tcb *mapper)
{
return 0;
}