Changeset e3c762cd in mainline for arch/ia32/src/asm.S

Timestamp:

2006-05-05T11:59:19Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

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

Children:

de07bcf

Parents:

22cf454d

Message:

Complete implementation of copy_from_uspace() and copy_to_uspace()
for amd64 and ia32. Other architectures still compile and run,
but need to implement their own assembly-only memcpy(), memcpy_from_uspace(),
memcpy_to_uspace() and their failover parts. For these architectures
only dummy implementations are provided.

File:

• arch/ia32/src/asm.S (modified) (1 diff)

arch/ia32/src/asm.S

@@ -38 +38 @@
 .global enable_l_apic_in_msr
 .global interrupt_handlers
+.global memcpy
+.global memcpy_from_uspace
+.global memcpy_from_uspace_failover_address
+.global memcpy_to_uspace
+.global memcpy_to_uspace_failover_address
+
+
+#define MEMCPY_DST      4
+#define MEMCPY_SRC      8
+#define MEMCPY_SIZE     12
+
+/** Copy memory to/from userspace.
+ *
+ * This is almost conventional memcpy().
+ * The difference is that there is a failover part
+ * to where control is returned from a page fault
+ * if the page fault occurs during copy_from_uspace()
+ * or copy_to_uspace().
+ *
+ * @param MEMCPY_DST(%esp)      Destination address.
+ * @param MEMCPY_SRC(%esp)      Source address.
+ * @param MEMCPY_SIZE(%esp)     Size.
+ *
+ * @return MEMCPY_SRC(%esp) on success and 0 on failure.
+ */
+memcpy:
+memcpy_from_uspace:
+memcpy_to_uspace:
+        movl %edi, %edx                         /* save %edi */
+        movl %esi, %eax                         /* save %esi */
+        
+        movl MEMCPY_SIZE(%esp), %ecx
+        shrl $2, %ecx                           /* size / 4 */
+        
+        movl MEMCPY_DST(%esp), %edi
+        movl MEMCPY_SRC(%esp), %esi
+        
+        rep movsl                               /* copy as much as possible word by word */
+
+        movl MEMCPY_SIZE(%esp), %ecx
+        andl $3, %ecx                           /* size % 4 */
+        jz 0f
+        
+        rep movsb                               /* copy the rest byte by byte */
+
+0:
+        movl %edx, %edi
+        movl %eax, %esi
+        movl MEMCPY_SRC(%esp), %eax             /* MEMCPY_SRC(%esp), success */
+        ret
+        
+/*
+ * We got here from as_page_fault() after the memory operations
+ * above had caused a page fault.
+ */
+memcpy_from_uspace_failover_address:
+memcpy_to_uspace_failover_address:
+        movl %edx, %edi
+        movl %eax, %esi
+        xorl %eax, %eax                         /* return 0, failure */
+        ret
 
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