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

Timestamp:

2011-12-19T17:30:39Z (13 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/ddi.c (modified) (6 diffs)

uspace/lib/c/generic/ddi.c

@@ -45 +45 @@
 #include <align.h>
 #include <libarch/config.h>
+#include "private/libc.h"
 
 /** Return unique device number.
@@ -61 +62 @@
  *
  * @param phys  Physical address of the starting frame.
- * @param virt  Virtual address of the starting page.
  * @param pages Number of pages to map.
  * @param flags Flags for the new address space area.
+ * @param virt  Virtual address of the starting page.
  *
  * @return EOK on success
@@ -72 +73 @@
  *
  */
-int physmem_map(void *phys, void *virt, size_t pages, unsigned int flags)
+int physmem_map(void *phys, size_t pages, unsigned int flags, void **virt)
 {
-        return __SYSCALL4(SYS_PHYSMEM_MAP, (sysarg_t) phys,
-            (sysarg_t) virt, pages, flags);
+        return __SYSCALL5(SYS_PHYSMEM_MAP, (sysarg_t) phys,
+            pages, flags, (sysarg_t) virt, (sysarg_t) __entry);
 }
 
@@ -81 +82 @@
     unsigned int flags, void **phys)
 {
-        return (int) __SYSCALL5(SYS_DMAMEM_MAP, (sysarg_t) virt,
-            (sysarg_t) size, (sysarg_t) map_flags, (sysarg_t) flags,
-            (sysarg_t) phys);
+        return (int) __SYSCALL6(SYS_DMAMEM_MAP, (sysarg_t) size,
+            (sysarg_t) map_flags, (sysarg_t) flags & ~DMAMEM_FLAGS_ANONYMOUS,
+            (sysarg_t) phys, (sysarg_t) virt, 0);
 }
 
@@ -89 +90 @@
     unsigned int flags, void **phys, void **virt)
 {
-        *virt = as_get_mappable_page(size);
-        if (*virt == NULL)
-                return ENOMEM;
-        
-        return dmamem_map(*virt, size, map_flags,
-            flags | DMAMEM_FLAGS_ANONYMOUS, phys);
+        return (int) __SYSCALL6(SYS_DMAMEM_MAP, (sysarg_t) size,
+            (sysarg_t) map_flags, (sysarg_t) flags | DMAMEM_FLAGS_ANONYMOUS,
+            (sysarg_t) phys, (sysarg_t) virt, (sysarg_t) __entry);
 }
 
-int dmamem_unmap(void *virt, size_t size, unsigned int flags)
+int dmamem_unmap(void *virt, size_t size)
 {
-        return __SYSCALL3(SYS_DMAMEM_UNMAP, (sysarg_t) virt, (sysarg_t) size,
-            (sysarg_t) flags);
+        return __SYSCALL3(SYS_DMAMEM_UNMAP, (sysarg_t) virt, (sysarg_t) size, 0);
 }
 
@@ -138 +135 @@
  * @param pio_addr I/O start address.
  * @param size     Size of the I/O region.
- * @param use_addr Address where the final address for
- *                 application's PIO will be stored.
+ * @param virt     Virtual address for application's
+ *                 PIO operations.
  *
- * @return Zero on success or negative error code.
+ * @return EOK on success.
+ * @return Negative error code on failure.
  *
  */
-int pio_enable(void *pio_addr, size_t size, void **use_addr)
+int pio_enable(void *pio_addr, size_t size, void **virt)
 {
-        void *phys;
-        void *virt;
-        size_t offset;
-        unsigned int pages;
-        
 #ifdef IO_SPACE_BOUNDARY
         if (pio_addr < IO_SPACE_BOUNDARY) {
-                *use_addr = pio_addr;
+                *virt = pio_addr;
                 return iospace_enable(task_get_id(), pio_addr, size);
         }
 #endif
         
-        phys = (void *) ALIGN_DOWN((uintptr_t) pio_addr, PAGE_SIZE);
-        offset = pio_addr - phys;
-        pages = ALIGN_UP(offset + size, PAGE_SIZE) >> PAGE_WIDTH;
-        virt = as_get_mappable_page(pages << PAGE_WIDTH);
-        *use_addr = virt + offset;
-        return physmem_map(phys, virt, pages, AS_AREA_READ | AS_AREA_WRITE);
+        void *phys_frame =
+            (void *) ALIGN_DOWN((uintptr_t) pio_addr, PAGE_SIZE);
+        size_t offset = pio_addr - phys_frame;
+        size_t pages = SIZE2PAGES(offset + size);
+        
+        void *virt_page;
+        int rc = physmem_map(phys_frame, pages,
+            AS_AREA_READ | AS_AREA_WRITE, &virt_page);
+        if (rc != EOK)
+                return rc;
+        
+        *virt = virt_page + offset;
+        return EOK;
 }