Changeset fbcdeb8 in mainline for kernel/generic/include/mm/as.h

Timestamp:

2011-12-19T17:30:39Z (12 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

58f6229

Parents:

24cf31f1

Message:

Remove the two-phase way of creating virtual memory areas (first asking for a mappable address and then mapping it) which was prone to race conditions when two or more calls to as_get_mappable_page() and as_area_create() were interleaved. This for example caused the e1k driver to randomly fail.

The memory area related syscalls and IPC calls have all been altered to accept a special value (void *) -1, representing a demand to atomically search for a mappable address space "hole" and map to it.

Individual changes:

• IPC_M_SHARE_OUT: the destination address space area is supplied by the kernel, the callee only specifies the lower bound

(the address is returned to the callee via a pointer in an IPC reply argument)

• IPC_M_SHARE_IN: the destination address space ares is supplied by the kernel, the callee only specifies the lower bound

(the address is returned to the caller as usual via an IPC argument)

• SYS_AS_GET_UNMAPPED_AREA was removed
• dummy implementations of SYS_PHYSMEM_UNMAP and SYS_IOSPACE_DISABLE were added for the sake of symmetry (they do nothing yet)
• SYS_PHYSMEM_MAP and SYS_DMAMEM_MAP were altered to accept (void *) -1 as address space area base and a lower bound
• kernel as_area_create() and as_area_share() were altered to accept (void *) -1 as address space area base and a lower bound
• uspace libraries and programs were altered to reflect the new API

File:

• kernel/generic/include/mm/as.h (modified) (2 diffs)

kernel/generic/include/mm/as.h

@@ -242 +242 @@
 extern int as_page_fault(uintptr_t, pf_access_t, istate_t *);
 
-extern as_area_t *as_area_create(as_t *, unsigned int, size_t, uintptr_t,
-    unsigned int, mem_backend_t *, mem_backend_data_t *);
+extern as_area_t *as_area_create(as_t *, unsigned int, size_t, unsigned int,
+    mem_backend_t *, mem_backend_data_t *, uintptr_t *, uintptr_t);
 extern int as_area_destroy(as_t *, uintptr_t);
 extern int as_area_resize(as_t *, uintptr_t, size_t, unsigned int);
-extern int as_area_share(as_t *, uintptr_t, size_t, as_t *, uintptr_t,
-    unsigned int);
+extern int as_area_share(as_t *, uintptr_t, size_t, as_t *, unsigned int,
+    uintptr_t *, uintptr_t);
 extern int as_area_change_flags(as_t *, unsigned int, uintptr_t);
 
@@ -284 +284 @@
 
 /* Address space area related syscalls. */
-extern sysarg_t sys_as_area_create(uintptr_t, size_t, unsigned int);
+extern sysarg_t sys_as_area_create(uintptr_t, size_t, unsigned int, uintptr_t);
 extern sysarg_t sys_as_area_resize(uintptr_t, size_t, unsigned int);
 extern sysarg_t sys_as_area_change_flags(uintptr_t, unsigned int);
 extern sysarg_t sys_as_area_destroy(uintptr_t);
-extern sysarg_t sys_as_get_unmapped_area(uintptr_t, size_t);
 
 /* Introspection functions. */