Changeset fbcdeb8 in mainline for uspace/lib/c/generic/ipc.c

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:

• uspace/lib/c/generic/ipc.c (modified) (5 diffs)

uspace/lib/c/generic/ipc.c

@@ -48 +48 @@
 #include <fibril.h>
 #include <macros.h>
+#include "private/libc.h"
 
 /**
@@ -760 +761 @@
  *
  * @param phoneid Phone that will be used to contact the receiving side.
- * @param dst     Destination address space area base.
  * @param size    Size of the destination address space area.
  * @param arg     User defined argument.
  * @param flags   Storage for received flags. Can be NULL.
+ * @param dst     Destination address space area base. Cannot be NULL.
  *
  * @return Zero on success or a negative error code from errno.h.
  *
  */
-int ipc_share_in_start(int phoneid, void *dst, size_t size, sysarg_t arg,
-    unsigned int *flags)
-{
-        sysarg_t tmp_flags = 0;
-        int res = ipc_call_sync_3_2(phoneid, IPC_M_SHARE_IN, (sysarg_t) dst,
-            (sysarg_t) size, arg, NULL, &tmp_flags);
+int ipc_share_in_start(int phoneid, size_t size, sysarg_t arg,
+    unsigned int *flags, void **dst)
+{
+        sysarg_t _flags = 0;
+        sysarg_t _dst = (sysarg_t) -1;
+        int res = ipc_call_sync_2_4(phoneid, IPC_M_SHARE_IN, (sysarg_t) size,
+            arg, NULL, &_flags, NULL, &_dst);
         
         if (flags)
-                *flags = (unsigned int) tmp_flags;
-        
+                *flags = (unsigned int) _flags;
+        
+        *dst = (void *) _dst;
         return res;
 }
@@ -783 +786 @@
 /** Wrapper for answering the IPC_M_SHARE_IN calls.
  *
- * This wrapper only makes it more comfortable to answer IPC_M_DATA_READ
+ * This wrapper only makes it more comfortable to answer IPC_M_SHARE_IN
  * calls so that the user doesn't have to remember the meaning of each
  * IPC argument.
@@ -796 +799 @@
 int ipc_share_in_finalize(ipc_callid_t callid, void *src, unsigned int flags)
 {
-        return ipc_answer_2(callid, EOK, (sysarg_t) src, (sysarg_t) flags);
+        return ipc_answer_3(callid, EOK, (sysarg_t) src, (sysarg_t) flags,
+            (sysarg_t) __entry);
 }
 
@@ -826 +830 @@
  *
  */
-int ipc_share_out_finalize(ipc_callid_t callid, void *dst)
-{
-        return ipc_answer_1(callid, EOK, (sysarg_t) dst);
+int ipc_share_out_finalize(ipc_callid_t callid, void **dst)
+{
+        return ipc_answer_2(callid, EOK, (sysarg_t) __entry, (sysarg_t) dst);
 }